catheter pump

Abstract

The catheter pump (100) includes a connecting case (2045) in which its drive catheter handle (204) is removably connected to a motor (102), and a proximal end of the drive shaft (202) is connected to a rotor (2046), which transmits the rotational force of the motor (102) to the drive shaft (202), which in turn rotates an impeller (2052) of a pump head (205). A housing cavity (2049) is formed within the connecting case (2045) to support the rotor (2046) and to communicate with the catheter (201). A flushing fluid inlet (2043) and a flushing fluid outlet (246) are provided in communication with the housing cavity (2049). The cleaning liquid inlet (2043) and the cleaning liquid outlet (246) are respectively connected to a cleaning liquid inlet pipe (501) and a cleaning liquid outlet pipe (502), which is connected to the cleaning liquid inlet pipe (501). The cleaning liquid outlet pipe (502), the cleaning liquid inlet pipe (501) and the receiving cavity (2049) form a cooling circulation circuit, which is provided with a circulation drive member (503), and which is connected to a pressure maintaining module (600) for maintaining the pressure of the cleaning liquid in the cooling circulation circuit.

Description

[Technical Field]

[0001] This application relates to catheter pumps. [Background technology]

[0002] Heart disease is a health problem with a very high mortality rate, and doctors are increasingly using mechanical circulatory support systems to treat heart failure. Treatment of acute heart failure requires a device that can provide rapid support to patients, and doctors are hoping to implement treatment plans quickly and minimally invasively.

[0003] Mechanical circulatory support (MCS) systems and ventricular assist devices (VADs) are increasingly being used in the treatment of acute heart failure, for example, to stabilize patients after cardiogenic shock, treat acute myocardial infarction (MI) and decompensated heart failure, or provide support to patients during high-risk percutaneous coronary intervention (PCI). One example of an MCS system is a rotational catheter pump, which is placed percutaneously via a catheter.

[0004] Traditionally, catheter pumps are inserted into the body and connected to the cardiovascular system (e.g., connecting the left ventricle to the ascending aorta) to assist the pumping function of the heart. Other known applications include assisting the right side of the heart by pumping venous blood from the right ventricle to the pulmonary artery. Acute circulatory support devices are typically used to unload the myocardium for a period of time to stabilize patients before heart transplantation or for continuous support.

[0005] For example, a known embodiment, publication number CN113856036A, provides a catheter pump with a small interventional size, i.e., an external motor. The general operating principle of this catheter pump is that the external motor transmits rotational power to a distal impeller via a drive shaft drilled into the catheter, rotating the impeller to provide fluid flow to the blood, thereby pumping the blood from the left ventricle to the aorta. The impeller's power transmission process involves multiple rotating components, such as the drive shaft and bearings supporting the proximal and distal ends of the impeller. Therefore, during the operation of the catheter pump, a flushing liquid must be injected into the catheter to lubricate and cool the rotating components.

[0006] Conventional catheter pumps use non-contact power transmission mechanisms to prevent cleaning fluid leakage, particularly to prevent the cleaning fluid from entering the motor, such as the magnetic coupling scheme disclosed in Publication No. CN101820933B and the vortex coupling scheme disclosed in Publication Nos. CN114452527A and CN216061675U. A liquid-isolating wall is provided between the driving member and the driven member (both of which are magnetic in the magnetic coupling scheme and which are magnetic and conductive in the vortex coupling scheme), thereby achieving a seal against the cleaning fluid and allowing the cleaning fluid to flow only to the distal end, flushing the drive shaft and bearings at the proximal and distal ends without entering the motor.

[0007] The driving member is driven to rotate by a motor, and the driven member is mounted on and supported by a rotor shaft, which is fixedly connected circumferentially to a proximal end of the driving shaft, so that the rotation of the motor is transmitted to the rotor shaft, and then to the driving shaft and impeller, by magnetic coupling between the driving member and the driven member.

[0008] The rotor, including a driven member and a rotor shaft, is mounted in a drive catheter handle that is detachably connected to the motor. The rotor further includes a protective layer covering the outside of the driven member and an end cap that limits the axial position of the driven member. The rotor shaft is rotatably supported on the drive catheter handle by two bearings. A flushing fluid port is provided in the drive catheter handle. In this way, the flushing fluid first enters the drive catheter handle and then the catheter. Therefore, the rotor is immersed in the flushing fluid. Therefore, the flushing fluid also serves to lubricate and cool the two bearings that support the rotor shaft.

[0009] In addition, the torque of a non-contact power transmission mechanism is inversely correlated with the distance between the driving and driven members, which is particularly evident in vortex coupling solutions. Therefore, in order to increase the torque of the power transmission, compressing the distance between the driving and driven members by increasing the diameter of the rotor is a viable solution.

[0010] However, increasing the rotor diameter also reduces the distance between the rotor's outer wall and the inner wall of the drive catheter handle. Because the rotor is immersed in irrigation fluid, when the rotor rotates at high speed, the irrigation fluid is driven by the rotor due to the viscosity of the fluid in the narrow space inside the drive catheter handle, resulting in large eddy current losses and a large temperature rise in the irrigation fluid. Because at least a portion of the irrigation fluid enters the human body through the catheter, the large temperature rise in the irrigation fluid can have adverse effects on the human body.

[0011] Therefore, how to solve the problem of the temperature rise of the cleaning liquid is a technical issue that needs to be resolved as soon as possible. Summary of the Invention [Problem to be solved by the invention]

[0012] In light of this, embodiments of the present invention provide a catheter pump to at least partially solve the above problems. [Means for solving the problem]

[0013] To achieve the above object, the present invention provides the following technical solutions.

[0014] The catheter pump includes a drive assembly, an operating assembly, a cooling circulation module, and a pressure maintenance module.

[0015] The drive assembly includes a motor.

[0016] The operating assembly includes a catheter, a drive shaft inserted through the catheter, a driven member connected to the proximal end of the drive shaft, and a drive catheter handle and pump head connected to the proximal and distal ends of the catheter, respectively. The pump head includes a pump case connected to the distal end of the catheter and an impeller housed within the pump case. The impeller is connected to the distal end of the drive shaft and is driven to rotate to pump blood. The drive catheter handle includes a coupling case connected to the proximal end of the catheter and detachably connected to a motor, and a rotor driven by the motor, the proximal end of the drive shaft connected to the rotor. A housing cavity is formed within the coupling case to rotatably support the rotor therein. The coupling case has a flushing fluid inlet and a flushing fluid outlet communicating with the housing cavity, and the housing cavity is connected to the catheter. The flushing fluid inlet is connected to a flushing fluid source, and flushing fluid entering the housing cavity through the flushing fluid inlet is divided into two portions: a first portion that enters the catheter and a second portion that passes through the rotor and is discharged from the flushing fluid outlet.

[0017] The first portion of the flushing fluid is eventually completely discharged from the pump head into the human body. This also means that the first portion of the flushing fluid that entered through the catheter does not flow back and completely enters the human body. Backflow means that the flushing fluid reflows through the catheter or drive shaft from the distal end (approximately where the pump head is located) to the proximal end (which may be specifically where the drive catheter handle is located).

[0018] The first portion of the flushing fluid is discharged mainly at two locations at the distal end (pump head), for example, at the distal end of the catheter and at the distal end of the drive shaft.

[0019] The catheter pump includes a first flow path for the first portion of flushing fluid, the first flow path being defined by the interior spaces of the structures, such as the flushing fluid inlet, the storage cavity, the catheter, and the pump head, such that the flow path of the first portion of flushing fluid is from the flushing fluid inlet into the storage cavity, from the storage cavity into the catheter, and finally out of the pump head.

[0020] The catheter pump further includes a second flow path for the second portion of the flushing fluid to flow, the second flow path being defined by the internal space of the structure, such as the flushing fluid inlet, the containing cavity, and the flushing fluid outlet, such that the flow path of the second portion of the flushing fluid is from the flushing fluid inlet into the containing cavity and out through the flushing fluid outlet.

[0021] Note that the first and second portions of the cleaning fluid do not have a clear boundary surface during the flow process. For simplicity, this description is adopted. For convenience, the cleaning fluid that finally enters the catheter is defined as the first portion of the cleaning fluid, and the cleaning fluid that finally exits the cleaning fluid outlet is defined as the second portion of the cleaning fluid.

[0022] In the technical solution disclosed herein, the flushing fluid is divided within the drive catheter handle. The first flushing fluid entering the catheter can lubricate and cool the drive shaft, bearings, and other rotating parts as it flows to the distal pump head. The second flushing fluid flowing out of the flushing fluid outlet can release the high temperature of the rotor caused by high speed, thereby preventing the flushing fluid from becoming too hot.

[0023] The cooling circulation module includes a cleaning liquid inlet pipe connected to the cleaning liquid inlet and a cleaning liquid outlet pipe connected to the cleaning liquid outlet, and the cleaning liquid outlet pipe is connected to the cleaning liquid inlet pipe, and the cleaning liquid outlet pipe, the cleaning liquid inlet pipe, and the receiving cavity form a cooling circulation circuit. The cooling circulation module further includes a circulation driving member provided in the cooling circulation circuit for driving the flow of the cleaning liquid.

[0024] The pressure maintaining module is connected to the cooling circuit and is for maintaining the pressure of the cleaning liquid in the cooling circuit higher than the environmental pressure of the pump head during operation.

[0025] The cooling circuit, comprised of the flushing fluid inlet pipe, flushing fluid outlet pipe, and receiving cavity, allows the circulation drive member to circulate most of the flushing fluid through the cooling circuit, preventing the flushing fluid from forming a flow dead zone in the receiving cavity and avoiding high temperatures caused by eddy current loss due to the rotor rotating at high speed within the receiving cavity. At the same time, the pressure maintenance module maintains the flushing fluid pressure in the cooling circuit higher than the ambient pressure of the pump head, allowing the flushing fluid to enter the human body through the catheter. This eliminates the high temperature of the flushing fluid, preventing it from causing discomfort to the human body.

[0026] The circulation drive member is a first pump provided in the cleaning liquid inlet pipe and / or the cleaning liquid outlet pipe.

[0027] As described above, during the flow process, part of the cleaning fluid enters the catheter and part of it flows out from the cleaning fluid outlet. The amount of cleaning fluid entering the catheter (first partial cleaning fluid) is less than the amount flowing out from the cleaning fluid outlet (second partial cleaning fluid). The above "amount" may be a volume or a flow rate. In this specification, it will be described as a flow rate.

[0028] The liquid flow rate distribution can be achieved by controlling the pressure maintenance module to maintain the pressure of the cleaning liquid in the cooling circuit higher than the environmental pressure of the pump head during operation.

[0029] The pressure maintaining module includes a cleaning liquid source connected to the cooling circuit via a refilling line, and a second pump provided in the refilling line for refilling the cooling circuit with cleaning liquid supplied from the cleaning liquid source. In this way, the power required for circulating the cleaning liquid and the pressure required for maintaining the pressure of the cleaning liquid are achieved by the circulation drive member and the second pump, respectively.

[0030] Because pump control technology is relatively mature, when the circulation driving member uses the first pump, the first pump and the second pump provide the power required to circulate the cleaning liquid and the pressure required to maintain the pressure of the cleaning liquid, respectively, thereby enabling accurate control of the flow rate of the cleaning liquid entering the human body.

[0031] To facilitate the connection of the lines, the cooling circulation module further includes a buffer container, and the cleaning solution inlet pipe, cleaning solution outlet pipe, and refilling pipe are all connected to the buffer container via a Luer taper. Furthermore, in order to offset to some extent the instability (decrease) in the pressure of the cleaning solution due to the expansion of the pipe diameter that may occur when the cleaning solution inlet pipe or the cleaning solution outlet pipe uses a hose, and ultimately the instability in the flow rate of the cleaning solution entering the human body, the buffer container must have a constant volume and must be able to withstand at least the pressure compensation of the pressure maintenance module. It is preferable to use a solid tank or a three-way joint whose volume does not change.

[0032] To prevent gases precipitated in the cleaning solution due to the rotor rotating at high speed from entering the human body, the cooling circuit is provided with a bubble filter for capturing or filtering the precipitated bubbles. The bubble filter is preferably provided in the cleaning solution inlet pipe, which basically prevents the bubbles from entering the human body via the catheter. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a diagram showing a three-dimensional structure of a catheter pump according to an embodiment of the present invention. FIG.

[0034] [Figure 2] 2 is a cross-sectional view of a front end pump head portion of the actuation assembly of FIG. 1.

[0035] [Figure 3] FIG. 1 is a cross-sectional view of the drive assembly and drive catheter handle separated.

[0036] [Figure 4] FIG. 10 is a schematic diagram of a structure corresponding to the solution for high temperature of the cleaning liquid in the third embodiment, in which the circulation driving member is a pump. DETAILED DESCRIPTION OF THE INVENTION

[0037] The terms "near," "rear," "far," and "front" used in the present invention are those seen from the perspective of a clinician operating the catheter pump. The terms "near" and "rear" refer to portions relatively closer to the clinician, and the terms "far" and "front" refer to portions relatively farther from the clinician. For example, the drive assembly is located at the proximal end and rear end, and the operating assembly is located at the distal end and front end. Also, for example, the proximal end of a member / assembly refers to the end relatively closer to the drive assembly, and the distal end refers to the end relatively closer to the operating assembly.

[0038] The orientations of "near," "far," "posterior," and "anterior" are defined for ease of explanation, however, the catheter pump can be used in many orientations and positions, and these relative positional terms are not limiting or absolute.

[0039] The catheter pump according to the embodiment of the present invention can at least partially assist the blood pumping function of the heart, thereby at least partially relieving the burden on the heart. In one exemplary scenario, the catheter pump is used to assist the left ventricle, and its operating part (specifically, the pump head described below) is inserted into the left ventricle, and when the pump head operates, it can pump blood in the left ventricle to the ascending aorta.

[0040] The above-described example of use as an assist for the left ventricle is merely one possible application scenario for the catheter pump. In another possible, not clearly excluded, scenario, the catheter pump may be used as an assist for the right ventricle, with the pump head inserted in the right ventricle and pumping blood in the vein into the right ventricle when the pump head operates.

[0041] The following description will be focused on the main scenario in which the catheter pump is used for left ventricular assist, but as can be seen from the above description, the scope of protection of the embodiments of the present invention is not limited thereto.

[0042] As shown in Fig. 1, catheter pump 1000 includes drive assembly 100 and operating assembly 200. As shown in Fig. 3, drive assembly 100 includes motor case 101, motor 102 housed in motor case 101, and driver 103 driven by motor 102. As shown in Fig. 2, operating assembly 200 includes catheter 201, drive shaft 202 drilled through catheter 201, follower 203 connected to the proximal end of drive shaft 202, and drive catheter handle 204 and pump head 205 connected to the proximal and distal ends of catheter 201, respectively. Pump head 205 includes pump case 2051 having inlet 2051a and outlet 2051b and impeller 2052 housed in pump case 2051, impeller 2052 connected to the distal end of drive shaft 202. When the impeller 2052 rotates, blood is drawn into the pump case 2051 through the inlet 2051a and then expelled from the pump case 2051 through the outlet 2051b.

[0043] In one embodiment, the pump case 2051 includes a bracket 20511 and an elastic covering 20512 that covers the bracket 20511. The metal lattice of the bracket 20511 has a mesh design, and the covering 20512 covers the middle and rear ends of the bracket 20511, with the mesh at the front end of the bracket 20511 that is not covered by the covering 20512 forming the inlet 2051a. The rear end of the covering 20512 is covered on the exterior of the distal end of the catheter, and the outlet 2051b is an opening formed at the rear end of the covering 20512. The impeller 2052 includes a hub 20521 and blades 20522 that are supported on the outer wall of the hub 20521. The blade 20522 is made of a flexible material and forms a foldable pump head 205 with the bracket 20511 and the coating 20512, which are also made of the nickel-titanium memory alloy described above.

[0044] Of course, in other embodiments, the pump head 205 may be non-collapsible. Correspondingly, the pump casing 2051 may be a metallic sleeve that does not radially collapse and self-expand. The impeller 2052 is also made of a rigid, biocompatible material.

[0045] The drive shaft 202 includes a bendable flexible shaft 2021 and a rigid shaft 2022 connected to the distal end of the flexible shaft 2021, the flexible shaft 2021 being drilled into the catheter 201, the rigid shaft 2022 being drilled into the hollow passage of the hub 20521, and the outer wall of the rigid shaft 2022 and the inner wall of the hollow passage of the hub 20521 being fixed by adhesive.

[0046] The near end and far end of bracket 20511 are connected to near end bearing chamber 206 and far end bearing chamber 207, respectively, and near end bearing 208 and far end bearing 209 are provided in near end bearing chamber 206 and far end bearing chamber 207, respectively. The near end and far end of rigid shaft 2022 are drilled into near end bearing 208 and far end bearing 209, respectively. In this way, both ends of rigid shaft 2022 are supported by bearings 208, 209, and further, because rigid shaft 2022 has high rigidity, impeller 2052 is suitably held within pump case 2051.

[0047] 3, the actuation catheter handle 204 includes a mating case 2045 within which an irrigation bracket 2041 is mounted, the irrigation bracket 2041 defining an irrigation cavity 2042. The proximal end of the catheter 201 passes through the mating case 2045, is connected to the irrigation bracket 2041, and communicates with the irrigation cavity 2042. The actuation catheter handle 204 is provided with an irrigation fluid inlet 2043 that passes through a side wall of the mating case 2045, and the inner end of the irrigation fluid inlet 2043 communicates with the irrigation cavity 2042.

[0048] As described above, non-contact power transmission is realized by magnetic coupling between the driver 103 and the driven body 203, and further, a liquid isolation wall 2048 can be provided between them or outside the driven body 203 to seal in the cleaning liquid and prevent the cleaning liquid from entering the motor 102. In addition, the liquid isolation wall 2048 limits the flow direction of the cleaning liquid, allowing the cleaning liquid to flow only to the far end, i.e., the operating assembly 200, thereby lubricating and cooling the above-mentioned rotating members in the operating assembly 200, such as the drive shaft 202 and bearings.

[0049] 3, the drive catheter handle 204 further includes a rotor 2046 rotatably mounted within the coupling case 2045. The rotor 2046 includes a rotor shaft 2047 on which the follower 203 is mounted, and the proximal end of the drive shaft 202 is connected to the rotor shaft 2047. A liquid isolation wall 2048 is mounted on the coupling case 2045 and is located at the rear end of the cleaning bracket 2041. The liquid isolation wall 2048 abuts the cleaning bracket 2041 to jointly define a receiving cavity 2049 that receives the rotor 2046.

[0050] The receiving cavity 2049 includes a flushing cavity 2042 defined by the flushing bracket 2041 and a liquid isolation cavity 2050 defined by a liquid isolation wall 2048. The flushing cavity 2042 is in communication with the liquid isolation cavity 2050. As shown in FIG. 4 , the flushing cavity 2042 is in communication with a flushing fluid source 602 (such as a flushing fluid saline solution, a glucose solution, an anticoagulant, or any combination thereof) via a flushing fluid inlet 2043. After the flushing fluid enters the flushing cavity 2042 via the flushing fluid inlet 2043, it fills the receiving cavity 2049, enters the proximal end of the catheter 201, which is in communication with the flushing bracket 2041, and flows through the catheter 201 to the distal end. During this process, the drive shaft 202 is lubricated. At the same time, the flexible shaft 2021 has a braided structure, allowing liquid to penetrate into the flexible shaft. In this way, the cleaning liquid that has flowed out of the flexible shaft 2021 washes the near-end bearing 208 and flows out from the gap between the near-end bearing 208 and the rigid shaft 2022, thereby lubricating and cooling the near-end bearing 208. The cleaning liquid flowing forward inside the flexible shaft 2021 enters the rigid shaft 2022 and flows out from the far end of the rigid shaft 2022. The sealing of the seal 213 provided in the far-end bearing chamber 207 and located on the far side of the far end of the rigid shaft 2022 causes the cleaning liquid to flow in the opposite direction and flows out from the gap between the rigid shaft 2022 and the far-end bearing 209, thereby lubricating and cooling the far-end bearing 209.

[0051] 4, in order to solve the problem of high temperature of the cleaning liquid due to the high speed rotation of rotor 2046, coupling case 2045 is further provided with cleaning liquid outlet 246 communicating with receiving cavity 2049. Cleaning liquid outlet 246 specifically communicates with liquid isolation wall 2048. Catheter pump 100 includes cooling circulation module 500 that can circulate most of the cleaning liquid outside the body, and pressure maintenance module 600 that maintains the pressure of the cleaning liquid in the cooling circulation circuit.

[0052] The cooling circulation module 500 includes a cleaning liquid inlet pipe 501 communicating with the cleaning liquid inlet 2043 and a cleaning liquid outlet pipe 502 communicating with the cleaning liquid outlet 246. The cleaning liquid outlet pipe 502 communicates with the cleaning liquid inlet pipe 501, and the two pipes together with the receiving cavity 2049 form a cooling circulation circuit, and the cooling circulation circuit is provided with a circulation driving member 503 that drives the flow of the cleaning liquid.

[0053] The pressure maintenance module 600 is connected to the cooling circuit and maintains the pressure of the cleaning liquid in the cooling circuit higher than the environmental pressure of the pump head 205 during operation. In this way, a portion of the cleaning liquid in the cooling circuit enters the human body through the catheter 201, thereby cooling and lubricating the rotating members of the operating assembly 200. At the same time, the driving action of the circulation drive member 503 keeps the cleaning liquid circulating in the cooling circuit, thereby dissipating the high temperature of the cleaning liquid caused by the high-speed rotation of the rotor 2046 and cooling the cleaning liquid.

[0054] During the operation of the catheter pump 1000, the pump head 205 has its front end (blood inlet 2051a) inserted into the left ventricle and its rear end (blood outlet 2051b) located in the aorta. When the impeller 2052 rotates to pump blood, the distal end of the catheter 201 is located in a positive blood pressure region. Therefore, the environmental pressure during operation of the pump head 205 includes ventricular pressure, aortic pressure, and positive blood pressure. The resistance of the cleaning solution to enter the catheter 201 is greater than the resistance to flow out from the cleaning solution outlet 246. This means that the cleaning solution must overcome the above environmental pressure when it attempts to enter the human body through the catheter 201.

[0055] Furthermore, as the first portion of cleaning fluid flows forward from the catheter 201 to the proximal bearing 208, it must continue to flow forward through the bearing gaps. Specifically, the bearing gaps are the gaps between the outer wall of the rigid shaft 2022 and the inner wall of the proximal bearing 208, and the gaps between the outer wall of the rigid shaft 2022 and the inner wall of the distal bearing 209. The first portion of cleaning fluid encounters flow resistance in the bearing gaps as it flows forward, and this flow resistance is inversely correlated with the size of the bearing gaps. That is, the larger the bearing gap, the smaller the flow resistance of the cleaning fluid. Conversely, the smaller the bearing gap, the greater the flow resistance of the cleaning fluid. The flow resistance due to the bearing gaps also constitutes at least a part of the environmental pressure.

[0056] Furthermore, in the process in which the first portion of the cleaning liquid flows forward inside catheter 201 and then inside drive shaft 202, there is also a flow resistance that constitutes at least a part of the above-mentioned environmental pressure.

[0057] To avoid discomfort to the human body, the amount of cleaning liquid entering the human body through catheter 201 should not be too large, and should be less than the amount flowing out from cleaning liquid outlet 246. As described above, the reason why cleaning liquid enters catheter 201, which has a high resistance, is that the pressure of the cleaning liquid in the cooling circuit is maintained by pressure maintenance module 600 to be higher than the environmental pressure when pump head 205 is in operation. Therefore, by controlling the pressure of the cleaning liquid in the cooling circuit by pressure maintenance module 600, the cleaning liquid can satisfy the above flow rate distribution.

[0058] The amount of flushing fluid that needs to enter the human body through the catheter 201 varies depending on the clinical situation. However, in various scenarios, the amount of flushing fluid that enters the human body through the catheter 201 is generally much smaller than the amount that flows out from the flushing fluid outlet 246. Therefore, the pressure maintenance module 600 only needs to control the pressure of the flushing fluid in the cooling circuit to be slightly higher than the environmental pressure during the operation of the pump head 205.

[0059] 3 and 4 , the rotor shaft 2047 has a through-hole 2053 penetrating in the axial direction, and the cleaning cavity 2042 and the liquid isolation cavity 2050 communicate with each other via the through-hole 2053 (the proximal end of the through-hole 2053 is located in the cleaning cavity 2042, and the distal end is located in the liquid isolation cavity 2050), the catheter 202 and the cleaning liquid inlet 2043 communicate with the cleaning cavity 2042, and the cleaning liquid outlet 2046 communicates with the liquid isolation cavity 2050. In this way, the cleaning liquid that has entered the cleaning cavity 2042 flows backward through the through-hole 2053 to the liquid isolation cavity 2050 and finally flows out from the cleaning liquid outlet 2046, thereby realizing the cleaning liquid to continuously circulate and cool the rotor 2046.

[0060] A first bearing 235 for rotatably supporting the distal end of the rotor shaft 2047 is provided within the accommodation cavity 2049. The first bearing 235 partially liquid-isolates the cleaning cavity 2042 and the liquid isolation cavity 2050, and the cleaning liquid inlet 2043 and the cleaning liquid outlet 2046 are located on either side of the bearing 235. The liquid isolation effect of the first bearing 235 prevents the cleaning liquid that has entered the cleaning cavity 2043 from flowing directly to the cleaning liquid outlet 2046 and limits the cleaning liquid to flow mainly backward through the through-holes 2053, thereby achieving cooling of the rotor 2046.

[0061] The diameter of rotor shaft 2047 is smaller than the inner diameter of first bearing 235, and a first gap 2351 exists between them, and cleaning liquid passes through first gap 2351 to lubricate first bearing 235. Because the cross-sectional area of first gap 2351 is smaller than the cross-sectional area of through hole 2053, cleaning liquid flows mainly backward through through hole 2053, which has a larger cross-sectional area, thereby ensuring a flow rate of cleaning liquid for circulating cooling.

[0062] A second bearing 236 for rotationally supporting the proximal end of rotor shaft 2047 is further provided within accommodating cavity 2049. Second bearing 236 is located at the proximal end of first bearing 235 and cooperates with first bearing 235 to realize rotational support at both ends of rotor 2046, which is advantageous for maintaining rotational stability of rotor 2046. Similarly, the diameter of rotor shaft 2047 is smaller than the inner diameter of second bearing 236, and a second gap 2362 exists between them. Cleaning liquid passes through second gap 2362 to lubricate second bearing 236.

[0063] The second bearing 236 is provided with a through hole 2361 that penetrates in the axial direction, and the cross-sectional area of the through hole 2361 is larger than the cross-sectional area of the second gap 2362. In this way, the area of the passage through which the cleaning liquid returns to the front is increased, and the resistance of the cleaning liquid can be reduced, which is advantageous for realizing a large circulation flow rate.

[0064] As shown in FIG. 4, the pressure maintenance module 600 includes a cleaning liquid source 602 connected to the cooling circulation circuit via a refill line 601, and a pump 603 provided in the refill line 601 for replenishing the cleaning liquid supplied from the cleaning liquid source 602 to the cooling circulation circuit.

[0065] In this embodiment, the cleaning liquid consumed by entering catheter 201 is replenished from a separately provided cleaning liquid source 602. The pressure of the cleaning liquid in the cooling circulation circuit is maintained by pump 603, which is the other driving mechanism. In this way, the circulation of the cleaning liquid and the maintenance of the cleaning liquid pressure are accomplished by circulation drive member 503 and pump 603, respectively, and the pressure required to circulate the cleaning liquid and the pressure required to maintain the cleaning liquid pressure are different (generally, the pressure required to circulate the cleaning liquid is smaller than the pressure required to maintain the cleaning liquid pressure). Therefore, by separately driving the circulation of the cleaning liquid and the maintenance of the pressure, the control of circulation drive member 503 and pump 603 can be simplified, and the pressure control and flow rate control of the cleaning liquid can be more accurate.

[0066] To facilitate the connection of the lines, the cooling circulation module 600 further includes a buffer container 504, and the cleaning solution inlet pipe 501, the cleaning solution outlet pipe 502, and the refilling pipe 603 are all connected to the buffer container 504. The lines can be connected to the buffer container 504 using a luer taper, which makes the connection of the lines convenient.

[0067] To further improve the accuracy of pressure maintenance or control of the cleaning solution, the buffer container 504 has a volume that does not change and can at least withstand the pressure created by the pressure maintenance module 600. Furthermore, the buffer container 504 is a solid tank with high pressure resistance and a volume that does not change under typical pressure. Alternatively, in some embodiments, the buffer container 504 may directly employ a three-way joint, whose three ports are connected to the cleaning solution inlet pipe 501, the cleaning solution outlet pipe 502, and the refill pipe 603, respectively, and the internal cavity of the three-way joint forms a cavity whose volume does not change when subjected to the above pressures. Therefore, by using a three-way joint to configure the buffer container 504, the cleaning pipes are significantly simplified.

[0068] It has been proven through practice that the provision of a buffer container 504 with a constant volume in the cooling circuit significantly improves the accuracy of maintaining or controlling the pressure of the cleaning solution. This effect is surprising because, before adopting this design, the cleaning solution inlet pipe 501, the cleaning solution outlet pipe 502, and the refilling pipe 603 were connected by flexible joints, and after multiple tests, researchers and engineers always found that it was difficult to stably control the pressure of the cleaning solution and achieve the expected results.

[0069] The inventors have attempted to find the reason why this design can achieve the above effects, but at present it is not clear, and they speculate that the principle may be as follows.

[0070] To facilitate the layout and wiring of clinical conduits, the irrigation fluid inlet pipe 501 and the irrigation fluid outlet pipe 502 that constitute the cooling circuit are generally hoses, but the diameter of the hoses expands under the action of high pressure of the irrigation fluid, further changing the volume of the cooling circuit. If the volume of the cooling circuit changes but the pressure maintenance module 600 continues to operate in the same state (e.g., the rotation speed of the pump), the pressure of the irrigation fluid in the cooling circuit may change (decrease), and the amount of irrigation fluid entering the catheter 201 may become unstable.

[0071] Furthermore, by providing a buffer container 504 in the cooling circuit whose volume does not change (the volume of the buffer container 504 constitutes part of the cooling circuit), even though the expansion of the pipe diameters of the cleaning liquid inlet pipe 501 and the cleaning liquid outlet pipe 502 cannot be changed, the volume of the buffer container 504 is larger than the volumes of the cleaning liquid inlet pipe 501 and the cleaning liquid outlet pipe 502, and the volume of the buffer container 504 is unlikely to change, so the rate of change in the volume of the cooling circuit can be significantly reduced. In the embodiment shown in FIG. 4, a pump 603, which maintains pressure in the cooling circuit, is connected to the buffer container 504 by a refill pipe 601. In this way, the pumping pressure of the pump 603 acts directly on the buffer container 504, not on the cleaning liquid inlet pipe 501 or the cleaning liquid outlet pipe 502, and this can also serve to mitigate to some extent the change in the pipe diameters of the cleaning liquid inlet pipe 501 and the cleaning liquid outlet pipe 502.

[0072] As described above, by providing the buffer container 504, whose volume does not change, in the cooling circulation circuit, the problem of volume change in the cooling circulation circuit is at least partially solved, and further the accuracy of maintaining or controlling the pressure of the cleaning liquid is improved.

[0073] 4, in one embodiment, the circulation drive member 503 is provided in the cleaning liquid inlet pipe 501 and / or the cleaning liquid outlet pipe 502, and is a pump different from the pump 603 (for the sake of distinction, the pump is defined as the first pump, and the pump 603 is defined as the second pump). Because pump control technology has matured, using a pump as the circulation drive member 503 can simplify control.

[0074] When rotor 2046 rotates at high speed while immersed in cleaning solution, bubbles are generated, and research has found that these bubbles may be gases originally dissolved in the cleaning solution that precipitate due to the agitation and temperature increase caused by rotor 2046. Since it is clinically undesirable for these bubbles to enter the human body, it is necessary to capture the generated bubbles.

[0075] In one alternative embodiment, the cooling circuit is provided with a bubble filter 258 for filtering or capturing bubbles, preventing the bubbles from entering the human body through the catheter 201. Furthermore, the bubble filter 258 is provided in the irrigation liquid inlet pipe 501. This design is advantageous for installing the bubble filter 258, avoiding interference with other structures.

[0076] Furthermore, air bubbles are mainly generated within the liquid isolation cavity 2050, then flow out of the cleaning liquid outlet 246 together with the cleaning liquid, circulate through the cleaning liquid outlet pipe 502 and the cleaning liquid inlet pipe 501, and then re-enter the cleaning cavity 2042 through the cleaning liquid inlet 2043. As can be seen from this, air bubbles do not enter the human body via the catheter 201 after they are generated until they re-enter the cleaning cavity 2042 via the cleaning liquid inlet 2043. This means that air bubbles can be largely prevented from entering the human body before they enter the cleaning cavity 2042. Therefore, by providing the air bubble filter 258 to the cleaning liquid inlet pipe 501, the above-mentioned object can be achieved.

[0077] The bubble filter 258 may have any suitable conventional structure, such as a filter screen or membrane, but is not limited thereto in this embodiment. The filter screen or membrane is housed in a case structure, and the passage area of the filter screen or membrane can be maximized to reduce the flow resistance of the cleaning liquid through the filter screen or membrane, and the case housing the filter screen or membrane can have a flat, bulging structure.

[0078] It has been proven through practice that the cleaning method of this embodiment not only significantly reduces the high temperature of the cleaning fluid, but also provides a cooling effect to the drive assembly 100. Specifically, as shown in FIG. 3 , a rotating bracket 105 is mounted on the motor shaft 1021, and a driver 103 is mounted on the inner wall of the rotating bracket 105. A bearing chamber 109 is provided within the motor case 101, and the bearing chamber 109 is connected to the motor 102 via a flange 111. A bearing 110 for supporting the rotation of the rotating bracket 105 is provided within the bearing chamber 109. Therefore, the rotating components within the drive assembly 100, such as the motor 102, the driver 103, and the bearing 110, generate a large amount of heat. To solve the heat dissipation problem of these components, the motor 102 contacts the bearing chamber 109 via the flange 111. During operation, the driver 103, rotating bracket 105, bearing 110, bearing chamber 109, flange 111, and motor 102 are connected and physically in contact with each other. This physical contact forms a heat conduction path from the motor 102, flange, bearing chamber 109, bearing 110, and rotating bracket 105 to the driver 103. The heat from the motor 102, bearing 110, and driver 103, which are the main heat-generating components in the driver assembly 110, is absorbed by the large flow of cleaning fluid circulating within the driver catheter handle 204, and is then released into the air when the cleaning fluid is involved in extracorporeal circulation, thereby cooling the above components. Since the driver 103 is the component closest to the cleaning liquid, the heat of the driver 103 is transferred to the cleaning liquid in the liquid isolation cavity 2050 through the liquid isolation wall 2048, where it is cooled to a relatively low temperature, and the heat of other components in physical contact with it is transferred to the driver 103 and then to the liquid isolation cavity 2050 through the liquid isolation wall 2048, thereby achieving a temperature reduction.

[0079] Because the main heat-generating components in the drive assembly 100 are cooled by the flushing fluid in the drive catheter handle 204, the drive assembly 100 can simplify its heat dissipation design. As shown in FIG. 3 , the motor case 101 is made of plastic. Compared to a metal case, the plastic motor case 101 is less expensive, lighter in weight, and has a better feel, but it has a poorer heat dissipation effect. The poorer heat dissipation effect is actually more beneficial in clinical practice because the human body inevitably comes into contact with the outer surface of the motor case 101. If the motor case 101 is made of a material with good thermal conductivity, such as metal, heat may be rapidly transferred to the human body when it comes into contact with a part of the human body, such as a hand, and may cause burns. Conversely, if the surface temperature is the same, the plastic motor case 101 will not cause any damage when touched by the human body due to its poor thermal conductivity.

[0080] It should be noted that the above description is illustrative only and not limiting. Many embodiments and applications other than the examples provided herein will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings is limited not by the above description, but by the claims and the full scope of equivalents thereto.

[0081] In its entirety, all texts and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the following claims does not indicate a disclaimer of that subject matter, and should not be interpreted as the inventors not considering that subject matter to be part of the disclosed inventive subject matter.

Claims

1. A motor; A catheter, a drive shaft rotatably mounted in the catheter; a pump head including a pump case connected to a distal end of the catheter and an impeller housed in the pump case, the impeller being connected to a distal end of the drive shaft and being driven to rotate to pump blood; a drive catheter handle including a coupling case connected to a proximal end of the catheter and detachably connected to the motor, and a rotor driven by the motor, the proximal end of the drive shaft connected to the rotor, a housing cavity formed in the coupling case for rotatably supporting the rotor therein, the catheter communicating with the housing cavity, and the coupling case provided with a flushing fluid inlet and a flushing fluid outlet communicating with the housing cavity; a cooling circulation module including a cleaning liquid inlet pipe communicating with the cleaning liquid inlet and a cleaning liquid outlet pipe communicating with the cleaning liquid outlet, wherein a cooling circulation circuit is formed by the cleaning liquid inlet pipe, the accommodating cavity, and the cleaning liquid outlet pipe, and a first pump is provided in the cooling circulation circuit to drive the flow of the cleaning liquid; a pressure maintenance module including a cleaning liquid source communicating with the cooling circuit by a refill line, and a second pump provided in the refill line for refilling the cooling circuit with cleaning liquid supplied from the cleaning liquid source; Catheter pump.

2. the second pump is for maintaining a pressure of the cleaning liquid in the cooling circuit higher than the environmental pressure of the pump head during operation; The catheter pump of claim 1.

3. A part of the cleaning liquid that has entered the containing cavity through the cleaning liquid inlet enters the catheter and is entirely discharged into the human body by the pump head, and the other part passes through the rotor and is discharged from the cleaning liquid outlet. The catheter pump according to claim 1 or 2.

4. the amount of flushing fluid entering the catheter is less than the amount of flushing fluid exiting the flushing fluid outlet; The catheter pump of claim 3.

5. the cooling circulation module further includes a buffer vessel; the cleaning solution inlet pipe, the cleaning solution outlet pipe, and the refilling pipe all communicate with the buffer container; The buffer container does not change in volume and can withstand at least the pressure compensation of the pressure maintenance module. The catheter pump of claim 1.

6. The buffer vessel comprises a solid tank or a three-way joint. The catheter pump of claim 5.

7. The cooling circuit is provided with an air bubble filter. The catheter pump of claim 1.

8. The bubble filter is provided in the cleaning liquid inlet pipe. The catheter pump of claim 7.

9. the rotor includes a rotor shaft connected to a proximal end of the drive shaft, the rotor shaft having a through hole extending therethrough along the axial direction; the actuation catheter handle further includes an irrigation bracket and a liquid isolation wall disposed within the mating case, the irrigation bracket defining an irrigation cavity, and the liquid isolation wall defining a liquid isolation cavity; the cleaning cavity and the liquid isolation cavity are in communication with each other through the through hole; the catheter and irrigation fluid inlet are in communication with the irrigation cavity, and the irrigation fluid outlet is in communication with the liquid isolation cavity; The catheter pump of claim 1.

10. the motor drives a driving body and transmits the rotational force of the motor to a driven body coupled to the driving body; the liquid isolation wall is located between the driver and the driven body; the heat of the driving body is transferred to the cleaning liquid in the liquid isolation cavity by the liquid isolation wall; 10. The catheter pump of claim 9.

11. a motor shaft of the motor connected to a rotating bracket; the driver is provided on an inner wall of the rotation bracket, The motor is housed in a motor case, A bearing chamber is provided within the motor case, The bearing chamber is connected to the motor by a flange; A bearing for rotationally supporting the rotating bracket is provided in the bearing chamber. The catheter pump of claim 10.

12. The motor case is made of plastic. The catheter pump according to claim 10 or 11.

13. a first bearing for rotatably supporting a distal end of the rotor shaft is provided within the accommodating cavity; the first bearing partially fluidly isolates the cleaning cavity from the fluid isolation cavity; the cleaning liquid inlet and the cleaning liquid outlet are located on opposite sides of the first bearing; 10. The catheter pump of claim 9.

14. a first gap exists between the first bearing and the rotor shaft; 14. The catheter pump of claim 13.

15. The cross-sectional area of the first gap is smaller than the cross-sectional area of the through hole.

15. The catheter pump of claim 14.

16. a second bearing is provided within the receiving cavity for rotatably supporting a proximal end of the rotor shaft; a second gap exists between the second bearing and the rotor shaft; 14. The catheter pump of claim 13.

17. The second bearing is provided with a through hole that penetrates along the axial direction, The cross-sectional area of the passage hole is larger than the cross-sectional area of the second gap.

17. The catheter pump of claim 16.

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