CN103598931A - Wide-inlet large-flow heart valve prosthesis - Google Patents

Abstract

The invention relates to a heart valve prosthesis device for replacing a damaged heart valve caused by congenital or acquired reasons and provides a wide-inlet large-flow heart valve prosthesis. The existing defects are overcome by increasing the inlet area. The heart valve prosthesis comprises a valve and a valve ring and is characterized in that the section area of an inflow port of the valve ring is larger than that of an outflow port. Compared with a common valve, the novel valve is structurally characterized in that a blood inflow face of the valve ring of the valve is a streamlined horn mouth, the inlet area is increased, under the same condition, compared with the common valve, outlet flow is larger, and haemodynamics performance of the valve is improved.

Description

The large flow Cardiac valve prosthesis of a kind of wide portion

Technical field

The present invention relates to implantable device.More particularly, the present invention relates to for to because of congenital or day after tomorrow reason damage the cardiac valve prosthetic appliance that ring cardiac valve is replaced.

Background technology

Cardiac valve prosthesis since nineteen sixty first Application in clinical, development through decades, along with artificial mechanical heart valve's structure is optimized day by day, and the application of the related discipline advanced technology such as materialogy, the performance of Cardiac valve prosthesis is greatly improved, cause bolt rate and greatly decline, obtained clinically good effect.Current application is widely in valve, due to the easy calcification of bioprosthetic valve and damaged service life of causing shorter, the 70% left and right ，Er developing country that mechanical valve prosthesis accounts for whole market, the whole world is almost that 100% ， China artificial mechanical heart lobe is also to account for more than 90%.

But as said in Cardiac valve prosthesis international standard IS05840-2005, " not yet having up to now desirable Cardiac valve prosthesis ".According in recent years a large amount of clinical follow up results, although at present clinical practice the widest the 4th generation valve---bifolium artificial mechanical valve prosthesis hemodynamics function admirable, the complication rate relevant with valve is low, but the intrinsic defect of mechanical valve prosthesis still exists, show that its hemodynamics performance is still undesirable, do not reach satisfied flow, and the case of the thrombosis that happens occasionally.

How to make artificial mechanical valve prosthesis's defect index be reduced to less or even eliminate, be still the emphasis of current artificial mechanical heart valve's research and development

Summary of the invention

For above deficiency, the invention provides the large flow Cardiac valve prosthesis of a kind of wide portion, by being added to open area, overcome existing defect.

The object of the invention is to realize by following technical proposals:

A Cardiac valve prosthesis, comprises limb, lobe ring; It is characterized in that: the head piece area of section that enters of described lobe ring is greater than out head piece area of section.

In addition, lobe ring is in addition round and smooth in area of section sudden change place, forms streamlined fluid passage.

Further, lobe ring enters head piece side and has an arc shade.Shade height is defined as organizing 8%～15% of ring diameter; Shade outward flanging 0.6～3mm; Shade flange radian is R1～R6.

Novel valve structurally different from common valve be in: novel valve is fairshaped horn mouth at the blood inflow face of lobe ring, increased inlet area, the flow of comparing out under the same conditions stream with common valve is larger, thereby has improved the hemodynamics performance of valve.

Accompanying drawing explanation

The novel valve of Fig. 1 and common valve comparison

Fig. 2 valve cutaway view (lobe leaf open state);

Fig. 3 valve cutaway view (lobe leaf closed condition);

Fig. 4 pipeline fluid schematic diagram;

Fig. 5 lobe ring size figure;

Fig. 6 constriction coefficient and local loss coefficient form

The hydraulic characteristic(s) form of Fig. 7 aperture, ozzle

The specific embodiment

Current artificial mechanical heart valve's development is mainly carried out aspect two: the one, material science aspect, constantly explore durable and without the new material of hyperamization bolt effect.The 2nd, structural design aspect, further improve blood flow and hydrodynamic performance.

The present invention be directed to the improvement of structural design.

1, artificial mechanical heart valve's designing requirement

The requirement of artificial mechanical heart valve design should have: the mechanical property that (1) is good, show the good endurance of valve, and the valve sound is low, and cavitation corrosion threshold values is high, and the lobe leaf proportion close with blood.(2) good Hydrodynamic character, shows that pressure gradient is little, and regurgitation volume is low, and energy loss is low, the effective vent area that intracardiac occupation rate is low and desirable.(3) good histocompatibility, shows the low bolt that causes, low hemolytic.

2, the Elementary Fluid Mechanics of structure of the present invention

The normal mitral hemodynamics in human body of take is example, and Bicuspid valve is the valve between left atrium and left ventricle, and during ventricular diastole, Bicuspid valve is opened, and blood flows into ventricle from atrium by Bicuspid valve.

Blood flows in pipeline two kinds of nowed formings, and a kind of is flow velocity when slower, and blood flow is well arranged, there is no horizontal mixing, and is called Laminar Flow; Another kind is flow velocity when very fast, and blood flow is disorderly and unsystematic, mutually mixes, and is called turbulent flow.Experiment shows, blood flow is crossed normal mitral flowing for stable laminar flow.

In unit interval, flow through mitral volumetric blood and be called flow, flow Q equals the product that blood flow is crossed mitral speed V and Bicuspid valve porch sectional area A, i.e. Q=V*A.

According to describing for rate of flow of fluid and cross-section relation in the continuity theorem of fluid, when fluid successively and stably flows through the pipeline that a thickness does not wait, because the fluid of any part in pipe all can not interrupt or push, so at one time, flow to the fluid mass of arbitrary section and should equate from the fluid mass of another cross section outflow.Be formulated as: A1V1=A2V2=constant, in formula: A represents that pipe section is long-pending; V represents flow velocity.

Bernoulli equation draw thus, and its content is: during perfect fluid steady flow, on same streamline, the gross head of arbitrary point equates.Gross head equals velocity head, head, pressure head sum.Be formulated as:

V ²/ 2g+h+p/ ρ g=constant.

V in formula ²/ 2g is velocity head, and v is flow velocity (m/s), and g is acceleration of gravity (9.8m/s ²); H is head, is exactly the height (m) of flow section; P/ ρ g be pressure head, and p is the static pressure (Pa) of flow section, and ρ is the density (kg/m of liquid ³).

In actual applications, energy loss when fluid flows in pipeline not only have along its length along journey energy loss, but also occur the local energy loss at local pipeline section.Local energy loss is mainly the sharply variation due to passage section, flow direction, cause the rapid change of velocity field, the reasons such as the friction between increase fluid, collision and formation whirlpool cause, and the local energy loss of Flows Unit Weight fluid is expressed as conventionally:

$h_j=\mathrm{\ξ}\frac{v_2^2}{2g}$

In formula, ξ is local loss coefficient, is a non dimensional coefficient.Local loss coefficient is except minority pipe fitting available analyses method is tried to achieve, and most of pipe fitting is all by measuring.

As shown in Figure 4, when fluid flows to the pipeline of minor diameter from large diameter pipeline, streamline must be crooked, and a fluid stream must shrink.When fluid enters after small diameter pipeline, because fluid has inertia, fluid shrinks continuing until the smallest cross-sectional Ac of undergauge then expands again gradually, is even full of whole minor diameter cross section.Between near a fluid stream undergauge and tube wall, have a low-pressure area that is full of little whirlpool, the convex shoulder place being connected with minor diameter cross section in major diameter cross section, also often has whirlpool to form.All vortex movement are all wanted consumed energy; In the acceleration and moderating process of streamline bending, fluid, fluid particle collision, VELOCITY DISTRIBUTION variation etc. also all will cause energy loss.Because fluid is first to shrink rear diffusion along dwindling the mobile of pipeline suddenly, therefore its energy loss also should be comprised of two parts.This loss is expressed as

$h_j=\mathrm{\ξ}\frac{v_2^2}{2g}={\mathrm{\ξ}}_c\frac{v_c^2}{2g}+\frac{{(v_c-v_2)}^2}{2g}$

Make Cc=Ac/A2, claim the constriction coefficient of a fluid stream.According to continuity equation AcVc=A2V2, can be obtained fom the above equation:

$\mathrm{\ξ}=\frac{{\mathrm{\ξ}}_c}{C_c^2}+{(\frac{1}{C_c}-1)}^2$

According to experiment, when A2/A1=0.01, ξ=0.5, Cc=0.618, so

ξ c=0.045, it serves to show that its shrinkage loss is very little; When A2/A1=1, for waiting straight pipeline, do not shrink and expansion, therefore suppose

along with being reduced to linearly 0 by 0.118, can try to achieve the approximation that cross section dwindles suddenly the local loss coefficient of pipeline.

The measured value of constriction coefficient and local loss coefficient as shown in Figure 6.

The fluid of data representation shown in Fig. 6 is flowed in small pipeline by large pipeline, maximum resistance coefficient ξ=0.5, if porch abrupt change of cross-section place is in addition round and smooth, resistance coefficient can reduce with the increase of round and smooth degree.When the extremely even cunning of entrance becomes streamlined, ξ can be as small as and ignores.

As shown in Figure 7, in Fig. 7, listed coefficient is all for tube nozzle outlet section to the hydraulic characteristic(s) of aperture, ozzle.

3, concrete structure of the present invention

With reference to Fig. 1, Fig. 2, Fig. 3, it is different from the area of section that common same model valve enters head piece that newly-designed valve enters head piece, its lobe ring of common valve is cylindrical, its side that becomes a mandarin is with to go out to flow lateral section area identical, and the lateral section area that becomes a mandarin that newly designs valve is greater than out stream lateral section area, and the resistance coefficient when thering is fairshaped fluid passage and reducing changes of section.In a preferred forms, the design adds an arc shade in the valve side that becomes a mandarin, and expands and becomes a mandarin lateral area and form streamlined path, and determining from following several respects of shade size considered:

In the valve side that becomes a mandarin, add after shade, can increase the flow in the unit interval on the one hand, and the flow by wide portion valve can increase along with the increase of shade height and physical dimension, but is increased to after certain flow, even if the increase of shade size can not make flow increase yet; Increase on the other hand after a shade, the shiny surface of shade can stop thrombosis excessive increase, prevents the adverse consequences that aforementioned thrombus growth hinders the activity of lobe leaf.

Hence one can see that, if shade is undersized, not obvious by the flow increase of valve, also can not reach the object that stops thrombus growth; But shade is oversize, also can exert an adverse impact, as: between shade outer rim and blood vessel, can form a dead angle, can produce eddy current herein, and blood is piled up meeting generation thrombosis; The operation that shade is too high also can affect the movable and doctor of valve chordae tendineae and perform the operation time etc.

Take 27M Bicuspid valve as example, and its valvular tissue ring diameter D is 27mm,

In conjunction with above clinical practice situation and flow dynamics analysis, calculate, shade height (H1) can be defined as organize approximately 8%～15% of ring diameter; Shade outward flanging is 0.6～3mm (being that in Fig. 5, φ c size increases 0.6-3mm on φ b basis) approximately; Shade flange radian is R1～R6 (unit: mm).

Determine accordingly and respectively organize the corresponding lobe ring size of ring gauge lattice valve as shown in Fig. 5 and following table:

Claims (6)

1. a Cardiac valve prosthesis, comprises limb, lobe ring; It is characterized in that: the head piece area of section that enters of described lobe ring is greater than out head piece area of section.

2. Cardiac valve prosthesis as claimed in claim 1, is characterized in that: lobe ring is in addition round and smooth in area of section sudden change place, forms streamlined fluid passage.

3. Cardiac valve prosthesis as claimed in claim 1, is characterized in that: lobe ring enters head piece side and has an arc shade.

4. Cardiac valve prosthesis as claimed in claim 3, is characterized in that: shade height is defined as organizing 8%～15% of ring diameter.

5. Cardiac valve prosthesis as claimed in claim 3, is characterized in that: shade outward flanging 0.6～3mm.

6. Cardiac valve prosthesis as claimed in claim 3, is characterized in that: shade flange radian is R1～R6.

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