CN111419493A

CN111419493A - Medical intravascular implantation device

Info

Publication number: CN111419493A
Application number: CN202010214902.0A
Authority: CN
Inventors: 杨世峰; 解立怡
Original assignee: Xian Jiaotong University
Current assignee: First Affiliated Hospital of Medical College of Xian Jiaotong University
Priority date: 2020-03-24
Filing date: 2020-03-24
Publication date: 2020-07-17
Anticipated expiration: 2040-03-24
Also published as: CN111419493B

Abstract

The invention discloses a medical intravascular implant device which comprises a pipeline and a flange arranged on the circumference of one end of the pipeline. The device comprises a pipeline and a flange. The pipeline consists of an inner expanded polytetrafluoroethylene (ePTFE) lining and an outer nickel-titanium alloy net, wherein the flanges extend from the ePTFE lining at one end of the pipeline and are turned up to the periphery to form an oval shape. When the device is implanted into an internal fistula during operation, the pipeline is positioned on the vein side of an anastomotic stoma and has the functions of isolating blood flow shearing force and supporting a blood vessel cavity. The flange is located on the arterial side of the anastomosis and can fix the pipeline to prevent the pipeline from being displaced. The device disclosed by the invention has the functions of isolating blood flow shearing force and supporting a blood vessel cavity, and can effectively prevent the internal fistula anastomotic stoma from being narrowed.

Description

Medical intravascular implantation device

Technical Field

The invention relates to a medical intravascular implantation device which is suitable for preventing stenosis of an anastomotic stoma of an arteriovenous internal fistula (hereinafter referred to as internal fistula) of a hemodialysis patient.

Background

Hemodialysis is a kidney replacement therapy that maintains the life of uremic patients. Hemodialysis in uremic patients relies on a good dialysis access. The blood is led out of the body of the patient from the dialysis passage through the blood leading passage 7, filtered by the dialysis machine and then returned to the body of the patient through the blood returning passage 8. Internal fistulas are the most commonly used dialysis access for uremic patients. The internal fistula is generally established on the wrist of a patient, and the cephalic vein 2 and the radial artery 1 are anastomosed end to end by a surgical method to form an artificially established fistula between the artery and the vein, so that the blood of the radial artery 1 directly flows back to the heart through the cephalic vein 2. The blood flow of the radial artery 1 is reserved in the lumen of the posterior cephalic vein 2 after the internal fistula is established, meanwhile, the position of the cephalic vein 2 is shallow compared, and a blood flow circuit for dialysis can be formed by puncturing the cephalic vein 2 by two puncture needles 6 (figure 1).

A good internal fistula requires sufficient blood flow to ensure that the patient is successfully hemodialysis and that adequate dialysis is achieved. International guidelines recommend a qualified internal fistula natural blood flow of greater than 600 ml/min. However, internal fistulas have faced a problem since the beginning of the establishment, that is, the inevitable occurrence of stenosis of the stoma 3. The stenosis of the anastomotic orifice 3 obstructs the blood flow in the radial artery 1 from entering the cephalic vein 2, resulting in insufficient blood flow in the cephalic vein 2 and affecting the dialysis effect of the patient. The severe stenosis of the anastomotic orifice 3 may even result in the occlusion and loss of work of the internal fistula, which may render the patient unable to perform dialysis. The cause of stenosis of the internal fistula stoma 3 is the proliferation of the intima 11 of the blood vessel close to the stoma 3, by the following mechanism: the blood flow in the posterior cephalic vein 2 after the internal fistula is established is increased, the blood flow speed is accelerated, and the shearing force of the blood flow to the blood vessel wall is increased due to the hemodynamic change. The blood flow shear force damages the vascular intima 11, thereby activating inflammatory cells to release a series of inflammatory factors, and the inflammatory factors promote the proliferation and fibrosis of vascular endothelial cells, and finally cause the stenosis of blood vessels. Because the radial artery 1 of internal fistula and the cephalic vein 2 far away from the anastomotic stoma have a straight shape, the blood in the blood vessel is in a laminar state, and therefore, the shearing force of the blood flow to the blood vessel wall is small. The vein turns at a large angle at the anastomotic stoma 3 of the internal fistula, so the blood flow at the anastomotic stoma is in a turbulent flow state, the shearing force of the blood flow is large, the endangium 11 is easily lost, and the intima hyperplasia is caused, so the cephalic vein 2 close to the anastomotic stoma 3 is the part of the internal fistula where stenosis is most easily generated (figure 2).

Disclosure of Invention

The invention provides a medical intravascular implant device, which aims to solve the problem of internal fistula anastomotic stenosis caused by vein intimal hyperplasia. When the internal fistula operation is carried out, the device is implanted into an anastomotic orifice of the internal fistula and is used for preventing the anastomotic orifice of the internal fistula from being narrowed.

The invention is realized by adopting the following technical scheme:

a medical intravascular implant device includes a tube and a flange disposed circumferentially on an end of the tube.

The invention is further improved in that the pipeline is a conical hollow pipeline, the inner diameter of the thin end of the pipeline is 3mm, the inner diameter of the thick end of the pipeline is 4mm, the length of the pipeline is 2cm, and the flange is positioned at the thin end of the pipeline.

The invention is further improved in that the pipeline consists of an inner expanded polytetrafluoroethylene lining and an outer nickel-titanium alloy net.

The invention has the further improvement that the expanded polytetrafluoroethylene lining is made into a seamless film with the thickness of 0.2mm by an ePTFE material and is tightly attached to the nickel-titanium alloy net on the outer layer; the nickel-titanium alloy net is formed by weaving nickel-titanium wires with the diameter of 0.1mm, and the nickel-titanium wires are arranged in a wave shape around the expanded polytetrafluoroethylene lining in a circle.

The invention has the further improvement that the flange is an expanded polytetrafluoroethylene lining extension of the thin end of the conical hollow pipeline and is turned up to be in an oval structure; the minor axis of the flange is 5mm, and the major axis is 7 mm; the included angle between the long axis of the elliptical plane and the thin end of the conical hollow pipeline is 40 degrees, and the short axis of the elliptical plane is perpendicular to the thin end of the conical hollow pipeline.

Compared with the prior art, the invention has at least the following beneficial technical effects:

at present, no effective prevention method for internal fistula anastomotic stenosis exists, and most hemodialysis patients have internal fistula loss caused by anastomotic stenosis. The previous clinical practice proves that the intravascular stent is an effective method for treating the angiostenosis. The intravascular implant device provided by the invention has the functions similar to an intravascular covered stent, and the mechanism for preventing the stenosis of the internal fistula anastomotic stoma comprises two points: firstly, the device isolates the injury of blood flow shearing force to the intima of the internal fistula, and can prevent the stenosis of the vascular cavity caused by reactive hyperplasia of the intima of the fistula. Secondly, the device has strong supporting function to the vascular wall of the internal fistula, so that the intimal hyperplasia of the blood vessel can not develop centripetally and the stenosis of the vascular cavity can be prevented. When the device is implanted into the internal fistula when an internal fistula operation is carried out, the internal fistula anastomotic stoma stenosis can be effectively prevented, and the service time of the internal fistula is prolonged. The device has the advantages of preventing internal fistula anastomotic stenosis:

1. the device is implanted during the creation of an internal fistula operation, eliminating the need for additional surgery on the patient.

2. The device can continuously play a role after being implanted without later maintenance, and long-time continuous benefits are brought by one-time investment.

3. Because the blood flow speed of the internal fistula is very high, thrombus can not be formed even if medical equipment is implanted, and anticoagulation or platelet aggregation resistant medicines do not need to be taken conventionally after the device is implanted, so that patients have better compliance.

Drawings

FIG. 1 is a schematic view of the operation principle of an arteriovenous internal fistula;

FIG. 2 is a schematic view of an arteriovenous internal fistula stenosis;

FIG. 3 is a schematic view of the apparatus of the present invention;

fig. 4 is a schematic view of a surgical insertion device.

Description of reference numerals:

1. radial artery, 2 cephalic vein, 3 anastomotic stoma, 4 arterial distal end, 5 venous distal end, 6 puncture needle, 7 blood leading pipeline, 8 blood returning pipeline, 9 arterial proximal end, 10 venous proximal end, 11 endovascular intima, 12 vascular cavity, 13 nickel titanium alloy net, 14 expanded polytetrafluoroethylene lining, 15 pipeline and 16 flange.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

The invention provides a medical intravascular implant device which is divided into two parts (figure 3): 1. the pipeline 15: the inner diameter of the thin end of the conical hollow pipeline is 3mm, the inner diameter of the thick end of the conical hollow pipeline is 4mm, and the length of the conical hollow pipeline is 2 cm. Consists of an inner layer of expanded polytetrafluoroethylene (ePTFE) lining 14 and an outer layer of nickel-titanium alloy mesh 13. The expanded polytetrafluoroethylene lining 14 is made of ePTFE material into a seamless film with the thickness of 0.2mm, and is tightly attached to the nickel-titanium alloy net 13 on the outer layer. The nickel-titanium alloy net 13 is woven by nickel-titanium wires with the diameter of 0.1mm, and the nickel-titanium wires are arranged in a wave shape around the expanded polytetrafluoroethylene lining 14 in a circle. The nickel-titanium wire has better toughness, so the nickel-titanium alloy net 13 woven by the nickel-titanium wire has good elasticity, can be retracted and thinned by pinching with hands, is convenient for implanting into a blood vessel in an operation, has the function of resisting peripheral extrusion in a natural state, and has strong supporting function on the blood vessel wall. When the device is implanted into an internal fistula, the pipeline is positioned in the cephalic vein 2, the thin end is close to the anastomotic stoma 3, and the thick end is far away from the anastomotic stoma 3 (figure 4). Because the nickel-titanium net has certain elasticity, the pipeline part can be bent along with the shape of the blood vessel and is well attached to the cephalic vein 2. After being implanted into the cephalic vein (2), the tube has the functions of isolating the shearing force of blood flow and supporting the blood vessel cavity (12). 2. Flange 16: the expanded ptfe liner 14, which is the narrow end of the tapered pipe 15, extends and is turned up in an oval shape. The minor axis of the flange 16 is 5mm and the major axis is 7 mm. The major axis of the elliptical plane forms an angle of 40 degrees with the duct, and the minor axis is perpendicular to the duct 15. Because of the flexibility of the ePTFE material, this angle can be slightly swept, allowing the angle between the long axis and the tube 15 to be between 30 and 50 degrees. When the device of the invention is implanted in an internal fistula, the flange 16 is located within the radial artery 1, with the major axis of the ellipse positioned along the radial artery 1 (fig. 4). The flange 16 acts as a fixation for the tubing 15, preventing the tubing 15 from being displaced downstream of the cephalic vein 2. The device is sterilized by ethylene oxide, and then is sealed and packaged for operation.

The mechanism of the device for preventing internal fistula anastomotic stenosis is as follows: 1. the tubing portion of the device is embedded in the lumen of the cephalic vein 2 adjacent the stoma 3, and blood flowing through the stoma 3 flows within the device, so that blood flow shear forces act on the expanded polytetrafluoroethylene lining 14 of the device rather than the vessel wall. That is, the device isolates the blood flow shearing force acting on the wall of the cephalic vein 2, thereby preventing the endangium 11 from being damaged and preventing the lumen stenosis caused by the hyperplasia of the endangium 11. 2. The outer layer of the pipeline 15 part of the device is the titanium-nickel alloy net 13, and the nickel titanium has toughness and elasticity after being woven into a net, so that the device has a strong supporting effect on the vein wall, the supporting effect enables the hyperplasia of the blood vessel intima 11 not to develop centripetally, and the stenosis of the vein lumen can be prevented.

Examples

When the internal fistula operation is carried out, a 3cm long longitudinal incision is made on the wrist of a patient after local infiltration anesthesia, subcutaneous tissues and fascia are separated, and a radial artery 1 and a cephalic vein 2 are separated. The proximal end 10 of the vein is blocked by a vascular clamp, the distal end 5 of the vein is ligated by silk thread, the cephalic vein 2 is cut off at the proximal end of the ligation site, and the lumen of the severed cephalic vein 2 is washed by heparin saline. The free radial artery 1 is clamped by two vascular clamps to the proximal artery end 9 and the distal artery end 4 to block blood flow. A 6mm long longitudinal incision was made in the side wall of the artery leaving a section of artery between the two clamps and the lumen of the artery was flushed with heparin saline. The device is then implanted by pinching the tubing 15 portion of the device down with the hand and inserting it into the lumen of the cephalic vein 2, and after releasing the hand, the tubing 15 springs open to return to its original shape, spreading the cephalic vein 2 lumen open. The flange of the device was then grasped with forceps and inserted into the lumen of radial artery 1 from the side incision in the wall of the artery. After releasing the forceps, the flange 16 opens, bearing against the inner wall of the artery so that the device does not slip off. Following vascular anastomosis, the severed end of the cephalic vein 2 is anastomosed to the side incision of the radial artery 1 using 7-0 polypropylene thread using a conventional eversion continuous suture. After the anastomosis is finished, the vascular clamps on the first vein 2 and the radial artery 1 are loosened, and the blood flow is restored to be smooth. The skin is sutured conventionally, and the wound is bandaged with sterile auxiliary materials.

Claims

1. A medical intravascular implant device comprises a tube (15) and a flange (16) disposed circumferentially at one end of the tube (15).

2. The medical intravascular implant device according to claim 1, wherein the tube (15) is a tapered hollow tube with a thin end having an inner diameter of 3mm and a thick end having an inner diameter of 4mm, the tube having a length of 2cm, and the flange (16) is located at the thin end of the tube (15).

3. The medical intravascular implant device according to claim 1 or 2, wherein the tubing (15) consists of an inner expanded polytetrafluoroethylene lining (14) and an outer nickel titanium alloy mesh (13).

4. The medical intravascular implant device according to claim 3, wherein the expanded polytetrafluoroethylene lining (14) is made of ePTFE material into a seamless film with the thickness of 0.2mm, and is tightly attached to the nickel-titanium alloy net (13) of the outer layer; the nickel-titanium alloy net (13) is formed by weaving nickel-titanium wires with the diameter of 0.1mm, and the nickel-titanium wires are arranged in a wave shape and are wound around the expanded polytetrafluoroethylene lining (14) in a circle.

5. A medical endovascular implant device according to claim 3, wherein the flange (16) is an expanded polytetrafluoroethylene lining (14) of the narrow end of the tapered hollow conduit, extended and turned up in an elliptical configuration; the minor axis of the flange (16) is 5mm, and the major axis is 7 mm; the included angle between the long axis of the elliptical plane and the thin end of the conical hollow pipeline is 40 degrees, and the short axis of the elliptical plane is perpendicular to the thin end of the conical hollow pipeline.