Minimally invasive catheter-based left ventricular assist device

Abstract

The application discloses a minimally invasive catheter type left ventricular assist device, which comprises a sleeve, an elastic metal support, a flexible film, an inflatable and contractible balloon and a guide wire; the sleeve is sequentially divided into a front section, a middle section and a tail section; a plurality of inflow small holes are formed in the front section of the sleeve, and a one-way valve is arranged in the front section of the sleeve to control the one-way inflow of blood from the front section to the middle section of the sleeve; the middle section of the sleeve is a bending pipe capable of changing direction at will; a plurality of first outflow small holes are formed in the surface of the tail section of the sleeve; the elastic metal support is tightly attached to the outer surface of the tail section of the sleeve and limits the deformation of the tail section of the sleeve; the flexible film is connected to the outer surface of the elastic metal support and the tail section of the sleeve, and the elastic modulus of the flexible film is smaller than that of the tail section of the sleeve; a plurality of second outflow small holes are formed in the surface of the flexible film, and the first outflow small holes and the second outflow small holes are arranged in a staggered mode and located at positions not overlapping with each other; the inflatable and contractible balloon is arranged in the tail section of the sleeve; and the guide wire penetrates through the whole sleeve and extends out of the front section of the sleeve.

Description

Technical Field

[0001] This invention relates to a minimally invasive catheter-type left ventricular assist device, belonging to the field of medical devices. Background Technology

[0002] Ventricular assist devices (VADs) are a common clinical treatment for critical heart failure, with left ventricular assist devices (LVADs) being the most prevalent. Currently, the main type of LVAD is the magnetically levitated centrifugal blood pump. However, the high-speed rotation of its metal impeller can generate high shear stress on the blood, potentially leading to complications such as hemolysis and thrombosis, which can be life-threatening. Furthermore, implanting a magnetically levitated centrifugal blood pump creates a large surgical incision, hindering postoperative recovery. Additionally, the magnetically levitated centrifugal blood pump primarily provides a continuous blood flow, reducing the pulsatility of the blood and potentially causing other related complications.

[0003] Therefore, there is a need to develop a new type of left ventricular assist device that can reduce complications such as hemolysis and thrombosis, and also reduce surgical wounds for patients, thereby improving postoperative recovery. Summary of the Invention

[0004] The purpose of this invention is to provide a minimally invasive catheter-based left ventricular assist device that can reduce complications such as hemolysis and thrombosis, and also reduce surgical wounds for patients, thereby improving postoperative recovery.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A minimally invasive catheter-based left ventricular assist device includes a cannula, a flexible metal stent, a flexible membrane, an inflatable-contractable balloon, and a guidewire; wherein,

[0007] The cannula is divided into a front section, a middle section, and a tail section in sequence. The front section of the cannula has multiple inflow holes and a one-way valve inside to control the unidirectional flow of blood from the front section to the middle section. The middle section of the cannula is a bendable tube that can be changed in any direction to adapt to complex blood vessel circuits. The tail section of the cannula has multiple first outflow holes on its surface.

[0008] The elastic metal support is tightly attached to the outer surface of the sleeve tail section and restricts the deformation of the sleeve tail section; a flexible film is connected to the outer surface of the elastic metal support and the sleeve tail section, the elastic modulus of which is less than that of the sleeve tail section, and multiple second outflow holes are opened on the surface of the flexible film. The second outflow holes are staggered with the first outflow holes and are located in non-overlapping positions.

[0009] An inflatable-contractable balloon is placed in the end of the cannula to control blood intake and drainage;

[0010] The guide wire runs sequentially through the tail section, middle section, and front section of the casing, penetrating the entire casing and extending out from the front section.

[0011] According to one embodiment of the present invention, the shape of the inflow orifice opened at the front end of the cannula can be any shape, but circular or elliptical is preferred. The area of ​​a single inflow orifice is in the range of 20-30 mm2. The inflow orifices are evenly arranged 360 degrees around the circumference of the cannula and are arranged in multiple layers axially at the same time. The number of layers is 2-4 and the number of inflow orifices in each layer is equal. The inflow orifices of each adjacent two layers are staggered to ensure that blood can flow in from any direction.

[0012] According to one embodiment of the present invention, the inner diameter of the front section of the cannula is 8-9 mm, and the one-way valve is a duckbill valve, which serves to ensure that blood can flow in in one direction.

[0013] According to one embodiment of the present invention, the middle section of the cannula is corrugated, made of soft material and can be arbitrarily adjusted to adapt to the blood vessel path, the inner diameter is equal to the size of the front section of the cannula, and the outer diameter ranges from 12 to 14 mm.

[0014] According to one embodiment of the present invention, the elastic metal stent structure is woven into a mesh shape, which can resist radial pressure and prevent radial deformation of the sleeve tail section; the elastic metal stent can be made of alloys such as nickel-titanium or cobalt-chromium, which have good biocompatibility and superelasticity.

[0015] According to one embodiment of the present invention, the size of the first outflow hole opened on the surface of the sleeve tail section is 3-8 mm. 2 The orifices are circular in shape and are evenly arranged 360 degrees around the circumference of the sleeve, and are also arranged in multiple layers axially, with 6-10 layers and an equal number of orifices flowing out of each layer.

[0016] According to one embodiment of the present invention, the flexible film has a certain length of annular film along the axial direction, and the thickness of the flexible film is in the range of 0.05-0.3 mm; the size of the second outflow hole on the flexible film is equal to or smaller than the size of the first outflow hole; the second outflow hole is uniformly arranged 360 degrees along the circumference of the flexible film and is arranged in multiple layers along the axial direction.

[0017] According to the above technical solution of the present invention, the cannula tail section and the flexible membrane constitute an outflow one-way valve, and blood can flow out from the first outflow hole and the second outflow hole in sequence; if the blood has a backflow tendency along the second outflow hole, since the flexible membrane is softer than the cannula tail section, the flexible membrane will be tightly adhered to the surface of the cannula tail section by the blood with the backflow tendency; at the same time, the first outflow hole and the second outflow hole are arranged alternately and there is no overlap between the two types of outflow holes, so that a good seal is formed on the outer surface of the cannula tail section.

[0018] According to one embodiment of the present invention, the length of the inflatable-contractor balloon is equal to or slightly smaller than the length of the cannula tail section; fluid is injected or aspirated into the balloon at a certain frequency to cause it to expand or contract, thereby enabling blood to flow out or in. The fluid injected into it can be physiological saline, silicone oil, or helium gas.

[0019] According to one embodiment of the present invention, the number of flexible films is 2-4, and flexible films are connected at least at both ends of the sleeve tail section.

[0020] According to one embodiment of the present invention, the outer diameter of the sleeve tail section is 15-18 mm.

[0021] The beneficial effects of this invention are:

[0022] The left ventricular assist device of this invention does not rely on a high-speed rotating impeller to deliver blood. Instead, it controls the expansion and contraction of a balloon at a certain frequency to achieve blood inflow and outflow. This design principle results in less shear stress on the blood compared to a magnetically levitated centrifugal blood pump, reducing the risk of hemoglobin ionization and platelet activation, decreasing the risk of complications such as hemolysis and thrombosis, and improving blood compatibility in the human body. Simultaneously, the balloon's periodic contraction and expansion enhances blood flow pulsatility, improving perfusion of various organs and reducing other complications. Furthermore, the left ventricular assist device of this invention is designed as a catheter, allowing for minimally invasive implantation via the femoral artery, reducing the surgical incision area and thus improving postoperative recovery. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the left ventricular assist device of the present invention.

[0024] Figure 2 This is a schematic diagram of the front section of the casing.

[0025] Figure 3 This is a schematic diagram of the flexible thin film structure.

[0026] Figure 4 This is a schematic diagram of the structure of a flexible metal support.

[0027] Figure 5 This is a schematic diagram of the structure of an inflatable-contractable balloon.

[0028] Figure 6 This is a schematic diagram of blood flowing out of the cannula's tail section.

[0029] Figure 7 This is a schematic diagram of the internal structure of the front and middle sections of the casing.

[0030] Figure 8It is a schematic diagram showing the spatial relationship between the first and second outflow orifices.

[0031] Figure 9 This is a schematic diagram illustrating the implantation effect of the left ventricular assist device of the present invention. Detailed Implementation

[0032] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] It should be noted that in the textual description of this invention, terms such as "front," "middle," and "rear," which indicate direction or positional relationship, are given based on the relative positional relationship between the device and the ventricle. The position of the device closer to the ventricle is indicated as "front," and the position farther from the ventricle is indicated as "middle" and "rear," respectively. This is merely for ease of description and does not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0034] like Figures 1 to 7 As shown, the catheter-type left ventricular assist device of the present invention includes a cannula 1, a flexible membrane 2, an elastic metal stent 3, an inflatable-contractable balloon 4, and a guide wire 5. The cannula 1 sequentially includes a cannula tip 11, a cannula midsection 12, and a cannula tail section 13; the cannula tip 11 is placed in the left ventricle A, the cannula midsection 12 is located in the aortic arch, and the cannula tail section 13 is located in the descending aorta. The cannula tip 11 and the cannula midsection 12 are made of flexible material, allowing for arbitrary angle adjustment to adapt to tortuous vascular pathways. The cannula tip 11 has multiple inflow orifices 111, and a one-way valve 112 is provided inside the cannula tip 11 to control the unidirectional flow of blood from the cannula tip 11 to the cannula midsection 12; the cannula tail section 13 has multiple first outflow orifices 131. The elastic metal stent 3 is tightly attached to the outer surface of the cannula tail section 13 and restricts the deformation of the cannula tail section 13. A flexible membrane 2 is connected to the outer surface of the elastic metal stent 3 and the cannula tail section 13. Its elastic modulus is less than that of the cannula tail section 13. The surface of the flexible membrane 2 has multiple second outflow holes 21, which are staggered with the first outflow holes 131 and located in non-overlapping positions. An inflatable-contractable balloon 4 is built into the cannula tail section 13 to control blood aspiration and drainage. The area enclosed by the outer surface of the inflatable-contractable balloon 4 and the inner surface of the cannula tail section is the core area of ​​the flow channel. The guide wire 5 runs sequentially along the cannula tail section 13, the middle section 12, and the front section 11, passing through the entire cannula, and extends from the front section 11 to form a spiral of a certain length. The main function of the guide wire is to enable visualization of angiography, so as to facilitate observation during surgery, and to accurately deliver and fix the device to the designated position.

[0035] like Figure 2As shown, the front section 11 of the sleeve has an inflow orifice 111. The shape of the inflow orifice 111 can be any shape, with circular and elliptical shapes being optimal. The area of ​​a single inflow orifice 111 ranges from 20 to 30 mm². 2 The inflow orifices are evenly arranged 360 degrees around the circumference of the cannula and simultaneously arranged in multiple layers axially, with 2-4 layers and an equal number of inflow orifices in each layer. The inflow orifices between adjacent layers are staggered to ensure that blood can flow in from any direction. The front section 11 of the cannula is provided with a tapered tip 113, which has a small hole to allow a percutaneously inserted 0.035-inch guide wire 5 to pass through.

[0036] like Figure 3 As shown, the flexible film 2 is an annular shape with a certain axial length, between 60-100 mm. The thickness of the flexible film 2 is between 0.05-0.3 mm. It can be made of a polymer material with good compatibility, such as polyurethane, silicone rubber, or high-density polyethylene film (DHPE). A second outflow hole 21 is formed on the surface of the flexible film 2, with a single hole size of 3-8 mm. 2 The orifices are circular. Second outflow orifices 21 are evenly distributed within the circumference of the flexible membrane 2, and arranged in multiple layers along the axial direction, with 6-10 layers in total. The end edge 22 of the flexible membrane is fixed to the sleeve tail section 13 and the elastic metal support 3. The fixing method can be adhesive bonding. Blood leakage is not allowed at the end edge 22 of the flexible membrane to ensure a complete seal.

[0037] like Figure 4 As shown, the elastic metal stent 3 is made of woven shape memory alloy wires 31. The shape memory alloy can be made of materials with superelasticity and good biocompatibility, such as nickel-titanium or cobalt-chromium alloys. The elastic metal stent 3 is radially or rotationally symmetrical, with the diameter of the middle portion larger than the diameters of the two side portions, and the outer envelope ends 32 on both sides are designed to be circular. The wire diameter of the metal wires 31 is between 0.3-0.5 mm, and the length of the elastic metal stent 3 should be equal to the length of the sleeve tail section 13. The elastic metal stent 3 can resist radial pressure and prevent radial deformation of the sleeve tail section.

[0038] like Figure 5 As shown, the inflatable-contractable balloon 4 consists of a balloon inlet tube 41 and a balloon 42, which is placed inside the cannula tail section cavity 133 through the inlet 132. Physiological saline, silicone oil, or helium gas is periodically injected into or aspirated from the balloon 42 through the balloon inlet tube 41 at a certain frequency. The injection method can use a micro-piston pump or gear pump (not shown in the figure), with an injection pressure of 0.1-0.2 MPa. The length of the inflatable-contractable balloon 4 is equal to or slightly smaller than the cannula tail section, and the outer diameter of the cannula tail section is 15-18 mm.

[0039] like Figure 6 As shown, the surface of the cannula tail section 13 has a first outflow orifice 131, which is uniformly arranged circumferentially. The size and number of individual outflow orifices can be equal to those of the second outflow orifice 21. The first outflow orifice 131 on the surface of the cannula tail section 13 must be completely covered by the flexible membrane 2, and the first outflow orifice 131 and the second outflow orifice 21 must not overlap. The elastic modulus of the flexible membrane 2 is less than that of the cannula tail section 13, and the first outflow orifice 131 and the second outflow orifice 21 are spatially staggered. This design aims to reduce blood flow resistance and prevent blood backflow, acting as a one-way valve. The specific principle is: when there is a tendency for blood to flow back in the blood vessel, because the material of the flexible membrane 2 is softer than that of the cannula tail section 13, the flexible membrane 2 will be pressed by the blood and adhere tightly to the surface of the cannula tail section 13. At the same time, due to the staggered arrangement of the first outflow orifice 131 and the second outflow orifice 21, as... Figure 8 As shown, the first outflow hole 131 is completely covered by the flexible film 2, so that there will be no gaps that allow blood to flow back into the cannula 1.

[0040] The blood flow rate depends on two factors: firstly, the volume of the cannula lumen 133, which can be adjusted by changing the inner diameter and length of the cannula tail section 13; secondly, the blood flow rate also depends on the number of flexible membranes 2 and the corresponding number of first outflow orifices 131 and second outflow orifices 21. The number of flexible membranes 2 is 2-4, and it is necessary to have flexible membranes 2 at both ends of the cannula tail section 13. Figure 6 As shown, this design ensures better perfusion of the aortic arch, descending aorta, and venous branches when blood flows through the first outflow orifice 131 and the second outflow orifice 21. The inner wall 134 of the cannula tail section 13 should be smooth to facilitate blood flow.

[0041] like Figure 7 As shown, the inner diameter of the front section 11 of the cannula is 8-9 mm, and it is equipped with a one-way valve 112, which is shaped like a duckbill valve. The one-way valve 112 is located at any position between the inflow orifice 111 and the middle section 12 of the cannula. The bent tube of the middle section 12 of the cannula is corrugated, made of flexible material, and can be adjusted at any angle to adapt to the blood vessel path. The inner diameter D2 is equal to the size of the front section 11 of the cannula, and the outer diameter D1 is in the range of 12-14 mm.

[0042] like Figure 9As shown, the device of this invention is implanted percutaneously via the femoral artery, passing through the descending aorta, aortic arch, and ascending aorta. Finally, the anterior segment 11 of the cannula extends into the left ventricle A. By contracting the balloon, negative pressure is created within the cannula; blood from the left ventricle A enters the cannula through the inlet orifice. The balloon is then expanded, creating pressure on its outer surface to expel the blood, thus achieving organ perfusion. The working principle of this invention is as follows: fluid is injected into the balloon 42 at specific intervals, increasing the diameter of the outer surface of the balloon 42 until it approaches the inner diameter of the cannula's tail segment 13. At this time, the outer surface of the balloon 42 exerts pressure on the blood, causing it to flow out through the first outlet orifice 131. Due to the blood pressure, the flexible membrane 2 is pushed away from the outer surface of the cannula's tail segment 13, and the blood then flows into the blood vessel through the second outlet orifice 21. The inlet orifice 111, the first outlet orifice 131, and the second outlet orifice 21 can be manufactured using processes such as stamping or laser technology.

[0043] The advantages of this invention are:

[0044] The left ventricular assist device of the present invention does not rely on a high-speed rotating rotor to deliver blood. Instead, it achieves blood intake and output through balloon contraction or expansion, reducing blood shear stress, improving the blood's anti-hemolysis and anti-thrombotic properties, and the simple internal structure of the catheter can reduce blood stagnation and backflow. On the other hand, the balloon expands and contracts at a certain frequency, which can enhance blood flow pulsatility and improve the blood perfusion effect of various organs. Since the left ventricular assist device of the present invention adopts a catheter-type structure, it can be implanted minimally invasively, reducing the probability of surgical wounds and related complications for patients.

[0045] Finally, it should be noted that the above-described embodiments are preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A minimally invasive catheter-based left ventricular assist device, characterized in that: It includes a cannula, a flexible metal stent, a flexible membrane, an inflatable-contractable balloon, and a guidewire; among which, The cannula is divided into a front section, a middle section, and a tail section in sequence. The front section of the cannula has multiple inflow holes and a one-way valve inside to control the unidirectional flow of blood from the front section to the middle section. The middle section of the cannula is a bent tube that can be arbitrarily changed in direction. The tail section of the cannula has multiple first outflow holes on its surface. The first outflow holes are evenly arranged 360 degrees around the circumference of the cannula and are also arranged in multiple layers axially. An elastic metal support is tightly attached to the outer surface of the sleeve tail section and restricts the deformation of the sleeve tail section; a flexible film is connected to the outer surface of the elastic metal support and the sleeve tail section, the elastic modulus of which is less than that of the sleeve tail section; multiple second outflow holes are opened on the surface of the flexible film, the second outflow holes are staggered with the first outflow holes and located in non-overlapping positions; the size of the second outflow holes is equal to or smaller than the size of the first outflow holes; the second outflow holes are uniformly arranged 360 degrees circumferentially along the flexible film and are arranged in multiple layers axially. An inflatable-contractable balloon is placed in the end of the cannula to control blood intake and drainage; The guide wire runs sequentially through the tail section, middle section, and front section of the casing, penetrating the entire casing and extending out from the front section.

2. The minimally invasive catheter-based left ventricular assist device as described in claim 1, characterized in that: The inflow orifice at the front end of the sleeve is circular or elliptical in shape, and the area of ​​a single inflow orifice ranges from 20 to 30 mm². 2 The inflow holes are evenly arranged 360 degrees around the circumference of the casing and are also arranged in multiple layers axially. The number of layers is 2-4 and the number of inflow holes in each layer is equal. The inflow holes between each two adjacent layers are staggered.

3. The minimally invasive catheter-based left ventricular assist device as described in claim 1, characterized in that: The inner diameter of the front section of the sleeve is 8-9mm, and the one-way valve is a duckbill valve.

4. The minimally invasive catheter-based left ventricular assist device as described in claim 1, characterized in that: The middle section of the cannula is corrugated, made of soft material, and can be adjusted at any angle to adapt to the blood vessel path. The inner diameter is equal to the size of the front section of the cannula, and the outer diameter ranges from 12 to 14 mm.

5. The minimally invasive catheter-based left ventricular assist device as described in claim 1, characterized in that: The elastic metal scaffold structure is woven into a mesh shape and is made of nickel-titanium alloy or cobalt-chromium alloy, which have good biocompatibility and super elasticity.

6. The minimally invasive catheter-based left ventricular assist device as described in claim 1, characterized in that: The size of the first outflow hole on the surface of the sleeve tail section is 3-8mm. 2 The orifices are circular in shape, with 6-10 layers and an equal number of orifices flowing out of each layer.

7. The minimally invasive catheter-based left ventricular assist device as described in claim 1, characterized in that: The flexible film has a certain length of annular film along the axial direction, and the thickness of the flexible film is in the range of 0.05-0.3 mm.

8. The minimally invasive catheter-based left ventricular assist device as described in claim 1, characterized in that: The length of the inflatable-contractable balloon is equal to or slightly smaller than the length of the cannula tail section; the fluid injected into it is saline, silicone oil, or helium.

9. The minimally invasive catheter-based left ventricular assist device as described in claim 7, characterized in that: The number of flexible films is 2-4, and flexible films are connected at least at both ends of the sleeve tail section.

10. The minimally invasive catheter-based left ventricular assist device as described in claim 4, characterized in that: The outer diameter of the sleeve tail section is 15-18mm.

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