Balloon type left ventricle auxiliary device for preventing thrombus generation

Abstract

The balloon type left ventricle auxiliary device comprises an outer cup-shaped element, an inner balloon, a catheter assembly, a baffle valve, a far-end connecting piece, a connector, a Y-shaped connector and a traction wire, and the outer cup-shaped element is provided with a plurality of inflow holes and an outflow opening; the inner balloon is arranged on the inner side of the outer cup-shaped element and is communicated with the catheter assembly; the baffle valve is arranged between the outer cup-shaped element and the inner balloon and serves as a one-way valve to control blood to flow into the inner cavity in a one-way mode. The far-end connecting piece is provided with a backflow hole, and thrombus generation can be prevented; the Y-shaped connector is connected with the joint; the far end of the traction wire is connected with the elastic support of the external cup-shaped element, extends out of the body through the catheter inner cavity, the connector and the Y-shaped connector and is used for assisting the device in being recycled to the sheathing canal. According to the device, blood is pumped into the ascending aorta from the left ventricle through periodic contraction and expansion of the internal balloon and periodic change of the internal volume in combination with the inflow hole, the outflow hole and the baffle valve, and the cardiac output is increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical device ventricular assist devices, and in particular relates to a balloon-type left ventricular assist device to prevent thrombus formation. Background Art

[0002] Percutaneous mechanical circulatory support (PMCS) is widely used in the interventional treatment of complex, high-risk coronary artery disease and cardiogenic shock. Currently, common PMCS products include intra-aortic balloon pump (IABP) and Impella.

[0003] IABP places the balloon in the descending aorta, inflates it during the heart's diastole and deflates it during its systole, increasing cardiac output and improving coronary artery perfusion with minimal damage to the blood and blood vessels. However, the increase in cardiac output is only 0.5-1L / min, and the effect on ventricular assist pumping is limited.

[0004] Impella works on the blood through high-speed rotation of the rotor, and the blood is pumped from the left ventricle into the ascending aorta through the inlet tube. It can provide active forward blood flow, directly reduce the left ventricular preload, reduce myocardial oxygen consumption, and increase cardiac output by 2.5-5.0L / min. However, the high shear stress generated by the high-speed rotation of the blood pump rotor has a high risk of blood damage, especially in the case of long-term use.

[0005] Chinese patent application CN116472086A discloses a cardiac assist device, which includes a cup-shaped element with an externally defined volume, an internal balloon and a pipe. The cup wall of the cup-shaped element is provided with an inflow hole and an outflow element. The internal balloon is inflated and deflated through the pipe to directionally pump the left ventricular blood to the ascending aorta. The device has a small intervention size and provides a large flow rate, and causes less damage to the blood. However, the distal end of the device is prone to form a stagnation zone, thrombus formation, and thrombus formation at the inlet valve restraint position. Once it falls off, it will have an adverse effect on the patient. Summary of the invention

[0006] The purpose of the present invention is to solve the above-mentioned problem and provide a balloon-type left ventricular assist device that can prevent thrombus formation, avoid the formation of stagnation zones, and prevent thrombus formation.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] The present invention provides a balloon-type left ventricular assist device for preventing thrombosis, which includes an external cup-shaped element, an internal balloon, a catheter assembly, a baffle valve, a distal connector, a joint, a Y-type connector and a traction wire, wherein the external cup-shaped element is made of an elastic support and a membrane material, and has two states: folded and expanded, and includes an olive-shaped pumping part and an equal-diameter outflow channel, the free end of the outflow channel is an outflow port, and a plurality of inflow holes are arranged on the side wall of the pumping part; the internal balloon is arranged on the inner side of the external cup-shaped element, installed on the distal end of the catheter assembly, and can be inflated and deflated; the baffle valve is arranged between the external cup-shaped element and the internal balloon, and is used to intermittently block the inflow hole to control blood mononuclear cells. The distal connector is tubular and used for connecting the baffle valve with the external cup-shaped element and the catheter assembly. A reflux hole is provided on the tube wall of the distal connector for flushing and liquid renewal of the connection position to avoid the formation of a stagnation zone and reduce thrombus formation. The catheter assembly includes a guide wire tube, a balloon filling tube and a traction wire tube. The connector is connected to the proximal end of the catheter assembly, including a guide wire cavity interface, a filling cavity interface and a traction wire cavity interface, which are correspondingly connected to multiple cavities of the catheter assembly. The Y-type connector includes a Luer interface, a hemostatic locking valve and a side tube, which are connected to the traction wire cavity interface of the connector. The traction wire is connected to the elastic support of the external cup-shaped element, and extends to the outside of the body through the catheter, the inner cavity of the connector and the Y-type connector.

[0009] The device is folded and delivered to the left ventricle through the delivery sheath via femoral artery puncture. After reaching the designated position, the external cup-shaped element is placed in an expanded state, and the volume of the inner cavity changes periodically by periodically filling the internal balloon with gas. Combined with the inflow hole, outflow port and baffle valve, blood is pumped from the left ventricle into the ascending aorta to increase cardiac output, providing blood circulation assistance for high-risk PCI patients and patients with cardiogenic shock. After the operation, the device is gradually folded and recovered into the delivery sheath by pulling the traction wire and withdrawn from the body.

[0010] Furthermore, in the expanded state, the distal curvature of the pumping portion of the external cup-shaped element is greater than the proximal curvature, the maximum outer diameter of the pumping portion is greater than the outflow channel, and the overall outer diameter of the external cup-shaped element is less than 25 mm.

[0011] Further, the total area of ​​the inflow holes of the external cup-shaped element satisfies the following equation,

[0012]

[0013] Where A1 is the total area of ​​multiple inflow holes, ρ is the blood density, which is 1055 kg / m 3 , Q is the maximum flow rate of pumped blood, which is 5L / min, and ΔP is the pressure difference on both sides of the wall of the external cup-shaped element when the device inhales blood, which is preferably 50mmHg.

[0014] Furthermore, the inner diameter cross-sectional area of ​​the outflow channel of the external cup-shaped element in the expanded state satisfies the following equation:

[0015]

[0016] Wherein, A2 is the cross-sectional area of ​​the outflow channel, and ΔP2 is the pressure difference between the inner cavity of the device and the aorta when discharging blood, preferably 100 mmHg.

[0017] Furthermore, the proximal region of the elastic support of the external cup-shaped element is conical, and a traction wire mounting hole is also provided at the proximal end of the elastic support. The distal end of the traction wire is connected to the mounting hole, and the proximal end extends to the body through the traction wire cavity and the connector of the catheter. The traction wire is a wire with high yield strength and good biocompatibility, and can be a nickel-titanium alloy wire. The traction wire is sealed by bundling with a heat shrink tube to prevent thrombus formation. The elastic support material is a nickel-titanium alloy with shape memory properties and biocompatibility.

[0018] Furthermore, the membrane material of the external cup-shaped element is attached to the inner and outer surfaces of the elastic support, and the membrane material at the conical structure of the support can be partially collapsed and closed to prevent blood backflow. The membrane material is required to have a large elastic modulus, good flexibility and high hardness, and is preferably a polyurethane material with a Shore hardness of 72D.

[0019] Furthermore, the internal balloon is a non-compliant balloon, which is olive-shaped, the same shape as the external cup-shaped element, and the distal curvature is greater than the proximal curvature; when the internal balloon is inflated, the distal outer surface fits tightly with the baffle valve, and a certain gap is retained between the proximal end and the external cup-shaped element to ensure the directionality of the blood pumping process; the inner cavity volume of the external cup-shaped element and the internal balloon is about 10ml, the pumping frequency is 300-600 times / min, and the intervention size is 18F.

[0020] Furthermore, the catheter assembly includes a guide wire tube, a balloon filling tube and a traction wire tube, the distal end of the catheter assembly is bonded and fixed to the baffle valve, and the proximal end is connected to the joint. The interior of the guide wire tube is a guide wire cavity; the balloon filling tube is coaxially sleeved on the outside of the guide wire tube, and the gap between the two is the balloon filling cavity, the balloon filling tube is bonded or welded to the internal balloon, and a plurality of holes are provided on the wall of the balloon filling tube to communicate with the internal balloon for inflating and deflating the internal balloon; the traction wire tube itself is a double-lumen tube, the large cavity is bonded and fixed to the balloon filling tube, and the small cavity is used as the traction wire cavity, the distal end of the traction wire tube ends at the ascending aorta, and the traction wire cavity can also be used to measure the ascending aorta pressure.

[0021] Furthermore, the baffle valve includes a plurality of baffle plates and a tubular body, and the baffle plates are fixed on the body; the baffle valve body is coaxially bonded or welded with the external cup-shaped element and the conduit, and the surface contour curvature of the baffle plate is the same as the surface curvature of the corresponding position of the external cup-shaped element, thereby ensuring the blocking effect of the baffle on the inflow hole; the thickness of the baffle valve gradually increases from the baffle plate to the body, and the baffle valve is provided with a structural reinforcement as a whole, and the material of the baffle valve is nickel-titanium alloy.

[0022] Furthermore, the distal connector includes a first connector and a second connector, and the thin walls of the first connector and the second connector are axially provided with reflow holes, which are equidistantly distributed and have a cross-sectional area of ​​less than 5% of the total area of ​​the inflow holes.

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

[0024] (1) The device of the present invention has a small intervention size, can generate a large forward, pulsatile blood flow, has a small non-physiological shear force, and causes less damage to blood vessels and blood.

[0025] (2) During the blood pumping process of the device of the present invention, a stagnation zone can be avoided from forming in the distal region of the device, thereby reducing the risk of thrombus formation and facilitating the safe and long-term use of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention.

[0027] Figure 2A It is a cross-sectional view of the pump body part of an embodiment of the present invention.

[0028] Figure 2B for Figure 2A A local enlarged view of the distal I region.

[0029] Figure 2C , Figure 2D yes Figure 2A Cross-sectional views of the mid-tube assembly at two positions AA and BB.

[0030] Figure 3A Schematic diagram of an external cup-shaped element according to an embodiment of the present invention.

[0031] Figure 3B This is a schematic diagram of another viewing angle of the external cup-shaped element of an embodiment of the present invention.

[0032] Figure 4A Schematic diagram of a baffle valve according to an embodiment of the present invention.

[0033] Figure 4B Schematic diagram of a baffle valve according to another embodiment of the present invention.

[0034] Figure 5Schematic diagram of a distal connector according to an embodiment of the present invention.

[0035] Figure 6 It is a schematic diagram of the assembly of the connector and the catheter assembly according to an embodiment of the present invention.

[0036] Figure 7 Schematic diagram of a Y-type connecting valve according to an embodiment of the present invention.

[0037] Figure 8 It is a schematic diagram of the assembly of the traction wire and the elastic bracket mounting hole according to an embodiment of the present invention.

[0038] Fig.9A This is a schematic diagram of the device according to an embodiment of the present invention being recovered into the delivery sheath.

[0039] Fig. 9B It is a schematic diagram of another state of the device according to an embodiment of the present invention being recovered to the delivery sheath.

[0040] Fig. 10A Schematic diagram of the flow of blood sucked into the inner cavity according to an embodiment of the present invention.

[0041] Fig. 10B for Fig. 10A Schematic diagram of blood flow in the mid-distal J region.

[0042] Fig. 10C for Fig. 10A Cross-sectional view at the CC position.

[0043] Fig.11A This is a schematic diagram of blood discharge flow according to an embodiment of the present invention.

[0044] Fig. 11B for Fig.11A Schematic diagram of blood flow in the mid-distal K area.

[0045] Fig. 11C for Fig.11A Cross-section view at the middle DD position.

[0046] Fig.12 Schematic diagram of the transdermal delivery process of an embodiment of the present invention.

[0047] Fig.13 It is a schematic diagram of an embodiment of the present invention when the left ventricle is working.

[0048] 1 external cup-shaped element; 2 internal balloon; 3 catheter assembly; 4 flapper valve; 6 connector; 7 Y-type connector; 8 traction wire; 9 delivery sheath; 10 aortic blood vessel;

[0049] 11 elastic bracket; 12 membrane material; 111 mounting hole; 121 inflow hole; 122 outflow port;

[0050] 30: guide wire, 31 guide wire tube; 32 balloon filling tube; 33 traction wire tube; 321 balloon filling connecting hole; 322 first developing ring; 323 second developing ring;

[0051] 41 baffle plate; 42 main body; 43 structural reinforcement member;

[0052] 51 distal first connecting piece; 52 distal second connecting piece; 511 reflux hole;

[0053] 61 guide wire cavity interface; 62 filling cavity interface; 63 traction wire cavity interface;

[0054] 71 Luer connector end; 72 hemostatic locking valve; 73 side tube;

[0055] 81 heat shrink tubing. DETAILED DESCRIPTION

[0056] In order to make the above-mentioned objects and features of the present invention more obvious and understandable, the specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings, but the present invention is not limited to the following contents.

[0057] In the description of the present application, it should be understood that descriptions of positions, such as distal end, proximal end, etc., are based on the surgeon, with the position close to the surgeon being the proximal end and the position far from the surgeon being the distal end. This is for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0058] like Figures 1 to 13 As shown, an embodiment of the balloon-type left ventricular assist device for preventing thrombosis of the present invention includes an external cup-shaped element 1, an internal balloon 2, a catheter assembly 3, a baffle valve 4, a distal first and second connecting parts 51 and 52, a connector 6, a Y-type connector 7 and a traction wire 8.

[0059] The external cup-shaped element 1 of the embodiment of the present invention is composed of an elastic support 11 and a membrane material 12, see Figure 3A-B Structural diagram of the external cup-shaped element, including an olive-shaped pumping part and an outflow channel of equal diameter, the free end of the outflow channel is an outflow port 122, the distal curvature of the pumping part is greater than the proximal curvature, and a plurality of inflow holes 121 are arranged on the side wall of the pumping part. The elastic bracket 11 runs through the entire external cup-shaped element, and the axial length is slightly greater than the membrane material. The proximal end of the outflow channel is close to the outflow port 122 area. The elastic bracket is conical, and two traction wire mounting holes 111 are arranged at the proximal end of the elastic bracket. The design of the elastic bracket combined with the membrane material increases the radial stiffness of the external cup-shaped element in the expanded state and limits its volume on the one hand; on the other hand, the switching between the folded and expanded states can realize the transportation and recovery through the sheath. In addition, in the conical structure area, the membrane material can be partially concave under the action of the blood filling pressure of the ascending aorta, acting as a one-way valve to prevent the backflow of blood.

[0060] The inner and outer surfaces of the elastic bracket 11 of the embodiment of the present invention are both covered with a membrane material 12, and the membrane material 12 has a high elastic modulus and hardness, and the material is preferably polyurethane with a Shore hardness of 72. The inner and outer surfaces of the bracket are covered with a polyurethane layer through a coating process, and four groups of inflow holes 121 are laser cut on the distal side wall of the external cup-shaped element 1, each group has two rows, and the inflow holes are staggered. Finally, a layer of anti-coagulation coating is sprayed on the outer surface. The total area A1 of the inflow holes in the embodiment of the present invention is 136mm 2 , satisfying the following equation,

[0061]

[0062] Where A1 is the total area of ​​multiple inflow holes, ρ is the blood density, which is 1055 kg / m 3 , Q is the maximum flow rate of pumped blood, which is 5L / min, and ΔP1 is the pressure difference on both sides of the external cup-shaped element wall when the device absorbs blood, which is preferably 50mmHg. It shows that when the total area of ​​the inflow hole reaches 136mm 2 , and when the pumping flow rate is 5L / min, the pressure difference on both sides of the external cup-shaped element wall does not exceed 50mmHg, which can reduce the elastic deformation of the external cup-shaped element during pumping.

[0063] The inner diameter of the outflow channel of the external cup-shaped element of the embodiment of the present invention is 10 mm, and the area A2 is 78.5 mm 2 , satisfying the following equation,

[0064]

[0065] Wherein, A2 is the cross-sectional area of ​​the outflow channel, and ΔP2 is the pressure difference between the inner cavity of the device and the aorta when discharging blood, preferably 100 mmHg.

[0066] It shows that when the inner diameter of the outflow channel is 10mm and the pumping flow rate is 5L / min, the pressure difference between the inner cavity of the device and the ascending aorta does not exceed 100mmHg. According to the existing balloon materials and manufacturing technology, this pressure level belongs to a low-pressure balloon, the risk of fatigue damage of the internal balloon is small, and the safety is relatively high.

[0067] The inner balloon 2 of the embodiment of the present invention is a non-compliant balloon made of nylon and is arranged on the inner side of the pumping part of the outer cup-shaped element 1. The inner balloon 2 is bonded or welded to the catheter assembly 3. Figure 2A When inflated, the internal balloon has the same olive-shaped shape as the pumping part of the external cup-shaped element 1, with a distal curvature greater than a proximal curvature. The distal end of the internal balloon 2 fits tightly against the baffle valve 4, and there is a certain gap between the proximal end and the external cup-shaped element 1. This design ensures the directionality of blood during the pumping process of the device and improves the pumping efficiency.

[0068] The catheter assembly 3 of the embodiment of the present invention includes a guide wire tube 31, a balloon filling tube 32 and a traction wire lumen tube 33. The catheter assembly has strong axial rigidity and torsional rigidity, which can meet the rigidity requirements of the device pushed through the sheath tube, and is preferably made of nylon. Figure 2A-2D The interior of the guide wire tube 31 is a guide wire cavity, and the balloon filling tube 32 is coaxially sleeved on the outside of the guide wire tube. The two are welded at the distal ends, and the gap is the balloon filling cavity. The balloon filling tube 32 is connected to the internal balloon 2 by a thermal bonding process or a welding process. At the area corresponding to the largest diameter of the internal balloon, three connecting holes 321 are opened to communicate with the internal balloon for filling and decompression of helium, so that the internal balloon can be inflated and deflated. A first developing ring 322 and a second developing ring 323 are also provided on the balloon filling tube for determining the position of the device during surgery; the traction wire tube 33 itself is a double-lumen catheter, and the distal end ends at the position of the ascending aorta, with a large cavity and a small cavity. The large cavity is bonded and fixed to the balloon filling tube 32, and the small cavity serves as a channel for accommodating the traction wire 8. The proximal ends of the three tubes are connected to the joint.

[0069] The baffle valve 4 of the embodiment of the present invention is shaped like a bunch of petals. Figure 4A , including 4 baffles 41 and 1 main body 42, the baffle 41 is fixed on the main body 42, and is required to have high toughness, strength and elasticity. The material is preferably segmented polyetheramide resin (Pebax), which is formed by integral molding and then laser cutting. Figure 2A-2BThe baffle plate 41 is disposed between the internal balloon 1 and the external cup-shaped element 2 to block the inflow hole. The main body 42 is connected to the external cup-shaped element 1 and the catheter assembly 3 through the distal connector 5 by bonding or welding. The curvature of the baffle plate 42 is the same as the inner contour of the external cup-shaped element 1, and can fit tightly to improve the sealing effect. In addition, the thickness of the baffle valve gradually increases from the baffle plate to the main body (the part close to the connection is thicker, and the part away from the connection is thinner), which increases the rigidity of the distal restraint position. In another embodiment, the baffle valve 4 also has a structural reinforcement 43, see Figure 4B The structural reinforcement is embedded in the flapper valve to improve the response speed of the flapper valve. The material of the structural reinforcement is required to have superelasticity, and is preferably a nickel-titanium alloy material.

[0070] The distal connector of the embodiment of the present invention is tubular in shape, and is divided into a distal first connector 51 and a distal second connector 52. The first connector 51 is used to connect the baffle valve 4 and the external cup-shaped element 1, and the second connector 52 is used to connect the baffle valve 4 and the distal end of the catheter assembly 3. A reflux hole 511 is provided on the tube wall of the two connectors. During the operation of the device, the reflux hole can flush the distal area of ​​the device and the restraint position of the baffle valve to prevent thrombus formation.

[0071] The connector 6 of the embodiment of the present invention is connected to the proximal end of the catheter assembly 3, and is made of polycarbonate (PC), including a guidewire cavity interface 61, a filling cavity interface 62, and a traction wire cavity interface 63, which are respectively connected to the three lumens of the catheter assembly. After the guidewire 30 enters the guidewire cavity 31 from the far end of the device, it passes through the guidewire cavity interface 61 for the surgeon to operate, so as to guide and assist the device to smoothly reach the corresponding positions of the left ventricle and the aorta. After the guidewire is withdrawn from the designated position, the guidewire cavity interface 61 can be connected to the pressure sensor to detect the pressure in the left ventricle; the filling cavity interface 62 is connected to the air supply system to realize the inflation and deflation of the internal balloon; the traction wire cavity interface 63 is connected to the Y-type connector 7 to accommodate and constrain the traction wire, which is convenient for the surgeon to operate.

[0072] The Y-type connector 7 of the embodiment of the present invention is connected to the traction wire cavity interface 63, and includes a Luer connector end 71, a hemostatic locking valve 72, and a side tube 73, which are used to establish a working channel for the traction wire. The Y-type connector of the embodiment of the present invention is a Y-type valve with hemostasis and locking functions well known in the art. The side tube 73 of the Y-type connector can be connected to an infusion device to flush the traction wire cavity and reduce the risk of thrombosis. It can also be connected to a pressure sensor to detect the pressure of the ascending aorta.

[0073] The traction wire 8 of the embodiment of the present invention can provide external force to transform the device from an expanded state to a folded state with a small diameter during the device removal process, and gradually retract it into the delivery sheath. The material is a wire with high yield strength and good biocompatibility, preferably a nickel-titanium alloy wire. Figure 8The distal end of the traction wire 8 passes through the two mounting holes 111 of the elastic bracket, merges into two strands, passes through the traction wire cavity together, and extends to the outside of the body through the joint and the Y-type connector. The two strands provide traction together, with high strength, to ensure safety during traction. In the embodiment of the present invention, the traction wire is bundled and sealed by a PET heat shrink tube to avoid thrombosis. The outer diameter of the traction wire does not exceed 1.5 mm. Fig.9A , Fig. 9B This is a schematic diagram of an embodiment of the present invention being recovered into a sheath. By pulling the traction wire, the conical structure region of the elastic support of the external cup-shaped element is folded and recovered into the delivery sheath. Further pulling the traction wire can make the device leave the body through the delivery sheath.

[0074] The embodiment of the present invention includes two processes of blood suction and blood discharge during actual use. The reflux hole 511 of the distal connector can prevent blood clots from forming. Figure 10A-10C During the process of blood being sucked from the left ventricle into the inner cavity of the device, the internal balloon deflates and contracts, and the inner cavity is in a low-pressure state. The pressure of the left ventricle and the aorta is greater than that of the inner cavity. Under the action of pressure, the inlet baffle valve 4 opens, and the outflow membrane material is concave and closed, and the left ventricular blood enters the inner cavity through the inflow hole 121. Specifically, most of the blood flows into the inner cavity of the device through the inflow hole 121, and a very small part of the blood enters the inner cavity from the return hole 511 until the internal balloon is completely deflated and the inner cavity is filled with blood; then the internal balloon is inflated, and blood is pumped from the inner cavity of the device to the ascending aorta, see Figures 11A-11C Most of the blood flows into the ascending aorta from the outflow port 122, and a small part of the blood flows back to the left ventricle from the return hole 511. During the whole process, the blood flow rate circulating through the return hole is very small, which has little effect on the pumping efficiency of the device. At the same time, the distal area of ​​the device and the restraining position of the flapper valve can be flushed and renewed in time, avoiding the formation of a flow stagnation zone and preventing thrombosis. The area of ​​the return hole of the distal connector is required to be less than 6mm 2 , blood reflux is less than 5%, which does not have a significant impact on pumping efficiency. The inner cavity volume of the device of the embodiment of the present invention is about 10ml, and the working frequency of the internal balloon is 300-600 times / min, which can provide a pumping flow of 3-5L / min for high-risk PCI and cardiogenic shock patients.

[0075] The embodiment of the present invention includes two states: folded and expanded. Fig.12 The device is folded and delivered to the left ventricle through a delivery sheath with a diameter of 18F. After reaching the designated position, the device leaves the sheath and is in an expanded state. Fig.13The figure shows a schematic diagram of the actual working of an embodiment of the present invention. By periodically filling the internal balloon with helium, the volume of the inner cavity of the device changes periodically. When the internal balloon is deflated and contracted, the blood in the left ventricle enters the inner cavity of the device through the inlet hole. When the balloon is inflated, the blood in the inner cavity enters the ascending aorta through the outlet. The reciprocating cycle can continuously assist the ventricular pumping and provide blood circulation support for high-risk PCI patients and patients with cardiogenic shock. After the operation, the device is gradually folded and recovered into the delivery sheath by pulling the traction wire and withdrawn from the body.

[0076] The balloon-type left ventricular assist device for preventing thrombus formation in the embodiment of the present invention provides active forward, pulsatile blood flow from the left ventricle to the ascending aorta through periodic changes in the inner cavity volume combined with the inflow hole, outflow hole and flapper valve, thereby increasing cardiac output, maintaining vascular elasticity and improving blood circulation levels.

Claims

1. A balloon-type left ventricular assist device for preventing thrombosis, characterized in that: The device includes an external cup-shaped element, an internal balloon, a catheter assembly, a flapper valve, a distal connector, a connector, a Y-connector and a traction wire, wherein: The external cup-shaped element is made of an elastic support and a membrane material, has two states: folded and expanded, and includes an olive-shaped pumping portion and an equal-diameter outflow channel, the free end of the outflow channel is an outflow port, and a plurality of inflow holes are arranged on the side wall of the pumping portion; The inner balloon is arranged inside the outer cup-shaped element, mounted on the distal end of the catheter assembly, and can be inflated and deflated; The flapper valve is disposed between the external cup-shaped element and the internal balloon, and is used to intermittently block the inflow hole and control the unidirectional flow of blood into the inner cavity; The distal connector is tubular and used for connecting the flapper valve with the external cup-shaped element and the catheter assembly. A reflux hole is provided on the tube wall of the distal connector for flushing and liquid renewal at the connection position to avoid the formation of a stagnation zone and reduce thrombosis. The catheter assembly includes a guide wire tube, a balloon filling tube and a traction wire tube; The connector is connected to the proximal end of the catheter assembly, and includes a guidewire cavity interface, a filling cavity interface, and a traction wire cavity interface, and is correspondingly connected to multiple cavities of the catheter assembly; The Y-type connector includes a Luer interface, a hemostatic locking valve and a side tube, which are connected to the traction wire cavity interface of the connector; The traction wire is connected to the elastic support of the external cup-shaped element and extends outside the body through the catheter, the lumen of the joint and the Y-shaped connector; The device is folded and delivered to the left ventricle through the delivery sheath via femoral artery puncture. After reaching the designated position, the external cup-shaped element is expanded, and the volume of the inner cavity changes periodically by periodically filling the internal balloon with gas. Combined with the inflow hole, outflow port and baffle valve, blood is pumped from the left ventricle into the ascending aorta to increase cardiac output and provide blood circulation assistance for high-risk PCI patients and patients with cardiogenic shock. After the operation, the device is gradually folded and recovered into the delivery sheath by pulling the traction wire and withdrawn from the body.

2. The anti-thrombotic balloon left ventricular assist device according to claim 1, characterized in that: The distal curvature of the pumping portion of the external cup-shaped element is greater than the proximal curvature in the expanded state, the maximum outer diameter of the pumping portion is greater than the outflow channel, and the overall outer diameter of the external cup-shaped element is less than 25 mm.

3. The anti-thrombotic balloon left ventricular assist device according to claim 1, characterized in that: The total area of ​​the inflow holes of the outer cup-shaped element satisfies the following equation, Where A1 is the total area of ​​multiple inflow holes, ρ is the blood density, which is 1055 kg / m 3 , Q is the maximum flow rate of pumped blood, which is 5L / min, and ΔP1 is the pressure difference on both sides of the wall of the external cup-shaped element when the device inhales blood, preferably 50mmHg.

4. The anti-thrombotic balloon left ventricular assist device according to claim 1, characterized in that: The inner diameter cross-sectional area of ​​the outflow channel of the external cup-shaped element in the expanded state satisfies the following equation: Wherein, A2 is the cross-sectional area of ​​the outflow channel, and ΔP2 is the pressure difference between the inner cavity of the device and the aorta when discharging blood, preferably 100 mmHg.

5. The anti-thrombotic balloon left ventricular assist device according to claim 1, characterized in that: The proximal region of the elastic support of the external cup-shaped element is conical, and a traction wire mounting hole is also provided at the proximal end of the elastic support. The distal end of the traction wire is connected to the mounting hole, and the proximal end extends to the body through the traction wire cavity and the connector of the catheter. The traction wire is a wire material with high yield strength and good biocompatibility, and can be a nickel-titanium alloy wire. The traction wire is sealed by bundling with a heat shrink tube to prevent the formation of thrombus. The elastic support material is a nickel-titanium alloy with shape memory properties and biocompatibility.

6. The anti-thrombotic balloon left ventricular assist device according to claim 5, characterized in that: The membrane material of the external cup-shaped element is attached to the inner and outer surfaces of the elastic support. The membrane material at the conical structure of the support can be partially collapsed and closed to prevent blood backflow. The membrane material is a polyurethane material with a Shore hardness of 72D and a large elastic modulus, good flexibility and high hardness.

7. The anti-thrombotic balloon left ventricular assist device according to claim 1, characterized in that: The internal balloon is a non-compliant balloon, which is olive-shaped, the same shape as the external cup-shaped element, and the distal curvature is greater than the proximal curvature; when the internal balloon is inflated, the distal outer surface is tightly fitted with the baffle valve, and a certain gap is retained between the proximal end and the external cup-shaped element to ensure the directionality of the blood pumping process. The inner cavity volume of the external cup-shaped element and the internal balloon is about 10ml, the pumping frequency is 300-600 times / min, and the intervention size is 18F.

8. The anti-thrombotic balloon left ventricular assist device according to claim 1, characterized in that: The catheter assembly includes a guide wire tube, a balloon filling tube and a traction wire tube. The distal end of the catheter assembly is bonded and fixed to the baffle valve, and the proximal end is connected to the joint. The interior of the guide wire tube is a guide wire cavity; the balloon filling tube is coaxially sleeved on the outside of the guide wire tube, and the gap between the two is the balloon filling cavity. The balloon filling tube is bonded or welded to the internal balloon, and a plurality of holes are provided on the wall of the balloon filling tube to communicate with the internal balloon for inflating and deflating the internal balloon; the traction wire tube itself is a double-lumen tube, the large cavity is bonded and fixed to the balloon filling tube, and the small cavity is used as the traction wire cavity. The distal end of the traction wire tube ends at the ascending aorta, and the traction wire cavity can also be used to measure the ascending aorta pressure.

9. The anti-thrombotic balloon left ventricular assist device according to claim 1, characterized in that: The baffle valve includes a plurality of baffle plates and a tubular body, the baffle plates are fixed on the body; the baffle valve body is coaxially bonded or welded with the external cup-shaped element and the conduit, the surface contour curvature of the baffle plate is the same as the surface curvature of the corresponding position of the external cup-shaped element, thereby ensuring the blocking effect of the baffle on the inflow hole; the thickness of the baffle valve gradually increases from the baffle plate to the body, and the baffle valve is provided with a structural reinforcement as a whole, and the material of the baffle valve is nickel-titanium alloy.

10. The anti-thrombotic balloon left ventricular assist device according to claim 1, characterized in that: The distal connecting piece includes a first connecting piece and a second connecting piece. The thin walls of the first connecting piece and the second connecting piece are axially provided with reflow holes. The reflow holes are equidistantly distributed, and the cross-sectional area accounts for less than 5% of the total area of ​​the inflow holes.

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