Foldable blood pump for right heart assistance

Abstract

The foldable blood pump for right heart assistance is small in intervention size, large in flow and small in blood damage and comprises an expandable and contractible pumping assembly, the near end of the pumping assembly is connected with an in-vitro driving unit through a flexible transmission unit, the pumping assembly comprises a foldable impeller and an expandable shell arranged on the periphery of the foldable impeller in a covering mode, and the expandable shell is connected with the foldable impeller. The thin film extends from the middle section of the expandable shell to the far side and extends to the catheter outside the expandable shell, the near section of the expandable shell forms a blood inflow port, and a blood outflow port is formed in the far end of the thin film. The impeller is of a foldable structure, large flow can be obtained at a low rotating speed, damage to cells in blood caused by too large rotating speed is reduced, the motor is externally arranged, and the temperature rise and fault risks of motor operation are effectively avoided. Meanwhile, an interventional artery passage is straight and short, abrasion and vibration of the shaft sleeve caused by bending of the flexible shaft are greatly reduced, power loss is reduced, power transmission efficiency is greatly improved, and controllability of the motor to the impeller and stability of power transmission are also improved.

Description

Technical Field

[0001] The utility model relates to the technical field of medical devices, and particularly relates to a foldable blood pump for right heart assistance. Background Art

[0002] A percutaneous implantable artificial ventricular assist device (VAD, hereinafter simply referred to as a catheter pump) is a miniaturized blood pumping device that can be introduced into the heart and can be configured to assist or replace the natural heart function by circulating pumping or continuous pumping of blood, providing hemodynamic support for cardiogenic shock and acute heart failure. When the catheter pump is deployed on the right side of the heart, the catheter pump intervenes through the external iliac vein, passes through the common iliac vein and the inferior vena cava to reach the right atrium, then passes through the tricuspid valve and the pulmonary valve. The blood inlet is located in the inferior vena cava, and the outlet is located in the pulmonary artery; or the catheter pump intervenes through the internal jugular vein, reaches the right atrium via the brachiocephalic vein and the superior vena cava, then passes through the tricuspid valve and the pulmonary valve. The blood inlet is located in the superior vena cava, and the outlet is located in the pulmonary artery. How to ensure the balance of hemodynamic performance while meeting the miniaturization of the catheter pump has always been a major problem in the industry. Summary of the Utility Model

[0003] The purpose of the utility model is to provide a foldable blood pump for right heart assistance with a small intervention size, a large flow rate and little blood damage.

[0004] To achieve the above purpose, the technical solution adopted by the utility model is: a foldable blood pump for right heart assistance, including an expandable and contractible pumping component. The proximal end of the pumping component is connected to an external driving unit through a flexible transmission unit. The pumping component includes a foldable impeller and an expandable housing covering the periphery thereof. A film extends distally from the middle section of the expandable housing and extends to a catheter outside the expandable housing. The proximal section of the expandable housing constitutes a blood inlet, and a blood outlet is opened at the distal end of the film.

[0005] Proximal bearings and distal bearings are respectively arranged at both ends of the expandable housing. The proximal bearing forms an axial limit and a circumferential rotation fit with the flexible drive shaft of the flexible transmission unit, and the distal bearing forms an axial sliding and a circumferential rotation fit with the flexible drive shaft. The foldable impeller is fixed on the flexible drive shaft between the proximal bearing and the distal bearing and rotates synchronously.

[0006] The proximal bearing includes a proximal rigid tube sleeved on the flexible drive shaft and a proximal shaft sleeve outside the proximal rigid tube. The proximal connection sleeve of the expandable housing is fixed to the proximal shaft sleeve. A limit retaining ring is further arranged at the proximal end of the proximal connection sleeve. A proximal sheath is sleeved outside the proximal connection sleeve and the limit retaining ring. The flexible sleeve of the flexible transmission unit is inserted into the proximal sheath to form a fixed connection.

[0007] The distal bearing includes a distal rigid tube sleeved on the flexible drive shaft, the distal connection sleeve of the expandable shell is sleeved on the distal rigid tube and fixed to form axial sliding and circumferential rotation cooperation, the distal connection sleeve is sleeved with a distal sheath on the outer periphery, and the catheter is inserted into the distal sheath to form a fixed connection. The flexible transmission unit includes a flexible drive shaft and a flexible sleeve arranged on the outer periphery thereof, the flexible sleeve extends from the proximal end to the distal end to the proximal sheath, and the flexible drive shaft extends from the proximal end to the distal end to the distal sheath.

[0008] The flexible drive shaft is a double-layer hollow structure formed by two coil springs coaxially wound in opposite directions. The double-layer structure extends from the proximal end to the proximal bearing position and becomes a single-layer structure. A capillary flushing tube is arranged in the hollow inner cavity, and a flushing hole is opened on the flexible drive shaft at the position corresponding to the proximal and distal bearings.

[0009] The distal end of the distal bearing is connected with a catheter, the proximal end of the catheter is connected with the distal sheath, and the distal end is connected with a pigtail tube, and a one-way valve is arranged at the distal end of the pigtail tube.

[0010] The catheter is a PEBAX hollow tube, and a nickel-titanium mesh reinforcement structure is embedded in the tube wall.

[0011] The catheter comprises a flexible outer tube and a single-layer hollow flexible shaft in its inner cavity. A gap is left between the proximal end of the single-layer hollow flexible shaft and the distal end of the single-layer section of the flexible driving shaft. The proximal end of the single-layer hollow flexible shaft and the distal end sheath form a supporting fit.

[0012] The expandable shell is a grid structure made of shape memory alloy material. The expandable shell includes a central cylindrical section and conical cylindrical sections at both ends. The cross-section of the expandable shell is circular or elliptical when it is under force or not. An inner layer coating is provided on the inner wall of the central cylindrical section of the expandable shell.

[0013] The foldable impeller comprises a rigid hub and foldable blades on its circumference. The rigid hub is in the shape of a hollow tube. The power drives the impeller to rotate and push the venous blood into the pulmonary artery.

[0014] The extracorporeal driving unit comprises a driving motor and a flushing fluid system.

[0015] The above scheme has at least the following beneficial effects:

[0016] 1. The impeller is a foldable structure. During intervention and withdrawal, the overall structure can be compressed into an external sheath with an inner diameter of 2.7 mm. When the restraining force of the sheath is removed, it can expand to its original size with an outer diameter of 7 mm. It can obtain a large flow at a lower speed and reduce the damage to blood cells caused by excessive speed.

[0017] 2. The motor is external, which effectively avoids the risk of heating and failure during motor operation.

[0018] 3. The intervened arterial access is straight. Whether it is the internal jugular vein or the external iliac vein access, compared with the arterial arch through which the left ventricle is intervened by artery, the abrasion and vibration caused by the flexible shaft bending are greatly reduced.

[0019] 4. The expandable housing and the foldable impeller only intervene outside the tricuspid valve of the right atrium and do not pass through the tricuspid valve and the pulmonary valve. Therefore, the damage to the tricuspid valve and the pulmonary valve is small.

[0020] 5. Since the expandable housing and the foldable impeller only intervene outside the tricuspid valve of the right atrium, the length of the flexible transmission structure is short, and the abrasion and vibration between the flexible shaft and the casing can be reduced.

[0021] 6. The expandable housing and the foldable impeller only intervene outside the tricuspid valve of the right atrium, the length of the flexible transmission structure is short, the power loss is reduced, the power transmission efficiency is greatly increased, and the controllability of the motor to the impeller and the stability of the power transmission are also improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the overall structure of the right heart assist system;

[0023] Figure 2 is Figure 1 a partial enlarged schematic diagram of

[0024] Figure 3 is a schematic diagram of the structure of the pumping assembly;

[0025] Figure 4 is Figure 3 an embodiment diagram of the A-A cross-section in

[0026] Figure 5 is Figure 3 another embodiment diagram of the A-A cross-section in

[0027] Figure 6 is Figure 3 a schematic diagram of the structure with the inner lining film removed in

[0028] Figure 7 is Figure 6 a B-B cross-sectional view in

[0029] Figure 8 is Figure 6 a C-C cross-sectional view in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] For the convenience of understanding, first, we define the directions involved in the following text: "proximal" and "proximal side" refer to the side close to the operator / doctor, and "distal" and "distal side" refer to the side far from the operator / doctor, that is, the side close to the heart. The following is combined with the attachedFigures 1 - 8 The utility model is further described in detail.

[0031] See also Figure 1 , Figure 2 As shown, a foldable blood pump for right heart assist includes an expandable and contractible pumping component 10, the proximal end of the pumping component 10 is connected to an extracorporeal drive unit 30 via a flexible transmission unit 20, the pumping component 10 includes a foldable impeller 11 and an expandable shell 12 covered on its periphery, a film 13 extends distally from the middle section of the expandable shell 12 and extends to a catheter 40 outside the expandable shell 12, the proximal section of the expandable shell 12 constitutes a blood inlet a, and the distal end of the film 13 is provided with a blood outlet b.

[0032] For the foldable blood pump for right heart assist, there are two types of intervention: 1. Intervention through the external iliac vein, passing through the common iliac vein and inferior vena cava to reach the right atrium, then passing through the tricuspid valve and pulmonary valve, the blood inlet is located in the inferior vena cava, and the outlet is located in the pulmonary artery; 2. Intervention through the internal jugular vein, via the brachiocephalic vein and superior vena cava to reach the right atrium, then passing through the tricuspid valve and pulmonary valve, the blood inlet is located in the superior vena cava, and the outlet is located in the pulmonary artery. The traditional foldable blood pump for right heart assist adopts the technical solution of rigid impeller + built-in motor. The amount of blood pumped is related to the speed of the motor and the size of the impeller. In order to ensure sufficient blood pumping, a high-power motor and / or a large-sized impeller are required. However, high-power motors are usually too large in diameter. Since the catheter pump is inserted into the heart through the blood vessels, it is limited by the size of the blood vessels. The diameter of the motor cannot be too large, otherwise it may cause bleeding during intervention, and the high-power motor has a high speed, which will increase the probability of hemolysis.

[0033] In order to solve the above problems, the utility model adopts the technical solution of foldable impeller + external motor. The impeller is a foldable structure. During intervention and withdrawal, the whole structure can be compressed into the outer sheath with an inner diameter of 2.7mm. When the restraining force of the sheath is removed, it can expand to the original size of the outer diameter of 7mm. It can obtain a large flow at a lower speed and reduce the damage to blood cells caused by excessive speed. At the same time, the motor is external to avoid the risk of heating and failure of the motor operation.

[0034] In addition, the utility model also has the beneficial effects unique to right heart assistance:

[0035] 1. The arterial access for intervention is straight, whether it is the internal jugular vein or the external iliac vein. Compared with the arterial arch through which the left ventricle is passed during arterial intervention, the wear and vibration of the sleeve caused by the bending of the flexible shaft is greatly reduced.

[0036] 2. The inflatable housing 12 and the foldable impeller 11 only intervene outside the tricuspid valve of the right atrium and do not pass through the tricuspid valve and the pulmonary valve, so the damage to the tricuspid valve and the pulmonary valve is small.

[0037] 3. Since the inflatable housing 12 and the foldable impeller 11 only intervene outside the tricuspid valve of the right atrium, the length of the flexible transmission structure is short, which can reduce the wear and vibration between the flexible shaft and the sleeve.

[0038] 4. The inflatable housing 12 and the foldable impeller 11 only intervene outside the tricuspid valve of the right atrium, the length of the flexible transmission structure is short, the power loss is reduced, the power transmission efficiency is greatly increased, and the controllability of the motor on the impeller and the stability of power transmission are also improved.

[0039] As a preferred solution of the present invention, proximal bearings 14 and distal bearings 15 are respectively arranged at both ends of the inflatable housing 12. The proximal bearing 14 forms an axially limited and circumferentially rotatable fit with the flexible drive shaft 21 of the flexible transmission unit 20, and the distal bearing 15 forms an axially slidable and circumferentially rotatable fit with the flexible drive shaft 21. The foldable impeller 11 is fixed on the flexible drive shaft 21 between the proximal bearing 14 and the distal bearing 15 and rotates synchronously. Since the inflatable housing 12 has a short axial length in the inflated state and a long axial length in the compressed state, at least one end of the inflatable housing 12 can axially slide with the shaft. Here, it is preferably the way of fixing the proximal end and allowing the distal end to axially slide.

[0040] The specific structure is as follows: Combining Figure 4 、 Figure 5 、 Figure 7 As shown, the proximal bearing 14 includes a proximal rigid tube 141 sleeved on the flexible drive shaft 21 and a proximal shaft sleeve 142 on the outer periphery of the proximal rigid tube 141. The function of the proximal rigid tube 141 is to improve the smooth operation of the pump body. The proximal connection sleeve 121 of the inflatable housing 12 is fixed to the proximal shaft sleeve 142. A limit retaining ring 143 is further arranged at the proximal end of the proximal connection sleeve 121. A proximal protective sleeve 144 is arranged on the outer peripheries of the proximal connection sleeve 121 and the limit retaining ring 143, which serves to fix the proximal connection sleeve 121, the limit retaining ring 143 and the sleeve 22.

[0041] Similarly, combining Figure 4 、 Figure 5 、 Figure 8As shown, the distal bearing 15 includes a distal rigid tube 151 sleeved on the flexible drive shaft 21. The distal connection sleeve 122 of the expandable housing 12 is sleeved on the distal rigid tube 151 and is fixed to form an axially sliding and circumferentially rotating fit. A distal sheath 152 is provided on the outer periphery of the distal connection sleeve 122. The catheter 40 is inserted into the distal sheath 152 to form a fixed connection. The distal sheath 152 serves to connect the distal connection sleeve 12 and the catheter 40 together. Here, the distal rigid tube 151 serves to improve the smooth operation of the pump body. At the same time, the relationship between the distal rigid tube 151 and the distal sheath 152 is equivalent to that of a plug and a socket. The distal end of the distal rigid tube 151 is inserted into the insertion hole of the distal sheath 152 and abuts against the end step surface. In the expanded state and the contracted state of the expandable housing 12, as the length of the expandable housing 12 changes, the distal connection sleeve 122 will push and pull the distal sheath 152 to axially slide relative to the distal rigid tube 151 to adapt to the state change of the expandable housing 12. At this time, the flexible drive shaft 21 will also axially slide within the distal connection sleeve 122. It should be noted that the length of the distal sheath 152 should be such that during the entire sliding process, the distal rigid tube 151 will not slip out of the distal sheath 152, ensuring effective support for the flexible drive shaft 21.

[0042] Further, the flexible transmission unit 20 includes a flexible drive shaft 21 and a flexible sleeve 22 provided on its outer periphery. The flexible sleeve extends from the proximal end to the distal end to the proximal sheath 144, and the flexible drive shaft 21 extends from the proximal end to the distal end to the distal sheath 152.

[0043] The flexible drive shaft 21 is a double-layer hollow structure formed by coaxially winding two helical springs in opposite directions. When bent, one spring is compressed and the other spring is stretched, and there is no overall deformation in the axial direction. The double-layer structure becomes a single-layer structure when extending from the proximal end to the position of the proximal bearing 14, and only the outer spring transmits torque. A capillary flushing tube is provided in the hollow inner cavity, and flushing holes are provided on the flexible drive shaft 21 at positions corresponding to the proximal and distal bearings. The flushing liquid flows out from the proximal bearing 14 and the distal bearing 15, serving to lubricate the bearings.

[0044] The distal end of the distal bearing 15 is connected to a catheter 40. The proximal end of the catheter 40 is connected to the distal sheath 152, and the distal end is connected to a pigtail tube 50. A one-way valve 51 is provided at the distal end of the pigtail tube 50. A guide wire can be inserted through the one-way valve 51, passed through the central hole of the catheter 40, and reach the end of the flexible drive shaft 21. After the pump body reaches the designated position via the guide wire, the guide wire is withdrawn, and the one-way valve 51 closes, preventing the flushing liquid from flowing out of the pigtail tube 50, ensuring the flushing pressure, and enabling the flushing liquid to flow out from the proximal bearing 14 and the distal bearing 15, serving to lubricate the bearings.

[0045] The catheter 40 can be arranged in various ways, and two implementation methods are listed below.

[0046] Embodiment 1

[0047] The catheter 40 described is a PEBAX hollow tube, and a nitinol mesh reinforcement structure is embedded in the tube wall. In this embodiment, the flexible drive shaft 21 terminates at the distal sheath 152, enabling the flexible drive shaft 21 to adapt to the expansion and contraction of the expandable housing 12. The catheter 40 distal to the distal sheath 152 has a completely different structure from the flexible transmission unit 20. There is no shaft in its inner cavity, and it is a hollow structure through which a guide wire can pass. By adding a nitinol mesh reinforcement structure, the stiffness of the catheter 40 is ensured to meet the requirements, as Figure 4 shown.

[0048] Embodiment 2

[0049] The catheter 40 includes a flexible outer tube 41 and a single-layer hollow flexible shaft 42 in its inner cavity. There is a gap between the proximal end of the single-layer hollow flexible shaft 42 and the distal end of the single-layer section of the flexible drive shaft 21. The proximal end of the single-layer hollow flexible shaft 42 and the distal sheath 152 form a supporting fit. In this embodiment, the flexible drive shaft 21 terminates at the distal sheath 152, enabling the flexible drive shaft 21 to adapt to the expansion and contraction of the expandable housing 12. The structure of the catheter 40 is similar to that of the flexible transmission unit and can provide reliable stiffness, as Figure 5 shown.

[0050] Furthermore, the expandable housing 12 is a grid-like structure made of a shape memory alloy material. The expandable housing 12 includes a middle cylindrical section and tapered cylindrical sections at both ends. In the states with and without an applied force, the cross-section of the expandable housing 12 is circular or elliptical. An inner layer film 123 is provided on the inner wall of the middle cylindrical section of the expandable housing 12 to protect the foldable impeller 11 and prevent its flexible blades from being scratched by the grid-like structure.

[0051] Furthermore, the foldable impeller 11 includes a rigid hub 111 and circumferential foldable blades 112. The rigid hub 111 is in the shape of a hollow tube. The power drives the impeller 11 to rotate to pump venous blood into the pulmonary artery. The rigid hub 111 is sleeved on the outer wall of the flexible drive shaft 21 and rotates synchronously with the flexible drive shaft 21. The foldable blades 112 are in a folded state during the intervention and withdrawal processes, wrapped around the outer periphery of the rigid hub 111, with a small overall diameter, reducing the trauma to blood vessels. After reaching the specified position, the foldable blades 112 expand and the diameter becomes larger to achieve the pumping of a large volume of blood.

[0052] Preferably, the extracorporeal drive unit 30 includes a drive motor and a flushing liquid system. The drive motor provides a torque to drive the foldable impeller 11 to rotate, and the flushing liquid system provides a cleaning liquid that flows through the inner cavity of the flexible drive shaft 21. Since the flexible drive shaft 21 is a structure formed by winding two springs, the flushing liquid can be counted into the annular cavity between the flexible drive shaft 21 and the flexible sleeve 22, which can reduce the friction between the two on the one hand, lubricate the bearing on the other hand, and take away the heat generated during the working process to ensure the reliable operation of the ventricular assist device.

[0053] The embodiments described above are only some embodiments of the present application, rather than all embodiments. The preferred embodiments of the present application are given in the accompanying drawings, but they do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive. Although the present application is described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific implementation methods, or to replace some of the technical features therein with equivalents. Any equivalent structure made using the contents of the specification and drawings of this application, directly or indirectly used in other related technical fields, is also within the scope of patent protection of this application.

Claims

1. A collapsible blood pump for right heart assistance, comprising an expandable and contractible pumping assembly (10), wherein the proximal end of the pumping assembly (10) is connected to an external driving unit (30) through a flexible transmission unit (20), and is characterized in that: The described pumping assembly (10) includes a collapsible impeller (11) and an expandable housing (12) covering its outer periphery. A membrane (13) extends distally from the middle section of the expandable housing (12) and reaches a conduit (40) outside the expandable housing (12). The proximal section of the expandable housing (12) forms a blood inlet (a), and a blood outlet (b) is provided at the distal end of the membrane (13).

2. The collapsible blood pump for right heart assistance according to claim 1, wherein: Proximal bearings (14) and distal bearings (15) are respectively provided at both ends of the expandable housing (12). The proximal bearing (14) forms an axially limited and circumferentially rotatable fit with the flexible drive shaft (21) of the flexible drive unit (20). The distal bearing (15) forms an axially slidable and circumferentially rotatable fit with the flexible drive shaft (21). The collapsible impeller (11) is fixed on the flexible drive shaft (21) between the proximal bearing (14) and the distal bearing (15) and rotates synchronously.

3. The collapsible blood pump for right heart assistance according to claim 2, characterized in that: The proximal bearing (14) includes a proximal rigid tube (141) sleeved on the flexible drive shaft (21) and a proximal bushing (142) on the outer periphery of the proximal rigid tube (141). The proximal connecting sleeve (121) of the expandable housing (12) is fixed to the proximal bushing (142). A limiting retaining ring (143) is further provided at the proximal end of the proximal connecting sleeve (121). A proximal sheath (144) is sleeved on the outer peripheries of the proximal connecting sleeve (121) and the limiting retaining ring (143). The flexible sleeve (22) of the flexible drive unit (20) is inserted into the proximal sheath (144) to form a fixed connection.

4. The collapsible blood pump for right heart assistance according to claim 2, wherein: The distal bearing (15) includes a distal rigid tube (151) sleeved on the flexible drive shaft (21). The distal connecting sleeve (122) of the expandable housing (12) is sleeved on the distal rigid tube (151) and fixed to form an axially slidable and circumferentially rotatable fit. A distal sheath (152) is sleeved on the outer periphery of the distal connecting sleeve (122). The conduit (40) is inserted into the distal sheath (152) to form a fixed connection.

5. The collapsible blood pump for right heart assistance according to claim 2, wherein: The flexible drive unit (20) includes a flexible drive shaft (21) and a flexible sleeve (22) provided on its outer periphery. The flexible sleeve extends from the proximal end to the distal end to the proximal sheath (144), and the flexible drive shaft (21) extends from the proximal end to the distal end to the distal sheath (152).

6. The collapsible blood pump for right heart assistance according to claim 5, characterized in that: The flexible drive shaft (21) is a double-layer hollow structure formed by coaxially winding two helical springs in opposite directions. The double-layer structure becomes a single-layer structure when extending from the proximal end to the position of the proximal bearing (14). A capillary flushing tube is provided in the hollow inner cavity, and flushing holes are provided on the flexible drive shaft (21) corresponding to the positions of the proximal and distal bearings.

7. The collapsible blood pump for right heart assistance according to claim 2, characterized in that: A conduit (40) is connected to the distal end of the distal bearing (15). The proximal end of the conduit (40) is connected to the distal sheath (152), and the distal end is connected to a pigtail tube (50). A one-way valve (51) is provided at the distal end of the pigtail tube (50). The conduit (40) is a PEBAX hollow tube, and a nickel-titanium mesh reinforcement structure is embedded in the tube wall.

8. The collapsible blood pump for right heart assistance according to claim 7, characterized in that: The catheter (40) described above includes a flexible outer tube (41) and a single-layer hollow flexible shaft (42) in its inner cavity. There is a gap between the proximal end of the single-layer hollow flexible shaft (42) and the distal end of the single-layer section of the flexible drive shaft (21). The proximal end of the single-layer hollow flexible shaft (42) forms a supporting fit with the distal sheath (152).

9. The collapsible blood pump for right heart assistance according to claim 1, wherein: The expandable housing (12) is a grid-like structure made of a shape memory alloy material. The expandable housing (12) includes a middle cylindrical section and tapered cylindrical sections at both ends. In the states with and without being applied force, the cross-section of the expandable housing (12) is circular or elliptical. An inner layer film (123) is provided on the inner wall of the middle cylindrical section of the expandable housing (12).

10. The collapsible blood pump for right heart assistance according to claim 1, characterized in that: The foldable impeller (11) includes a rigid hub (111) and circumferential foldable blades (112) thereof. The rigid hub (111) is in a hollow tubular shape. The power drives the impeller (11) to rotate to push venous blood into the pulmonary artery. The external drive unit (30) includes a drive motor and a flushing liquid system.

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