A hemodynamic testing system for pulsatile ventricular assist devices

Abstract

The application discloses a kind of pulsatile ventricular assist device's hemodynamic test system, and test system includes: left atrial cavity, left ventricular cavity, aortic cavity, venous cavity and pulsatile blood flow generator module.The two ends of aortic valve module are connected with left ventricular cavity and aortic cavity respectively;Ventricular assist device passes through aortic cavity, aortic valve module and left ventricular cavity in turn by the sealing tool of aortic cavity, and respectively makes blunt head be placed in left ventricular cavity and bidirectional valve be placed in aortic cavity;Pulsatile blood flow generator module is connected left ventricular cavity, and left ventricular cavity is filled with liquid, and by reciprocating movement of piston extruding left ventricular model, to simulate the flow rule of human blood.The test system of the application can be used to simulate the preload and afterload of pulsatile ventricular assist device, detect the hemodynamic performance of ventricular assist device after implanting in human body, help ventricular assist device structure optimization and controller design.

Description

Technical Field

[0001] The present invention relates to the field of performance testing of ventricular assist devices, and in particular provides a hemodynamic testing system for a pulsatile ventricular assist device. Background Art

[0002] A pulsatile ventricular assist device (VAD) is a new catheter-based pump that provides pulsatile blood flow. It is minimally invasively implanted via the femoral or axillary artery in patients with cardiogenic shock or high-risk percutaneous coronary intervention (PCI). This pulsatile blood flow improves perfusion of the patient's organs, improves microcirculation, and reduces the risk of blood damage associated with traditional rotary pumps, thereby increasing the patient's chances of postoperative recovery and reducing the risk of complications.

[0003] Compared to the principles and structure of rotary blood pumps, pulsatile VADs have unique structural characteristics. Their perfusion flow and pressure vary depending on preload (left ventricular pressure) and afterload (aortic pressure). Therefore, to evaluate whether the hemodynamic performance of pulsatile VADs meets clinical needs, a test system that can simulate a patient's actual hemodynamic state is required. By varying the pressures within the left ventricle and aorta, the sensitivity of the VAD's output flow and pressure to preload and afterload can be analyzed, which will help optimize the VAD's gas drive controller and device structure. Summary of the Invention

[0004] Therefore, an object of the present invention is to provide a hemodynamic testing system for a pulsatile ventricular assist device, which can simulate the working state of a ventricular assist device implanted in a patient.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A hemodynamic test system for a pulsatile ventricular assist device, comprising: a left atrial cavity, a left ventricular cavity, an aortic cavity, a venous cavity, and a pulsatile blood flow generator module.

[0007] The first interface of the left ventricular cavity is connected to the aortic cavity through the aortic valve module; the second interface of the left ventricular cavity is connected to the left atrial cavity, the left atrial cavity is connected to the venous cavity, and the venous cavity is connected to the aortic cavity;

[0008] The ventricular assist device consists of a catheter assembly and a membrane pump assembly. The catheter assembly includes a blunt tip and a short arterial tube, a two-way valve, and a long arterial tube connected to the blunt tip in sequence. The catheter assembly passes through the aortic cavity, the aortic valve module, and the left ventricular cavity in sequence through the sealing tool of the aortic cavity, with the blunt tip placed in the left ventricular cavity and the two-way valve placed in the aortic cavity; one end of the membrane pump assembly is connected to the long arterial tube of the catheter assembly, and the other end is connected to the gas drive controller;

[0009] The pulsatile blood flow generator module includes a piston pump and a compliance cavity, wherein the compliance cavity is connected to the power source interface at the bottom of the left ventricular cavity;

[0010] A left ventricular model is provided in the left ventricular cavity, which divides the left ventricular cavity into an inner cavity and an outer cavity, and the inner and outer cavities are not interconnected; the inner cavity is connected to the aortic cavity, the venous cavity and the left atrial cavity, and is filled with liquid; the outer cavity is connected to the piston pump and the compliance cavity, and is filled with liquid;

[0011] The reciprocating motion of the piston of the piston pump squeezes the left ventricular model in the left ventricular cavity, and the liquid is first introduced from the left ventricular cavity into the membrane pump assembly. Then, the membrane pump assembly works to infuse the liquid into the aorta cavity, thereby simulating the flow pattern of human blood.

[0012] Furthermore, the left atrial cavity, left ventricular cavity, aortic cavity and venous cavity are all equipped with pressure sensors for monitoring, and the left ventricular cavity is measured using a disposable invasive pressure sensor.

[0013] Furthermore, a first pipeline connects the aortic cavity and the venous cavity, and a throttle valve is provided on the first pipeline; a second pipeline connects the venous cavity and the left atrial cavity, and an ultrasonic flow sensor is installed on the second pipeline for measurement.

[0014] Furthermore, the left ventricle model has two interfaces, which are respectively connected to a first interface and a second interface of the left ventricle cavity.

[0015] Furthermore, the inner cavity of the left ventricular cavity is filled with liquid such as water or a glycerol-water mixture, and the outer cavity is filled with distilled water.

[0016] Furthermore, the left atrial cavity, left ventricular cavity, aortic cavity and venous cavity are all made of transparent materials, such as acrylic, polycarbonate and the like.

[0017] Further, the aortic cavity comprises a liquid storage cylinder, a piston slider, a gland plate, a lead screw, a luer tee and a sealing ring; wherein the gland plate is connected with the top end of the liquid storage cylinder by bolts, the lead screw is arranged in the gland plate and connected with the piston slider and the luer tee at both ends respectively; the lead screw and the piston slider are both provided with a through hole in the center for the function of exhausting air before the test.

[0018] Further, the height between the piston slider and the bottom of the liquid storage cylinder is changed by rotating the lead screw to drive the piston slider to move up and down, so as to realize the function of adjusting the compliance of different aortas.

[0019] Further, the top of the left atrial cavity is provided with a diaphragm and a compression ring; wherein the diaphragm is placed between the compression ring and the left atrial cavity, and the three are fixed by bolts; wherein the thickness of the diaphragm ranges from 0.2 to 0.5 mm.

[0020] Further, the aortic valve module comprises an aortic valve, a first clamp plate, a second clamp plate, a first clamping piece and a second clamping piece; wherein the aortic valve is fixed by screwing the flange surface at one end of the aortic valve between the first clamp plate and the first clamping piece, and the flange surface at the other end of the aortic valve is fixed by screwing the second clamp plate and the second clamping piece.

[0021] Further, the left ventricular model and the aortic valve are made of elastic body materials such as transparent silicone or polyurethane, and are processed by 3D printing or mold forming.

[0022] Further, the sealing tool is installed at the bottom of the aortic cavity, mainly comprising a sealing body, a conical silicone pad and a locking cap; wherein the conical silicone pad is placed in the conical groove of the sealing body, and the sealing body, the conical silicone pad and the locking cap are all provided with a central through hole; the inner annular surface of the locking cap is pressed against the end surface of the conical silicone pad, and the outer annular surface of the locking cap is connected with the sealing body by threads; rotating the locking cap extrudes the conical silicone pad downward through the inner annular surface, forcing the conical silicone pad to deform under stress, resulting in a decrease in the diameter of the central hole, so that the contact with the ventricular assist device and the extrusion sealing are formed.

[0023] The beneficial effects of the present application are:

[0024] The blood flow hemodynamic test system of the pulsatile ventricular assist device comprises a main part of the body circulation from the left atrium to the vein, and can generate a pulsatile blood flow environment, and can more truly reproduce the blood flow hemodynamic characteristics of the patient and the front and rear loads of the ventricular assist device. This test system can help the in-vitro performance detection of the pulsatile ventricular assist device, and provide guidance for optimizing the device structure and the controller performance. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to make the technical solutions in the embodiments of the present application clearer, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows.

[0026] Figure 1 is a general diagram of the ventricular assist device testing system provided by the present application.

[0027] Figure 2 is a structural diagram of the pulsatile ventricular assist device.

[0028] Figure 3 is Figure 1 is a top view of the testing system.

[0029] Figure 4 is Figure 3 is a sectional view along the direction of A-A.

[0030] Figure 5 is a schematic diagram of the connection between the left ventricular cavity and the aortic cavity.

[0031] Figure 6 is a structural diagram of the left ventricular cavity.

[0032] Figure 7 is an exploded view of the aortic cavity.

[0033] Figure 8 is a structural diagram of the left atrial cavity.

[0034] Figure 9 is an exploded view of the aortic valve module.

[0035] Figure 10 is a sectional view of the sealing tool.

[0036] Figure 11 is a schematic diagram of the sealing tool in perspective view. DETAILED DESCRIPTION

[0037] In order to make the technical solutions in the embodiments of the present application clearer, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows.

[0038] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application, and therefore cannot be understood as indicating that the device or structure must have a specific position, and therefore cannot be understood as limiting the present application.

[0039] In addition, the terms "first", "second", etc. are used only for descriptive purposes and should not be construed as implying or suggesting relative importance or an indicated number of technical features. Therefore, the features defined as "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality" is two or more, unless otherwise specifically limited.

[0040] The blood flow performance test system of the pulsatile ventricular assist device provided by the embodiments of the present application can simulate the blood flow performance characteristics in the cardiovascular system of a patient and can evaluate the output flow, pressure and other performances of the pulsatile ventricular assist device under a real condition.

[0041] Referring to Figure 1 As shown in the figure, the present application provides a test system 1 of a pulsatile ventricular assist device for testing the blood flow performance of the pulsatile ventricular assist device 2 in vitro. The test system 1 comprises a left atrium cavity 11, a left ventricle cavity 12, an aorta cavity 13, a vein cavity 14 and a pulsatile blood flow generator module 15. The left ventricle cavity 12 is connected with the aorta cavity 13 through an aortic valve module 16, a first pipeline 17 connects the aorta cavity 13 and the vein cavity 14, the left ventricle cavity 12 is connected with the vein cavity 14 through the left atrium cavity 11, and a second pipeline 18 connects the vein cavity 14 and the left atrium cavity 11.

[0042] Referring to Figure 2 As shown in the figure, the pulsatile ventricular assist device 2 is composed of a catheter assembly 21 and a membrane pump assembly 22. The catheter assembly 21 comprises a blunt head 211, an arterial short tube 213, a bidirectional valve 212 and an arterial long tube 214, and the blunt head 211 is connected with the arterial short tube 213, the bidirectional valve 212 and the arterial long tube 214 in sequence. The catheter assembly 21 is implanted into the patient's body through the femoral artery or the axillary artery, so that the blunt head 211 is placed in the left ventricle and the bidirectional valve 212 is placed in the aortic arch. Figure 1 and Figure 2 As shown in the figure, one end of the membrane pump assembly 22 is connected with the arterial long tube 214 of the catheter assembly 21, and the other end is connected with a gas driving controller. The gas driving controller applies cyclic positive pressure and negative pressure to the membrane pump assembly 22, so that the blood is periodically introduced from the left ventricle through the blunt head 211 into the membrane pump assembly 22, and then driven by the positive pressure of the membrane pump assembly 22 to flow through the bidirectional valve 212 and perfuse into the aorta. This principle can reduce the load on the left ventricle and provide pulsatile blood flow perfusion for the patient, thereby reducing the probability of complications caused by continuous flow ventricular assist devices. The test system 1 can evaluate the working state of the pulsatile ventricular assist device 2 in a real blood flow environment, which is helpful to judge the rationality of the structure of the bidirectional valve 212 or the membrane pump assembly 22, and also provides a reference for the pressure regulation of the gas driving controller.

[0043] Referring to Figure 3 As shown, the test system 1 is provided with a plurality of pressure sensors, including a first pressure sensor 1111, a second pressure sensor 1211, a third pressure sensor 1311 and a fourth pressure sensor 1411, which are used to monitor the pressures in the left atrial cavity 11, the left ventricular cavity 12, the aortic cavity 13 and the venous cavity 14, respectively. Among them, the second sensor 1211 adopts a disposable invasive pressure sensor connected to the Luer connector, and the disposable invasive pressure sensor and the Luer connector are both standard purchased parts. A flow sensor 1511 is installed on the second pipeline 18 to monitor the flow changes in the test system. The flow sensor 1511 is an ultrasonic flow sensor. In addition, the flow sensor 1511 can also be installed on the first pipeline 17. In order to adjust the peripheral resistance of the test system, a throttle valve 1611 is installed on the first pipeline 17. Combined with Figure 1 and Figure 3 As shown, the left atrial cavity 11, the left ventricular cavity 12, the aortic cavity 13 and the venous cavity 14 are interconnected, and liquid is perfused in the cavities to simulate blood flow. The liquid can be water, glycerol-water mixture, etc.

[0044] See Figure 4 As shown, the pulsatile ventricular assist device 2 is installed in the left ventricular cavity 12 and the aortic cavity 13. Through the action of the membrane pump assembly 22, blood is first introduced from the left ventricular cavity 12 into the membrane pump assembly 22, and then the blood is perfused into the aortic cavity 13 through the work of the membrane pump assembly 22. The pulsatile blood flow generator module 15 includes a piston pump 151 and a compliance cavity 152, which are sequentially connected to the bottom of the left ventricular cavity 12 through pipelines. Figure 5 As shown, a left ventricular model 121 is positioned within the left ventricular cavity 12. The left ventricular model 121 is made of an elastomeric material such as silicone or polyurethane and can be manufactured through 3D printing or compression molding. Its volume ranges from 150 to 300 mL. A power source interface 125 is provided at the bottom of the left ventricular cavity 12 for connecting to the pulsatile blood flow generator module 15. Furthermore, a sealing fixture 19 is provided on the bottom side of the aortic cavity 13.

[0045] Combine Figure 5 and Figure 6As shown, the left ventricle model 121 is fixed within the left ventricle cavity 12 and connected to a first port 123 and a second port 124, respectively. The first port 123 communicates with the aortic cavity 13, and the second port 124 communicates with the left atrial cavity 11. A square cover plate 122 is installed on the top of the left ventricle cavity 12 and is sealed to the gasket and the left ventricle cavity 12 by bolts. The left ventricle model 121 divides the left ventricle cavity 12 into an inner chamber a and an outer chamber b. The outer chamber b is connected to the piston pump 151 and the compliance chamber 152 and is filled with distilled water. The inner chamber a communicates with the left atrial cavity 11 and the aortic cavity 13, respectively. Therefore, the left ventricle model 121 separates the inner chamber a and the outer chamber b, which are not interconnected. A pressure measuring tube 125 is provided on the side of the left ventricle model 121, extending through the side panel of the left ventricle cavity 12 and used to connect to a Luer connector and a disposable invasive pressure sensor.

[0046] See Figure 7 As shown, the aorta cavity 13 includes a liquid storage cylinder 131, a piston slider 132, a gland plate 133, a screw rod 134, a Luer tee 135 and a sealing ring 136. Figure 5 and Figure 7 As shown, the piston slider 132 is tightly fitted with the inner wall of the liquid storage cylinder 131 via a sealing ring 136, and the pressure cover plate 133 is installed on the top of the liquid storage cylinder 131 and fixed by bolts. The screw rod 134 is passed through the center of the pressure cover plate 133 and is fixed to the piston block 132; wherein, the screw rod 134 and the pressure cover plate 133 are threadedly transmitted. Through holes are provided in the center of the piston slider 132 and the screw rod 134, and the two are interconnected. The Luer tee 135 is connected to the top of the screw rod 134. The function of adjusting the aortic compliance is achieved by changing the height H between the piston slider 132 and the bottom of the liquid storage cylinder. Increasing the height H can improve the aortic compliance, and vice versa, it can weaken the aortic compliance. In order to improve the airtightness between the piston slider 132 and the liquid storage cylinder 132, at least two sealing rings 136 are selected and used in a superimposed manner.

[0047] Before the test system is used, the Luer tee 135 needs to be opened to allow the aortic cavity 13 to communicate with the atmosphere. After the test system is injected with liquid, the Luer tee 135 is closed.

[0048] See Figure 8As shown, the left atrial cavity 11 includes a cavity body 111, a pressure ring 112 and a film 113. The film 113 can be made of a polymer elastomer such as silicone or polyurethane, with a thickness between 0.2-0.5 mm. The pressure ring 112 fixes the film 113 to the top of the cavity body 111 by bolts, sealing the top of the left atrial cavity 11. This method can simulate the weak pulsation effect of the left atrium, thus approaching the actual situation of the patient. An interface 1112 and a protrusion 1114 are provided on the side of the bottom of the left atrial cavity 11 for connecting to the second interface 124 of the left ventricular cavity 12, and a sealing gasket is used between the two to prevent liquid leakage. In addition, an interface 1113 is provided at the bottom of the left atrial cavity 11 for installing a first pressure sensor 1111.

[0049] See Figure 9 As shown, the aortic valve module includes an aortic valve 161, a first splint 162, a second splint 163, a first clip 164 and a second clip 165. The aortic valve 161 is made of the same material and processing method as the left ventricle model 121, and is made of elastomeric materials such as silicone or polyurethane, and is made by 3D printing or molding. A first flange surface 1611 and a first flange surface 1612 are provided at both ends of the aortic valve 161, and a plurality of through holes are provided on the flange surface. The first clip 164 presses the first flange surface 1611 into the groove of the first splint 162 and is connected by screws; and the second flange surface 1612 is fixed between the second splint 163 and the second clip 165 in the same way.

[0050] The left atrial cavity 11, left ventricular cavity 12, aortic cavity 13, and venous cavity 14 are all made of transparent materials such as acrylic or polycarbonate. This allows for easy observation of the fluid flow within the test system and monitoring of the circulation loop for air bubbles. Both the first and second conduits 17, 18, connect to the respective cavities using pagoda connectors.

[0051] See Figure 5 、 Figure 10 and Figure 11As shown, the sealing tool 19 is installed at the bottom of the aortic cavity 13 to facilitate the implantation of the ventricular assist device 2 and prevent liquid from leaking from the implantation site. The sealing tool 19 includes a sealing body 191, a conical silicone pad 192 and a locking cap 193, and through holes are provided at the centers of these three parts. The conical silicone pad 192 is placed in the conical groove of the sealing body 191, and the inner annular surface 1931 of the locking cap 193 abuts the upper end surface of the conical silicone pad 192. At the same time, the outer annular surface 1932 is connected to the outer surface of the sealing body 191 by a thread. By rotating the locking cap handle 1933, the locking cap 193 moves downward along the axial direction of the sealing tool 19, thereby continuously squeezing the conical silicone pad 192, forcing the center hole of the conical silicone pad 192 to be continuously compressed and reduced, and finally forming an extrusion seal with the catheter assembly of the ventricular assist device 2.

[0052] The above are preferred embodiments of the present invention and the technical principles used therein. For those skilled in the art, any obvious changes such as equivalent transformations, simple replacements, etc. based on the technical solution of the present invention, without departing from the spirit and scope of the present invention, are within the scope of protection of the present invention.

Claims

1. A hemodynamic testing system for a pulsatile ventricular assist device, the testing system comprising: Left atrial cavity, left ventricular cavity, aortic cavity, venous cavity and pulsatile blood flow generator module, The first interface of the left ventricular cavity is connected to the aortic cavity through the aortic valve module; the second interface of the left ventricular cavity is connected to the left atrial cavity, the left atrial cavity is connected to the venous cavity, and the venous cavity is connected to the aortic cavity; The ventricular assist device consists of a catheter assembly and a membrane pump assembly. The catheter assembly includes a blunt tip and a short arterial tube, a two-way valve, and a long arterial tube connected to the blunt tip in sequence. The catheter assembly passes through the aortic cavity, the aortic valve module, and the left ventricular cavity in sequence through the sealing tool of the aortic cavity, with the blunt tip placed in the left ventricular cavity and the two-way valve placed in the aortic cavity; one end of the membrane pump assembly is connected to the long arterial tube of the catheter assembly, and the other end is connected to the gas drive controller; The pulsatile blood flow generator module includes a piston pump and a compliance cavity, wherein the compliance cavity is connected to the power source interface at the bottom of the left ventricular cavity; A left ventricular model is provided in the left ventricular cavity, which divides the left ventricular cavity into an inner cavity and an outer cavity, and the inner and outer cavities are not interconnected; the inner cavity is connected to the aortic cavity, the venous cavity and the left atrial cavity, and is filled with liquid; the outer cavity is connected to the piston pump and the compliance cavity, and is filled with liquid; The reciprocating motion of the piston of the piston pump squeezes the left ventricular model in the left ventricular cavity, and the liquid is first introduced from the left ventricular cavity into the membrane pump assembly. Then, the membrane pump assembly works to infuse the liquid into the aorta cavity, thereby simulating the flow pattern of human blood.

2. The test system according to claim 1, wherein: The left atrial cavity, left ventricular cavity, aortic cavity and venous cavity are all equipped with pressure sensors for monitoring, and the left ventricular cavity is measured using a disposable invasive pressure sensor.

3. The test system according to claim 1, wherein: The first pipeline connects the aorta cavity and the venous cavity, and a throttle valve is provided on the first pipeline; the second pipeline connects the venous cavity and the left atrial cavity, and an ultrasonic flow sensor is provided on the second pipeline for measurement.

4. The left ventricular cavity according to claim 1, wherein: The left ventricle model has two interfaces, which are respectively connected to a first interface and a second interface of the left ventricle cavity.

5. The left ventricular cavity according to claim 1, characterized in that: The inner cavity of the left ventricular cavity is filled with water or a glycerol-water mixture; and the outer cavity of the left ventricular cavity is filled with distilled water.

6. The test system according to claim 1, wherein: The left atrial cavity, left ventricular cavity, aortic cavity and venous cavity are all made of transparent acrylic or polycarbonate.

7. The test system according to claim 1, wherein: The aortic cavity includes a liquid storage cylinder, a piston slider, a pressure cover plate, a screw, a Luer tee and a sealing ring; wherein, the pressure cover plate is connected to the top of the liquid storage cylinder by bolts, the screw is passed through the pressure cover plate and its two ends are respectively connected to the piston slider and the Luer tee; through holes are provided in the center of the screw and the piston slider for exhaust function before the test.

8. The aortic cavity according to claim 7, characterized in that: The piston slider is driven up and down by rotating the screw rod, thereby changing the height between the piston slider and the bottom of the liquid storage cylinder, thereby achieving the function of adjusting different aortic compliances.

9. The test system according to claim 1, wherein: A film and a pressure ring are installed on the top of the left atrial cavity; wherein, a film is placed between the pressure ring and the left atrial cavity, and the three are fixed by bolts; wherein, the thickness of the film ranges from 0.2 to 0.5 mm.

10. The test system according to claim 1, wherein: The aortic valve module includes an aortic valve, a first splint, a second splint, a first clip and a second clip; wherein, the first splint and the first clip are connected by screws to fix the flange surface at one end of the aortic valve, and the second splint and the second clip are connected by screws to fix the flange surface at the other end of the aortic valve.

11. The left ventricle model and aortic valve according to claim 1 or 10, characterized in that: The left ventricle model and the aortic valve are both made of transparent silicone or polyurethane elastomeric materials and are processed by 3D printing or compression molding.

12. The test system according to claim 1, wherein: The sealing tool is installed at the bottom of the aortic cavity, and mainly includes a sealing body, a conical silicone pad and a locking cap; wherein, the conical silicone pad is placed in the conical groove of the sealing body, and the sealing body, the conical silicone pad and the locking cap are all provided with a central through hole; the inner annular surface of the locking cap is pressed against the end face of the conical silicone pad, and the outer annular side surface of the locking cap is connected to the sealing body through a thread; the locking cap is rotated to squeeze the conical silicone pad downward through the inner annular surface, forcing the conical silicone pad to deform under force, resulting in a reduction in the diameter of the central through hole, so that it contacts the ventricular assist device and forms an extrusion seal.

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