CA2105935C - Electrohydraulic ventricular assist device - Google Patents
Electrohydraulic ventricular assist device Download PDFInfo
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- CA2105935C CA2105935C CA002105935A CA2105935A CA2105935C CA 2105935 C CA2105935 C CA 2105935C CA 002105935 A CA002105935 A CA 002105935A CA 2105935 A CA2105935 A CA 2105935A CA 2105935 C CA2105935 C CA 2105935C
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
- A61M60/40—Details relating to driving
- A61M60/424—Details relating to driving for positive displacement blood pumps
- A61M60/427—Details relating to driving for positive displacement blood pumps the force acting on the blood contacting member being hydraulic or pneumatic
- A61M60/432—Details relating to driving for positive displacement blood pumps the force acting on the blood contacting member being hydraulic or pneumatic with diastole or systole switching by stopping or reversing the blood pump operating at a much higher cyclical speed than the heart beat
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
- A61M60/10—Location thereof with respect to the patient's body
- A61M60/122—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body
- A61M60/165—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable in, on, or around the heart
- A61M60/178—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable in, on, or around the heart drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
- A61M60/50—Details relating to control
- A61M60/508—Electronic control means, e.g. for feedback regulation
- A61M60/562—Electronic control means, e.g. for feedback regulation for making blood flow pulsatile in blood pumps that do not intrinsically create pulsatile flow
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
- A61M60/80—Constructional details other than related to driving
- A61M60/835—Constructional details other than related to driving of positive displacement blood pumps
- A61M60/837—Aspects of flexible displacement members, e.g. shapes or materials
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
- A61M60/80—Constructional details other than related to driving
- A61M60/855—Constructional details other than related to driving of implantable pumps or pumping devices
- A61M60/869—Compliance chambers containing a gas or liquid other than blood to compensate volume variations of a blood chamber
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
- A61M60/80—Constructional details other than related to driving
- A61M60/855—Constructional details other than related to driving of implantable pumps or pumping devices
- A61M60/871—Energy supply devices; Converters therefor
- A61M60/873—Energy supply devices; Converters therefor specially adapted for wireless or transcutaneous energy transfer [TET], e.g. inductive charging
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
- A61M60/80—Constructional details other than related to driving
- A61M60/855—Constructional details other than related to driving of implantable pumps or pumping devices
- A61M60/871—Energy supply devices; Converters therefor
- A61M60/876—Implantable batteries
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
- A61M60/80—Constructional details other than related to driving
- A61M60/855—Constructional details other than related to driving of implantable pumps or pumping devices
- A61M60/871—Energy supply devices; Converters therefor
- A61M60/878—Electrical connections within the patient's body
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
- A61M60/80—Constructional details other than related to driving
- A61M60/855—Constructional details other than related to driving of implantable pumps or pumping devices
- A61M60/89—Valves
- A61M60/894—Passive valves, i.e. valves actuated by the blood
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M2205/00—General characteristics of the apparatus
- A61M2205/82—Internal energy supply devices
- A61M2205/8237—Charging means
- A61M2205/8243—Charging means by induction
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
- A61M60/10—Location thereof with respect to the patient's body
- A61M60/122—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body
- A61M60/126—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable via, into, inside, in line, branching on, or around a blood vessel
- A61M60/148—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable via, into, inside, in line, branching on, or around a blood vessel in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
Abstract
The invention is directed to a unified system for an electrohydraulic ventricular assist device adapted for implantation in the thorax and for cannulation to the blood circulatory system comprising an internal electronic controller for generating an actuating signal actuating means for converting the actuating signal into a back and forth rhythmic displacement of a fluid, a blood pumping chamber having an inflow blood port and an outflow blood port for converting the back and forth displacement of the fluid into a rhythmic unidirectional displacement of blood through the inflow and outflow ports, coupling means for supplying the internal electronic controller with a supply voltage, detecting means for generating the actuating signal in response to the status of the blood pumping chamber, a volume displacement chamber (VDC) acting as a reservoir for the back and forth rhythmic displacement of a fluid, and a support with a surface curvature compatible with the internal human sagittal and transverse chest wall curvatures for supporting the internal electronic controller, the actuating means, the blood pumping chamber, the hermetic coupling means and the detecting means in a compact structure with the blood pumping chamber arranged with the inflow and outflow ports oriented away from the support and the structure with an overall size that when the unified system is placed within the human thorax with the the support surface adjacent the chest wall, the structure does not adversely compress adjacent organs.
Description
210~9~5 The present invention relates to the field of equipment and prothesis as a circulatory device aid for assisting or replacing the right or the left ventricle. More particularly, this invention is concerned with an electrohydraulic ventricular assist device where the major pumping and controlling functions are integrated into a package implantable into the human thorax.
Cardiac transplantation using a natural heart taken from a donor and grafting it into a recipient is now a relatively routine surgical technique. Recent advances have resulted in an appreciable reduction of rejection. However, practical transplantation is limited to the availability of natural heart donors and effective immunosuppressive drugs.
Clinical experience has shown that the cardiovascular circulation of patients in severe or total heart failure can be sustained with proper right and left ventricular assist devices (RVAD
and LVAD).
For these and other reasons, a number of mechanical circulatory devices have been designed to replace and/or assist the diseased natural heart. Total artificial hearts (TAIL and ventricular assist devices (VAD) have been valuable clinical tools in recent years with their primary benefit as a bridge to transplantation following acute cardiac failure.
For serious cases of heart failure, one should aim for long farm support rather than support limited in weeks, days or hours. In addition, it is preferable to have an assisting device which can be used for both left and/or right ventricular support. Typically, devices for assisting the left ventricle are located in the abdominal cavity or outside the chest.
Traditional artificial hearts fit less than ideally inside the chest.
Generally, the requirements for a ventricular assist device are multiple and not easy to satisfy. It is desirable that such device be implanted in the thoracic cavity.
The intrathoracic blood pumping components of the TCP must be similar in size and weight to the natural heart.
The artificial heart life must be sufficiently long and the reliability sufficiently high to avoid the risk of sudden prosthesis failure. The formation of adherent thrombus must be prevented.
Thromboemboli and extensive blood damage must also be prevented. The device must not ,,,...w.
damage adjacent tissue or traumatize adjacent organs by compression or by excessive local temperatures. The artificial hearts must also avoid skin penetration by connections to the exterior to prevent infections. As well, shortening of the length of the artificial blood vessels or cannulae employed for connecting the device to the natural heart or circulatory system is another desirable requirement for the device.
There has been a great deal of development activity in the area of artificial hearts, and especially for devices to assist the left ventricle (LVADs). Generally, a ventricular assist device comprises an elastomeric blood chamber or diaphragm capped cavity. The blood chamber is provided with an inflow and an outflow valve for cannulation to the circulatory system.
Generally an artificial heart device operates as follows, the left pump receives blood from the pulmonary vein and impels blood into the main circulatory system via the aorta. The right pump receives blood from the inferior and superior versa cava and impels it into the pulmonary artery.
The blood chamber volume is controlled with the elastomeric diaphragm which is actuated to oscillate between a systolic and a diastolic position.
To transform electrical triggering signals generated outside the body into the rhythmic movement of the diaphragm while obtaining suitable values for the above parameters and hemodynamics, various types of energy convertors have been tested.
The displacement of the diaphragm is obtained by various methods. Among these, electrohydraulic operation of the diaphragm proves to be a dependable and reliable method.
Electmhydraulic ventricular assist devices are provided with a pump which displaces a hydraulic fluid (oil) between a fluid reservoir and a fluid chamber, which is adjacent with the blood chamber so as to share the elastomeric diaphragm. The rhythmic fill and drain of the oil, in and out of the fluid chamber, displaces the diaphragm which in turn moves the blood in and out the blood chamber.
Canadian Patent No. 1,188,852 (Robinson) discloses a hydraulically actuated cardiac prosthesis with a hydraulic fluid reservoir, a hydraulic fluid pumping means and a blood pumping chamber with a flexible diaphragm. United States Patient No. 4,222,127 (Donachy et al.) discloses the Fierce-Donachy artificial heart including a blood pump, flexible diaphragm and an inflow and an outflow valves which can be used paracorporeally or intrathoracically. United States Patents Nos. 4,588,404 (Lapeyre) and 5,089,018 (Lapeyre et al.) disclose a biventricular cardiac prothesis. The device is a sealed case with a dual membrane system for pumping the systemic and pulmonary circulations.
However, a major limitation of these past devices is their physical shape and complexity which increase the surgical difficulty of implanting the device in either the thorax or abdomen of a patient. Power and information transfer requirements of the past devices have also required percutaneous access to the implantation site with its associated risk of infection. These limitations have also had an effect on the length of time that these devices can be implanted.
Recently, devices for establishing communication of electrical signals between the implanted device and an external power source and electronics controller have been developed as disclosed in Canadian Patent application No. 2,007,439 {2,074,150} (Miller) and U.K Patent application #9009713.0 (Miller). Such transcutaneous energy transformers employ electromagnetic induction using a pair of coupled coils, one outside and one inside the patient body. The ventricular assist device then can have an internal control mechanism for adjusting the frequency of oscillation of the diaphragm. To maintain maximum power transfer as the coils move relative to one another, a phase locked loop system in the external power converter maintains a constant phase relationship between voltage and current in the primary coil, thus minimizing voltage fluctuations. This was disclosed by Mussivand et al.
(Performance evaluation of a transcutaneous energy transfer system, ASAIO Abstr 21:39, 1992).
The bidirectional communication of information between the implanted device and its portable external control unit is achieved by an infrared data link. Data is transmitted across the skin without perforating it using a standard synchronous data transmission protocol. This protocol awards hardware compatibility with any computes having an RS232 type interface. It was disclosed by Miller J. et al. (Performance Evaluation of a transcutaneous infrared telemetry system, ASAIO Abstr 21:39, 1992). , An ideal artificial heart device should integrate the major pumping and controlling components into a single unified system for reducing the length of the electrical connections and of fluid conduits. There are also requirements for a material that should be accepted by the human body. Fluid dynamics of the device should not cause thrombus formations and the potential for thromboemboli.
Anatomical fit has a significant impact on the ease of surgical implantation, organ compression, patient comfort and postoperative complications. The internal body cavity dimensions have been recognized as a prime limitation in the design of implantable, mechanical circulatory devices.
The present invention is based on the concept proposed by Dr. T. Mussivand in which forms the base for a copending patent application entitled "Integrated System" .
It is an object of the present invention to provide a totally implantable mechanical circulatory device which integrates the major components of the system into a single unified system which is small enough to implant in the patient's chest cavity without giving rise to any serious clinical disadvantage or inconvenience to the recipient's organs. The device of the present invention takes into account the best location for implantation in the patient and the best shape which is compatible with this location.
It is another object of the present invention to provide a ventricular assist device which can be fixed into the human chest in the proximity of the natural heart thereby shortening the length of the artificial blood vessels or cannulae employed for connecting the device to the natural heart. This in turn reduces the surgical complexity associated with implanting other cardiac protheses.
It is another object of the present invention to provide an electrohydraulic ventricular assist device with a reduced fluid conduit length, which further allows for the hydraulic fluid to be used not only to actuate the device and act as a bearing lubricant, but also to remove heat from the device and to disperse it via the lungs and the circulatory system.
It is still another object of the present invention to provide an edectrohydraulic ventricular assist device having a design which allows for shorter electrical connections due to the integration of the major components.
It is a further object of the present invention to provide a totally implantable mechanical circulatory device that may be used to assist or replace both the left and/or the right heart, with a relatively simple surgical procedure.
It is a further object of the present invention to provide an electrohydraulic ventricular assist device with a portion of the control electronics integrated into the back of the unified system and the remainder of the control electronics ~~ p 9 ~d~ on a small portable unit to be worn on a belt thus eliminating the requirement for tethering the patient to a large bulky external console to drive the device.
In accordance with the present invention, there is provided an unified system for an electrohydraulic ventricular assist device adapted for implantation in the thorax and for cannulation to the blood circulatory system comprising: an internal electronic controller for receiving both an AC and DC supply voltages, an external communication channel data stream and generating an actuating signal, communication channel data stream and internal battery recharging signals; an actuating means for converting said actuating signal into a back and forth rhythmic displacement of a fluid; a blood pumping chamber having an inflow blood port and an outflow blood port for converting said back and forth displacement of said fluid into a rhythmic unidirectional displacement of blood through said inflow and outflow ports; a volume displacement chamber acting as a reservoir for said back and forth fluid displacement; a hermetic coupling means for connecting said controller by conductors carrying said AC/DC supply voltages, said communication channel data streams and internal battery recharging signal; a detecting means for generating said actuating signal in response to the status of said blood pumping chamber; and a support with a surface curvature compatible with the internal human sagittal and transverse chest wall curvatures for supporting said electronic controller, said actuating means, said blood pumping chamber, said hermetic coupling means and said detecting means in a compact structure with said blood pumping chamber arranged with said inflow and outflow ports (and one way valves) oriented away from said support and said structure with an overall size that when the unified system is placed within the human thorax with said support surface adjacent the chest wall, said structure does not adversely compress adjacent organs.
According to another aspect of the present invention, there is provided an unified system wherein said support is a base cover having a longitudinal radius of curvature of (11 t 0.5 cm) and a transversal radius of curvature of (9.4 t 0.5 cm).
According to still another aspect of the present invention, there is provided an unified system further comprising a first cannula connected to said inflow port for carmulation with the blood circulatory system. Said inflow port is oriented for cannulation to the systemic circulation when the unified system is implanted in the thorax for assisting or replacing a left ventricle.
,,,....
The length of said first cannula is between 5 and 14 cm and can be adjusted to fit the patient.
A second cannula connected to said outflow port is oriented for cannulation to the systemic circulation, when the unified system is implanted in the thorax for assisting or replacing a left ventricle. Said inflow port is oriented for cannulation with the pulmonary circulation when said unified system is implanted for assisting or replacing a right ventricle. Said outflow port is oriented for cannulation with the pulmonary circulation when said unified system is implanted for assisting or replacing a right ventricle.
According to still another aspect of the preset invention, there is provided a unified system having an overall thickness of less than 4 cm, an overall length less than 18 cm and an overall width less than 12 cm.
The device according to another aspect of the present invention is adapted for cannulation to the blood circulatory system and comprises: of said unified system for implantation in a human thorax proximal to the human heart to replace or assist a ventricle; a rechargeable internal battery for subcutaneous implantation to supply said unified system with an internal DC
supply voltage; an external battery for providing a DC voltage to said external controller; an external controller for converting DC voltage received from the external battery and/or external power supply to AC voltage for transfer by a transcutaneous energy transformer to the said unified system, for recharging the external battery; a computer interface for connecting said device to a computer for control and monitoring of the device; a display means for control status and alarm display; a transcutaneous energy transformer for transmitting said AC voltage across the skin to said unified system; a transcutaneous information telemetry system for bidirectional transmitting said communication channel data streams between said external controller and said unified system; a connector for connecting said internal battery to said unified system and an in-line connector for connecting said transcutaneous energy transformer to said unified system.
Brief Description of the Drawines These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, wherein:
Figure 1 illustrates a block diagram of the electrohydraulic ventricular assist device of the present invention;
Figure 2 illustrates a schematic front view (from the heart) of the unified system; and Figure 3 shows a schematic back view of the unified system (from the chest cavity), back cover removed.
Figure 4 illustrates a back view of the back cover;
Figure 5 shows transversal cross-section view along lines A-A of Figure 2.
Figure 6 shows longitudinal cross section view along lines B-B of Figure 2.
Referring to the drawings, a preferred embodiment of an electrohydraulic ventricular assist device in accordance with the present invention is described.
Figures 1 - 6 show the preferred embodiment of the device of the present invention.
A unified system 1 incorporates the major units of an electmhydraulic ventricular assist device and is sized for convenient implantation into the thorax and for facile cannulation to the blood circulatory system. The unified system 1 comprises an internal electronic controller 3 which receives a DC supply voltage on conductor set 5, an AC supply voltage and communication channel data stream on conductor set 7 and signals from detecting means 9. The controller 3 processes these signals and accordingly generates an actuating signal on conductor 10. Actuating means il converts the actuating signal into a back and forth rhythmic displacement of a fluid, causing a rhythmic fill and drain of a fluid compartment 13 of a blood pumping chamber 15 with a fluid. A volume displacement chamber 17 acts as a reservoir for the fluid as it is displaced into and out of the fluid compartment 13. The blood pumping chamber 15 has an inflow blood port 19 and an outflow blood port 21. The blood pumping chamber converts the back and forth displacement of the fluid into a rhythmic unidirectional displacement of blood through the inflow and outflow ports. The ports are equipped with unidirectional valves (not shown) and cannulation means (not shown) for connection to the circulatory system. Hermetic coupling means 23 houses electrical feedthmughs 25, 27 which connect to the conductors sets carrying the DC supply voltage, AC supply voltage and communication channel data streams to the internal electronic controller 3 and units outside the unified system 1.
210~93~
A support 29 with a surface curvature compatible with the internal human sagittal and transverse chest wall curvatures supports the internal electronic controller 3, the actuating means 11, the blood pumping chamber 15, the volume displacement chamber 17 and the hermetic coupling means 23 in a compact structure. The entire structure has an overall size and shape such that when the unified system 1 is placed within the human thorax with the support 29 adjacent the chest wall, the unified system does not adversely compress adjacent organs. The blood pumping chamber is awanged with the inflow and outflow ports 19 and 21 oriented away from the support surface such that the cannulae (not shown) are oriented towards their respective destinations of the blood circulatory system.
The shape of the blood pumping chamber 15 is flat and low ellipsoidal, as a sac defining a back face and a front face, the back face being placed in contact with the feedthrough cover, and the inflow and outflow ports protruding through the front face.
In the preferred embodiment represented in Figures 5 and 6, the blood pumping chamber has an elastomeric membrane 31 which converts the back and forth displacement of the fluid, 15 driven by the actuating means 11, into the rhythmic displacement of the blood. Membrane 31 divides the sac longitudinally in a plane normal to the axis of the blood pumping chamber 15 so that the height of the membrane oscillation is low. Membrane 31 defines a blood compartment 33 and a fluid compartment 13. The blood compartment 33 is comprised between the membrane 31 and the front face of blood pumping chamber 15. The fluid compartment 13 is comprised between membrane 31 and the back face of blood pumping chamber 15. Membrane 31 oscillates between a systolic position, where blood is displaced from the blood compartment and a diastolic position, where the blood compartment is filled with blood. The shape of the blood pumping chamber allows the membrane to travel a short distance between the systolic and diastolic positions, this short distance improves the mechanical properties of the membrane, thus increasing long term reliability. The systolic and diastolic positions of the membrane 31 and VDC membrane 35 are shown in Figure 6.
The actuating means 11 converts the actuating signal received from the internal electronic controller 3 into a back and forth rhythmic displacement of the fluid. It comprises a brushless DC motor 37 and a reversible axial pump 39. Whenever motor 37 receives the actuating signal _g_ it reverses its rotation and accordingly the direction of fluid displacement by pump 39, converting this alternating rotational movement of the motor into a back and forth displacement of the fluid. The motor 37 and pump 39 form a so called energy convertor 11.
The energy convertor 11 transfers fluid from the volume displacement chamber through the energy convertor 11 and through oil conduit 41 to the fluid compartment 13. As a result of this alternating fluid dislodgement the membrane 31 and VDC membrane 35 oscillate alternately between the systolic (blood being ejected from the device) and diastolic (blood entering the device) positions. The brushless motor 37 has bearings which have an axial preload to decrease ball skidding and thereby improve bearing life. The motor stator is a toothless design and the permanent magnet material is made of neodium iron boron which creates high magnetic field density.
The energy convertor 11 is arranged in the hydraulic fluid such that the hydraulic fluid is both a lubricant for the bearings in the energy convertor il and a heat sink. In the embodiment shown in Figures 1 to 6 the energy converter 11 is preferably placed towards the lower side of the unified system, beside the blood chamber 15 to reduce the overall length of the fluid path. The oil conduit 41 provides a fluid pathway from one end of the energy convertor 11 to the fluid compartment 13 of the blood chamber 15. The other end of the energy convertor opens directly into the volume displacement chamber 17.
The internal electronic controller 3 comprises a microprocessor which gives the actuating signal for reversing the direction of rotation of motor 37. Detecting means 9 detects the position of the flexible membrane 31 and generates a signal to the microprocessor to indicate when membrane 31 has arrived at the end systolic or end diastolic positions.
Preferably, an infrared sensor is used as detector 9, which is provided directly on the internal controller and adjacent to the blood pumping chamber 15.
The unified system 1 is connected to the pulmonary circulation (when it is designed to assist the right ventricle) or to the systemic circulation (when it is designed to assist the left ventricle). The connection is effected through two unidirectional valves (not shown) arranged between the blood chamber inflow and outflow ports 19 and 21, and the respective cannulation.
The outputs from the cannulation are connected to the corresponding blood vessels.
It is important that the dimensions of the human chest cavity be known for designing the shape and size of the unified system. The :pacx available for intratlwracic pla~oanont of the device is very limited. The implantation utc for the unified system of the prma><t invention is in the letl and/or right hemithoiax anchored to the chest wall bexweat< the 4th and 9th ribs.
Advents;es of this placemadt include limited device nation whey fixed to the ribs, cosmetic acc~ability, shorter cannulae lemgtha and thec~fore less hydraulic loses, less potential for kinldng of the c~nnulae, no need to pate~atc the diaphragm a~ decreawd risk of possible pressure necrosis of abdominal organs.
Aa shov~m m Figures 4, 5 sad 6, a back cave forms the support ?9 whereon the implantable utrified system is fixed. The size and shape of the back cover 29 are selected to snugly fit the geography of the ribs against which the dtvioe is arranged when implanted.
A prime consideration in the back cover deaiga is the chest wall curvah><re.
Any pocloets formed bexwear< the device sad chest wall would create dead spaces and a potentially i>nc~sod risk of infection. The transverse r~lius of curvature of the intrathoracic wall at the 5th rib was de~nined to be 9. 4 t 0.5 cm (n =19) as disclosed by Mussivand T. et al.
(Critical Anatomic Dimensions for Intrathoracic Circulatory Assist Devices, Journal of Artificial Organs, June 1992, Volume 16 ~4).
Another critical measuremoat in the design of the unified rystem is the sagittal radius of curvature at the Sth rib. This was mearu~ed to be 11.1 t 0.5. Knowledge of this dimension is oecxssary for the des;go of the longibidinal curvature of the device.
Back coves x9 has a l~gid>Idinal and transversal curvat<ue compleascatary to the sagittal and tran:varsc internal curvatures.
A feodthrough cover 23 is placed on top of internal electronic oontrolla 3. As shown is Figure 3, two hoc e~le~ic~1 feedthrough comectioas 2S and Z7 are provided for electrical conductor sets s and 7. An oil filling port 43 is also mounted on fexdthrough cover 23 and is usod for filling the unifiod system 1 with the actuating fluid, the port uses a push-pull mechanism to opal and close the filling port. Once the system is filled the port is closed and a hermetic seal is provided by a compression O-ring.
The unified system of the presa>tt invention has an overall thickness of leis than 4 cm, an overall la~gth less than 16 cm and as overall e~tanal width less than 11 cm. It gives a s~cnoN s cc~t~ECTtow 8EE CERTtRCATE
ECi101~ - ARTK;LE ~t -lO-~OtR CEflTiFO~".~I1'~
,~. 210593 cardiac output of greater than 6 litreslminute with a mean preload pressure of between 5 to 10 mmHg and a mean afterload pressure of 150 mmHg. With the unified system of this invention, the stroke volume of the blood pumping chamber is between 55 and 70 ml.
As shown in Figures 2, 5 and 6, the blood pumping chamber 15 and the volume displacement chamber 17 are placed side by side. These chambers define a space at the back thereof to accommodate the internal electronic controller 3 which is placed directly beside the energy convertor 11 and connected thereto. This placement of the energy convertor 11 close to controller 3 allows short electrical connections, reduces electrical losses and increases the reliability and efficiency of the unified system.
The implantable components of the electmhydraulic ventricular assist device of the present invention consist of the unified system 1, inflow and outflow cannulae (not shown), an internal battery 45 and an internal TET/Telemetry coil 47.
The internal battery is connected to the unified system 1 via hermetic connector 49, electrical conductor set 5 and electrical feedthrough 25. The internal battery 45 is preferably implanted subcutaneously in the abdomen. In the preferred embodiment the internal battery package 45 uses rectangular prismatic nickel/cadmium cells, however other battery chemistries could be utilized. These cells are housed in a custom designed laser welded titanium enclosure with a hermetic connector 49 suitable for implantation. Preferably, the hermetic connector 49 is an internal connector, used for allowing an easy replacement of battery 45.
In this way, the part of conductor set 5 from connector 49 through feedthrough 25 to unified system 1, should not be changed when internal battery 45 is replaced periodically. The electrical conductor set 5 contains electrical connections for the supply of DC voltage to the internal electronic controller 3, for the recharging of the internal battery and for activation of an audible warning alarm housed in the battery enclosure.
The internal TET/Telemetry coil 47 is connected to the unified system 1 via the in-line hermetic connector 51, electrical conductor set 7 and the electrical feedthrough 27. The internal TET/Telemetry coil 47 is implanted subclavicularly. The transcutaneous energy transformer ('TET) and transcutaneous information telemetry (Telemetry) systems consist of electronic circuitry on both the internal electronic controller 3 and external electronic controller 53, the r.. 2105935 internal TET/Telemetry coil 47 and the external TET/Telemetry coil 55.
The TET uses wire coils 57,57 to electromagnetically couple power into the body without perforation of the skin. The Telemetry uses infrared components 59,59' embedded in the internal TET/Telemetry coil 47 and external TET/Telemetry coil 55 to transfer the communication channel data streams into and out of the body without perforation of the skin.
The external components of the electrohydraulic ventricular assist device of the present invention consist of the external electronic controller 53, an external battery 61 and an external TET/Telemetry coil 55.
The external electronic controller 53 contains a portion of the circuitry for both the TET
and Telemetry systems. External electronic controller 53 also produces and receives the communication channel data stream for control and monitoring of the unified system 1 and generates recharging signals for recharging the external battery 61 at predetermined intervals.
External electronic controller 53 is connected to the external TET/Telemetry coil 55.
Additionally, the external electronic controller of the device in the present invention further comprises a computer interface for connecting the device with a computer for control and monitoring of the device and a display means 65 which consists of a liquid crystal display (I,CD) screen for display of control status and alarms. The external electronics is a compact unit intended to be worn on a belt similar to a pager.
The external battery 61 is connected to the external electronic controller 53 via electrical conductor set 67. In the preferred embodiment the external battery uses silver/zinc cells, however other battery chemistries could be utilized. The electrical conductor set 67 contains electrical connections for the supply of DC voltage to the external electronic controller 53 and for the recharging of the external battery 61.
The external TET/Telemetry coil 55 is connected to the external electronic controller 53 via electrical conductor set 69.
The electrohydraulic ventricular assist device of the present invention comprises the unified system for implantation in a human thorax proximal to the human heart as described above.
The operation of the device is now described with reference to Figure 1.
.. 210593 The system is actuated by the hydraulic fluid that is pumped between the volume displacement chamber 17 and the fluid compartment 13 of blood pumping chamber 15, by the reversing axial flow pump 39 driven by the brushless DC motor. Whenever the motor 37 receives an actuating signal from the internal electronic controller 3, it reverses its direction of rotation which causes a reversal in the flow direction of the actuating fluid.
Actuating fluid is pumped into the fluid compartment 13 of the blood chamber 15 and the membrane 31 displaces the blood during the systole phase of the cardiac cycle thmugh the outflow port 21. When the axial flow pump 39 is reversed, the hydraulic fluid is pumped away from the fluid compartment 13 of the volume displacement chamber 17, causing outward displacement of the VDC membrane 35, the membrane 31 is pulled away from the blood compartment 33 causing active filling of blood to occur thmugh the inflow port 19. This action is further illustrated in Figures 5 and 6. Reversal points of the axial pump 37 are determined by the membrane position detector 9 which sends the status signal to the external electronic controller 3 for reversing the axial pump flow when the membrane 31 reaches the end points of systole and diastole.
In vitro Testing was conducted in vitro to verify that the system operated satisfactory prior to any in vivo experiments. Tests have been conducted on mock circulation with the device in air and completely submerged in saline solution to simulate expected chest pressures.
In vitro flow rates of over 8 litres per minute with a preload of 10 and a mean afterload of 100 mmhg have been obtained. The transcutaneous energy transformer has demonstrated a power transfer efficiency of over 809b at power levels of 10-35 Watts. The internal and the external batteries have been cycled tested to determine optimum charge and discharge requirements as well as to determine operating times and cycle lives.
In vivo The complete unified system has been implanted in 6 bovine for in vivo testing and has ~.... 210 ~ 9 3 5 maintained circulation from 3 to 27 hours. The performance of the complete unified system has proven satisfactory in acute experimentation. 1fie overall configuration of the device has also proven to be satisfactory, over a wide range of operating conditions.
Cardiac transplantation using a natural heart taken from a donor and grafting it into a recipient is now a relatively routine surgical technique. Recent advances have resulted in an appreciable reduction of rejection. However, practical transplantation is limited to the availability of natural heart donors and effective immunosuppressive drugs.
Clinical experience has shown that the cardiovascular circulation of patients in severe or total heart failure can be sustained with proper right and left ventricular assist devices (RVAD
and LVAD).
For these and other reasons, a number of mechanical circulatory devices have been designed to replace and/or assist the diseased natural heart. Total artificial hearts (TAIL and ventricular assist devices (VAD) have been valuable clinical tools in recent years with their primary benefit as a bridge to transplantation following acute cardiac failure.
For serious cases of heart failure, one should aim for long farm support rather than support limited in weeks, days or hours. In addition, it is preferable to have an assisting device which can be used for both left and/or right ventricular support. Typically, devices for assisting the left ventricle are located in the abdominal cavity or outside the chest.
Traditional artificial hearts fit less than ideally inside the chest.
Generally, the requirements for a ventricular assist device are multiple and not easy to satisfy. It is desirable that such device be implanted in the thoracic cavity.
The intrathoracic blood pumping components of the TCP must be similar in size and weight to the natural heart.
The artificial heart life must be sufficiently long and the reliability sufficiently high to avoid the risk of sudden prosthesis failure. The formation of adherent thrombus must be prevented.
Thromboemboli and extensive blood damage must also be prevented. The device must not ,,,...w.
damage adjacent tissue or traumatize adjacent organs by compression or by excessive local temperatures. The artificial hearts must also avoid skin penetration by connections to the exterior to prevent infections. As well, shortening of the length of the artificial blood vessels or cannulae employed for connecting the device to the natural heart or circulatory system is another desirable requirement for the device.
There has been a great deal of development activity in the area of artificial hearts, and especially for devices to assist the left ventricle (LVADs). Generally, a ventricular assist device comprises an elastomeric blood chamber or diaphragm capped cavity. The blood chamber is provided with an inflow and an outflow valve for cannulation to the circulatory system.
Generally an artificial heart device operates as follows, the left pump receives blood from the pulmonary vein and impels blood into the main circulatory system via the aorta. The right pump receives blood from the inferior and superior versa cava and impels it into the pulmonary artery.
The blood chamber volume is controlled with the elastomeric diaphragm which is actuated to oscillate between a systolic and a diastolic position.
To transform electrical triggering signals generated outside the body into the rhythmic movement of the diaphragm while obtaining suitable values for the above parameters and hemodynamics, various types of energy convertors have been tested.
The displacement of the diaphragm is obtained by various methods. Among these, electrohydraulic operation of the diaphragm proves to be a dependable and reliable method.
Electmhydraulic ventricular assist devices are provided with a pump which displaces a hydraulic fluid (oil) between a fluid reservoir and a fluid chamber, which is adjacent with the blood chamber so as to share the elastomeric diaphragm. The rhythmic fill and drain of the oil, in and out of the fluid chamber, displaces the diaphragm which in turn moves the blood in and out the blood chamber.
Canadian Patent No. 1,188,852 (Robinson) discloses a hydraulically actuated cardiac prosthesis with a hydraulic fluid reservoir, a hydraulic fluid pumping means and a blood pumping chamber with a flexible diaphragm. United States Patient No. 4,222,127 (Donachy et al.) discloses the Fierce-Donachy artificial heart including a blood pump, flexible diaphragm and an inflow and an outflow valves which can be used paracorporeally or intrathoracically. United States Patents Nos. 4,588,404 (Lapeyre) and 5,089,018 (Lapeyre et al.) disclose a biventricular cardiac prothesis. The device is a sealed case with a dual membrane system for pumping the systemic and pulmonary circulations.
However, a major limitation of these past devices is their physical shape and complexity which increase the surgical difficulty of implanting the device in either the thorax or abdomen of a patient. Power and information transfer requirements of the past devices have also required percutaneous access to the implantation site with its associated risk of infection. These limitations have also had an effect on the length of time that these devices can be implanted.
Recently, devices for establishing communication of electrical signals between the implanted device and an external power source and electronics controller have been developed as disclosed in Canadian Patent application No. 2,007,439 {2,074,150} (Miller) and U.K Patent application #9009713.0 (Miller). Such transcutaneous energy transformers employ electromagnetic induction using a pair of coupled coils, one outside and one inside the patient body. The ventricular assist device then can have an internal control mechanism for adjusting the frequency of oscillation of the diaphragm. To maintain maximum power transfer as the coils move relative to one another, a phase locked loop system in the external power converter maintains a constant phase relationship between voltage and current in the primary coil, thus minimizing voltage fluctuations. This was disclosed by Mussivand et al.
(Performance evaluation of a transcutaneous energy transfer system, ASAIO Abstr 21:39, 1992).
The bidirectional communication of information between the implanted device and its portable external control unit is achieved by an infrared data link. Data is transmitted across the skin without perforating it using a standard synchronous data transmission protocol. This protocol awards hardware compatibility with any computes having an RS232 type interface. It was disclosed by Miller J. et al. (Performance Evaluation of a transcutaneous infrared telemetry system, ASAIO Abstr 21:39, 1992). , An ideal artificial heart device should integrate the major pumping and controlling components into a single unified system for reducing the length of the electrical connections and of fluid conduits. There are also requirements for a material that should be accepted by the human body. Fluid dynamics of the device should not cause thrombus formations and the potential for thromboemboli.
Anatomical fit has a significant impact on the ease of surgical implantation, organ compression, patient comfort and postoperative complications. The internal body cavity dimensions have been recognized as a prime limitation in the design of implantable, mechanical circulatory devices.
The present invention is based on the concept proposed by Dr. T. Mussivand in which forms the base for a copending patent application entitled "Integrated System" .
It is an object of the present invention to provide a totally implantable mechanical circulatory device which integrates the major components of the system into a single unified system which is small enough to implant in the patient's chest cavity without giving rise to any serious clinical disadvantage or inconvenience to the recipient's organs. The device of the present invention takes into account the best location for implantation in the patient and the best shape which is compatible with this location.
It is another object of the present invention to provide a ventricular assist device which can be fixed into the human chest in the proximity of the natural heart thereby shortening the length of the artificial blood vessels or cannulae employed for connecting the device to the natural heart. This in turn reduces the surgical complexity associated with implanting other cardiac protheses.
It is another object of the present invention to provide an electrohydraulic ventricular assist device with a reduced fluid conduit length, which further allows for the hydraulic fluid to be used not only to actuate the device and act as a bearing lubricant, but also to remove heat from the device and to disperse it via the lungs and the circulatory system.
It is still another object of the present invention to provide an edectrohydraulic ventricular assist device having a design which allows for shorter electrical connections due to the integration of the major components.
It is a further object of the present invention to provide a totally implantable mechanical circulatory device that may be used to assist or replace both the left and/or the right heart, with a relatively simple surgical procedure.
It is a further object of the present invention to provide an electrohydraulic ventricular assist device with a portion of the control electronics integrated into the back of the unified system and the remainder of the control electronics ~~ p 9 ~d~ on a small portable unit to be worn on a belt thus eliminating the requirement for tethering the patient to a large bulky external console to drive the device.
In accordance with the present invention, there is provided an unified system for an electrohydraulic ventricular assist device adapted for implantation in the thorax and for cannulation to the blood circulatory system comprising: an internal electronic controller for receiving both an AC and DC supply voltages, an external communication channel data stream and generating an actuating signal, communication channel data stream and internal battery recharging signals; an actuating means for converting said actuating signal into a back and forth rhythmic displacement of a fluid; a blood pumping chamber having an inflow blood port and an outflow blood port for converting said back and forth displacement of said fluid into a rhythmic unidirectional displacement of blood through said inflow and outflow ports; a volume displacement chamber acting as a reservoir for said back and forth fluid displacement; a hermetic coupling means for connecting said controller by conductors carrying said AC/DC supply voltages, said communication channel data streams and internal battery recharging signal; a detecting means for generating said actuating signal in response to the status of said blood pumping chamber; and a support with a surface curvature compatible with the internal human sagittal and transverse chest wall curvatures for supporting said electronic controller, said actuating means, said blood pumping chamber, said hermetic coupling means and said detecting means in a compact structure with said blood pumping chamber arranged with said inflow and outflow ports (and one way valves) oriented away from said support and said structure with an overall size that when the unified system is placed within the human thorax with said support surface adjacent the chest wall, said structure does not adversely compress adjacent organs.
According to another aspect of the present invention, there is provided an unified system wherein said support is a base cover having a longitudinal radius of curvature of (11 t 0.5 cm) and a transversal radius of curvature of (9.4 t 0.5 cm).
According to still another aspect of the present invention, there is provided an unified system further comprising a first cannula connected to said inflow port for carmulation with the blood circulatory system. Said inflow port is oriented for cannulation to the systemic circulation when the unified system is implanted in the thorax for assisting or replacing a left ventricle.
,,,....
The length of said first cannula is between 5 and 14 cm and can be adjusted to fit the patient.
A second cannula connected to said outflow port is oriented for cannulation to the systemic circulation, when the unified system is implanted in the thorax for assisting or replacing a left ventricle. Said inflow port is oriented for cannulation with the pulmonary circulation when said unified system is implanted for assisting or replacing a right ventricle. Said outflow port is oriented for cannulation with the pulmonary circulation when said unified system is implanted for assisting or replacing a right ventricle.
According to still another aspect of the preset invention, there is provided a unified system having an overall thickness of less than 4 cm, an overall length less than 18 cm and an overall width less than 12 cm.
The device according to another aspect of the present invention is adapted for cannulation to the blood circulatory system and comprises: of said unified system for implantation in a human thorax proximal to the human heart to replace or assist a ventricle; a rechargeable internal battery for subcutaneous implantation to supply said unified system with an internal DC
supply voltage; an external battery for providing a DC voltage to said external controller; an external controller for converting DC voltage received from the external battery and/or external power supply to AC voltage for transfer by a transcutaneous energy transformer to the said unified system, for recharging the external battery; a computer interface for connecting said device to a computer for control and monitoring of the device; a display means for control status and alarm display; a transcutaneous energy transformer for transmitting said AC voltage across the skin to said unified system; a transcutaneous information telemetry system for bidirectional transmitting said communication channel data streams between said external controller and said unified system; a connector for connecting said internal battery to said unified system and an in-line connector for connecting said transcutaneous energy transformer to said unified system.
Brief Description of the Drawines These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, wherein:
Figure 1 illustrates a block diagram of the electrohydraulic ventricular assist device of the present invention;
Figure 2 illustrates a schematic front view (from the heart) of the unified system; and Figure 3 shows a schematic back view of the unified system (from the chest cavity), back cover removed.
Figure 4 illustrates a back view of the back cover;
Figure 5 shows transversal cross-section view along lines A-A of Figure 2.
Figure 6 shows longitudinal cross section view along lines B-B of Figure 2.
Referring to the drawings, a preferred embodiment of an electrohydraulic ventricular assist device in accordance with the present invention is described.
Figures 1 - 6 show the preferred embodiment of the device of the present invention.
A unified system 1 incorporates the major units of an electmhydraulic ventricular assist device and is sized for convenient implantation into the thorax and for facile cannulation to the blood circulatory system. The unified system 1 comprises an internal electronic controller 3 which receives a DC supply voltage on conductor set 5, an AC supply voltage and communication channel data stream on conductor set 7 and signals from detecting means 9. The controller 3 processes these signals and accordingly generates an actuating signal on conductor 10. Actuating means il converts the actuating signal into a back and forth rhythmic displacement of a fluid, causing a rhythmic fill and drain of a fluid compartment 13 of a blood pumping chamber 15 with a fluid. A volume displacement chamber 17 acts as a reservoir for the fluid as it is displaced into and out of the fluid compartment 13. The blood pumping chamber 15 has an inflow blood port 19 and an outflow blood port 21. The blood pumping chamber converts the back and forth displacement of the fluid into a rhythmic unidirectional displacement of blood through the inflow and outflow ports. The ports are equipped with unidirectional valves (not shown) and cannulation means (not shown) for connection to the circulatory system. Hermetic coupling means 23 houses electrical feedthmughs 25, 27 which connect to the conductors sets carrying the DC supply voltage, AC supply voltage and communication channel data streams to the internal electronic controller 3 and units outside the unified system 1.
210~93~
A support 29 with a surface curvature compatible with the internal human sagittal and transverse chest wall curvatures supports the internal electronic controller 3, the actuating means 11, the blood pumping chamber 15, the volume displacement chamber 17 and the hermetic coupling means 23 in a compact structure. The entire structure has an overall size and shape such that when the unified system 1 is placed within the human thorax with the support 29 adjacent the chest wall, the unified system does not adversely compress adjacent organs. The blood pumping chamber is awanged with the inflow and outflow ports 19 and 21 oriented away from the support surface such that the cannulae (not shown) are oriented towards their respective destinations of the blood circulatory system.
The shape of the blood pumping chamber 15 is flat and low ellipsoidal, as a sac defining a back face and a front face, the back face being placed in contact with the feedthrough cover, and the inflow and outflow ports protruding through the front face.
In the preferred embodiment represented in Figures 5 and 6, the blood pumping chamber has an elastomeric membrane 31 which converts the back and forth displacement of the fluid, 15 driven by the actuating means 11, into the rhythmic displacement of the blood. Membrane 31 divides the sac longitudinally in a plane normal to the axis of the blood pumping chamber 15 so that the height of the membrane oscillation is low. Membrane 31 defines a blood compartment 33 and a fluid compartment 13. The blood compartment 33 is comprised between the membrane 31 and the front face of blood pumping chamber 15. The fluid compartment 13 is comprised between membrane 31 and the back face of blood pumping chamber 15. Membrane 31 oscillates between a systolic position, where blood is displaced from the blood compartment and a diastolic position, where the blood compartment is filled with blood. The shape of the blood pumping chamber allows the membrane to travel a short distance between the systolic and diastolic positions, this short distance improves the mechanical properties of the membrane, thus increasing long term reliability. The systolic and diastolic positions of the membrane 31 and VDC membrane 35 are shown in Figure 6.
The actuating means 11 converts the actuating signal received from the internal electronic controller 3 into a back and forth rhythmic displacement of the fluid. It comprises a brushless DC motor 37 and a reversible axial pump 39. Whenever motor 37 receives the actuating signal _g_ it reverses its rotation and accordingly the direction of fluid displacement by pump 39, converting this alternating rotational movement of the motor into a back and forth displacement of the fluid. The motor 37 and pump 39 form a so called energy convertor 11.
The energy convertor 11 transfers fluid from the volume displacement chamber through the energy convertor 11 and through oil conduit 41 to the fluid compartment 13. As a result of this alternating fluid dislodgement the membrane 31 and VDC membrane 35 oscillate alternately between the systolic (blood being ejected from the device) and diastolic (blood entering the device) positions. The brushless motor 37 has bearings which have an axial preload to decrease ball skidding and thereby improve bearing life. The motor stator is a toothless design and the permanent magnet material is made of neodium iron boron which creates high magnetic field density.
The energy convertor 11 is arranged in the hydraulic fluid such that the hydraulic fluid is both a lubricant for the bearings in the energy convertor il and a heat sink. In the embodiment shown in Figures 1 to 6 the energy converter 11 is preferably placed towards the lower side of the unified system, beside the blood chamber 15 to reduce the overall length of the fluid path. The oil conduit 41 provides a fluid pathway from one end of the energy convertor 11 to the fluid compartment 13 of the blood chamber 15. The other end of the energy convertor opens directly into the volume displacement chamber 17.
The internal electronic controller 3 comprises a microprocessor which gives the actuating signal for reversing the direction of rotation of motor 37. Detecting means 9 detects the position of the flexible membrane 31 and generates a signal to the microprocessor to indicate when membrane 31 has arrived at the end systolic or end diastolic positions.
Preferably, an infrared sensor is used as detector 9, which is provided directly on the internal controller and adjacent to the blood pumping chamber 15.
The unified system 1 is connected to the pulmonary circulation (when it is designed to assist the right ventricle) or to the systemic circulation (when it is designed to assist the left ventricle). The connection is effected through two unidirectional valves (not shown) arranged between the blood chamber inflow and outflow ports 19 and 21, and the respective cannulation.
The outputs from the cannulation are connected to the corresponding blood vessels.
It is important that the dimensions of the human chest cavity be known for designing the shape and size of the unified system. The :pacx available for intratlwracic pla~oanont of the device is very limited. The implantation utc for the unified system of the prma><t invention is in the letl and/or right hemithoiax anchored to the chest wall bexweat< the 4th and 9th ribs.
Advents;es of this placemadt include limited device nation whey fixed to the ribs, cosmetic acc~ability, shorter cannulae lemgtha and thec~fore less hydraulic loses, less potential for kinldng of the c~nnulae, no need to pate~atc the diaphragm a~ decreawd risk of possible pressure necrosis of abdominal organs.
Aa shov~m m Figures 4, 5 sad 6, a back cave forms the support ?9 whereon the implantable utrified system is fixed. The size and shape of the back cover 29 are selected to snugly fit the geography of the ribs against which the dtvioe is arranged when implanted.
A prime consideration in the back cover deaiga is the chest wall curvah><re.
Any pocloets formed bexwear< the device sad chest wall would create dead spaces and a potentially i>nc~sod risk of infection. The transverse r~lius of curvature of the intrathoracic wall at the 5th rib was de~nined to be 9. 4 t 0.5 cm (n =19) as disclosed by Mussivand T. et al.
(Critical Anatomic Dimensions for Intrathoracic Circulatory Assist Devices, Journal of Artificial Organs, June 1992, Volume 16 ~4).
Another critical measuremoat in the design of the unified rystem is the sagittal radius of curvature at the Sth rib. This was mearu~ed to be 11.1 t 0.5. Knowledge of this dimension is oecxssary for the des;go of the longibidinal curvature of the device.
Back coves x9 has a l~gid>Idinal and transversal curvat<ue compleascatary to the sagittal and tran:varsc internal curvatures.
A feodthrough cover 23 is placed on top of internal electronic oontrolla 3. As shown is Figure 3, two hoc e~le~ic~1 feedthrough comectioas 2S and Z7 are provided for electrical conductor sets s and 7. An oil filling port 43 is also mounted on fexdthrough cover 23 and is usod for filling the unifiod system 1 with the actuating fluid, the port uses a push-pull mechanism to opal and close the filling port. Once the system is filled the port is closed and a hermetic seal is provided by a compression O-ring.
The unified system of the presa>tt invention has an overall thickness of leis than 4 cm, an overall la~gth less than 16 cm and as overall e~tanal width less than 11 cm. It gives a s~cnoN s cc~t~ECTtow 8EE CERTtRCATE
ECi101~ - ARTK;LE ~t -lO-~OtR CEflTiFO~".~I1'~
,~. 210593 cardiac output of greater than 6 litreslminute with a mean preload pressure of between 5 to 10 mmHg and a mean afterload pressure of 150 mmHg. With the unified system of this invention, the stroke volume of the blood pumping chamber is between 55 and 70 ml.
As shown in Figures 2, 5 and 6, the blood pumping chamber 15 and the volume displacement chamber 17 are placed side by side. These chambers define a space at the back thereof to accommodate the internal electronic controller 3 which is placed directly beside the energy convertor 11 and connected thereto. This placement of the energy convertor 11 close to controller 3 allows short electrical connections, reduces electrical losses and increases the reliability and efficiency of the unified system.
The implantable components of the electmhydraulic ventricular assist device of the present invention consist of the unified system 1, inflow and outflow cannulae (not shown), an internal battery 45 and an internal TET/Telemetry coil 47.
The internal battery is connected to the unified system 1 via hermetic connector 49, electrical conductor set 5 and electrical feedthrough 25. The internal battery 45 is preferably implanted subcutaneously in the abdomen. In the preferred embodiment the internal battery package 45 uses rectangular prismatic nickel/cadmium cells, however other battery chemistries could be utilized. These cells are housed in a custom designed laser welded titanium enclosure with a hermetic connector 49 suitable for implantation. Preferably, the hermetic connector 49 is an internal connector, used for allowing an easy replacement of battery 45.
In this way, the part of conductor set 5 from connector 49 through feedthrough 25 to unified system 1, should not be changed when internal battery 45 is replaced periodically. The electrical conductor set 5 contains electrical connections for the supply of DC voltage to the internal electronic controller 3, for the recharging of the internal battery and for activation of an audible warning alarm housed in the battery enclosure.
The internal TET/Telemetry coil 47 is connected to the unified system 1 via the in-line hermetic connector 51, electrical conductor set 7 and the electrical feedthrough 27. The internal TET/Telemetry coil 47 is implanted subclavicularly. The transcutaneous energy transformer ('TET) and transcutaneous information telemetry (Telemetry) systems consist of electronic circuitry on both the internal electronic controller 3 and external electronic controller 53, the r.. 2105935 internal TET/Telemetry coil 47 and the external TET/Telemetry coil 55.
The TET uses wire coils 57,57 to electromagnetically couple power into the body without perforation of the skin. The Telemetry uses infrared components 59,59' embedded in the internal TET/Telemetry coil 47 and external TET/Telemetry coil 55 to transfer the communication channel data streams into and out of the body without perforation of the skin.
The external components of the electrohydraulic ventricular assist device of the present invention consist of the external electronic controller 53, an external battery 61 and an external TET/Telemetry coil 55.
The external electronic controller 53 contains a portion of the circuitry for both the TET
and Telemetry systems. External electronic controller 53 also produces and receives the communication channel data stream for control and monitoring of the unified system 1 and generates recharging signals for recharging the external battery 61 at predetermined intervals.
External electronic controller 53 is connected to the external TET/Telemetry coil 55.
Additionally, the external electronic controller of the device in the present invention further comprises a computer interface for connecting the device with a computer for control and monitoring of the device and a display means 65 which consists of a liquid crystal display (I,CD) screen for display of control status and alarms. The external electronics is a compact unit intended to be worn on a belt similar to a pager.
The external battery 61 is connected to the external electronic controller 53 via electrical conductor set 67. In the preferred embodiment the external battery uses silver/zinc cells, however other battery chemistries could be utilized. The electrical conductor set 67 contains electrical connections for the supply of DC voltage to the external electronic controller 53 and for the recharging of the external battery 61.
The external TET/Telemetry coil 55 is connected to the external electronic controller 53 via electrical conductor set 69.
The electrohydraulic ventricular assist device of the present invention comprises the unified system for implantation in a human thorax proximal to the human heart as described above.
The operation of the device is now described with reference to Figure 1.
.. 210593 The system is actuated by the hydraulic fluid that is pumped between the volume displacement chamber 17 and the fluid compartment 13 of blood pumping chamber 15, by the reversing axial flow pump 39 driven by the brushless DC motor. Whenever the motor 37 receives an actuating signal from the internal electronic controller 3, it reverses its direction of rotation which causes a reversal in the flow direction of the actuating fluid.
Actuating fluid is pumped into the fluid compartment 13 of the blood chamber 15 and the membrane 31 displaces the blood during the systole phase of the cardiac cycle thmugh the outflow port 21. When the axial flow pump 39 is reversed, the hydraulic fluid is pumped away from the fluid compartment 13 of the volume displacement chamber 17, causing outward displacement of the VDC membrane 35, the membrane 31 is pulled away from the blood compartment 33 causing active filling of blood to occur thmugh the inflow port 19. This action is further illustrated in Figures 5 and 6. Reversal points of the axial pump 37 are determined by the membrane position detector 9 which sends the status signal to the external electronic controller 3 for reversing the axial pump flow when the membrane 31 reaches the end points of systole and diastole.
In vitro Testing was conducted in vitro to verify that the system operated satisfactory prior to any in vivo experiments. Tests have been conducted on mock circulation with the device in air and completely submerged in saline solution to simulate expected chest pressures.
In vitro flow rates of over 8 litres per minute with a preload of 10 and a mean afterload of 100 mmhg have been obtained. The transcutaneous energy transformer has demonstrated a power transfer efficiency of over 809b at power levels of 10-35 Watts. The internal and the external batteries have been cycled tested to determine optimum charge and discharge requirements as well as to determine operating times and cycle lives.
In vivo The complete unified system has been implanted in 6 bovine for in vivo testing and has ~.... 210 ~ 9 3 5 maintained circulation from 3 to 27 hours. The performance of the complete unified system has proven satisfactory in acute experimentation. 1fie overall configuration of the device has also proven to be satisfactory, over a wide range of operating conditions.
Claims (48)
1. A unified system for an electrohydraulic ventricular assist device adapted for implantation in the thorax and for cannulation to the blood circulatory system comprising;
an internal electronic controller for generating an actuating signal;
actuating means for converting said actuating signal into a back and forth rhythmic displacement of a fluid;
a blood pumping chamber having an inflow blood port and an outflow blood port for converting said back and forth displacement of said fluid into a rhythmic unidirectional displacement of blood through said inflow and outflow ports;
coupling means for supplying said internal electronic controller with a supply voltage;
detecting means for generating said actuating signal in response to the status of said blood pumping chamber;
a volume displacement chamber (VDC) acting as a reservoir for said back and forth rhythmic displacement of a fluid; and a support with a surface curvature compatible with the internal human sagittal and transverse chest wall curvatures for supporting said internal electronic controller, said actuating means, said blood pumping chamber, said hermetic coupling means and said detecting means in a compact structure with said blood pumping chamber arranged with said inflow and outflow ports oriented away from said support and said structure with an overall size that when the unified system is placed within the human thorax with the said support surface adjacent the chest wall, said structure does not adversely compress adjacent organs.
an internal electronic controller for generating an actuating signal;
actuating means for converting said actuating signal into a back and forth rhythmic displacement of a fluid;
a blood pumping chamber having an inflow blood port and an outflow blood port for converting said back and forth displacement of said fluid into a rhythmic unidirectional displacement of blood through said inflow and outflow ports;
coupling means for supplying said internal electronic controller with a supply voltage;
detecting means for generating said actuating signal in response to the status of said blood pumping chamber;
a volume displacement chamber (VDC) acting as a reservoir for said back and forth rhythmic displacement of a fluid; and a support with a surface curvature compatible with the internal human sagittal and transverse chest wall curvatures for supporting said internal electronic controller, said actuating means, said blood pumping chamber, said hermetic coupling means and said detecting means in a compact structure with said blood pumping chamber arranged with said inflow and outflow ports oriented away from said support and said structure with an overall size that when the unified system is placed within the human thorax with the said support surface adjacent the chest wall, said structure does not adversely compress adjacent organs.
2. A unified system as claimed in claim 1, wherein said support is a base cover having a longitudinal radius of curvature and a transversal radius of curvature such that dead space between said unified system and the rib cage is minimized.
3. A unified system as claimed in claim 1, further comprising a first cannula connected to said inflow port and a second cannula connected to said outflow port for cannulation with the blood circulatory system.
4. A unified system as claimed in claim 3, wherein said inflow port is oriented for cannulation to the systemic circulation when the unified system is implanted in the thorax for assisting or replacing a left ventricle.
5. A unified system as claimed in claim 4, wherein the length of said first cannula is between 5 and 14 cm.
6. A unified system as claimed in claim 3, wherein said outflow port is oriented for cannulation to the systemic circulation when said unified system is implanted in the thorax for assisting or replacing a left ventricle.
7. A unified system as claimed in claim 3, wherein said inflow port is oriented for cannulation with the pulmonary circulation when said unified system is implanted in the thorax for assisting or replacing a right ventricle.
8. A unified system as claimed in claim 3, wherein said outflow port is oriented for cannulation with the pulmonary circulation when said unified system is implanted for assisting or replacing a right ventricle.
9. A unified system as claimed in claim 1, having an overall thickness of less than 4 cm.
10. A unified system as claimed in claim 1, having an overall length less than 18 cm.
11. A unified system as claimed in claim 1, having an overall width less than
12 cm.
12. A unified system as claimed in claim 1, further comprising a feedthrough cover for hermetic trespass of a first set of conductors for said supply voltage.
12. A unified system as claimed in claim 1, further comprising a feedthrough cover for hermetic trespass of a first set of conductors for said supply voltage.
13. A unified system as claimed in claim 1, wherein said blood pumping chamber comprises:
a generally flat oval sac defining a back face and a front face and said inflow and outflow ports protruding from said front face;
a flexible membrane dividing said sac longitudinally, said flexible membrane oscillating between a systolic position, to displace blood from the blood pumping chamber into the circulatory system, and a diastolic position, to fill up said blood pumping chamber with blood from the circulatory system;
a blood compartment comprised between said front face and said flexible membrane;
a fluid compartment comprised between said flexible membrane and said back face;
a fluid conduit connector for rhythmic fill and drain of said fluid compartment with fluid to generate said oscillating displacement of said flexible membrane between said systolic position, where fluid is displaced in said fluid compartment and said diastolic position, where fluid drains off said fluid compartment.
a generally flat oval sac defining a back face and a front face and said inflow and outflow ports protruding from said front face;
a flexible membrane dividing said sac longitudinally, said flexible membrane oscillating between a systolic position, to displace blood from the blood pumping chamber into the circulatory system, and a diastolic position, to fill up said blood pumping chamber with blood from the circulatory system;
a blood compartment comprised between said front face and said flexible membrane;
a fluid compartment comprised between said flexible membrane and said back face;
a fluid conduit connector for rhythmic fill and drain of said fluid compartment with fluid to generate said oscillating displacement of said flexible membrane between said systolic position, where fluid is displaced in said fluid compartment and said diastolic position, where fluid drains off said fluid compartment.
14. A unified system as claimed in claim 13, wherein said inflow port is provided with a first one way valve which allows entry of blood into said blood compartment and said outflow port is provided with a second one-way valve which allows ejection of the blood from said blood compartment.
15. A unified system as claimed in claim 13, wherein the stroke volume of said blood pumping chamber is between 55 and 70 ml.
16. A unified system as claimed in claim 13, giving a cardiac output of greater than 3 litres/minute with a mean preload pressure of between 5 to 10 mmHg and an afterload pressure greater than 100 mmHg.
17. A unified system as claimed in claim 1, wherein said actuating means comprises:
a brushless DC motor for receiving said actuating signal and converting it into a forward and reverse rotational movement;
a reversible axial pump for converting said rotational movement into said back and forth displacement of a fluid;
a fluid conduit for transporting the fluid between said volume displacement chamber and said fluid compartment through said actuating means to displace said flexible membrane between said systolic and diastolic positions.
a brushless DC motor for receiving said actuating signal and converting it into a forward and reverse rotational movement;
a reversible axial pump for converting said rotational movement into said back and forth displacement of a fluid;
a fluid conduit for transporting the fluid between said volume displacement chamber and said fluid compartment through said actuating means to displace said flexible membrane between said systolic and diastolic positions.
18. A unified system as claimed in claim 12, wherein said feedthrough cover further comprises an oil port for filling device with a fluid.
19. A unified system as claimed in claim 17, wherein said motor and said pump form a unitary energy convertor.
20. A unified system as claimed in claim 19, wherein the the fluid further acts as a lubricant for bearings in said energy convertor and as a heat sink for said energy convertor and said internal electronic controller.
21. A unified system as claimed in claim 13, wherein said detecting means is placed for detecting the sistolic or diastolic position of said flexible membrane and for accordingly generating said actuating signal.
22. A unified system as claimed in claim 21, wherein said detector is an infrared sensor.
23. A unified system as claimed in claim 1, further comprising a feedthrough cover for hermetic trespass of a first set of conductors for said supply voltage and wherein said supply voltage is obtained from a battery which is implanted subcutaneously.
24. An electrohydraulic ventricular assist device adapted for cannulation to the blood circulatory system comprising;
an unified system for implantation in a human thorax proximal to the human heart to replace or assist a ventricle;
a rechargeable internal battery for subcutaneous implantation produce an internal supply voltage for said unified system;
an external power supply source for providing a DC voltage;
an external electronic controller for converting said DC voltage received from said external power supply source to an AC supply voltage and for generating a recharge signal for said internal battery;
a transcutaneous energy transformer (TET) for transmitting said AC supply voltage and said recharge signal across the skin to said unified system;
a first coulping means for connecting said internal battery to said unified system;
second coupling means for connecting said unified system to said transcutaneous energy transformer to receive external supply voltage and for establishing a communication channel between said external controller and said unified system.
an unified system for implantation in a human thorax proximal to the human heart to replace or assist a ventricle;
a rechargeable internal battery for subcutaneous implantation produce an internal supply voltage for said unified system;
an external power supply source for providing a DC voltage;
an external electronic controller for converting said DC voltage received from said external power supply source to an AC supply voltage and for generating a recharge signal for said internal battery;
a transcutaneous energy transformer (TET) for transmitting said AC supply voltage and said recharge signal across the skin to said unified system;
a first coulping means for connecting said internal battery to said unified system;
second coupling means for connecting said unified system to said transcutaneous energy transformer to receive external supply voltage and for establishing a communication channel between said external controller and said unified system.
25. A device as claimed in claim 24, wherein:
said external controller further comprises a computer interface for connecting said device to a computer for control and monitoring of the device and a display means for control status and alarm display;
said external controller further comprises a computer interface for connecting said device to a computer for control and monitoring of the device and a display means for control status and alarm display;
26. A device as claimed in claim 24, wherein said transcutaneous energy transformer comprises:
an external coil for transmitting said AC supply voltage;
an internal coil for receiving said AC supply voltage; and said TET further comprises a transcutaneous information telemetry system for transmitting and receiving said communication channel data streams carrying control and monitoring data between said external controller and said unified system via said external coil and said internal coil.
an external coil for transmitting said AC supply voltage;
an internal coil for receiving said AC supply voltage; and said TET further comprises a transcutaneous information telemetry system for transmitting and receiving said communication channel data streams carrying control and monitoring data between said external controller and said unified system via said external coil and said internal coil.
27. A unified system as claimed in claim 26, wherein said unified system compries a feedthrough cover for hermetic trespass of a first set of conductors for connection with said internal battery and a second set of conductors for connection to said TET.
28. A unified system for use in ventricular assist device and for total implantation in a thorax of a patient for cannulation to the blood circulatory system to replace or assist a ventricle of a natural heart of the patient, said unified system comprising:
an internal electronic controller for generating an actuating signal;
a blood pumping means provided proximate to said internal electronic controller, said blood pumping means comprising:
a blood pumping chamber comprising:
a blood compartment having an inflow blood port and an outflow blood port for cannulation to the blood circulatory system;
a fluid compartment for receiving a fluid; and a flexible membrane separating said blood compartment and said fluid compartment;
a volume displacement chamber for receiving the fluid;
a fluid conduit connecting said blood pumping chamber and said volume displacement chamber to allow flow of the fluid between said blood pumping chamber and said volume displacement chamber; and an actuating means, provided in said fluid conduit, for converting said actuating signal into a pulsating rhythmic displacement of the fluid between said blood pumping chamber and said volume displacement chamber through said fluid conduit and said actuating means;
wherein said actuating means is provided proximate to said internal electronic controller, said blood pumping chamber and said volume displacement chamber so that said unified system has a shape with a convex back surface having a curvature compatible with curvatures of an internal human sagittal and transverse chest wall, and an overall size and geometry such that, when the unified system is implanted in the patient, said unified system is accommodated within the thorax with the back surface of said unified system adjacent the chest wall without adversely compressing adjacent organs, creating dead space or limiting chest closure.
an internal electronic controller for generating an actuating signal;
a blood pumping means provided proximate to said internal electronic controller, said blood pumping means comprising:
a blood pumping chamber comprising:
a blood compartment having an inflow blood port and an outflow blood port for cannulation to the blood circulatory system;
a fluid compartment for receiving a fluid; and a flexible membrane separating said blood compartment and said fluid compartment;
a volume displacement chamber for receiving the fluid;
a fluid conduit connecting said blood pumping chamber and said volume displacement chamber to allow flow of the fluid between said blood pumping chamber and said volume displacement chamber; and an actuating means, provided in said fluid conduit, for converting said actuating signal into a pulsating rhythmic displacement of the fluid between said blood pumping chamber and said volume displacement chamber through said fluid conduit and said actuating means;
wherein said actuating means is provided proximate to said internal electronic controller, said blood pumping chamber and said volume displacement chamber so that said unified system has a shape with a convex back surface having a curvature compatible with curvatures of an internal human sagittal and transverse chest wall, and an overall size and geometry such that, when the unified system is implanted in the patient, said unified system is accommodated within the thorax with the back surface of said unified system adjacent the chest wall without adversely compressing adjacent organs, creating dead space or limiting chest closure.
29. A unified system as claimed in claim 28 wherein the back surface of said unified system has longitudinal curvature complementary to a sagittal radius of 11~0.5 cm and a transversal curvature complementary to an intrathoracic wall having a radius of 9.4~0.5 cm.
30. A unified system as claimed in claim 28 wherein said blood ports are equipped with one-way valves to ensure unidirectional flow of blood from the natural heart through said blood chamber to the systemic and/or pulmonary circulation systems.
31. A unified system as claimed in claim 28 further comprising an inflow cannula connected to said inflow port and an outflow cannula connected to said outflow port for cannulation with the blood circulatory system.
32. A unified system as claimed in claim 28 having an overall thickness of less than 4 cm.
33. A unified system as claimed in claim 28 having an overall length less than cm.
34. A unified system as claimed in claim 28 having an overall width less than cm.
35. A unified system as claimed in claim 28 wherein said inflow port is provided with a first one way valve which allows entry of blood into said blood compartment and said outflow port if provided with a second one-way valve which allows ejection of the blood from said blood compartment.
36. A unified system as claimed in claim 28 giving a cardiac out of greater than 3 liters/minute with a mean preload pressure of between 5 to 10 mm Hg and an afterload pressure greater than 100 mm Hg.
37. A unified system as claimed in claim 28 wherein said actuating means comprises:
a brushless DC motor for receiving said actuating signal and converting it into a forward and reverse rotational movement; and a reversible axial pump for converting said rotational movement into said back and forth displacement of fluid to displace said flexible membrane between systolic and diastolic positions.
a brushless DC motor for receiving said actuating signal and converting it into a forward and reverse rotational movement; and a reversible axial pump for converting said rotational movement into said back and forth displacement of fluid to displace said flexible membrane between systolic and diastolic positions.
38. A unified system as claimed in claim 37 wherein said motor and said pump form a unitary energy convertor.
39. A unified system as claimed in claim 38 wherein said fluid further acts as a lubricant for bearings in said energy convertor and as a means to disperse heat from the actuating means and the internal electronic controller throughout the device to minimize tissue necrosis due to heat.
40. A unified system as claimed in claim 28 comprising detecting means for detecting the systolic or diastolic position of said flexible membrane and for accordingly generating a control signal to said internal electronic controller for synchronizing said actuating signal with the displacement of said flexible membrane.
41. A unified system as claimed in claim 40 wherein said detector is an infrared sensor.
42. A device as claimed in claim 28 further comprising means for securing said support to a rib cage to prevent migration and the resulting organ compression.
43. A unified system as claimed in claim 28 further comprising a support for said internal electronic controller and said blood pumping means so that said inflow and outflow ports are orientated away from a front surface of said unified system.
44. A unified system as claimed in claim 28 wherein said blood pumping chamber converts said pulsating rhythmic displacement of the fluid into a rhythmic unidirectional displacement of blood into and from said blood compartment through said inflow and outflow ports.
45. A unified system as claimed in claim 28 wherein said internal electronic controller has a first set of conductors for providing said internal electronic controller with a supply voltage, and said unified system further comprises a feedthrough cover for hermetic trespass of said first set of conductors.
46. A unified system as claimed in claim 45 wherein said feedthrough cover further comprises a fluid port for filling said volume displacement chamber, said fluid compartment and said fluid conduit with fluid.
47. A unified system as claimed in claim 28 wherein said blood pumping chamber comprises a generally flat oval sac defining a back and face and a front face, and said inflow and outflow ports protrude from said front face;
said flexible membrane divides said sac longitudinally to define said blood compartment between said front face, and said flexible membrane, and said fluid compartment between said flexible membrane and said back face;
said flexible membrane oscillates between a systolic position, to displace blood compartment into the circulatory system, and a diastolic position, to full up said blood compartment with blood from the circulatory system; and said pulsating rhythmic displacement of the fluid generates said oscillating displacement of said flexible membrane between said systolic position, where the fluid is displaced in said fluid compartment, and said diastolic position, where the fluid drains off said fluid compartment.
said flexible membrane divides said sac longitudinally to define said blood compartment between said front face, and said flexible membrane, and said fluid compartment between said flexible membrane and said back face;
said flexible membrane oscillates between a systolic position, to displace blood compartment into the circulatory system, and a diastolic position, to full up said blood compartment with blood from the circulatory system; and said pulsating rhythmic displacement of the fluid generates said oscillating displacement of said flexible membrane between said systolic position, where the fluid is displaced in said fluid compartment, and said diastolic position, where the fluid drains off said fluid compartment.
48. A unified system for use in a ventricular assist device and for total implantation in a thorax of a patient for cannulation to the blood circulatory system to replace or assist a ventricle of a natural heart of the patient, said unified system comprising:
an internal electronic controller for generating an actuating signal;
a blood pumping means provided proximate to said internal electronic controller, said blood pumping means comprising:
a blood pumping chamber comprising:
a blood compartment having an inflow blood port and an outflow blood port for cannulation to the blood circulatory system;
a fluid compartment for receiving a fluid; and a flexible membrane separating said blood compartment and said fluid compartment;
a volume displacement chamber for receiving the fluid;
a fluid conduit connecting said blood pumping chamber and said volume displacement chamber to allow flow of the fluid between said blood pumping chamber and said volume displacement chamber;
an actuating means, provided in said fluid conduit for converting said actuating signal into a pulsating rhythmic displacement of the fluid between said blood pumping chamber and said volume displacement chamber through said fluid conduit and said actuating means;
hermetic coupling means for providing said internal electronic controller with a supply voltage; and detecting means for detecting the status of said blood pumping chamber and accordingly generating a control signal to said internal electronic controller for synchronizing said actuating signal with the status of said blood pumping chamber;
wherein said actuating means is provided proximate to said internal electronic controller, said blood pumping chamber and said volume displacement chamber so that said unified system has a shape with a convex back surface having a curvature compatible with curvatures of an internal human sagittal and transverse chest wall, and an overall size and geometry such that, when the unified system is implanted in the patient, said unified system is accommodated within the thorax with the back surface of said unified system adjacent the chest wall without adversely compressing adjacent organs, creating dead space or limiting chest closure.
an internal electronic controller for generating an actuating signal;
a blood pumping means provided proximate to said internal electronic controller, said blood pumping means comprising:
a blood pumping chamber comprising:
a blood compartment having an inflow blood port and an outflow blood port for cannulation to the blood circulatory system;
a fluid compartment for receiving a fluid; and a flexible membrane separating said blood compartment and said fluid compartment;
a volume displacement chamber for receiving the fluid;
a fluid conduit connecting said blood pumping chamber and said volume displacement chamber to allow flow of the fluid between said blood pumping chamber and said volume displacement chamber;
an actuating means, provided in said fluid conduit for converting said actuating signal into a pulsating rhythmic displacement of the fluid between said blood pumping chamber and said volume displacement chamber through said fluid conduit and said actuating means;
hermetic coupling means for providing said internal electronic controller with a supply voltage; and detecting means for detecting the status of said blood pumping chamber and accordingly generating a control signal to said internal electronic controller for synchronizing said actuating signal with the status of said blood pumping chamber;
wherein said actuating means is provided proximate to said internal electronic controller, said blood pumping chamber and said volume displacement chamber so that said unified system has a shape with a convex back surface having a curvature compatible with curvatures of an internal human sagittal and transverse chest wall, and an overall size and geometry such that, when the unified system is implanted in the patient, said unified system is accommodated within the thorax with the back surface of said unified system adjacent the chest wall without adversely compressing adjacent organs, creating dead space or limiting chest closure.
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002105935A CA2105935C (en) | 1993-09-10 | 1993-09-10 | Electrohydraulic ventricular assist device |
| JP50836995A JP3619520B2 (en) | 1993-09-10 | 1994-09-09 | Electro-hydraulic ventricular assist device |
| PCT/CA1994/000492 WO1995007109A1 (en) | 1993-09-10 | 1994-09-09 | Electrohydraulic ventricular assist device |
| EP94926076A EP0717640B1 (en) | 1993-09-10 | 1994-09-09 | Electrohydraulic ventricular assist device |
| AU76074/94A AU7607494A (en) | 1993-09-10 | 1994-09-09 | Electrohydraulic ventricular assist device |
| US08/303,766 US5569156A (en) | 1993-09-10 | 1994-09-09 | Electrohydraulic ventricular assist device |
| DE69419420T DE69419420T2 (en) | 1993-09-10 | 1994-09-09 | ELECTROHYDRAULIC VENTRICULAR SUPPORT SYSTEM |
| US08/451,522 US5704891A (en) | 1993-09-10 | 1995-05-26 | Electrohydraulic ventricular assist device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002105935A CA2105935C (en) | 1993-09-10 | 1993-09-10 | Electrohydraulic ventricular assist device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2105935A1 CA2105935A1 (en) | 1995-03-11 |
| CA2105935C true CA2105935C (en) | 2001-03-27 |
Family
ID=4152295
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002105935A Expired - Fee Related CA2105935C (en) | 1993-09-10 | 1993-09-10 | Electrohydraulic ventricular assist device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2105935C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6197055B1 (en) | 1999-07-06 | 2001-03-06 | Herbert L. Matthews | Single chamber mechanical heart |
| CN109847127A (en) * | 2017-11-30 | 2019-06-07 | 上海微创医疗器械（集团）有限公司 | Magnetic liquid suspension formula centrifugal blood pump |
-
1993
- 1993-09-10 CA CA002105935A patent/CA2105935C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2105935A1 (en) | 1995-03-11 |
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