WO2016115533A1

WO2016115533A1 - Flow reversal catheter assembly with emboli detection hub

Info

Publication number: WO2016115533A1
Application number: PCT/US2016/013719
Authority: WO
Inventors: Bahram VARJAVAND
Original assignee: Varjavand Bahram
Priority date: 2015-01-16
Filing date: 2016-01-15
Publication date: 2016-07-21

Abstract

Apparatus and methods for protecting against embolization during vascular interventions, such as carotid artery angioplasty and endarterectomy, are disclosed. The apparatus and methods induce substantially continuous retrograde flow through the internal carotid artery during treatment during an interventional procedure, without significant blood loss. The apparatus includes a flow reversal catheter assembly provided with an emboli detection hub to detect emboli in the retrograde blood flow and help determine when it is safe to remove the apparatus.

Description

FLOW REVERSAL CATHETER ASSEMBLY WITH EMBOLI DETECTION HUB

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 62/104,660, filed on January 16, 2015, the content of which is hereby incorporated by reference in its entirety for all purposes.

FIELD

[0002] This invention relates to apparatus and methods for protecting against embolization during vascular interventions, such as carotid artery angioplasty and endarterectomy. Particularly, the apparatus and methods of the present invention induce substantially continuous retrograde flow through the internal carotid artery during treatment during an interventional procedure, without significant blood loss. More particularly, the apparatus includes a flow reversal catheter assembly provided with an emboli detection hub to detect emboli in the retrograde blood flow and help determine when it is safe to remove the apparatus.

BACKGROUND

[0003] Carotid artery stenoses typically manifest in the common carotid artery, internal carotid artery or external carotid artery as a pathologic narrowing of the vascular wall, for example, caused by the deposition of plaque, that inhibits normal blood flow. Endarterectomy, an open surgical procedure, traditionally has been used to treat such stenosis of the carotid artery.

[0004] An important problem encountered in carotid artery surgery is that emboli may be formed during the course of the procedure, and these emboli can rapidly pass into the cerebral vasculature and cause ischemic stroke.

[0005] In view of the trauma and long recuperation times generally associated with open surgical procedures, considerable interest has arisen in the endovascular treatment of carotid artery stenosis. In particular, widespread interest has arisen in transforming interventional techniques developed for treating coronary artery disease, such as angioplasty and stenting, for use in the carotid arteries. Such endovascular treatments, however, are especially prone to the formation of emboli.

[0006] Such emboli may be created, for example, when an interventional instrument, such as a guide wire or angioplasty balloon, is forcefully passed into or through the stenosis, as well as after dilatation and deflation of the angioplasty balloon or stent deployment. Because such instruments are advanced into the carotid artery in the same direction as blood flow, emboli generated by operation of the instruments are carried directly into the brain by antegrade blood flow.

[0007] Stroke rates after carotid artery stenting have widely varied in different clinical series, from as low as 4.4% to as high as 30%. One review of carotid artery stenting including data from twenty-four major interventional centers in Europe, North America, South America and Asia, had a combined initial failure and combined mortality/stroke rate of more than 7%. Cognitive studies and reports of intellectual changes after carotid artery stenting indicate that embolization is a common event causing subclinical cerebral damage.

[0008] Several previously known apparatus and methods attempt to remove emboli formed during endovascular procedures by trapping or suctioning the emboli out of the vessel of interest. The two most commonly used cerebral protection devices are distal filters that capture and remove debris from antegrade blood flow, and proximal protection devices that allow blood flow cessation or flow reversal. These previously known systems, however, provide less than optimal solutions to the problems of effectively removing emboli.

[0009] Solano et al. U.S. Pat. No. 4,921,478 describes cerebral angioplasty methods and devices wherein two concentric shafts are coupled at a distal end to a distally-facing funnel-shaped balloon. A lumen of the innermost shaft communicates with an opening in the funnel-shaped balloon at the distal end, and is open to atmospheric pressure at the proximal end. In use, the funnel-shaped balloon is deployed proximally (in the direction of flow) of a stenosis, occluding antegrade flow. An angioplasty balloon catheter is passed through the innermost lumen and into the stenosis, and then inflated to dilate the stenosis. The patent states that when the angioplasty balloon is deflated, a pressure differential between atmospheric pressure and the blood distal to the angioplasty balloon causes a reversal of flow in the vessel that flushes any emboli created by the angioplasty balloon through the lumen of the innermost catheter.

[0010] While a seemingly elegant solution to the problem of emboli removal, several drawbacks of the device and methods described in the Solano et al. patent seem to have lead to abandonment of that approach. Chief among these problems is the inability of that system to generate flow reversal during placement of the guide wire and the angioplasty balloon across the stenosis. Because flow reversal does not occur until after deflation of the angioplasty balloon, there is a substantial risk that any emboli created during placement of the angioplasty balloon will travel too far downstream to be captured by the subsequent flow reversal. It is expected that this problem is further compounded because only a relatively small volume of blood is removed by the pressure differential induced after deflation of the angioplasty balloon.

[0011] Another drawback of the method described in the Solano patent: deployment of the funnel- shaped balloon in the common carotid artery ("CCA") causes reversal of flow from the external carotid artery ("ECA") into the internal carotid artery ("ICA"), due to the lower flow impedance of the ICA. Consequently, when a guide wire or interventional instrument is passed across a lesion in either the ECA or ICA, emboli dislodged from the stenosis are introduced into the blood flow and carried into the cerebral vasculature via the ICA.

[0012] The insufficient flow drawback identified for the system of the Solano patent is believed to have prevented development of a commercial embodiment of the similar system described in EP Publication No. 0 427 429. EP Publication No. 0 427 429 describes use of a separate balloon to occlude the ECA prior to crossing the lesion in the ICA. However, like Solano, that publication discloses that flow reversal occurs only when the dilatation balloon in the ICA is deflated.

[0013] Chapter 46 of Interventional Neuroradiology: strategies and practical techniques (J. J. Connors & J. Wojak, 1999), published by Saunders of Philadelphia, Pa., describes using a coaxial balloon angioplasty system for patients having with proximal ICA stenoses. In particular, a small, deflated occlusion balloon on a wire is introduced into the origin of the ECA, and a guide catheter with a deflated occlusion balloon is positioned in the CCA just proximal to the origin of the ECA. A dilation catheter is advanced through a lumen of the guide catheter and dilated to disrupt the stenosis. Before deflation of the dilation catheter, the occlusion balloons on the guide catheter and in the ECA are inflated to block antegrade blood flow to the brain. The dilation balloon then is deflated, the dilation catheter is removed, and blood is aspirated from the ICA to remove emboli.

[0014] Cerebral damage still may result from the foregoing previously known procedure, which is similar to that described in EP Publication No. 0 427 429, except that the ICA is occluded prior to the ECA. Consequently, both of these previously known systems and methods suffer from the same drawback— the inability to generate flow reversal at sufficiently high volumes during placement of the guide wire and dilation catheter across the stenosis. Both methods entail a substantial risk that any emboli created during placement of the balloon will travel too far downstream to be captured by the flow reversal.

[0015] Irrespective of the method of aspiration employed with the method described in the foregoing Interventional Neuroradiology article, substantial drawbacks are attendant. If, for example, natural aspiration is used (i.e., induced by the pressure gradient between the atmosphere and the artery), then only a relatively small volume of blood is expected to be removed by the pressure differential induced after deflation of the angioplasty balloon. If, on the other hand, an external pump is utilized, retrieval of these downstream emboli may require a flow rate that cannot be sustained for more than a few seconds, resulting insufficient removal of emboli.

[0016] Furthermore, with the dilation balloon in position, the occlusion balloons are not inflated until after inflation of the dilation balloon. Microemboli generated during advancement of the dilation catheter into the stenosed segment may therefore be carried by retrograde blood flow into the brain before dilation, occlusion, and aspiration are even attempted.

[0017] Imran U.S. Pat. No. 5,833,650 describes a system for treating stenoses that comprises three concentric shafts. The outermost shaft includes a proximal balloon at its distal end that is deployed proximal of a stenosis to occlude antegrade blood flow. A suction pump then draws suction through a lumen in the outermost shaft to cause a reversal of flow in the vessel while the innermost shaft is passed across the stenosis. Once located distal to the stenosis, a distal balloon on the innermost shaft is deployed to occlude flow distal to the stenosis. Autologous blood taken from a femoral artery using an extracorporeal blood pump is infused through a central lumen of the innermost catheter to provide continued antegrade blood flow distal to the distal balloon. The third concentric shaft, which includes an angioplasty balloon, is then advanced through the annulus between the innermost and outermost catheters to dilate the stenosis.

[0018] Like the device of the Solano patent, the device of the Imran patent appears to suffer the drawback of potentially dislodging emboli that are carried into the cerebral vasculature. In particular, once the distal balloon of Imran's innermost shaft is deployed, flow reversal in the vasculature distal to the distal balloon ceases, and the blood perfused through the central lumen of the innermost shaft establishes antegrade flow. Importantly, if emboli are generated during deployment of the distal balloon, those emboli will be carried by the perfused blood directly into the cerebral vasculature, and again pose a risk of ischemic stroke. Moreover, there is some evidence that reperfusion of blood under pressure through a small diameter catheter may contribute to hemolysis and possible dislodgment of emboli.

[0019] In U.S. patent application Ser. No. 09/333,074, filed Jun. 14, 1999, which is incorporated herein by reference, the use of external suction to induce regional reversal of flow is described. That application further described that intermittently induced regional flow reversal overcomes the drawbacks of naturally-aspirated systems such as described hereinabove. However, the use of external suction may in some instances result in flow rates that are too high to be sustained for more than a few seconds. In addition, continuous use of an external pump may result in excessive blood loss, requiring infusion of non-autologous blood and/or saline that causes hemodilution, reduced blood pressure, or raise related safety issues.

[0020] Another drawback of the above mentioned and other known flow reversal systems is their inability to detect when most or all of the emboli have been captured and indicate when it is safe to remove the system. The existing systems are designed to be removed upon completion of a therapeutic treatment of a blood vessel. However, any additional emboli that may be formed upon removal of the system when antegrade blood flow is restored may pose a risk for passing to the cerebral vasculature. BRIEF SUMMARY

[0021] In view of the foregoing, it is an object of this invention to provide methods and apparatus for removing emboli from within the carotid arteries during interventional procedures, such as angioplasty or carotid stenting, that reduce the risk that emboli are carried into the cerebral vasculature.

[0022] It also is an object of the present invention to provide methods and apparatus for removing emboli from within the carotid arteries during interventional procedures, such as angioplasty or carotid stenting, that provide substantially continuous low retrograde blood flow from the treatment zone, thereby reducing the risk that emboli are carried into the cerebral vasculature.

[0023] It is another object of the present invention to provide emboli removal methods and apparatus that prevent the development of reverse flow between the ECA and ICA once the common carotid artery has been occluded, thereby enhancing the likelihood that emboli generated by a surgical or interventional procedure are effectively removed from the vessel.

[0024] It is yet another object of the present invention to provide methods and apparatus for removing emboli during a carotid stenting procedure that enable filtering of emboli and reduced blood loss.

[0025] It is a further object of this invention to provide methods and apparatus for detecting the presence or absence of emboli prior to restoring blood flow in the blood vessel.

[0026] Described here is a method of performing a procedure. In some variations, the method may comprise occluding a blood vessel of a patient at a first location, the blood vessel having an antegrade blood flow direction and a retrograde flow direction; initiating blood flow in the blood vessel in the retrograde flow direction by withdrawing blood from the blood vessel distal to the first location; performing a therapeutic treatment of the blood vessel; detecting the presence or absence of emboli in the withdrawn blood; providing a signal indicating the presence or absence of emboli in the withdrawn blood; filtering any emboli from the withdrawn blood after detecting the presence or absence of emboli in the withdrawn blood; returning the filtered withdrawn blood to the patient; and restoring blood flow in the blood vessel in the antegrade flow direction after performing the therapeutic treatment if the signal indicates the absence of emboli in the withdrawn blood. In some variations, the method may further comprise occluding the blood vessel of the patient at a second location before initiating blood flow in the blood vessel in the reverse flow direction. In some of these variations, the first location may be in the common carotid artery. In some variations, the first location may be in the common carotid artery and the second location may be in the external carotid artery. In some variations, the method may further comprise inserting a first balloon catheter to the first location and wherein occluding a vessel of the patient at the first location may comprise inflating a first balloon of the first balloon catheter at the first location. In some of these variations, occluding the blood vessel of the patient at the second location may comprise inflating a second balloon of the first balloon catheter at the second location. In other variations, the method may further comprise inserting a second balloon catheter into the first balloon catheter and wherein occluding the blood vessel of the patient at the second location may comprise inflating a second balloon of the second balloon catheter at the second location. In some variations, the method may further comprise attaching an imaging probe to the first balloon catheter. In some of those variations, the imaging probe may be a transcranial Doppler probe or a light scattering probe. In some variations, the first balloon catheter may be configured to position the imaging probe to image blood flow in a catheter hub of the first balloon catheter.

[0027] Described here is a catheter assembly. In some variations, the catheter assembly may comprise a catheter hub with a distal port, a filter port, a lumen between the distal port and the filter port, the lumen containing an imaging zone, an imaging port configured to position an imaging probe to image the imaging zone; a catheter body with a proximal end and a distal end, wherein the proximal end is attached to the distal port of the catheter hub; and a filter configured to be in fluid communication with the filter port, comprising a filter inlet, a filter outlet, and filter element therebetween. In some variations, the catheter body may be a multi-lumen catheter body. In some of these variations, the catheter hub may further comprise a first working port with a first working lumen, and the catheter body may comprise a first lumen in fluid communication with the first working lumen. In some of these variations, the catheter hub may further comprise a proximal balloon port and a proximal occlusion balloon attached to the catheter body, wherein the proximal balloon port may be in fluid communication with the proximal occlusion balloon. In some of these variations, the catheter body may comprise a distal working opening in communication with the working lumen, and the proximal occlusion balloon may be located proximal to the distal working opening. In some of these variations, the catheter assembly may further comprise a distal occlusion balloon and wherein the catheter hub may further comprise a distal balloon port. In some of these variations, the distal occlusion balloon may be attached to the catheter body, wherein the distal balloon port may be in fluid communication with the distal occlusion balloon. In some variations, the distal occlusion balloon may be slidably positionable relative to the catheter body. In some variations, the catheter hub may further comprise a window structure between the imaging zone and the imaging port. In some of these variations, the catheter hub may further comprise an imaging stop structure between the imaging zone and the imaging port to restrict distal displacement of an imaging probe. In some of these variations, the catheter assembly may further comprise an imaging probe configured to be removably coupled to the imaging port. In other variations, the catheter assembly may further comprise an imaging probe fixedly coupled to the imaging port. In some variations, the imaging probe may comprise a distal end configured to be coupled to the imaging port, and a proximal end configured to be removably coupled to an imaging base unit. In some variations, the imaging probe may be an ultrasound probe. In other variations, the imaging probe may be a Doppler probe. In some variations, the catheter assembly may further comprise an imaging base unit. In some of these variations, the imaging base unit may be configured to output real-time quantification of emboli in the imaging zone of the catheter hub. In some variations, the catheter assembly may further comprise an infusion catheter with a proximal end configured to attach to the filter outlet and a distal end configured for insertion into a blood vessel.

[0028] Disclosed here is an imaging system. In some variations, the imaging system may comprise a connector body comprising a first Luer lock, a second Luer lock, a lumen therebetween and containing an imaging zone, an imaging port configured to receive and lock a transcranial Doppler probe to image the imaging zone.

[0029] Disclosed here is a treatment method for a patient. In some variations, the treatment method may comprise initiating retrograde blood flow along a vascular segment using a catheter system to withdraw blood from the vasculature segment; performing a therapeutic procedure on the vascular segment; imaging blood within the catheter system to detect emboli; providing a real-time visual signal of the presence or absence of emboli within the blood in the catheter system; and confirming the real-time visual signal for the absence of emboli before restoring antegrade blood flow along the vascular segment. In some variations, the method may further comprise occluding a first location of the vascular segment using a first occluding element of the catheter system. In some of these variations, the method may further comprise occluding a second location of the vascular segment using a second occluding element of the catheter system. In some variations, the method may further comprise filtering the blood for emboli after providing the real-time visual signal; and returning the filtered blood to the patient. In some variations, the method may further comprise coupling a transcranial Doppler probe to the catheter system. In some of these variations, the method may further comprise locking the transcranial Doppler probe the catheter system using a universal clamp.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred

embodiments, in which:

[0031] FIGS. 1A and IB are schematic views of previously known emboli protection systems;

[0032] FIG. 2 is a partial schematic view of an illustrative variation of a catheter assembly in situ;

[0033] FIG. 3 is a partial schematic view of another illustrative variation of a catheter assembly in situ; and

[0034] FIG. 4 is a schematic view of an illustrative variation of a catheter hub.

[0035] FIG. 5A and 5B are schematic perspective and superior views of a system with the imaging housing and emboli filter.

DETAILED DESCRIPTION

[0036] Referring to FIGS. 1A and IB, drawbacks of previously known emboli removal catheters are described with reference to performing percutaneous angioplasty of stenosis S in common carotid artery CCA. [0037] With respect to FIG. 1A, drawbacks associated with naturally-aspirated emboli removal systems, such as described in the above-mentioned patent to Solano and European Patent

Publication, are described. No flow reversal is induced by those systems until after balloon 10 of angioplasty catheter 1 1 first is passed across the stenosis, inflated, and then deflated. However, applicant has determined that once member 15 of emboli removal catheter 16 is inflated, flow within the ECA reverses and provides antegrade flow into the ICA, due to the lower hemodynamic resistance of the ICA. Consequently, emboli E generated while passing guide wire 20 or catheter 11 across stenosis S may be carried irretrievably into the cerebral vasculature before flow in the vessel is reversed and directed into the aspiration lumen of emboli removal catheter 16 by opening the proximal end of the aspiration lumen to atmospheric pressure. Furthermore, natural-aspiration may not remove an adequate volume of blood to retrieve even those emboli that have not yet been carried all the way into the cerebral vasculature.

[0038] In FIG. IB, system 17 described in the above-mentioned patent to Imran is shown. As described hereinabove, deployment of distal balloon 18, and ejection of blood out of the distal end of the inner catheter, may dislodge emboli from the vessel wall distal to balloon 18. The introduction of antegrade flow through inner catheter 19 is expected only to exacerbate the problem by pushing the emboli further into the cerebral vasculature. Thus, while the use of positive suction in the Imran system may remove emboli located in the confined treatment field defined by the proximal and distal balloons, such suction is not expected to provide any benefit for emboli dislodged distal of distal balloon 18.

[0039] The apparatus and methods of the present invention induce substantially continuous retrograde flow through the internal carotid artery during treatment during an interventional procedure, without significant blood loss. A flow reversal catheter assembly is provided with an emboli detection hub that employs ultrasonic interrogation of the blood aspirated through a catheter body in order to detect emboli. The term "emboli" used herein includes both macroemboli and microemboli.

[0040] The catheter assembly of the present invention comprises a catheter hub, a catheter body and a filter. FIG. 2 shows a partial catheter assembly 20 comprising a catheter body 21 having a lumen and proximal occlusion balloon 22. A guide wire or second catheter 25 having distal occlusion balloon 26 disposed on its distal end is slidably positionable relative to the catheter body 21. In accordance with the principles of the present invention, antegrade blood flow is stopped when both proximal occlusion balloon 22 in the CCA and distal occlusion balloon 26 are deployed. Furthermore, the aspiration lumen of catheter body 21 is connected to an infusion catheter, disposed, for example, in the patient's femoral vein. In this manner a substantially continuous flow of blood is induced between the treatment site and the patient's venous vasculature. Because flow through the artery is towards catheter body 21, any emboli dislodged by advancing a guide wire or angioplasty catheter 23 across stenosis S causes the emboli to be aspirated by catheter body 21.

[0041] Unlike the previously known naturally-aspirated systems, the present invention provides substantially continuous retrograde blood flow through the ICA while preventing blood from flowing retrograde in the ECA and antegrade into the ICA, thereby preventing emboli from being carried into the cerebral vasculature. Because the apparatus and methods of the present invention "recycle" emboli-laden blood from the arterial catheter through the blood filter and to the venous return catheter, the patient experiences significantly less blood loss.

[0042] Referring now to FIG. 3, an alternative assembly of the present invention is described. Catheter assembly 30 comprises catheter body 31 having an aspiration lumen, a proximal occlusion balloon 32 and a distal occlusion balloon 36 attached to the catheter body 31. As described above with respect to FIG. 2, antegrade blood flow is stopped when both proximal occlusion balloon 32 in the CCA and distal occlusion balloon 36 are deployed. The aspiration lumen of catheter body 31 is connected to an infusion catheter to induce substantially continuous flow of blood between the treatment site and the patient's venous vasculature. Any emboli dislodged by advancing a guide wire or angioplasty catheter 33 across stenosis S causes the emboli to be aspirated by catheter body 31.

[0043] The catheter assembly 20, 30 further includes a catheter hub 40 connected to the catheter body 21, 31. The catheter hub may have a rigid plastic smooth body hermetically sealing blood from the environment. It may be formed of a biocompatible thermoplastic and integrally molded as a one piece for simple, disposable use and for ease of manufacturing. The catheter hub may be preinstalled as part of a complete reverse flow catheter assembly or installed into a preexisting assembly prior to being coupled to the patient. As shown in FIG. 4, catheter hub 40 comprises a distal port 42 attached to a proximal end 50 of the catheter body, a filter port 44, a lumen between the distal port 42 and the filter port 44, and an imaging port 46 comprising an inner chamber. The lumen contains an imaging zone 48, wherein the imaging port 46 is configured to position an imaging probe (not shown) to image the imaging zone 48. An imaging stop structure between the imaging zone 48 and the imaging port 46 restricts displacement of the imaging probe. The imaging probe may be a reusable, conventional ultrasound probe or Doppler probe, and may optionally include a protective sheath. The imaging probe may have a distal end configured to be removably coupled (such as by universal clamp, rubber band, press-fitting, or tab or groove design) or fixedly coupled (such as by glue or sonic- welding) to the imaging port 46, and a proximal end configured to be removeably coupled to an imaging base unit (not shown). The imaging base unit is configured to output real-time quantification of emboli in the imaging zone 48 of the catheter hub 40.

[0044] The catheter hub 40 may further include a window structure of appropriate material and thickness between the imaging zone 48 and the imaging port 46 in order to transmit sufficient acoustic signal from the imaging probe to the retrograde blood to be interrogated for emboli.

Alternatively, the catheter hub 40 or just the imaging port 46 of the hub may be made from a transparent material. Properly coupling the acoustic waves between the imaging probe and the retrograde blood may further comprise an acoustic dampening material and an ultrasonic coupling gel in the inner chamber of the imaging port 46. The dampening material may be of sufficient thickness and dampening coefficient to eliminate background noise from the received signal picked up by the imaging probed. It may, for example, comprise a commercially available UV "cure-in- place" urethane acrylate A60 durometer gasket material.

[0045] In some variations, the catheter hub may have an imaging port, or an adapter for the imaging port, that is sized and configured to accommodate other types of imaging probes. For example, an imaging port for an intravascular ultrasound probe will be smaller in size than that for a transcranial Doppler probe.

[0046] The catheter body 21, 3 lis multi-luminal and has a distal end and a proximal end 50 attached to the distal port 42 of the catheter hub 40. Catheter hub 40 further includes a working port 52 with a first working lumen that is in fluid communication with a first lumen and first working opening of the catheter body. Guide wires, angioplasty catheters and other interventional instruments may be inserted into the working port 52 and advanced through the first lumen and first working opening of the catheter body in order to perform a therapeutic treatment on the blood vessel. The catheter hub also includes a proximal balloon port 54 that is in fluid communication with the proximal occlusion balloon 22, 32 attached to the catheter body 21, 31 proximal to the distal working opening. Catheter hub 40 may optionally include a distal balloon port 56 to be in fluid communication with distal occlusion balloon 36 attached to catheter body 31 of the catheter assembly 30 shown in FIG. 3.

[0047] The catheter assembly 20, 30 may further comprise a filter (not shown) and an infusion catheter (not shown). The filter is configured to be in fluid communication with the filter port 44 and comprises a filter inlet, a filter outlet and a filter element therebetween. The infusion catheter has a proximal end configured to attach to the filter outlet and a distal end configured for insertion into a blood vessel. The aspiration lumen of catheter body 21 , 31 is in fluid communication with the infusion catheter, which may be disposed, for example, in the patient's femoral vein. In use, aspirated blood flows through the catheter body proximal end 50 and through the lumen between the distal port 42 and filter port 44 of the catheter hub 40 where it is imaged for emboli in the imaging zone 48 by an imaging probe. The retrograde blood then flows through the filter port 44 to the filter where any emboli is captured, the infusion catheter and into the blood vessel (e.g., femoral vein). In this manner a substantially continuous flow of blood is induced between the treatment site and the patient's vasculature. Because flow through the artery is towards catheter body 21, 31, any emboli dislodged during treatment or after treatment (e.g., when the balloon of angioplasty catheter 23, 33 is deflated) will be aspirated by the catheter body, imaged by the emboli detection catheter hub, and filtered by the filtering element before being returned to the patient. When the absence of emboli is quantitatively confirmed in real-time by the imaging base unit, then the proximal occlusion balloon 22, 32 and the distal occlusion balloon 26, 36 may be deflated to restore blood flow in the antegrade direction and the catheter assembly safely removed.

[0048] FIGS. 5A and 5B depict another variation of the system, comprising a catheter hub 100, imaging housing 102 and an emboli filter 104. In this particular variation, the imaging housing 102 is in fluid communication with the side port 106 of the catheter 100 via connector tubing 108, and the emboli filter 104 is in fluid communication with the imaging housing 102 via a second connector tubing 110. In other embodiments, however, either or both of the connecting tubes 108, 1 10 may be eliminated and the imaging housing 102 and/or the emboli filter 104 may be configured to directly couple to the side port 106 and/or imaging housing 102, for example. In this particular example, the catheter hub 100 comprises a working port 1 12 into which a catheter 1 14 or other tool may be inserted. The side port 106 of the catheter hub 100 is in fluid communication with the distal end 116 of the imaging housing 102, either directly or via connector tubing 108. The proximal end 1 18 of the imaging housing is in fluid communication with the distal end 120 of the emboli filter 104. The imaging port 122 of the imaging housing 102 may be similarly configured as imaging port 46 described herein.

[0049] The catheter assembly described here may be used in a treatment method for a patient. The treatment method may comprise initiating retrograde blood flow along a vascular segment using a catheter system to withdraw blood from the vasculature segment. A therapeutic procedure, such as angioplasty or stenting, may be performed on the vascular segment. Blood within the catheter system is imaged using a transcranial Doppler probe, for example, to detect emboli. The probe may be locked to the catheter system using a universal clamp. A real-time visual signal of the presence or absence of emboli within the blood in the catheter system is provided, and the real-time visual signal for the absence of emboli before restoring antegrade blood flow along the vascular segment is confirmed. The blood may be filtered for emboli after providing the real-time visual signal and the filtered blood may be returned to the patient. In some variations, the method may further comprise occluding first and second locations of the vascular segment using first and second occluding elements, respectively, of the catheter system.

[0050] Also described here is a method of performing a procedure. In some variations, the method may comprise occluding a blood vessel of a patient at a first location (e.g., common carotid artery) by inserting a first balloon catheter to the first location and inflating a first balloon of the first balloon catheter at the first location, the blood vessel having an antegrade blood flow direction and a retrograde flow direction. Blood flow in the blood vessel is initiated in the retrograde flow direction by withdrawing blood from the blood vessel distal to the first location. A therapeutic treatment (e.g., angioplasty, stenting) is performed on the blood vessel. The presence or absence of emboli in the withdrawn blood is detected and a signal indicating the presence or absence of emboli in the withdrawn blood is provided. Emboli from the withdrawn blood may be filtered after detecting the presence or absence of emboli in the withdrawn blood, and the filtered withdrawn blood may be returned to the patient. Blood flow may be restored in the blood vessel in the antegrade flow direction after performing the therapeutic treatment if the signal indicates the absence of emboli in the withdrawn blood. As shown in FIG. 3, the method may further comprise occluding the blood vessel of the patient at a second location (e.g., external carotid artery) by inflating a second balloon of the first balloon catheter at the second location before initiating blood flow in the reverse flow direction. Alternatively, occlusion at the second location may comprise inserting a second balloon catheter into the first balloon catheter and inflating a second balloon of the second balloon catheter at the second location, as shown in FIG. 2. An imaging probe (e.g., transcranial Doppler probe, light scattering probe) may be attached to the first balloon catheter, which may be configured to position the imaging probe to image blood flow in a catheter hub of the first balloon catheter.

[0051] Also disclosed herein is an imaging system. The imaging system may comprise a connector body comprising a first Luer lock, a second Luer lock, and a lumen therebetween and containing an imaging zone. An imaging port is configured to receive and lock a transcranial Doppler probe to image the imaging zone.

[0052] While preferred illustrative embodiments of the invention are described above, it will be apparent to one skilled in the art that various changes and modifications may be made. The appended claims are intended to cover all such changes and modifications that fall within the true spirit and scope of the invention.

Claims

CLAIMS What is claimed as new and desired to be protected by Letters Patent of the United States is:

1. A method of performing a procedure, comprising:

occluding a blood vessel of a patient at a first location, the blood vessel having an antegrade blood flow direction and a retrograde flow direction;

initiating blood flow in the blood vessel in the retrograde flow direction by withdrawing blood from the blood vessel distal to the first location;

performing a therapeutic treatment of the blood vessel;

detecting the presence or absence of emboli in the withdrawn blood;

providing a signal indicating the presence or absence of emboli in the withdrawn blood; filtering any emboli from the withdrawn blood after detecting the presence or absence of emboli in the withdrawn blood;

returning the filtered withdrawn blood to the patient; and

restoring blood flow in the blood vessel in the antegrade flow direction after performing the therapeutic treatment if the signal indicates the absence of emboli in the withdrawn blood.

2. The method of claim 1, further comprising occluding the blood vessel of the patient at a second location before initiating blood flow in the blood vessel in the reverse flow direction.

3. The method of claim 1 or 2, wherein the first location is in the common carotid artery.

4. The method of claim 2, wherein the first location is in the common carotid artery and the second location is in the external carotid artery.

5. The method of claim 2, further comprising inserting a first balloon catheter to the first location; and

wherein occluding a vessel of the patient at the first location comprises inflating a first balloon of the first balloon catheter at the first location.

6. The method of claim 5, wherein occluding the blood vessel of the patient at the second location comprises inflating a second balloon of the first balloon catheter at the second location.

7. The method of claim 5, further comprising inserting a second balloon catheter into the first balloon catheter and wherein occluding the blood vessel of the patient at the second location comprises inflating a second balloon of the second balloon catheter at the second location.

8. The method of claim 5, further comprising attaching an imaging probe to the first balloon catheter.

9. The method of claim 8, wherein the imaging probe is a transcranial Doppler probe or a light scattering probe.

10. The method of claim 8 or 9, wherein the first balloon catheter is configured to position the imaging probe to image blood flow in a catheter hub of the first balloon catheter.

11. A catheter assembly, comprising:

a catheter hub with a distal port, a filter port, a lumen between the distal port and the filter port, the lumen containing an imaging zone, an imaging port configured to position an imaging probe to image the imaging zone;

a catheter body with a proximal end and a distal end, wherein the proximal end is attached to the distal port of the catheter hub; and

a filter configured to be in fluid communication with the filter port, comprising a filter inlet, a filter outlet, and filter element therebetween.

12. The catheter assembly of claim 11, wherein the catheter body is a multi-lumen catheter body.

13. The catheter assembly of claim 12, wherein the catheter hub further comprises a first working port with a first working lumen, and the catheter body comprises a first lumen in fluid communication with the first working lumen.

14. The catheter assembly of claim 13, wherein the catheter hub further comprises a proximal balloon port and a proximal occlusion balloon attached to the catheter body, wherein the proximal balloon port is in fluid communication with the proximal occlusion balloon.

15. The catheter assembly of claim 14, wherein the catheter body comprises a distal working opening in communication with the working lumen, and the proximal occlusion balloon is located proximal to the distal working opening.

16. The catheter assembly of claim 15, further comprising a distal occlusion balloon and wherein the catheter hub further comprises a distal balloon port.

17. The catheter assembly of claim 16, wherein the distal occlusion balloon is attached to the catheter body, wherein the distal balloon port is in fluid communication with the distal occlusion balloon.

18. The catheter assembly of claim 16, wherein the distal occlusion balloon is slidably positionable relative to the catheter body.

19. The catheter assembly of any one of claims 11 to 18, wherein the catheter hub further comprises a window structure between the imaging zone and the imaging port.

20. The catheter assembly of claim 19, wherein the catheter hub further comprises an imaging stop structure between the imaging zone and the imaging port to restrict distal displacement of an imaging probe.

21. The catheter assembly of claim 20, further comprising an imaging probe configured to be removably coupled to the imaging port.

22. The catheter assembly of claim 20, further comprising an imaging probe fixedly coupled to the imaging port.

23. The catheter assembly of claim 21 or 22, wherein the imaging probe comprises a distal end configured to be coupled to the imaging port, and a proximal end configured to be removably coupled to an imaging base unit.

24. The catheter assembly of any one of claims 21 to 23, wherein the imaging probe is an ultrasound probe.

25. The catheter assembly of any one of claims 21 to 23, wherein the imaging probe is a doppler probe.

26. The catheter assembly of claim 23, further comprising an imaging base unit.

27. The catheter assembly of claim 26, wherein the imaging base unit is configured to output real-time quantification of emboli in the imaging zone of the catheter hub.

28. The catheter assembly of any one of claims 11 to 27, further comprising an infusion catheter with a proximal end configured to attach to the filter outlet and a distal end configured for insertion into a blood vessel.

29. An imaging system, comprising a connector body comprising a first Luer lock, a second Luer lock, a lumen therebetween and containing an imaging zone, an imaging port configured to receive and lock a transcranial Doppler probe to image the imaging zone.

30. A treatment method for a patient, comprising:

initiating retrograde blood flow along a vascular segment using a catheter system to withdraw blood from the vasculature segment;

performing a therapeutic procedure on the vascular segment;

imaging blood within the catheter system to detect emboli;

providing a real-time visual signal of the presence or absence of emboli within the blood in the catheter system; and

confirming the real-time visual signal for the absence of emboli before restoring antegrade blood flow along the vascular segment.

31. The method of claim 30, further comprising occluding a first location of the vascular segment using a first occluding element of the catheter system.

32. The method of claim 31, further comprising occluding a second location of the vascular segment using a second occluding element of the catheter system.

33. The method of any one of claims 30 to 32, further comprising:

filtering the blood for emboli after providing the real-time visual signal; and

returning the filtered blood to the patient.

34. The method of any one of claims 30 to 33, further comprising coupling a transcranial Doppler probe to the catheter system.

35. The method of claim 34, further comprising locking the transcranial Doppler probe the catheter system using a universal clamp.