Sheath assembly for introducing catheter pump into body of subject

Abstract

A sheath assembly for introducing a catheter pump into a body of a subject includes a first sheath and a second sheath, the first sheath including a first section, an inner wall of the first section and an outer wall of the pump assembly at a first opening forming a gap for a guidewire to pass through.

Description

Technical Field

[0001] The invention relates to the technical field of medical devices, and in particular to a sheath component used for introducing a catheter pump into a subject's body. Background Art

[0002] US9402942B2 discloses the common practice of inserting a catheter pump into a subject's body in the art: a guide wire is inserted from a pigtail tube, passed through a pump assembly, and then led out from the pump outlet, so that the pump is loaded on the guide wire. By pushing the catheter forward, the pump is moved forward along the guide wire and inserted into the subject's heart. In the process of the pump moving forward along the guide wire, the pump outlet will scrape the guide wire, causing the guide wire coating to fall off. In particular, when the pump passes through a tearable sheath, the tearable sheath presses the guide wire tightly against the outer wall of the pump outlet, making it fit as closely as possible with the motor housing, and the guide wire and the pump outlet are strongly scraped, and the coating shedding phenomenon is particularly obvious. Summary of the invention

[0003] The present invention provides a sheath assembly, which is intended to minimize or even avoid the scraping of the coating of the guide wire by the catheter pump during the process of inserting the catheter pump into the body of a subject, thereby reducing the risk of particulate matter entering the human body.

[0004] To achieve the above-mentioned purpose, the present invention proposes a sheath assembly for introducing a catheter pump into a subject's body, the catheter pump comprising a catheter, a pump assembly connected to the distal end of the catheter and capable of being delivered into the subject's body under the guidance of a guide wire, the pump assembly being provided with a first opening and a second opening at the distal end of the first opening. The guide wire can be removably inserted into the pump assembly from the second opening and then passed out from the first opening. The sheath assembly comprises: a first sheath into which the pump assembly can be introduced outside the subject's body, and a second sheath that can be partially inserted into the subject's body through a puncture port. The first sheath comprises a first sheath seat, a first sheath tube connected to the distal end of the first sheath seat, and a first reusable seal provided in the first sheath seat. The second sheath comprises a second sheath seat, a second sheath tube connected to the distal end of the second sheath seat, and a second reusable seal provided in the second sheath seat. The first sheath tube comprises a first section, the inner diameter of the first section being greater than the outer diameter of the portion of the pump assembly corresponding to the first opening, so that a gap for the guide wire to pass through is formed between the inner wall of the first section and the outer wall of the portion of the pump assembly corresponding to the first opening. When the pump assembly is introduced into the first sheath, at least the portion of the pump assembly corresponding to the first opening is located in the first section and at the distal end of the first resealable seal. The first sheath is operably inserted into the second sheath through the second resealable seal, and at least part of the first section is located at the distal end of the second resealable seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 It is a schematic diagram of inserting the catheter pump of the first embodiment into a subject;

[0006] Figure 2 for Figure 1 Schematic diagram of the mid-catheter pump positioned within the subject's heart;

[0007] Figure 3 A schematic diagram of the catheter pump of the second embodiment being inserted into a subject's body;

[0008] Figure 4 is a schematic structural diagram of a first sheath of the first embodiment;

[0009] Figure 5 is a schematic structural diagram of a first sheath of a second embodiment;

[0010] Figure 6 A schematic diagram of introducing a first sheath into a catheter pump according to the first embodiment;

[0011] Figure 7 A schematic diagram of introducing a first sheath into a catheter pump according to a second embodiment;

[0012] Figure 8 A schematic diagram of inserting the first sheath into the second sheath;

[0013] Fig. 9 This is a schematic diagram of the first sheath after being inserted into the second sheath;

[0014] Fig.10 A schematic diagram of a catheter pump entering a second sheath from a first sheath;

[0015] Fig.11 Schematic diagram of the catheter pump entering the subject's body from the second sheath. DETAILED DESCRIPTION

[0016] The terms "proximal" and "distal" are relative to the doctor who operates the catheter pump 100. "Proximal" refers to the part relatively close to the doctor, and "distal" refers to the part relatively far from the doctor. For example, the catheter 110 is located at the proximal end of the pump assembly 120, and the pump assembly 120 is located at the distal end of the catheter 110. It should be understood that these positional terms are defined for the convenience of description and are not restrictive and absolute.

[0017] like Figures 1 to 3As shown, the catheter pump 100 includes a catheter 110 and a pump assembly 120, wherein the pump assembly 120 includes a motor 140 connected to the distal end of the catheter 110, a blood flow channel connected to the distal end of the motor 140, and an impeller located in the blood flow channel and driven by the motor 140 to rotate for pumping blood. A first opening 120a is provided at the proximal end of the blood flow channel, and a second opening 120b is provided at the distal end. The blood channel includes a curved cannula 121, a first blood window 122 connected to the proximal end of the cannula 121, and a second blood window 123 connected to the distal end of the cannula 121, and the impeller is located in the first blood window 122. The first opening 120a is formed on the side wall of the first blood window 122, and the side wall of the second blood window 123 is provided with a third opening 120c for blood to pass through. The first blood window 122 is connected between the cannula 121 and the motor 140, and the distal end of the second blood window 123 is connected to a protective structure 124 for preventing damage to blood vessels and left ventricle LV inner wall tissue.

[0018] like Figure 1 to Figure 2 As shown, in one embodiment, the protective structure 124 is a flexible hollow pigtail tube with an arc-shaped or coiled end in a natural state (when the guide wire 130 is inserted therein, the pigtail tube is partially straightened), and the second opening 120b is the distal end opening of the pigtail tube. Figure 3 As shown, in another embodiment, the distal end of the second blood window 123 is not provided with a pigtail tube, and the protective structure 124 is replaced by a round head structure with a rounded outer surface, and the second opening 120b is formed on the side wall of the second blood window 123, that is, the third opening 120c constitutes the second opening 120b.

[0019] One of the first opening 120a and the third opening 120c constitutes a blood inlet, and the other constitutes a bleeding outlet, which depends on the applicable scenario of the catheter pump 100. When the catheter pump 100 is used for left ventricular assistance, the first opening 120a is a bleeding outlet, and the third opening 120c is a blood inlet. When the catheter pump 100 is used for right ventricular assistance, the first opening 120a is a blood inlet, and the third opening 120c is a bleeding outlet.

[0020] Taking the catheter pump 100 for left ventricular assist as an example, the guidewire 130 can be inserted into the subject's body through a puncture port opened on the subject's skin, and its distal end passes through the aortic valve AV and enters the left ventricle LV. At this time, the distal end of the guidewire 130 is located in the subject's body, and the proximal end is exposed outside the subject's body. The doctor guides the pump assembly 120 onto the guidewire 130, and the guidewire 130 passes through the pump assembly 120 from the second opening 120b and then passes out from the first opening 120a. Then, the catheter 110 is pushed forward, so that the pump assembly 120 moves forward in the subject's body under the guidance of the guidewire 130, until the distal end of the pump assembly 120 passes through the aortic valve AV and enters the left ventricle LV, the cannula 121 spans the aortic valve AV, the third opening 120c is located in the left ventricle LV, and the first opening 120a is located in the aorta AO. The rotation of the impeller draws the blood in the left ventricle LV into the cannula 121 through the third opening 120c and pumps it from the first opening 120a to the aorta AO, so as to assist the heart's pumping function and reduce the heart's burden.

[0021] That is to say, the catheter pump 100 of this embodiment and the scheme described below using the guidewire 130 to assist the pump assembly 120 to be inserted into the subject's body are not only applicable to the scenario where the catheter pump 100 is used for left ventricular assistance, but also to the scenario where the right ventricular assistance is used. Of course, it can also be applied to assist the kidneys as a renal pump. The following mainly describes the scenario where the catheter pump 100 is used as a left ventricular assistance, but based on the above description, it can be seen that the protection scope of this embodiment is not limited thereto.

[0022] like Figures 4 to 11 As shown, the sheath assembly includes a first sheath 210 and a second sheath 220. The first sheath 210 can be used to introduce the pump assembly 120 outside the subject's body, and includes a first sheath seat 211, a first sheath tube 212 connected to the distal end of the first sheath seat 211, and a first reusable seal 213 disposed in the first sheath seat 211 (specifically, in the proximal end). The second sheath 220 can be partially inserted into the subject's body through the puncture port, and includes a second sheath seat 221, a second sheath tube 222 connected to the distal end of the second sheath seat 221, and a second reusable seal 223 disposed in the second sheath seat 221 (specifically, in the proximal end).

[0023] like Figures 4 to 5 As shown, the first sheath 212 includes a first section 212a located at the distal end of the first repeatable seal 213, and the inner diameter of the first section 212a is larger than the outer diameter of the portion of the pump assembly 120 corresponding to the first opening 120a (i.e., the first blood window 122), so that a gap is formed between the inner wall of the first section 212a and the outer wall of the first blood window 122 for the guide wire 130 to pass through.

[0024] When the pump assembly 120 is introduced into the first sheath 210, the first blood window 122 is located in the first section 212a and at the distal end of the first resealable seal 213. The first sheath 210 can be inserted into the second sheath 220 through the second resealable seal 223, and at least part of the first section 212a is located at the distal end of the second resealable seal 223. The pump assembly 120 moves from the first sheath 210 to the second sheath 220 when the catheter 110 is pushed forward, and moves from the second sheath 220 into the subject's body when the catheter 110 is further pushed forward.

[0025] Since a gap is formed between the first section 212a and the first blood window 122 where the first opening 120a is provided for the guide wire 130 to pass through, the guide wire 130 will not be squeezed and scraped against the wall of the first opening 120a during the process of the pump assembly 120 being introduced into the second sheath 220. Therefore, the first section 212a with a larger inner diameter separates the guide wire 130 from the second sheath 220, preventing the radial squeezing force from the second sheath 220 from pressing the guide wire 130 against the first opening 120a, so that during the process of the pump assembly 120 moving forward along the guide wire 130, the guide wire 130 can freely pass through the first opening 120a, reducing or even preventing the coating of the guide wire 130 from being scraped and falling off, thereby reducing the risk of coating particles entering the human body.

[0026] In addition, if Fig. 9 As shown, after the first sheath 210 is inserted into the second sheath 220 and the pump assembly 110 enters the exhaust position (described below), since the first blood window 122 of the first opening 120a is located at the distal end of the first repeatable seal 213, the blood flowing out of the first opening 120a is retained in the first sheath 210 by the first repeatable seal 213 and will not spill on the operating table, thereby avoiding blood contamination.

[0027] The first sheath tube 212 further includes a second section 212b located at the distal end of the first section 212a and having an inner diameter that gradually decreases from proximal to distal. The second section 212b is a closed section, and its inner diameter is slightly smaller than the outer diameter of the pump assembly 120 (specifically, the cannula 121). Fig. 9In the exhaust position shown, the second section 212b seals and wraps the outer wall of the pump assembly 120, clamps and seals the pump assembly 120, the third opening 120c is located in the second sheath 220, and the first opening 120a is located in the first sheath 210. In this way, the third opening 120c entering the second sheath 220 is connected to the blood vessel, and under the action of the internal and external pressure difference, blood enters the pump assembly 120 through the third opening 120c, and the pump assembly 120 is exhausted. When the blood flows out from the first opening 120a, it is considered that the pump assembly 120 has completed exhaust. Therefore, the closed second section 212b clamps and seals the outer wall of the pump assembly 120 in the exhaust position, and establishes a unique channel in which blood can only flow through the third opening 120c→pump assembly 120→first opening 120a. The establishment of this unique channel enables the pump assembly 120 to be fully pre-charged and exhausted.

[0028] The side wall of the first sheath 210 is provided with a through hole 215, and a waterproof and breathable material 216 is provided at the through hole 215. Figure 4 As shown, in one embodiment, the waterproof breathable material 216 may be a belt-shaped waterproof breathable membrane, which is wrapped around the outer wall of the first sheath 210 and covers the through hole 215. Alternatively, as Figure 5 As shown, in another embodiment, the waterproof breathable material 216 can be a hydrogel film as provided in US2004 / 0052689, which is filled in the through hole 215. The waterproof breathable material 216 allows the air exhausted by the pump assembly 120 to pass through and overflow from the first sheath 210, so as to establish a pressure balance inside and outside the first sheath 210, avoid excessive pressure inside the first sheath 210 to inhibit the exhaust of the pump assembly 110, and ensure that the exhaust of the pump assembly 110 is complete and sufficient. The waterproof breathable material 216 can further prevent blood from passing through, so that the blood that displaces the air in the pump assembly 110 is trapped in the first sheath 210 and does not overflow and spill on the operating table, thereby avoiding blood contamination.

[0029] At least a plurality of through holes 215 may be provided to improve exhaust efficiency. Furthermore, the through holes 215 are provided on the first sheath seat 211. Since the first sheath seat 211 has a larger inner diameter than the first sheath tube 212, and when the pump assembly 120 is in a position such as Fig. 9 In the exhaust position shown, the first opening 120a is closer to the first sheath seat 211. Therefore, the gas exhausted from the pump assembly 120 tends to first converge in the first sheath seat 211 with a larger space, and the through hole 215 provided on the first sheath seat 211 will facilitate the efficient exhaust of the gas. In addition, due to the existence of the stopper (described below), the first sheath seat 211 is always located outside the second sheath seat 221, that is, located outside the proximal end of the second repeatable seal 223. The through hole 215 provided on the first sheath seat 211 can always ensure that it is located outside the second sheath seat 221 without being blocked or sealed by the second repeatable seal 223, thereby ensuring smooth exhaust.

[0030] like Figure 6 As shown, the distance between the distal end surface of the first reusable seal 213 and the distal end surface of the first sheath tube 212 is L1, and the farthest distance between the first opening 120a and the third opening 120c is L2, L1>L2. In this way, the first sheath 210 forms an inner cavity of sufficient length to completely accommodate the pump assembly 120 at least in the section between the first opening 120a and the third opening 120c. At this time, the first opening 120a for blood to flow out during exhaust is located in the distal end of the first reusable seal 213, so that the blood flowing out of the first opening 120a when the pump assembly 120 is exhausted is trapped in the first sheath 210.

[0031] Furthermore, the farthest distance from the first opening 120a to the second opening 120b is L3, L1>L3. In this way, the inner cavity of the first sheath 210 completely accommodates the pump assembly 120 therein, and when the first sheath 210 is inserted into the second sheath 220, the second section 212b of the distal end of the first sheath 210 will penetrate the harder second repeatable seal 223, without the protection structure 124 having to undertake the penetration task, which is conducive to the smooth insertion of the first sheath 210 into the second sheath 220, improves the coupling efficiency of the two, and protects the protection structure 124 (especially when a flexible hollow pigtail tube is used) from being damaged.

[0032] In this embodiment, the farthest distance L2 is the distance between the proximal end of the first opening 120a and the distal end of the third opening 120c when the cannula 121 is straightened. The farthest distance L3 varies depending on the type of protective structure 124. Figure 3 When the protective structure 124 is in the rounded head structure shown in FIG. 1 , L3 is the distance between the proximal end of the first opening 120a and the distal end of the second opening 120b / third opening 120c when the cannula 121 is straightened; Figure 1 Or when the pigtail tube is shown in FIG. 2 , L3 is the distance between the proximal end of the first opening 120a and the distal end of the pigtail tube when the cannula 121 and the pigtail tube are straightened simultaneously.

[0033] like Figure 4 , Figure 5 , Figure 8-Figure 10 As shown, the outer diameter of the first sheath seat 211 is greater than the outer diameter of the first sheath tube 212, so as to form a first outer stopper 214 at the transitional connection between the two. The inner diameter of the second sheath seat 221 is greater than the inner diameter of the second sheath tube 222, so as to form an inner stopper 224 at the transitional connection between the two. The first outer stopper 214 and the inner stopper 224 are used to limit the depth of the first sheath 210 inserted into the second sheath 220, so that the first sheath tube 212 is located outside the puncture port, and the first sheath seat 211 is naturally located outside the second sheath seat 221.

[0034] For example, the solution for minimizing leakage during pump insertion disclosed in the prior art CN112867531B is to set a sleeve outside the pump, and the bleeding port of the pump is located inside the sleeve to receive the blood that seeps out from the bleeding port when the pump inlet at the distal end enters the body during the pump intervention process, thereby reducing blood leakage during pump intervention. However, the distal end of the sleeve needs to be inserted into the patient's blood vessel through a hemostatic valve. Although this can increase the rigidity of the cannula and make it easier for the pump to enter the patient's blood vessel, it will increase the outer diameter of the intervention sheath, resulting in an increase in the intervention size.

[0035] In contrast, in this embodiment, the first sheath tube 212 is limited outside the puncture port through the above-mentioned limiting design, so as to prevent the first sheath tube 212 from being inserted into the second sheath tube 222. Since the second sheath tube 222 is inserted into the puncture port, the first sheath tube 212 is limited outside the second sheath tube 222, so that the introduction of the first sheath tube 212 can prevent the second sheath tube 222 from radially expanding, which can keep the puncture port small in size and not expand, so as to reduce the risk of bleeding and infection at the puncture port.

[0036] like Figure 8 As shown, for basically the same purpose of preventing the puncture port from being enlarged, the outer diameter of the second sheath seat 221 is larger than the outer diameter of the second sheath tube 222, so as to form a second outer stopper 225 at the transition connection between the two that can be used to limit the insertion depth of the second sheath 220 into the subject's body, so that the second sheath seat 221 with a relatively larger outer diameter is located outside the puncture port.

[0037] The transitional connection mentioned above is generally set as a gradual slope or arc surface to avoid forming an obvious step structure. For the same purpose, a stop structure can also be set on the proximal outer wall of the first sheath tube 212 and the second sheath tube 222 to limit the insertion depth of the first sheath 210 and the second sheath 220 respectively.

[0038] The resealable parts 213 and 223 are made of silicone material and are fixed in the sheath seats 211 and 221 by interference fit and / or compression fit. The resealable parts 213 and 223 are provided with a cutout (such as Figure 4-Figure 8 The incision is closed by the dotted line (shown in the middle), and is used for the pump or sheath to pass through. After the pump or sheath is removed, the incision is closed by the elasticity of the material itself to achieve sealing.

[0039] Since the first reusable seal 213 generally only plays a sealing role when the pump assembly 120 needs to be vented as described above, the sealing pressure required is small and the sealing time is short (described below, the first sheath 210 will be peeled off in time). Therefore, the first reusable seal 213 is set to be softer, and the resistance of the pump assembly 120 to the first sheath 210 can be reduced while meeting the needs, which is important for protecting the non-rigid bendable and deformable cannula 121. The second reusable seal 223 needs to play a sealing role during the entire intervention process of the pump assembly 120 and the entire working process of the pump assembly 120 after the intervention is completed. A harder second reusable seal 223 is required to bear a greater sealing pressure and a longer sealing time. In addition, the second reusable seal 223 is used for the sheath tube 211 of the first sheath 210, which is harder than the cannula 121, to penetrate and enter, and the first sheath 210 is a tearable sheath, so it has a lower level of anti-damage protection than the cannula 121. The greater hardness design of the second resealable member 223 may require less consideration of damage protection against the harder and less disposable first sheath 210, which may also provide a better and longer-lasting seal.

[0040] The first sheath 210 is a peelable sheath, and a handle protruding outward is formed at the proximal end of the first sheath seat 211 to facilitate the operator to perform a tearing operation. Fig. 9 and Fig.10 As shown, after the pump assembly 110 is completely transferred from the first sheath 210 to the second sheath 220, the first sheath 210 can be peeled off. The peeling off of the first sheath 210 can reduce the resistance of the pump assembly 120 to push forward, and reduce the operational interference with the push catheter 110, so that the pump assembly 120 can be quickly inserted and the surgical deployment efficiency can be improved.

[0041] The pump assembly 120 can be selectively introduced into the first sheath 210 from the proximal end or the distal end, depending on how the first sheath 210 and the pump assembly 120 are arranged. Figure 6 As shown, in one embodiment, the first sheath 210 and the pump assembly 120 remain independent and separable from each other, and the pump assembly 120 can be introduced into the first sheath 210 from the proximal end thereof through the first resealable seal 213. Alternatively, as Figure 7 As shown, in another embodiment, the first sheath 210 is movably sleeved outside the catheter 110, and the pump assembly 120 is introduced into the first sheath 210 from the distal end thereof by pushing the first sheath 210 forward and / or pulling the catheter 110 backward. These two embodiments provide greater flexibility for introducing the pump assembly 120 into the first sheath 210.

[0042] The process of introducing the catheter pump 100 into the subject by the sheath assembly of this embodiment is roughly as follows:

[0043] Use Figure 6 or Figure 7In any of the methods shown, the pump assembly 120 is introduced into the first sheath 210 outside the subject's body, so that at least the section of the pump assembly 120 between the first opening 120a and the third opening 120c is completely received in the first sheath 210 (e.g., Figure 8 Then, as Fig. 9 and Fig.10 As shown, the first sheath 210 together with the pump assembly 120 is inserted into the second sheath 220, and the catheter 110 is pushed forward to move the pump assembly 120 from the first sheath 210 to the second sheath 220. After sufficient exhaust is performed at the exhaust position, the catheter 110 is pushed forward continuously, and the pump assembly 120 is pushed out of the first sheath 210 and into the second sheath 220. Subsequently, the first sheath 210 is peeled off, and the catheter 110 is pushed forward continuously, and the pump assembly 120 is pushed out of the second sheath 220 and into the blood vessel of the subject, as shown in FIG. Fig.11 Then, the catheter 110 is pushed forward continuously to move the pump assembly 120 forward in the subject's blood vessel until it is inserted into the heart.

[0044] The above description is only a preferred embodiment of the present invention, and does not limit the scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings, or directly / indirectly applied in other related technical fields under the concept of the present invention, are included in the protection scope of the present invention.

Claims

1. A sheath assembly for introducing a catheter pump into a subject's body, the catheter pump comprising a catheter, a pump assembly connected to the distal end of the catheter and capable of being delivered into the subject's body under the guidance of a guide wire, the pump assembly being provided with a first opening and a second opening located at the distal end of the first opening; the guide wire being removably passed through the pump assembly from the second opening and then passed out from the first opening; the sheath assembly comprising: A first sheath configured to allow the pump assembly to be introduced thereinto outside the body of a subject, comprising a first sheath seat, a first sheath tube connected to a distal end of the first sheath seat, and a first reusable seal disposed in the first sheath seat; A second sheath configured to be partially inserted into a subject through the puncture port, comprising a second sheath seat, a second sheath tube connected to a distal end of the second sheath seat, and a second reusable seal disposed in the second sheath seat; The first sheath comprises a first section, the inner diameter of the first section is larger than the outer diameter of the portion of the pump assembly corresponding to the first opening, so that a gap for the guide wire to pass through is formed between the inner wall of the first section and the outer wall of the portion of the pump assembly corresponding to the first opening; When the pump assembly is introduced into the first sheath, at least the portion of the pump assembly corresponding to the first opening is located within the first section and at the distal end of the first repeatable seal; the first sheath can be operably inserted into the second sheath through the second repeatable seal, and at least part of the first section is located at the distal end of the second repeatable seal.

2. In the sheath assembly as described in claim 1, the outer diameter of the first sheath seat is larger than the outer diameter of the first sheath tube to form a first outer stop at the transition connection between the two; and / or the inner diameter of the second sheath seat is larger than the inner diameter of the second sheath tube to form an inner stop at the transition connection between the two; the first outer stop and the inner stop are used to limit the depth of insertion of the first sheath into the second sheath so that the first sheath tube is located outside the puncture port.

3. In the sheath assembly as described in claim 1, the outer diameter of the second sheath seat is larger than the outer diameter of the second sheath tube to form a second outer stop at the transition connection between the two, and the second outer stop is used to limit the depth of insertion of the second sheath into the subject's body so that the second sheath seat is located outside the puncture port.

4. The sheath assembly as claimed in claim 1, wherein the distal end of the pump assembly is further provided with a third opening, and the third opening and the first opening are provided for blood circulation; the distance between the distal end surface of the first reusable seal and the distal end surface of the first sheath is L1, and the farthest distance between the first opening and the third opening is L2, and L1>L2; Preferably, the pump assembly further comprises a cannula, a first blood window connected to the proximal end of the cannula, and a second blood window connected to the distal end of the cannula; the first opening is provided on the first blood window, and the third opening is provided on the second blood window; A hollow pigtail tube is provided at the distal end of the second blood window, and the second opening is the distal opening of the pigtail tube; or, no pigtail tube is provided at the distal end of the second blood window, and the third opening constitutes the second opening; Preferably, when the catheter pump is used for left ventricular assistance, the first opening is the bleeding port and the third opening is the blood inlet; when the catheter pump is used for right ventricular assistance, the first opening is the blood inlet and the third opening is the bleeding port; Preferably, the longest distance from the first opening to the second opening is L3, and L1>L3.

5. The sheath assembly of claim 1, wherein the first resealable member is more flexible than the second resealable member.

6. The sheath assembly as claimed in claim 1, wherein the first sheath is independently provided with the catheter pump, and the pump assembly is operably introduced into the first sheath from the proximal end thereof through the first repeatable seal; or The first sheath is movably sleeved on the radially outer side of the catheter, and the pump assembly is introduced into the first sheath from the distal end thereof by pushing the first sheath forward and / or pulling the catheter backward.

7. The sheath assembly as claimed in claim 1, wherein a through hole is formed on the side wall of the first sheath, and a waterproof and breathable material is provided at the through hole.

8. The sheath assembly as claimed in claim 7, wherein the through hole is provided on the first sheath seat.

9. The sheath assembly as claimed in claim 1, wherein the first sheath tube further comprises a second section located at the distal end of the first section and having an inner diameter gradually reduced from proximal to distal; a third opening is further provided at the distal end of the pump assembly, and the third opening and the first opening are provided for blood circulation; During the movement of the pump assembly from the first sheath to the second sheath, there is a position suitable for exhausting the pump assembly: the second section seals and wraps the outer wall of the pump assembly, the third opening is located in the second sheath, and the first opening is located in the first sheath.

10. The sheath assembly of claim 1, wherein the first sheath is configured as a peelable sheath and is peeled away after the pump assembly is moved into the second sheath.

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