A tapered drug coated balloon catheter

Abstract

The present application relates to the technical field of medical devices, in particular to a drug-coated balloon catheter for interventional therapy technology, and specifically discloses a tapered drug-coated balloon catheter, which comprises a catheter and a balloon, the balloon is arranged in a folded state and expandable at the front part of the catheter, the surface of the balloon is provided with a drug coating, and the balloon comprises a distal end part, a main body part and a proximal end part along the catheter axis direction from the distal end to the proximal end; when the balloon is in an expanded state, the main body part is in a tapered structure, the diameter of the balloon gradually decreases from the side of the proximal end part to the side of the distal end part at the main body part, and the balloon is shrunk and fixed to the catheter through the distal end part and the proximal end part; when the balloon is in a folded state, an arc bending section is arranged at the side of the distal end part close to the catheter. The tapered drug-coated balloon catheter is suitable for long lesion sites, has good pushing capacity, the drug coating is perfectly attached to the inner wall of the blood vessel, and the drug can be more effectively released to the blood vessel wall of the lesion site.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a drug-coated balloon catheter for use in interventional therapy. BACKGROUND

[0002] From the 1970s to now, vascular interventional therapy has experienced the development of balloon dilatation, metal bare stent and drug-eluting stent. The 3-6 month restenosis rate of target vessels has dropped from 30%-50% to 5%-10%, which has made great progress. However, after the implantation of drug-eluting stents, patients need to take double anti-platelet drugs for a long time. Once in-stent restenosis occurs, the re-implantation of drug-eluting stents will cause high-risk adverse events. In addition, the delayed endothelial healing, late stent thrombosis and atherosclerosis caused by drug-eluting stents have become problems affecting clinical outcomes.

[0003] The emergence of drug-coated balloon (DCB) brings new hope to vascular interventional therapy. Drug-coated balloon catheter is a kind of balloon-based local drug delivery vascular interventional medical device. The surface of the expandable balloon is coated with a coating containing therapeutic drugs. When the balloon is expanded at the lesion site, the drugs are rapidly released within 30-120 seconds, penetrate into the vascular tissue, and inhibit the proliferation of the vascular intima, thereby achieving the purpose of treating vascular lesions.

[0004] Unlike drug-eluting stents, the drugs of drug-coated balloon are rapidly released in a short time. On the one hand, it requires that the drug loss on the surface of the drug-coated balloon catheter during intravascular delivery is small. On the other hand, when the drug-coated balloon catheter is delivered to the lesion site and inflated, the drugs on the surface of the balloon can be rapidly released to the vessel wall, thereby achieving the purpose of treating the lesion.

[0005] Good adhesion is one of the key factors for the rapid and effective release of drugs of drug-coated balloon catheter. Generally, during treatment, a drug-coated balloon catheter with a diameter 10%-20% larger than the diameter of the lesion site is selected to ensure that the drug-coated balloon catheter can completely adhere to the vessel wall. However, the diameters of blood vessels in the human body are not uniform. For example, the diameters of blood vessels in the lower extremities become smaller as they go down. For some long lesions, the diameters of the upper and lower ends of the lesion are quite different. During the operation, if the diameter of the selected drug-coated balloon catheter is too large, it may cause damage to the lower end of the lesion due to excessive tearing; if the diameter of the selected drug-coated balloon catheter is too small, the upper end of the lesion cannot be completely adhered, which affects the treatment effect of the drug-coated balloon catheter. Therefore, two or even more drug-coated balloon catheters with different diameters have to be implanted, which not only complicates the operation process, but also increases the economic burden of the patient.

[0006] The prior art patent with the application number 200720190054.4 discloses a tapered balloon dilatation catheter, which comprises a balloon, a catheter, and a luer joint. The balloon is located at the front part of the catheter, the catheter is connected with the luer joint or connected with the luer joint through a sheath, an inner tube is arranged in the catheter, the distal end and the proximal end of the balloon are two tapered segments, and the middle segment of the balloon is a tapered structure. The main technical problem to be solved is to improve the wall-adhesion effect of the balloon and to improve the transition injury caused by the balloon dilatation to the distal end of the blood vessel. However, the tapered balloon dilatation catheter does not belong to a drug-coated balloon catheter, and is mainly suitable for coronary balloon dilatation or stent placement, and thus is only used for the coronary artery lesion area.

[0007] The prior art patent with the application number 201310228389.0 discloses a tapered balloon dilatation catheter. The balloon is tapered, the diameter of the proximal end of the balloon is larger than that of the distal end, and the surface of the balloon can be coated with a polymer carrying an anti-proliferative drug.

[0008] The tapered balloon of the above prior art is only used for large and medium-sized arteries and coronary artery lesion areas. The length of the tapered balloon body is short. For example, the tapered balloon dilatation catheter described above, the length of the tapered middle segment of the balloon is 5-100 mm. The tapered balloon cannot be used for some long segment stenosis lesions of peripheral blood vessels, especially for the stenosis lesions of the inferior vena cava with a length of more than 150 mm.

[0009] In addition, the longer balloon will significantly increase the difficulty of transporting the balloon during the intervention. When the length of the balloon is longer, the early release of the drug on the surface of the balloon will be aggravated due to the difficulty in transportation, and the loss of the drug on the surface of the balloon caused by blood flushing during the pushing process of the balloon will be greater. SUMMARY

[0010] The technical problem to be solved by the present application is to provide a tapered drug-coated balloon catheter, which can solve the technical problems of poor adhesion of the drug coating of the drug balloon to the inner wall of the long segment blood vessel, poor pushing ability of the balloon, and early release of the drug caused thereby.

[0011] To solve the above technical problems, the technical solution adopted by the present application is as follows: a tapered drug-coated balloon catheter, which comprises a catheter and a balloon. The balloon is arranged in a folded state at the front part of the catheter. The surface of the balloon is provided with a drug coating. The balloon comprises a distal end part, a main body part, and a proximal end part along the catheter axis.

[0012] When the balloon is in an expanded state, the main body part is in a tapered structure. The diameter of the balloon gradually decreases from the proximal end part to the distal end part. The balloon is shrunk and fixed to the catheter at the distal end part and the proximal end part.

[0013] When the balloon is in the folded state, the balloon is provided with an arc-shaped bending section at the distal end close to the catheter, and the maximum diameter of the arc-shaped bending section is not greater than the folded outer diameter of the balloon main body.

[0014] Optionally, the distal end is provided as a whole or partially as an arc-shaped bending section.

[0015] Preferably, the distal end further comprises a straight section, one side of the arc-shaped bending section tends to the outer wall of the catheter, and the other side smoothly transitions to the straight section. The arc-shaped bending section smoothly transitions to the straight section, further reduces the passing resistance of the balloon, and enables the distal end of the balloon to smoothly and uniformly pass through the body lumen.

[0016] Further, the distal end is provided with a support body capable of supporting the arc-shaped bending section of the distal end of the balloon. In the folded state, the support body enables the balloon made of flexible material to form a stable structure at the arc-shaped bending section of the distal end.

[0017] Preferably, the arc-shaped bending section is arranged at the connection between the distal end and the outer wall of the catheter, the distal end and the outer wall of the catheter are welded by solder, and the arc-shaped bending section of the distal end and the outer wall of the catheter are filled with the solder, which serves as the support body of the arc-shaped bending section after welding.

[0018] Optionally, the solder has the same material as the balloon, and preferably, the solder has a low or no flexibility material, such as one of polyethylene, polyethylene terephthalate, nylon and polyurethane, and more preferably nylon-12, nylon-11, PEBAX or PEEK; the solder of the balloon and the catheter is laser welded, and one side of the arc-shaped bending section is smoothly connected with the outer wall of the catheter.

[0019] The support body uses solder, which on the one hand makes the soldering place more uniform under stress when the balloon is inflated and expanded, increases the soldering area, and makes the soldering more firm; on the other hand, the solder can support the arc-shaped bending section, so that the balloon main body can pass through the body lumen more smoothly, and the passing property of the balloon is enhanced.

[0020] Preferably, the laser welding comprises first welding the arc-shaped solder around the inner tube, and then welding the balloon along the solder and extending to the catheter to form the arc-shaped bending section by using the same welding process.

[0021] Preferably, the arc of the arc-shaped bending section is 10-30 degrees. The selected arc of the arc-shaped bending section of the balloon should not be too small, which may cause the overall length of the bending section to be too large, thereby affecting the overall length of the tip of the balloon, and too long tip length may cause damage to the blood vessel during intravascular transportation; if the selected arc is too large, it may increase the passing resistance of the arc-shaped bending section.

[0022] Preferably, the tapering angle of the tapered top of the balloon body part is 1.1±0.8 degrees. The preferred tapering angle enables the balloon body part to match the long section of the diameter-graduated blood vessel, and enables the drug coating loaded on the balloon body part to be well attached to the wall of the long section of the diseased blood vessel, so that the drug is released more accurately at the diseased site, thereby avoiding.

[0023] Preferably, the length of the balloon body part is greater than 100 mm, and further preferably 100-300 mm. The tapered drug-coated balloon catheter of the present application is particularly suitable for long section of diseased blood vessels, and can effectively improve the passability and pushability of the balloon catheter, and reduce the early release of the drug.

[0024] On the basis of the selection of the foregoing balloon structure features, the length ratio of the distal end part, the body part and the proximal end part along the catheter axis is preferably 7±4:200±100:8±5. The length ratio of the arc-shaped curved section and the straight section of the distal end part along the catheter axis is preferably 2-3:1. In the folded state, the maximum diameter of the balloon in the distal end arc-shaped curved section 11 is 1.2 mm-1.85 mm. The tapered drug-coated balloon with this structure can balance the better pushability and passability, has excellent operability, effectively avoids the physical damage to the blood vessel during the interventional procedure, reduces the delivery difficulty of the balloon catheter, and reduces the early release of the drug.

[0025] Further improvement of the present application is that the wall thickness of the balloon body part gradually decreases from the proximal end part side to the distal end part side. The balloon body part has a gradually decreasing wall thickness from the proximal end part side to the distal end part side, so that the folded outer diameter of the balloon body part near the distal end part side is smaller, thereby obtaining better flexibility, the ability to pass through the curved part is stronger, and the folded balloon body part also has an approximate tapered structure with the change of the balloon wall thickness, especially when the length of the balloon is greater than 100 mm, the folded balloon with the approximate tapered structure can improve the transmission effect of the push force from the proximal end to the distal end, thereby improving the pushability of the balloon catheter and further improving the pushability of the balloon catheter.

[0026] Preferably, the balloon wall thickness of the proximal end side and the distal end side of the balloon body part is 0.08±0.03 mm and 0.07±0.02 mm, respectively, and the ratio of the wall thickness of the two ends is 1-2:1.

[0027] The balloon catheter of the present application is internally structured with a delivery channel for the balloon inflation material. According to the need, the catheter can be selected as a sleeve, a double-lumen tube or a triple-lumen tube, and the sleeve gap or a separate lumen can be used as the delivery channel for the balloon inflation material in communication with the balloon.

[0028] Preferably, the catheter is a sleeve, comprising an outer tube and an inner tube, the inner tube being extended from the outer tube, the balloon distal end being fixedly connected to the extended inner tube, the proximal end being fixedly connected to the outer tube, and the inflation channel of the balloon being formed between the outer tube and the inner tube. The inner tube is extended from the outer tube, located at the front part of the catheter, has a smaller tube diameter, the balloon catheter has better passability, and the inflation channel can be annularly communicated with the balloon, the balloon expands more rapidly and efficiently.

[0029] The drug coating of the present application can optionally contain a therapeutic dose of drugs and a biocompatible carrier. The coating carrier material preferably includes poly-L-lactic acid (PLLA), poly-lactic-glycolic acid (PLGA), poly-D-lactic acid (PDLLA), polyethylene glycol, polyethylene glycol-polycaprolactone, polysorbate, PVP, polyxylitol, polyglycerol ester, sodium alginate, chitosan, chitin, dextran, polyhard acid ester, polylactic acid ester, etc. The drugs preferably include one or more of antioxidant drugs, anticoagulant drugs, anticancer drugs, drugs for inhibiting the proliferation of vascular smooth muscle cells, anti-inflammatory drugs or immunosuppressant drugs.

[0030] The antioxidant drugs include superoxide dismutase, catalase, coenzyme Q10, glutathione peroxidase; the anticoagulant drugs include aspirin, heparin, clopidogrel, etc.; the anticancer drugs include colchicine, paclitaxel; the drugs for inhibiting the proliferation of vascular smooth muscle cells include angiopeptide, corticosteroids, calcium ion antagonists; the anti-inflammatory drugs include more mycoses, Depsidomycin, Kanglemycin C, Spergualin, Mytiocin, Gllooxin; the immunosuppressant drugs include rapamycin, cyclosporin A, cyclosporin C, Brefeldin A.

[0031] The drug balloon catheter is pushed from the puncture port to the lesion site in about 1 min during use, and the effective use time of the drug release of the drug balloon is about 2 min. Therefore, the longer pushing time will directly lead to an increase in the early release amount of the drug during the delivery process. Moreover, since the drug is lipophilic and difficult to dissolve in water, it is easy to agglomerate and form large particles, and these large drug particles carried by the carrier are easy to be washed off by blood. If the number of the washed-off particles is large, it is easy to cause complications such as distal vascular occlusion and thrombosis, and in severe cases, it can lead to amputation. Therefore, in order to make the balloon structure have better hemodynamics, the arc-shaped bending section provided at the distal end of the balloon close to the catheter tip can reduce the washing of the balloon main body surface drug coating by blood flow during the delivery of the balloon, which helps to reduce the early release of the drug coating on the balloon main body caused by the influence of blood flow, so that the drug can be more concentratedly released at the lesion site, and the treatment effect is improved.

[0032] In summary, the tapered drug coating balloon catheter of the present application has the following advantages compared with the prior art:

[0033] (1), compared with the flat inclined surface commonly used in the prior art, the arc-shaped curved section provided at the distal end has a longer flat surface on the side of the catheter and a smaller included angle with the catheter under the same conditions, so that the ability of the balloon distal end to pass through the narrow lumen is enhanced. Moreover, since the maximum diameter of the arc-shaped curved section is not greater than the outer diameter of the folded balloon body, the provision of the arc-shaped curved section does not hinder the pushing of the balloon body, and the balloon as a whole has good pushing force.

[0034] (2), the balloon structure has better blood fluid mechanics, and the arc-shaped curved section provided at the distal end of the balloon near the catheter tip can reduce the erosion of the blood flow on the surface of the balloon body during the transportation of the balloon catheter, which helps to reduce the early release of the drug coating on the balloon body caused by the influence of the blood flow, so that the drug can be more concentrated in the lesion site, and the treatment effect is improved.

[0035] (3), the balloon body part has a decreasing thickness from the proximal end to the distal end, so that the folded outer diameter of the balloon body part near the distal end is smaller, thereby obtaining better flexibility, the ability to pass through the curved part is stronger, and the folded balloon body part can also have an approximate conical structure, which cooperates with the balloon distal end to smoothly transition, has better passing property, and further improves the pushing ability of the balloon catheter.

[0036] (4), the drug-coated balloon catheter can be applied to lesions with a length greater than 100 mm, especially peripheral vascular lesions, which overcomes the problem of poor adhesion of the balloon to the inner wall of the blood vessel and poor passing property of the balloon in the prior art, and the use of the balloon coating catheter of the present application can greatly reduce the medical cost of patients. BRIEF DESCRIPTION OF DRAWINGS

[0037] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0038] Figure 1 is a structural schematic diagram of an embodiment of the conical drug-coated balloon catheter of the present application;

[0039] Figure 2 is a structural schematic diagram of an embodiment of the conical drug-coated balloon catheter of the present application; Figure 1

[0040] Figure 3 is a structural schematic diagram of an embodiment of the conical drug-coated balloon catheter of the present application; Figure 1

[0041] Figure 4 is a structural schematic diagram of an embodiment of the conical drug-coated balloon catheter of the present application;

[0042] Figure 5 ​​is a structural schematic view of another conical balloon dilatation state in the prior art.

[0043] The drug coating and the balloon wall thickness are not shown in the drawings of the present specification. In each drawing, 1, distal end portion; 11, curved section; 12, straight section; 2, main body portion; 3, proximal end portion; 4, catheter; 41, outer tube; 42, inner tube; 5, needle seat; 6, guide wire lumen; 7, inflation lumen; 8, radiopaque ring; 9, solder. DETAILED DESCRIPTION

[0044] In view of the technical problems that the drug coating balloon catheter of the prior art does not adhere well to the long section of the uneven diameter lesion vessel wall, resulting in reduced treatment effect of the drug coating balloon catheter, and the pushability and passability of the long section of the balloon catheter are poor, causing difficult operation, long time consumption, and aggravated early drug release, the present application provides a conical drug coating balloon catheter. Through the cooperation of the conical structure of the balloon main body portion and the arc-shaped curved section of the distal end portion of the balloon, the balloon drug coating can adhere well to the long section of the lesion vessel wall, while reducing the early release of the drug, and the drug can be released more at the lesion site, thereby improving the treatment effect, and effectively improving the pushability and passability of the drug coating balloon catheter.

[0045] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0046] General embodiment

[0047] Reference Figures 1-3 A conical drug coating balloon catheter, comprising a catheter 4 and a balloon, the balloon in a folded state is expandable and arranged at the front of the catheter 4, the surface of the balloon is provided with a drug coating, and the balloon includes a distal end portion 1, a main body portion 2 and a proximal end portion 3 along the catheter 4 tube axis direction;

[0048] When the balloon is in an expanded state, referring to Figure 2 The main body portion 2 is in a conical structure, the diameter of the balloon gradually decreases from the proximal end portion 3 side to the distal end portion 1 side in the main body portion 2, and the balloon is shrunk and fixed to the catheter 4 at the distal end portion 1 and the proximal end portion 3;

[0049] When the balloon is in a folded state, referring to Figure 3 The balloon is provided with an arc-shaped curved section 11 near the catheter 4 at the distal end portion 1, and the maximum diameter of the arc-shaped curved section 11 of the balloon is not greater than the folded outer diameter of the main body of the balloon.

[0050] The catheter 4 is a sleeve, comprising an outer tube 41 and an inner tube 42, the inner tube 42 extends from the outer tube 41, the balloon distal end 1 is fixedly connected to the front extending inner tube 42, the proximal end 3 is fixedly connected to the outer tube 41, and the inflation channel of the balloon is formed between the outer tube 41 and the inner tube 42. The inner tube 42 extends from the outer tube 41 and is located at the front part of the catheter 4, has a smaller tube diameter, the balloon catheter 4 has better passability, and the inflation channel can be annular and in communication with the balloon, so that the balloon expands more quickly and efficiently.

[0051] It should be noted that other catheter forms can be selected by those skilled in the art as needed, such as a double-lumen tube or a triple-lumen tube, and a separate lumen is used to communicate with the balloon through the catheter side hole to form a delivery channel for the inflation material, and there is no technical difficulty.

[0052] Referring to Figure 1 As an optional component, a needle seat 5 with an inflation cavity 7 and a guide wire cavity 6 is arranged at the rear part of the catheter 4, the inflation cavity 7 and the guide wire cavity 6 are respectively in communication with the inflation channel and the inner tube 42, and are used to introduce or withdraw the inflation material and the guide wire. The inflation material can be selected to be a liquid or a gas. The inner tube 42 is further fixedly provided with a developing ring 88 at a position close to the two end parts of the balloon, which is used to indicate the position of the balloon in the body lumen during the operation.

[0053] Referring to Figure 2 When the balloon is in the expanded state, the distal end 1 and the proximal end 3 are both in a conical or approximately conical structure, the arc-shaped curved section 11 is arranged at the connection between the distal end 1 and the outer wall of the catheter 4, the distal end 1 further comprises a straight section 12, one side of the arc-shaped curved section 11 tends to the outer wall of the catheter 4, and the other side smoothly transitions to the straight section 12. The arc-shaped curved section 11 smoothly transitions to the straight section 12, further reduces the passing resistance of the balloon, and enables the distal end 1 of the balloon to smoothly, uniformly and stably pass through the body lumen. However, when the overall design length of the distal end 1 is relatively short and the diameter is relatively small, those skilled in the art can also select to arrange the distal end 1 of the balloon as an arc-shaped curved section 11 as a whole, and there is no technical difficulty.

[0054] Referring to Figure 3 When the balloon is in the folded state, the distal end 1 is provided with a support body, which can support the arc-shaped curved section 11 of the distal end 1 of the balloon. In the folded state, the arrangement of the support body can enable the balloon made of a flexible material to form a stable structure in the arc-shaped curved section 11 of the distal end 1.

[0055] Specifically, the distal end 1 and the outer wall of the inner tube 42 are welded by solder 9, the arc-shaped curved section 11 of the distal end 1 and the outer wall of the catheter 4 are filled with solder 9, and after welding, the solder 9 serves as the support body of the arc-shaped curved section 11, the balloon and the catheter 4 are laser welded by the solder 9, and one side of the arc-shaped curved section 11 is smoothly connected to the outer wall of the catheter 4.

[0056] The support body uses solder 9, which on the one hand makes the stress at the weld more uniform when the balloon is inflated, increases the welding area, and makes the weld more robust; on the other hand, solder 9 can support the arc-shaped curved section 11, allowing the main body of the balloon 2 to pass through the human body lumen more smoothly, thus enhancing the balloon's permeability. However, as an alternative, those skilled in the art can also choose other annular structural members with an arc-shaped longitudinal cross-section to be fixed to the outer periphery of the catheter 4, serving as a support body to support the distal end 1 of the balloon to form the arc-shaped curved section 11.

[0057] As a preferred embodiment, the solder 9 and the balloon are made of the same material, which is a low-flexibility or non-flexibility material, such as polyethylene, polyethylene terephthalate, nylon and polyurethane. More preferably, the solder 9 and the balloon are made of nylon-12, nylon-11, PEBAX (block polyether amide resin) or PEEK (polyether ether ketone).

[0058] The laser welding process includes first welding the solder 9 around the inner tube 42, and then welding the balloon along the solder 9 and extending it onto the conduit 4 to form an arc-shaped curved section 11.

[0059] Microscopic observation revealed that the cone apex angle of the selected conical structure of the main body 2 of the balloon was 1.1 ± 0.8 degrees, as shown in the attached figure. Figure 2 As shown in angle b, the selected cone apex angle allows the balloon body 2 to match the long segment of the gradually changing diameter vessel, enabling the drug coating loaded on the balloon body 2 to adhere well to the wall of the long segment of the diseased vessel, and the drug to be released more accurately at the lesion site.

[0060] Example 1

[0061] Based on the aforementioned general embodiment, and assuming that each feature is a definite selection in the aforementioned choices, different curvatures of the arc-shaped bending segments 11 are further set, such as... Figure 2 Shown at mid-angle a.

[0062] Extensive experimental studies have revealed that the curvature of the curved segment 11 of the balloon should not be too small, as this may result in a larger overall length of the curved segment 11, which in turn affects the overall length of the balloon tip. An excessively long tip may cause vascular damage during intravascular transport. If the selected curvature is too large, it may increase the resistance to passage of the curved segment 11.

[0063] As a preferred embodiment, the arc of the curved section 11 is 10-30 degrees to minimize the resistance to passage.

[0064] Example 2

[0065] Based on Example 1, the balloon is further configured to have different parameters as follows.

[0066] The lengths of the balloon distal end 1, the main body 2 and the proximal end 3 along the catheter 4 axis are 2-20mm, 50-350mm and 2-20mm respectively, and the length ratio of the curved segment 11 to the straight segment 12 of the distal end 1 along the catheter 4 axis is 1-5:1. The maximum diameter of the balloon in the curved segment 11 of the distal end in the folded state is 1mm-2mm.

[0067] Through the push force and delivery time statistics, it is found that the lengths of the balloon distal end 1, the main body 2 and the proximal end 3 along the catheter 4 axis are 7±4mm, 200±100mm and 8±5mm respectively, and the length ratio of the curved segment 11 to the straight segment 12 of the distal end 1 along the catheter 4 axis is preferably 2-3:1. The maximum diameter of the balloon in the curved segment 11 of the distal end in the folded state is 1.2mm-1.85mm. The tapered drug-coated balloon with the structure can balance the better pushability and passability, has excellent operability, effectively avoids the physical damage to the blood vessel during the interventional procedure, reduces the delivery difficulty of the balloon catheter 4 and reduces the early drug release.

[0068] Example 3

[0069] On the basis of the total examples, the wall thickness of the balloon main body 2 is gradually reduced from the proximal end 3 side to the distal end 1 side. The balloon wall thickness of the proximal end side and the distal end side of the balloon main body 2 is 0.03-0.15mm and 0.03-0.13mm respectively.

[0070] Through the push force and delivery time statistics, the balloon wall thickness of the balloon main body 2 is reduced from the proximal end 3 side to the distal end 1 side, so that the folded outer diameter of the balloon main body 2 near the distal end 1 side is smaller, thereby obtaining better flexibility, the ability to pass through the curved part is stronger, and the balloon main body 2 in the folded state can also be approximately tapered structure with the change of the balloon wall thickness, especially when the length of the balloon is more than 100mm, the folded balloon with the approximate tapered structure can improve the transmission effect of the push force from the proximal end to the distal end, thereby improving the pushability of the balloon catheter 4 and further improving the pushability of the balloon catheter 4.

[0071] As a preferred embodiment, the balloon wall thickness of the balloon main body 2 is reduced from the proximal end 3 side to the distal end 1 side, and the balloon wall thickness of the proximal end side and the distal end side of the balloon main body 2 is 0.08±0.03mm and 0.07±0.02mm respectively, and the ratio of the wall thickness of the two ends is 1-2:1. The pushability of the balloon catheter is effectively improved, and the early drug release rate is reduced.

[0072] In order to further explain the effect brought by the selection of the foregoing embodiments, the following comparative examples are used for illustration.

[0073] Comparative experiments were carried out on the prior art equal-diameter balloon catheter, the tapered balloon catheter and the tapered drug-coated balloon catheter of the preceding embodiment of the application. The balloon catheters were all made of the same size sheath as the catheter, and the balloons were all nylon-12 material. The only difference was the balloon structure, and the balloons were named DCB1, DCB2, …, DCB17 in turn.

[0074] In the following, the balloon size parameters of each balloon catheter were the same except for specific descriptions.

[0075] DCB1 was an equal-diameter balloon, as shown in Fig. 1. Figure 4 The balloon main body was a cylindrical shape in the expanded state, and the distal end and the proximal end of the balloon were both tapered. DCB2 was a tapered balloon, as shown in Fig. 2. Figure 5 The balloon main body was a tapered shape in the expanded state, and the distal end and the proximal end of the balloon were both tapered.

[0076] DCB3-DCB17 of the embodiment of the application were all drug-coated balloon catheters of different sizes of the preceding embodiment, and the balloon structure was shown in Fig. 3. Figure 1 .

[0077] All the balloons were prepared by the same process to form a drug coating. The drug coating carrier was poly-lactate, and the drug was paclitaxel.

[0078] Comparative Example 1

[0079] A simulated blood vessel was taken, and there was a 1cm long narrow site in the blood vessel. A guide wire was passed through each drug-coated balloon catheter, and the guide wire was fixed with each drug-coated balloon catheter. The guide wire passing through the distal end of the drug-coated balloon catheter was inserted into the simulated blood vessel, and the guide wire was clamped with a tension machine. The tension machine was turned on, and the maximum force F of the front end of each drug-coated balloon catheter passing through the narrow site of the simulated blood vessel was recorded.

[0080] Comparative Example 2

[0081] In addition, the blood vessels of pigs were taken to do a delivery test in vitro to study the loss of drugs in the delivery process.

[0082] Each drug-coated balloon catheter was passed through a guide wire and placed in a PBS solution at 37℃. A simulated blood vessel system was used to simulate the pushing process of the drug-coated balloon catheter in the blood, and the pipe diameter of the simulated blood vessel system was 5-8cm, and the blood flow rate was 35cm / s. After the simulation process, the loss of drugs S of each balloon was calculated.

[0083] The specifications of each drug-coated balloon catheter and the test results F and S are shown in the following table.

[0084]

[0085] From the above comparison results, it can be seen that the pushability and passability of the tapered drug coating balloon catheter of the embodiment of the present application are obviously improved compared with the equal-diameter drug coating balloon catheter and the tapered drug coating balloon catheter of the prior art, the early release amount of the drug during the balloon transportation process is significantly reduced, which is beneficial to the application of the peripheral long segment lesion blood vessel, can effectively reduce the operation difficulty, and improve the treatment effect.

[0086] The tapered drug coating balloon catheter provided by the present application is described in detail above, and the embodiment of the present application is described by applying specific examples. The above embodiment is only used to help understand the present application, and it should be pointed out that those skilled in the art can make some improvements to the present application without departing from the principle of the present application, and these improvements also fall within the protection scope of the claims of the present application.

Claims

1. A tapered drug-coated balloon catheter, comprising a catheter and a balloon, wherein the balloon is folded and expandable and disposed at the anterior portion of the catheter, and the surface of the balloon is coated with a drug coating, characterized in that: The balloon includes a distal end, a main body, and a proximal end along the catheter axis; When the balloon is in the inflated state, the main body has a conical structure, and the diameter of the balloon gradually decreases from the proximal end to the distal end of the main body. The balloon is fixed to the catheter by contraction at the distal and proximal ends. When the balloon is in a folded state, the balloon has an arc-shaped curved section at the distal end near the catheter, and the maximum diameter of the balloon at the arc-shaped curved section is not greater than the folded outer diameter of the balloon body; The distal end also includes a straight section, one side of the arc-shaped curved section tends toward the outer wall of the catheter, and the other side smoothly transitions to the straight section; The distal end is provided with a support body, which can support the arc-shaped curved section; The arc-shaped curved section is located at the connection between the distal end and the outer wall of the conduit; the distal end and the outer wall of the conduit are welded together with solder, and the solder is filled between the arc-shaped curved section of the distal end and the outer wall of the conduit, serving as a support for the arc-shaped curved section after welding. The arc of the curved section is 10-30 degrees, the cone apex angle of the main body of the balloon is 1.1±0.8 degrees, and the length of the main body of the balloon is 100-300 mm; the length ratio of the distal end, the main body and the proximal end along the catheter axis is 7±4:200±100:8±5; the length ratio of the distal curved section to the straight section along the catheter axis is 2-3:1; when folded, the maximum diameter of the balloon at the distal curved section is 1.2 mm-1.85 mm.

2. The tapered drug-coated balloon catheter according to claim 1, characterized in that: The solder is made of the same material as the balloon, which is one of polyethylene, polyethylene terephthalate, nylon, and polyurethane; the welding is laser welding.

3. The tapered drug-coated balloon catheter according to claim 1 or 2, characterized in that: The wall thickness of the main body of the balloon gradually decreases from the proximal end to the distal end. The wall thicknesses of the proximal and distal ends of the main body of the balloon are 0.08±0.03mm and 0.07±0.02mm, respectively, and the ratio of the wall thicknesses at both ends is 1-2:

1.

4. The tapered drug-coated balloon catheter according to claim 1 or 2, characterized in that: The catheter is a cannula, including an outer tube and an inner tube. The inner tube extends out from the outer tube. The distal end of the balloon is sealed and fixed to the proximal end of the extended inner tube, and the proximal end is sealed and fixed to the outer tube, forming an inflation channel for the balloon between the outer tube and the inner tube.

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