A self-expanding return cannula for ECMO

Abstract

The application discloses a self-expanding reflux cannula for ECMO and relates to the technical field of medical devices.The self-expanding reflux cannula comprises an implantation tube, a sleeve and a connecting pipe.The implantation tube comprises an inner covering film, an outer covering film and a self-expanding vascular stent.The inner covering film is arranged on the inner wall of the self-expanding vascular stent, and the outer covering film is arranged on the outer wall of the self-expanding vascular stent.The self-expanding vascular stent is in a mesh tube structure and can be radially expanded and contracted.The inner covering film and the outer covering film are both in a tubular shape and can be radially expanded and contracted with the self-expanding vascular stent.The sleeve is arranged on the implantation tube and can be separated from the implantation tube.The sleeve is used for maintaining the implantation tube in a radially contracted state.The one end of the connecting pipe is in communication with one end of the implantation tube, and the other end of the connecting pipe is used for being in communication with an arterial blood outlet of an ECMO system.The implantation tube, the sleeve and the connecting pipe are all flexible tubes.The cannula can be adapted to various blood vessels of different sizes, can avoid causing arterial blood vessel injury due to expansion of the blood vessel and can also supply blood to a distal limb end.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a self-expanding reflux cannula for ECMO. BACKGROUND

[0002] The cannula is a key component directly connected to the human body blood vessel in the extracorporeal membrane oxygenation (ECMO) system, which plays a role of connecting the extracorporeal circulation pipeline of the ECMO system and the human body blood vessel bridge, and plays a crucial role in the normal function of the ECMO system. Two cannulas are included in an ECMO system, one cannula is to draw venous blood from the human body, also known as a drainage tube, and the other cannula is to return the arterial blood after oxygenation by the ECMO system to the human body blood vessel, also known as a reflux tube.

[0003] In the clinical treatment of ECMO system, the veno-arterial (VA) cannula is a commonly used method, which draws blood from the vein through the venous cannula, and returns the arterial blood after oxygenation by the ECMO system to the human body through the arterial cannula. Since the flow of the ECMO system is often high when supporting patients with heart and lung failure, if a cannula with a small inner diameter is selected, the blood perfusion resistance will increase, and the same perfusion volume will require a higher blood pump speed to achieve, which also exacerbates the blood damage caused by ECMO. Therefore, when selecting a cannula, a cannula with a relatively large inner diameter is generally selected according to the size of the patient's arterial blood vessel. At the same time, the arterial cannula (reflux tube) often needs to be expanded once or multiple times before being implanted into the blood vessel to expand the implanted blood vessel for easy implantation of the cannula, and this method often damages the implanted blood vessel and causes complications such as bleeding and blood vessel rupture.

[0004] The femoral artery VA-ECMO refers to a method of establishing ECMO assistance for emergency treatment by drawing venous blood through the femoral vein, returning the arterial blood after oxygenation by the ECMOM through the femoral artery cannula. In the femoral artery VA-ECMO, the blood after oxygenation is often returned to the femoral artery through the arterial cannula, which often causes ischemic complications in the distal end of the femoral artery. Since the blood return direction of the cannula on the market is only one direction, after the femoral artery cannula is inserted into the femoral artery, only the blood can be guaranteed to flow along the femoral artery to the abdominal aorta, aortic arch, carotid artery, etc. for blood supply, and the distal end of the femoral artery, such as the calf and foot, may be insufficiently supplied with blood. Long-term support may cause long-term ischemia of the lower limbs, and the calf and foot may have a risk of necrosis.

[0005] For femoral artery cannulation, there is no arterial cannula in the clinic that can directly provide blood perfusion ECMO for lower extremities, so clinicians can only provide blood perfusion for the distal end of the cannula by adding a perfusion bypass to the distal end of the cannula. Although this method solves the problem of ischemia of the distal end of the VA-ECMO femoral artery cannula, it increases the complexity of the operation. Establishing a perfusion bypass requires another incision in the patient's lower extremity blood vessels to insert a bypass perfusion tube, which increases the complexity of the ECMO surgery, which is already very complex, and increases the patient's pain. SUMMARY

[0006] The purpose of the present application is to provide a self-expanding reflux cannula for ECMO to solve the problems existing in the prior art and avoid the damage to the arterial blood vessels caused by the over-thick expansion tube when the blood vessels are expanded before cannulation.

[0007] To achieve the above-mentioned purpose, the present application provides the following scheme:

[0008] The present application provides a self-expanding reflux cannula for ECMO, comprising:

[0009] An implant tube, the implant tube comprises an inner covering membrane, an outer covering membrane and a self-expanding vascular stent, the inner covering membrane is applied to the inner wall of the self-expanding vascular stent, and the outer covering membrane is applied to the outer wall of the self-expanding vascular stent; the self-expanding vascular stent is a net tube structure and can expand and contract radially, and the inner covering membrane and the outer covering membrane are both tubular and can expand and contract radially with the self-expanding vascular stent;

[0010] A sleeve is sleeved on the implant tube, and the sleeve can be separated from the implant tube, and the sleeve is used to maintain the implant tube in a radially contracted state;

[0011] A connecting tube having one end in communication with one end of the implant tube and the other end in communication with the arterial blood outlet of an ECMO system; the implant tube, the sleeve and the connecting tube are all flexible tubes.

[0012] Preferably, it further comprises a shunt structure, the shunt structure comprises a cylindrical shunt membrane and a shunt hole provided on the tube wall of the implant tube, the shunt hole penetrates the inner covering membrane, the self-expanding vascular stent and the outer covering membrane; the cylindrical shunt membrane is sleeved on the implant tube, the diameter of the cylindrical shunt membrane gradually increases from one end to the other end, the constricted end of the cylindrical shunt membrane is fixedly connected with the outer wall of the implant tube; there is a gap between the flared end of the cylindrical shunt membrane and the outer wall of the implant tube; the shunt hole is located between the constricted end and the flared end; and the flared end is closer to the connecting tube than the constricted end.

[0013] Preferably, the number of shunt holes is at least one.

[0014] Preferably, the sleeve is provided with a protruding part on the outer wall of the end close to the connecting pipe.

[0015] Preferably, the protruding part is annular.

[0016] Preferably, the inner covering film and the outer covering film are both made of biocompatible elastic film; the inner wall of the inner covering film and the outer wall of the outer covering film are both coated with an anticoagulant drug.

[0017] Preferably, the surface of the end of the implant pipe away from the connecting pipe is smooth.

[0018] Preferably, the end of the implant pipe connected with the connecting pipe is provided with a connecting ring, the outer wall of the connecting ring is provided with a plurality of convex rings, the inner wall of the end of the connecting pipe connected with the implant pipe is provided with a plurality of ring grooves, the ring grooves correspond to the convex rings one by one, the ring grooves can be clamped with the corresponding convex rings; the connecting ring and the convex ring are both made of elastic material.

[0019] Preferably, the length of the sleeve is greater than or equal to the length of the implant pipe, and the inner diameter of the sleeve is greater than the outer diameter of the connecting pipe.

[0020] The present application has the following technical effects relative to the prior art:

[0021] The self-expanding return cannula for ECMO of the present application can be inserted into the arterial blood vessel without expanding the arterial blood vessel, thereby avoiding damage to the arterial blood vessel caused by expansion; since the implant pipe in the present application is maintained in a relatively thin state under the action of the sleeve, the self-expanding return cannula for ECMO of the present application can also be inserted into a relatively thin blood vessel, and can be adapted to a variety of blood vessels of different sizes from thick to thin. Currently, different cannulas need to be selected according to different patients, different sizes of blood vessels in different parts, so a variety of different size cannulas need to be processed during production and processing. There are currently hundreds of different size cannulas on the market. The cannula designed in the present application can be adapted to different size blood vessels, and one cannula can replace many clinical return cannulas on the market.

[0022] Further, the self-expanding return cannula for ECMO of the present application only needs to be guided by a guide wire to be implanted into the artery during use, without the need for multiple insertions of a dilating tube to expand the arterial blood vessel.

[0023] Further, the implant tube in the self-expanding return flow cannula for ECMO of the present application has the feature of self-expanding tube diameter, and is in a compressed state before implantation. After implantation, the self-expanding vascular stent is stretched and opened by withdrawing the sleeve to form a vascular access. At the same time, under the pressure of blood, the implant tube can be expanded to fit the inner wall of the blood vessel, reducing the expansion of the blood vessel before implantation of the ECMO cannula and reducing the risk of damage to the blood vessel wall due to the excessive diameter of the cannula.

[0024] Further, the self-expanding return flow cannula for ECMO of the present application is provided with a shunt structure. Part of the blood in the implant tube flows into the arterial blood vessel, while the other part flows out through the shunt hole and flows into the arterial blood vessel in another direction, thereby supplying blood to the distal end of the femoral artery. This can solve the problem of ischemia at the distal end of the VA-ECMO femoral artery cannula, without the need to establish a bypass perfusion, without increasing the complexity of the operation, and can supply oxygenated blood to the upper extremity organs while meeting the blood supply to the distal end (lower leg, foot, etc.), without the need for additional bypass perfusion surgery, and is easy to use.

[0025] Further, the self-expanding return flow cannula for ECMO of the present application not only solves the problem of ischemia at the distal end of the VA-ECMO femoral artery cannula, but also can be applied to the blood supply of other arterial blood vessels with ischemia at the distal end, such as the common carotid artery and the axillary artery. For example, the self-expanding return flow cannula for ECMO of the present application can supply blood to the brain when applied to the common carotid artery, and can supply blood to the collateral when applied to the axillary artery. In summary, theoretically, any arterial blood vessel that needs to be shunted can be applied to the self-expanding return flow cannula for ECMO of the present application, i.e., the applicability of the present application is high. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 Part of the structure of the self-expanding return flow cannula for ECMO of the present application is shown in the figure.

[0028] Figure 2 Part of the structure of the self-expanding return flow cannula for ECMO of the present application is shown in the figure.

[0029] Figure 3 Part of the structure of the self-expanding return flow cannula for ECMO of the present application is shown in the figure.

[0030] Figure 4 Part structure diagram of self-expanding reflux cannula for ECMO of the present application;

[0031] Figure 5 Part structure diagram of self-expanding reflux cannula for ECMO of the present application;

[0032] Figure 6 Blood flow structure diagram of self-expanding reflux cannula for ECMO of the present application in working process.

[0033] Wherein, 1, implant tube; 101, outer covering membrane; 102, self-expanding vascular stent; 103, inner covering membrane; 104, shunt hole; 2, sleeve; 201, protruding part; 3, cylindrical shunt membrane; 4, connecting tube; 5, connecting ring; 501, protruding ring. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0035] The purpose of the present application is to provide a self-expanding reflux cannula for ECMO to solve the problems existing in the prior art, avoid the problems of ECMO surgery due to thin blood vessels and arterial vessel damage caused by the expansion tube being too thick when expanding the blood vessels before cannulation, and ischemia of the distal limb caused by the ECMO reflux cannula after insertion.

[0036] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0037] As shown in the drawings, Figures 1 to 6 The present embodiment provides a self-expanding reflux cannula for ECMO, which comprises an implant tube 1, a sleeve 2, a connecting tube 4 and a shunt structure.

[0038] The implantation tube 1 comprises an inner covering film 103, an outer covering film 101 and a self-expanding vascular stent 102. The inner covering film 103 is arranged on the inner wall of the self-expanding vascular stent 102, and the outer covering film 101 is arranged on the outer wall of the self-expanding vascular stent 102. The self-expanding vascular stent 102 is in a mesh tube structure and can expand and contract radially. The inner covering film 103 and the outer covering film 101 are both in a tube structure and can expand and contract radially with the self-expanding vascular stent 102. The inner covering film 103 and the outer covering film 101 are both made of an elastic biocompatible film. The contact surface of the elastic biocompatible film with the blood vessel is relatively smooth and will not damage the blood vessel. The inner wall of the inner covering film 103 and the outer wall of the outer covering film 101 are both coated with an anticoagulant drug, which is used to reduce the risk of thrombosis at the insertion site.

[0039] It should be noted that the material of the self-expanding vascular stent 102 is titanium-nickel shape memory alloy. The titanium-nickel shape memory alloy has good biocompatibility and corrosion resistance, especially has peculiar super-elasticity and memory performance. The alloy wire is relatively soft at 0-10 degrees Celsius and can be arbitrarily deformed into a shape that is easy to insert into a relatively thin catheter. The catheter is sent into the body to the predetermined narrow part. At body temperature, the stent quickly recovers to the original shape. At this time, the material becomes hard and generates a continuous and gentle restoring force, achieving the expansion and support effect. The stent is in a super-elastic state in the body for a long time. The elastic force does not increase with the increase of the deformation amount. The recoverable deformation amount is large, the deformation resistance is moderate, and the fatigue performance is good, which is unmatched by other materials. The self-expanding vascular stent 102 is a mature product. For example, the invention patent with the application number 201480040823.5, the utility model patent with the application number 200420022330.2 and the utility model patent with the application number 200620057977.8 all have been recorded. Therefore, the specific structure of the self-expanding vascular stent 102 will not be described in detail in this embodiment.

[0040] The inner covering film 103 and the outer covering film 101 need to expand and contract radially with the self-expanding vascular stent 102. Therefore, the inner covering film and the outer covering film need to be made of an elastic film.

[0041] The shunt structure comprises a cylindrical shunt film 3 and two shunt holes 104 arranged on the wall of the implantation tube 1. The shunt holes 104 penetrate the inner covering film 103, the self-expanding vascular stent 102 and the outer covering film 101. The cylindrical shunt film 3 is sleeved on the implantation tube 1. The diameter of the cylindrical shunt film gradually increases from one end to the other end. That is, the smaller-diameter end of the cylindrical shunt film 3 is the necked end, and the larger-diameter end is the flared end. The necked end of the cylindrical shunt film 3 is fixedly connected with the outer wall of the implantation tube 1. There is a gap between the flared end of the cylindrical shunt film 3 and the outer wall of the implantation tube 1. The shunt hole 104 is located between the necked end and the flared end. The flared end is closer to the connecting tube 4 than the necked end.

[0042] The sleeve 2 is sleeved on the implant tube 1, and the sleeve 2 can be separated from the implant tube 1, that is, the sleeve 2 and the implant tube 1 are not connected together, and the sleeve 2 is used to maintain the implant tube 1 in a radially contracted state; when the sleeve 2 is sleeved on the implant tube 1, the cylindrical shunt membrane 3 in the shunt structure is clamped between the sleeve 2 and the implant tube 1.

[0043] In the embodiment, the sleeve 2 is provided with an annular protruding portion 201 on the outer wall of one end close to the connecting tube 4, and the annular protruding portion 201 can facilitate the doctor to force the sleeve 2 when the sleeve 2 is pulled out. The length of the sleeve 2 is greater than or equal to the length of the implant tube 1, and the inner diameter of the sleeve 2 is greater than the outer diameter of the connecting tube 4.

[0044] One end of the connecting tube 4 communicates with one end of the implant tube 1, and the other end of the connecting tube 4 is used to communicate with the arterial blood outlet of the ECMO system, that is, the implant tube 1 is used to communicate with the arterial blood outlet of the ECMO system through the connecting tube 4.

[0045] In the embodiment, the end of the implant tube 1 connected with the connecting tube 4 is provided with a connecting ring 5, the outer wall of the connecting ring 5 is provided with a plurality of convex rings 501, the inner wall of the end of the connecting tube 4 connected with the implant tube 1 is provided with a plurality of ring grooves, the ring grooves correspond to the convex rings 501 one by one, and the ring grooves can be clamped with the corresponding convex rings 501; the connecting ring 5 and the convex ring 501 are both made of elastic material; so that the implant tube 1 and the connecting tube 4 are clamped through the convex ring 501 and the ring groove, which can facilitate connection and improve the connection speed. Since the connecting ring 5 and the convex ring 501 are both made of elastic material, the connecting ring 5 and the convex ring 501 can deform during connection, thereby facilitating the insertion of the connecting ring 5 into the connecting tube 4 and the clamping of the convex ring 501 into the corresponding ring groove.

[0046] In the embodiment, the implant tube 1, the sleeve 2 and the connecting tube 4 are all flexible tubes, and the use of flexible tubes can meet the needs of the surgical environment.

[0047] In the embodiment, the surface of the end of the implant tube 1 away from the connecting tube 4 is smooth, which avoids damaging the blood vessel when the implant tube 1 is implanted into the arterial blood vessel due to the existence of a sharp end.

[0048] The specific use process of the self-expanding reflux cannula for ECMO provided in the embodiment is as follows:

[0049] First, the connecting ring 5 at the end of the implant tube 1 is inserted into the end of the connecting tube 4 provided with a ring groove, so that each convex ring 501 is clamped in the corresponding ring groove; then the cylindrical shunt membrane 3 is attached to the outer wall of the implant tube 1, and the sleeve 2 is sleeved on the implant tube 1 from the end of the implant tube 1 away from the connecting tube 4 to the other end, under the action of the sleeve 2, the implant tube 1 is in a contracted state; then, the end of the implant tube 1 away from the connecting tube 4 is inserted into the femoral artery blood vessel of the patient, then the sleeve 2 is pulled out, and then the connecting tube 4 is connected with the arterial blood outlet of the ECMO system;

[0050] After the sleeve 2 is pulled out and the arterial blood in the ECMO system is pumped into the self-expanding return cannula for ECMO of the embodiment, the self-expanding vascular stent 102 in the implant tube 1 is self-expanded under the action of blood pressure, and the inner covering membrane 103 and the outer covering membrane 101 are opened with the self-expanding vascular stent 102, the inner covering membrane 103 forms a smooth blood flow passage, and under the pressure of the blood, the implant tube 1 can be expanded to adhere the outer covering membrane 101 to the inner wall of the blood vessel;

[0051] Part of the blood in the implant tube 1 flows in the implant tube 1 and flows into the femoral artery blood vessel, and the other part flows out through the shunt hole 104 (see Figure 6 The cylindrical shunt membrane 3 is opened by the action of blood flow to form a shunt passage, which can prevent the blood vessel from blocking the shunt hole 104, and can also reduce the direct damage of blood impact to the blood vessel; then flows into the distal end of the femoral artery blood vessel in another direction, thereby supplying blood to the distal end of the femoral artery; when the ECMO self-expanding return cannula for ECMO is used for VA-ECMO lower limb femoral artery return perfusion, bidirectional blood supply can be realized, the cylindrical shunt membrane 3 can effectively prevent the blood vessel from blocking the shunt hole 104, and can meet the oxygenation of the upper limb organs and arterial blood perfusion, and also can provide blood perfusion for the distal end (calf and foot, etc.), and also avoids additional bypass perfusion surgery, reduces the complexity of the surgery, and relieves the pain of the patient.

[0052] The specific examples are used to illustrate the principles and implementation modes of the present application, and the above examples are only used to help understand the method and core idea of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range can be changed. In view of the above, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A self-expanding reflux cannula for ECMO, characterized in that, include: An implantable catheter includes an inner lining, an outer lining, and a self-expanding vascular stent. The inner lining is applied to the inner wall of the self-expanding vascular stent, and the outer lining is applied to the outer wall of the self-expanding vascular stent. The self-expanding vascular stent has a tubular structure and is radially expandable and contractible. Both the inner and outer linings are tubular and can expand and contract radially with the self-expanding vascular stent. Both the inner and outer linings are made of biocompatible elastic films. The inner wall of the inner lining and the outer wall of the outer lining are coated with an anticoagulant. A cannula is fitted over the implantation tube and is separable from the implantation tube. The cannula is used to keep the implantation tube in a radially contracted state. An annular protrusion is provided on the outer wall of the end of the cannula near the connecting tube. The length of the cannula is greater than or equal to the length of the implantation tube, and the inner diameter of the cannula is greater than the outer diameter of the connecting tube. A connecting tube is provided, with one end connected to one end of the implantable tube and the other end connected to the arterial blood outlet of the ECMO system; the implantable tube, the cannula, and the connecting tube are all flexible tubes; a connecting ring is provided at the end of the implantable tube connected to the connecting tube, and multiple convex rings are provided on the outer wall of the connecting ring; multiple annular grooves are provided on the inner wall of the end of the connecting tube connected to the implantable tube, and the annular grooves correspond one-to-one with the convex rings, and the annular grooves can engage with the corresponding convex rings; both the connecting ring and the convex rings are made of elastic material; the surface of the end of the implantable tube away from the connecting tube is smooth. The shunt structure includes a cylindrical shunt membrane and a shunt hole disposed on the wall of the implantation tube. The shunt hole penetrates the inner lining, the self-expanding vascular stent, and the outer lining. The cylindrical shunt membrane is sleeved on the implantation tube, and the diameter of the cylindrical shunt membrane gradually increases from one end to the other. The constricted end of the cylindrical shunt membrane is fixedly connected to the outer wall of the implantation tube. There is a gap between the flared end of the cylindrical shunt membrane and the outer wall of the implantation tube. The shunt hole is located between the constricted end and the flared end, and the flared end is closer to the connecting tube than the constricted end.

2. The self-expanding reflux cannula for ECMO according to claim 1, characterized in that: The number of the diversion holes is at least one.

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