Disclosure of Invention
The embodiment of the invention provides a high polymer heart valve, which improves stress distribution, valve fatigue performance and valve service life by optimizing a valve leaf structure.
The embodiment of the invention provides an artificial high polymer heart valve, which comprises valve leaves and a valve frame, wherein the valve frame is of a hollow columnar structure, a plurality of columnar peaks are arranged at one end of the valve frame at intervals along the circumferential direction, the number of the valve leaves is consistent with that of the columnar peaks, the valve She Shezhi is arranged at the center of one end of the valve frame, which is provided with the columnar peaks, and the plurality of valve leaves are sequentially connected with two adjacent columnar peaks along the circumferential direction; the leaflet includes a free edge and a connecting edge connecting the leaflet frame, a line connecting a midpoint of the free edge and a midpoint of the connecting edge of the leaflet forming an abdomen curve on the leaflet, the leaflet having at least one thickness reduction along the abdomen curve.
Optionally, the section of the abdomen curve is an abdomen section, and the average thickness of the thickness-reduced part at the abdomen section is 50% -98% of the thickness of the leaflet.
Optionally, the average thickness of the reduced thickness portion at the abdomen section is 60% -90% of the leaflet thickness.
Optionally, the average thickness of the reduced thickness portion at the abdomen section is 72% -80% of the leaflet thickness.
Optionally, the total length of the thickness reduction portion along the abdomen curve is 20% -80% of the length of the abdomen curve.
Optionally, the total length of the thickness reduction portion along the abdomen curve is 40% -60% of the abdomen curve length.
Optionally, the surface of the thickness-reduced portion is a curved surface, the thickness of the thickness-reduced portion gradually increases from the center thereof to the edge thereof, and the thickness-reduced portion is smoothly connected with the leaflet surface.
Optionally, the thickness reduction portion is one, and the thickness reduction portion is disposed near the free edge.
Optionally, the thickness reduction portion is two, including first thickness reduction portion and second thickness reduction portion, first thickness reduction portion and second thickness reduction portion interval set up, first thickness reduction portion sets up in being close to free edge department, second thickness reduction portion sets up in being close to junction edge department.
Optionally, the reduced thickness portion is disposed on at least one of an outer surface of the leaflet and an inner surface of the leaflet.
Optionally, the thickness-reduced portion is disposed on an outer surface of the leaflet, and an inner surface of the leaflet is a smooth curved surface.
Optionally, the thickness-reduced portion is disposed on an inner surface of the leaflet, and an outer surface of the leaflet is a smooth curved surface.
Optionally, the thickness-reduced portion is disposed on an inner surface of the leaflet and an outer surface of the leaflet, the thickness-reduced portion on the outer surface of the leaflet is in smooth connection with the outer surface of the leaflet, and the thickness-reduced portion on the inner surface of the leaflet is in smooth connection with the inner surface of the leaflet.
Optionally, the leaflet has a thickness of 0.1mm to 0.5mm.
Optionally, an end of the valve frame remote from the valve leaflet is provided with a slit ring.
Optionally, the material of the valve leaflet and the valve frame is a polymer material.
Compared with the prior art, the technical scheme of the embodiment of the invention has the beneficial effects.
For example, the radial section of the valve leaflet is changed from uniform thickness to variable thickness, the thickness thinning part is increased, the stress distribution is improved, the fatigue resistance of the valve leaflet is improved, and the service life of the valve is prolonged; compared with the valve leaflet with uniform thickness, the valve leaflet with the thickness-reduced part can be opened earlier when being stressed, so that the overall opening efficiency of the valve leaflet is improved, and the hydrodynamic performance of the valve is improved.
For another example, the two thickness reduction parts are arranged, the first thickness reduction part is arranged at the position close to the free edge, and the second thickness reduction part is arranged at the position close to the connecting edge, so that peak stress distribution is more uniform and dispersed, the fatigue resistance of the valve leaflet is further improved, and the service life of the valve is prolonged.
Drawings
Fig. 1 is a radial cross-sectional view of a leaflet of a prior art prosthetic heart valve.
Fig. 2 is a graph of the pressure exerted by the leaflets of an aortic prosthetic heart valve of one cardiac cycle extracted from a pulsatile flow test of a prior art prosthetic heart valve.
Fig. 3 is a stress distribution diagram of a prior art prosthetic heart valve.
Fig. 4 is a schematic structural view of an artificial polymeric heart valve according to an embodiment of the invention.
Fig. 5 is a schematic view of the leaflets of an artificial polymeric heart valve in an embodiment of the invention.
Fig. 6 is a cross-sectional view of the leaflets of an artificial polymeric heart valve in an embodiment of the invention.
Fig. 7 is a stress distribution diagram of an artificial polymeric heart valve in an embodiment of the invention.
Fig. 8 is a cross-sectional view of the leaflets of another prosthetic polymeric heart valve in an embodiment of the present invention.
Fig. 9 is a stress distribution diagram of another prosthetic polymeric heart valve in an embodiment of the present invention.
Fig. 10 is a stress distribution diagram of a conventional prosthetic heart valve when opened.
Fig. 11 is a stress distribution diagram of an artificial polymeric heart valve according to an embodiment of the invention when opened.
Fig. 12 is a stress distribution diagram of a conventional prosthetic heart valve when closed.
Fig. 13 is a stress distribution diagram of an artificial polymeric heart valve in accordance with an embodiment of the invention.
Reference numerals illustrate:
1 valve frame, 11 column peaks, 12 slit rings;
2 valve leaves; 21 free edge, 22 connecting edge, 23 abdomen curve, 24 reduced thickness part, 241 first reduced thickness part; 242 second thickness reduction portion.
Detailed Description
In order to make the objects, features and advantageous effects of the present invention more comprehensible, embodiments accompanied with figures are described in detail below. It is to be understood that the following detailed description is merely illustrative of the invention, and not restrictive of the invention. Moreover, the use of the same, similar reference numbers in the figures may indicate the same, similar elements in different embodiments, and descriptions of the same, similar elements in different embodiments, as well as descriptions of prior art elements, features, effects, etc. may be omitted. The axial direction, the radial direction, and the circumferential direction according to the embodiment of the present invention respectively represent the axial direction, the radial direction, and the circumferential direction of the valve frame 1.
Referring to fig. 4-13, an embodiment of the present invention provides an artificial polymeric heart valve.
In a specific embodiment, the artificial high polymer heart valve comprises valve leaves 2 and a valve frame 1, wherein the valve frame 1 is of a hollow columnar structure, a plurality of columnar peaks 11 are arranged at one end of the valve frame 1 at intervals along the circumferential direction, the number of the valve leaves 2 is consistent with that of the columnar peaks 11, the valve leaves 2 are arranged at the center of one end of the valve frame 1 with the columnar peaks 11, and the valve leaves 2 are sequentially connected with two adjacent columnar peaks 11 along the circumferential direction; the leaflet 2 comprises a free edge 21 and a connecting edge 22 connecting the leaflet frame 1, a line connecting a midpoint of the free edge 21 and a midpoint of the connecting edge 22 of the leaflet 2 forms an abdomen curve 23 on the leaflet 2, and the leaflet 2 has at least one thickness reduction 24 along the abdomen curve 23.
The reduced thickness portion 24 is shaped like a circle or an ellipse on the leaflet surface or extends in a direction perpendicular to the abdomen curve 23, and its thickness gradually increases from the center to the edge. The quasi-circle comprises a circle and a graph similar to the circle, wherein the graph is formed by sequentially connecting corresponding circular arcs through multiple sections of curves; the ellipse-like shape comprises an ellipse and a graph similar to the ellipse, wherein the circular arcs of the corresponding ellipse are formed by sequentially connecting a plurality of sections of curves.
In one embodiment, the thickness of the leaflet 2 in the region outside the reduced thickness portion 24 is 0.1mm-0.5mm.
FIG. 6 is a cross-sectional view of the leaflets of an artificial polymeric heart valve in an embodiment of the invention; fig. 7 is a stress distribution diagram of an artificial polymeric heart valve in an embodiment of the invention. Referring to fig. 6 and 7, in one embodiment, the thickness reducing portion 24 is one, and the thickness reducing portion 24 is provided near the free edge 21 to appropriately reduce the region where stress is concentrated.
As can be seen from comparison of valve stress distribution diagrams (fig. 3 and 7) before and after adjustment, the maximum Mi Saisi stress is reduced from 1.312MPa to 1.084MPa, 17.4% is reduced, meanwhile, the phenomenon of abdominal stress concentration of the valve leaflet 2 is eliminated, the stress distribution is improved, and the valve fatigue resistance life is prolonged.
FIG. 8 is a cross-sectional view of the leaflets of another prosthetic polymeric heart valve in an embodiment of the present invention; fig. 9 is a stress distribution diagram of another prosthetic polymeric heart valve in an embodiment of the present invention. Referring to fig. 8 and 9, in one embodiment, the thickness reducing portions 24 are two, including a first thickness reducing portion 241 and a second thickness reducing portion 242, the first thickness reducing portion 241 and the second thickness reducing portion 242 are disposed at intervals, the first thickness reducing portion 241 is disposed near the free edge 21, and the second thickness reducing portion 242 is disposed near the connecting edge 22.
As can be seen from comparison of the valve stress distribution diagrams before and after adjustment (fig. 3 and 9), the maximum Mi Saisi stress is reduced from 1.312MPa to 0.877MPa by 33.2%, and the peak stress distribution is more uniform and dispersed than the leaflet 2 having a uniform thickness and the leaflet 2 provided with one thickness-reduced portion 24. The improved stress distribution level relieves the problem of stress concentration of the valve leaflet 2, so that the overall fatigue performance of the valve leaflet 2 is improved.
FIG. 10 is a stress distribution diagram of a prior art prosthetic heart valve when opened; fig. 11 is a stress distribution diagram of an artificial polymeric heart valve according to an embodiment of the invention when opened. Referring to fig. 10 and 11, when the leaflet 2 is opened, the opening of the non-uniform thickness leaflet 2 provided with the thickness-reduced portion 24 is larger than that of the uniform thickness leaflet 2 at the time of 0.06s after the opening, i.e., the time when the liquid starts to flow. The second thickness reduction 242 is disposed proximate the connecting edge 22 such that the leaflet 2 is reduced proximate the bottom end and opens earlier when the leaflet 2 is compressed.
By calculating the effective orifice area of the valveTo evaluate hydrodynamic performance; the effective orifice area is calculated by the following formula:
；
wherein,,the calculation unit is cm for the effective orifice area2 ；/>Calculating the root mean square forward flow rate in mL/s for the positive pressure difference period; />Calculating the average differential pressure during the positive differential pressure in mmHg; />To test the density of the fluid, a sheet is calculatedThe position is g/cm3 。
From the above calculation formula, the flow rate flowing through the valve during the valve opening and closing periodThe larger the valve opening area, the larger.
FIG. 12 is a stress distribution diagram of a prior art prosthetic heart valve when closed; fig. 13 is a stress distribution diagram of an artificial polymeric heart valve in accordance with an embodiment of the invention. Referring to fig. 12 and 13, when the leaflet 2 is closed, the closing condition of the non-uniform thickness leaflet 2 provided with the thickness-reduced portion 24 at the time of 0.23s is close to the closing condition of the uniform thickness leaflet 2. As can be seen from the opening condition of the valve leaflet 2 in fig. 10 and 11, the non-uniform thickness valve leaflet 2 provided with the thickness-reduced portion 24 is opened earlier than the uniform thickness valve leaflet 2, and is closed at the same time, that is, the valve is opened and closed, the blood flow through the non-uniform thickness valve leaflet 2 provided with the thickness-reduced portion 24 is larger, that is, the effective orifice areaWould be larger, which optimizes the hemodynamic performance of the leaflet.
In particular embodiments, the section of the abdomen curve 23 is an abdomen section, and the average thickness of the thickness-reduced portion 24 at the abdomen section is 50% -98% of the thickness of the leaflet 2. Preferably, the average thickness of the reduced thickness portion 24 at the abdominal section is 60% -90% of the thickness of the leaflet 2. More preferably, the average thickness of the reduced thickness portion 24 at the abdominal section is 72% -80% of the thickness of the leaflet 2. In one embodiment, the overall length of reduced thickness portion 24 along abdomen curve 23 is 20% -80% of the length of abdomen curve 23. Preferably, the total length of the reduced thickness portion 24 along the abdomen curve 23 is 40% -60% of the length of the abdomen curve 23.
In a specific embodiment, when the thickness-reduced portion 24 is in a circular-like shape, the thickness-reduced portion 24 is centered on the abdomen curve 23 and extends outwardly from the center point along the outer surface and/or the inner surface of the leaflet 2 by the same length, and the length of the thickness-reduced portion 24 extending along the abdomen curve 23 is 40% -60% of the length of the abdomen curve 23; when the thickness reduction part 24 is elliptical, the center of the thickness reduction part is on the abdomen curve 23, and the thickness reduction part 24 extends outwards from the center point along the outer surface and/or the inner surface of the valve leaflet 2 for different lengths, and the length of the thickness reduction part 24 extending along the abdomen curve 23 is 20% -40% or 60% -80% of the length of the abdomen curve 23; when the thickness-reduced portion 24 extends in a direction perpendicular to the abdomen curve 23, the side thereof parallel to the abdomen curve 23 is 50% -80% of the length of the abdomen curve 23, and the side thereof perpendicular to the abdomen curve 23 is 50% -80% of the length of the free edge 21.
In one embodiment, the surface of the reduced thickness portion 24 is curved, and the thickness of the reduced thickness portion 24 gradually increases from the center thereof to the edge thereof, and the reduced thickness portion 24 is smoothly connected to the surface of the leaflet 2.
In an embodiment, the reduced thickness portion 24 is provided on at least one of the outer surface of the leaflet 2 and the inner surface of the leaflet 2.
In particular, the reduced thickness portion 24 is provided on the outer surface of the leaflet 2, and the inner surface of the leaflet 2 is a smooth curved surface.
In another embodiment, the reduced thickness portion 24 is provided on the inner surface of the leaflet 2, and the outer surface of the leaflet 2 is a smooth curved surface.
In yet another embodiment, the thickness-reduced portion 24 may also be provided on both the inner and outer surfaces of the leaflet 2, and the variation in the thickness of the leaflet 2 is formed by the thickness-reduced portion 24 being provided on both the inner and outer surfaces of the leaflet 2. The thickness-reduced portion 24 on the outer surface of the leaflet 2 is in smooth connection with the outer surface of the leaflet 2, and the thickness-reduced portion 24 on the inner surface of the leaflet 2 is in smooth connection with the inner surface of the leaflet 2. The thickness reduction portions 24 may be 2, 4, 6, or the like.
In particular embodiments, the end of the valve frame 1 remote from the leaflet 2 is provided with a slit ring 12.
In the specific implementation, the valve leaflet 2 and the valve frame 1 are made of high polymer materials.
In summary, in the embodiment of the present invention, the radial section of the valve leaflet 2 is changed from uniform thickness to variable thickness, that is, the stress distribution is improved by increasing the thickness reduction portion 24, the fatigue resistance of the valve leaflet 2 is improved, and the service life of the valve is prolonged; compared with the valve leaflet 2 with uniform thickness, the valve leaflet 2 with the thickness reduction part 24 can be opened earlier when being pressed, so that the overall opening efficiency of the valve leaflet 2 is improved, and the hydrodynamic performance of the valve is improved.
Further, in the embodiment of the invention, the number of the thickness reduction parts 24 is two, the first thickness reduction part 241 is arranged near the free edge 21, and the second thickness reduction part 242 is arranged near the connecting edge 22, so that peak stress distribution is more uniform and dispersed, the fatigue resistance of the valve leaflet 2 is further improved, and the service life of the valve is prolonged.
Although specific embodiments have been described above, these embodiments are not intended to limit the scope of the disclosure, even where only a single embodiment is described with respect to a particular feature. The characteristic examples provided in the present disclosure are intended to be illustrative, not limiting, unless stated differently. In practice, the features of one or more of the dependent claims may be combined with the features of the independent claims where technically possible, according to the actual needs, and the features from the respective independent claims may be combined in any appropriate way, not merely by the specific combinations enumerated in the claims.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.