JP6982790B1 - Tapered balloon catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tapered balloon catheter having a novel structure having performance suitable for treating a stenotic lesion of a pulmonary artery, such as being able to inflate a balloon while being positioned at a treatment target site with high accuracy. SOLUTION: A tapered balloon catheter 10 having a balloon 14 used for treating a pulmonary artery P, in which a central portion 30 in the length direction of the balloon 14 has an outer diameter from a distal side 36 toward a proximal side 38. Is a tapered shape that gradually increases, the length dimension L0 of the central portion 30 is set within the range of 15 to 25 mm, and the outer diameter R2 of the distal side 36 is set within the range of 1.0 to 3.5 mm. The outer diameter R1 of the proximal side 38 is set within the range of 1.2 to 1.8 times the outer diameter R2 of the distal side 36, and the thickness of the proximal side 38 is set to the inside. The taper dimension t1 is smaller than the thickness dimension t2 on the distal side 36, and the guaranteed pressure resistance value of the balloon 14 is 16 atm or less. [Selection diagram] Fig. 1

Description

The present invention relates to a tapered balloon catheter with a balloon used for the treatment of pulmonary arteries.

In recent years, regarding the treatment of chronic thromboembolic pulmonary hypertension (CTEPH), in addition to surgical radical surgery, balloon-based pulmonary artery dilatation (BPA) has also been investigated. BPA is a treatment method in which a balloon catheter is percutaneously inserted into a stenotic lesion of a pulmonary artery, and the balloon is inflated in the stenotic lesion to expand the stenotic lesion with a balloon and eliminate the stenosis.

By the way, for the treatment of the pulmonary artery, a general-purpose balloon catheter for the periphery is used instead of a dedicated balloon catheter used for the treatment of the heart and the brain. The balloon catheter is disclosed in, for example, Japanese Patent Application Laid-Open No. 2012-223426 (Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-223426

However, the pulmonary artery has a special tapered shape that has a sharply smaller diameter toward the peripheral side than peripheral blood vessels such as limbs, and a general-purpose balloon catheter slips when the balloon is inflated. It was found that it is easy to occur and it is difficult to inflate the balloon while holding the balloon at the position for treatment (stenotic lesion) with high accuracy. In addition, the stenotic lesion of the pulmonary artery due to CTEPH is different from the stenotic lesion caused by calcification, and is mainly caused by the organizing of the thrombus. Therefore, the shape, size, performance, etc. required for the balloon are also peripheral balloons. It is often different from. As described above, it may be difficult to effectively deal with the treatment of special pulmonary arteries with general-purpose balloon catheters for peripheral use, but in the past, balloon catheters for peripheral use were also used for the treatment of pulmonary arteries. In some cases, difficult procedures were forced.

An object of the present invention is to provide a tapered balloon catheter having a novel structure, which has performance suitable for treating a stenotic lesion of a pulmonary artery, such as being able to inflate a balloon while being positioned at a treatment target site with high accuracy. It is in.

Hereinafter, preferred embodiments for grasping the present invention will be described, but each of the embodiments described below is described as an example, and not only can be appropriately combined with each other and adopted, but also described in each embodiment. The plurality of components of the above can be recognized and adopted independently as much as possible, and can be appropriately adopted in combination with any of the components described in another embodiment. Thereby, in the present invention, various other embodiments can be realized without being limited to the embodiments described below.

In order to deal with the new problem of slippage during the expansion operation of the balloon, the present inventor also considered to accurately follow the shape of the outer peripheral surface of the balloon to the shape of the inner peripheral surface of the pulmonary artery, but simply the outer peripheral surface of the balloon. It was found that it is difficult to stably achieve both the positioning effect and the therapeutic effect only by making the taper shape of the taper angle corresponding to the inner peripheral surface of the pulmonary artery. In particular, considering individual differences in patients and differences in treatment sites, it was even more difficult to achieve stable effects.

Therefore, as a result of further studies by the present inventor, the strong contact of the distal side of the balloon with the inner peripheral surface of the pulmonary artery is a major cause of the balloon slipping, and the proximal side of the balloon is contacted first. By doing so, we have obtained new findings that it is possible to achieve a more stable balance between the positioning effect and the therapeutic effect.

The present invention has been completed based on such findings, and the first aspect is a tapered balloon catheter provided with a balloon used for treating a pulmonary artery, wherein the central portion in the length direction of the balloon is a central portion. , It has a tapered shape in which the outer diameter gradually increases from the distal side to the proximal side, and the length dimension of the central part is set within the range of 15 to 25 mm, and the outer side of the distal side. The diameter is set within the range of 1.0 to 3.5 mm, and the outer diameter of the proximal side is set within the range of 1.2 to 1.8 times the outer diameter of the distal side. The thickness dimension on the proximal side is smaller than the thickness dimension on the distal side, and the guaranteed pressure resistance value of the balloon is 16 atm or less.

According to the tapered balloon catheter having a structure according to this embodiment, when the pulmonary artery is treated with the balloon, the shape of the balloon in which the proximal side preferentially abuts on the inner surface of the blood vessel wall and exerts an expanding force on the proximal side rather than the distal side is formed. It was specified by the length and diameter of the balloon. At the same time, since the proximal side of the balloon is thinner than the distal side, the proximal side of the balloon is easily expanded and deformed when the internal pressure of the balloon is increased, and the proximal side of the balloon is smaller than the distal side. The swelling mode that is preferentially pressed against the blood vessel can be stably expressed. As a result, the proximal side of the balloon can be pressed preferentially against the blood vessel, and the action of vasodilation due to the expansion of the balloon is stabilized while suppressing the unintended movement due to the slip of the balloon. Is demonstrated.

In addition, by shortening the length of the balloon compared to general balloons used for limbs, it becomes easier to realize a shape that fits a specific part of the pulmonary artery that sharply narrows toward the periphery, and the balloon. It was possible to reduce the reaction force exerted on the outer peripheral surface of the balloon in the sliding direction. Therefore, the movement of the balloon due to slipping can be suppressed more effectively.

In addition, by limiting the guaranteed pressure resistance value of the balloon, it is possible to prevent the proximal side of the thin balloon from being excessively expanded in diameter, and it is possible to avoid slipping due to the action of excessive expansion force. An effective vasodilatory effect can be expressed more stably. Pulmonary artery stenotic lesions caused by thrombus organization often have a smaller force (balloon internal pressure) required for diameter expansion than coronary artery stenotic lesions that require high-pressure dilation such as calcified lesions. Therefore, the tapered balloon catheter used for the treatment of stenotic lesions of the pulmonary artery can be expected to have a sufficient therapeutic effect even if the guaranteed pressure resistance value of the balloon is limited. The guaranteed pressure resistance value of the balloon can be clearly recognizable by describing it in, for example, an attached document of a tapered balloon catheter.

The present invention is a newly developed tapered balloon catheter in consideration of special circumstances regarding the treatment of the pulmonary artery. Balloon pulmonary artery dilatation is performed by providing the balloon catheter dedicated to the treatment of the pulmonary artery to the medical field for the first time. Can help with procedures for pulmonary arteries such as.

The second aspect is the tapered balloon catheter according to the first aspect, wherein the central portion has a substantially constant taper angle.

According to the tapered balloon catheter having a structure according to this embodiment, the diameter of the balloon changes at a substantially constant rate of change in the length direction in the central portion, so that the dilation effect of the stenotic lesion due to the expansion of the balloon is centralized. It can be effectively exerted over the entire part.

The third aspect is that in the tapered balloon catheter according to the first or second aspect, the outer diameter of the distal side in the central portion is 3.0 mm or less, and the balloon is distal. The outer diameter of the shaft provided in the above is 0.5 mm or more.

According to the tapered balloon catheter having a structure according to this embodiment, a shaft having an outer diameter of 0.5 mm or more is combined with a balloon having an outer diameter of 3.0 mm or less on the distal side of the central portion. By adopting it, a tapered balloon catheter with excellent pushability will be realized, and it will be easier to insert a balloon into a stenosis lesion located on the peripheral side of the pulmonary artery.

A fourth aspect is the tapered balloon catheter according to any one of the first to third aspects, wherein the balloon is made of a polyamide elastomer and the proximal side has a minimum thickness of 20 to 50 μm. It is set within the range.

According to the tapered balloon catheter having a structure according to this embodiment, the balloon made of polyamide elastomer has a softness that can be expanded at a relatively low pressure, and is inserted into a stenotic lesion in a contracted state such as being folded. It has low resistance and can be easily inserted into a stenotic lesion, and has excellent delivery performance to a stenotic lesion of a balloon. The soft balloon made of a polyamide elastomer suppresses resistance when inserted into a guiding catheter, and has excellent insertability into a guiding catheter. In addition, since the minimum thickness dimension of the proximal side of the balloon is within the range of 20 to 50 μm, the proximal side is preferentially inflated over the distal side and easily pressed against the inner surface of the blood vessel wall. The movement of the balloon can be suppressed when the balloon is inflated.

According to the present invention, it is possible to provide a tapered balloon catheter having performance suitable for treating a stenotic lesion of a pulmonary artery, such as being able to inflate a balloon while being positioned at a treatment target site with high accuracy.

Sectional drawing which shows the distal end part of the taper balloon catheter as the 1st Embodiment of this invention. Enlarged sectional view of the main part showing the II part of FIG. 1 in an enlarged manner. Sectional drawing which shows the distal end part of the taper balloon catheter as the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the distal end of a tapered balloon catheter 10 as a first embodiment of the present invention. The tapered balloon catheter 10 is used for balloon pulmonary artery dilatation (BPA) in which a stenotic lesion of the pulmonary artery is dilated by a balloon to treat the stenosis or occlusion of the pulmonary artery. The tapered balloon catheter 10 has a structure in which the balloon 14 is attached to the distal end of the shaft 12. In the following description, as a general rule, the proximal side is the proximal end side (upper side in FIG. 1) that is the practitioner's side at the time of treatment, and the distal is the distal end side (lower side in FIG. 1) that is the patient side at the time of treatment. ), Respectively.

The shaft 12 is made of a soft resin or the like, and has flexibility that can be curved and deformed along the curvature of a blood vessel. The shaft 12 may be of the Over the Wire (OTW) type, but in the present embodiment, it is of the Rapid Exchange (RX) type. The shaft 12 includes an outer shaft 16 and an inner shaft 18. The outer shaft 16 has a hollow tubular shape having a pressure regulating lumen 20 as an inner cavity.

An inner shaft 18 is arranged on the inner circumference of the outer shaft 16. The inner shaft 18 has a tubular shape having a smaller diameter than the outer shaft 16, and has a guide wire lumen 24 as an inner cavity. The inner shaft 18 is provided in the distal portion of the outer shaft 16, the proximal end thereof is open to the outer peripheral surface of the outer shaft 16, and the tip portion protrudes distally from the outer shaft 16. A tip 22 is provided at the distal end of the inner shaft 18. The tip tip 22 has, for example, a tapered cylindrical shape. The tip 22 is preferably made of a material containing an X-ray impermeable material such as bismuth oxide or tungsten, so that visibility under fluoroscopy is ensured. The guide wire lumen 24 of the inner shaft 18 penetrates the tip tip 22 and is opened distally.

The inner shaft 18 provided in the distal portion of the outer shaft 16 projects distally to the outer shaft 16. The protruding portion of the inner shaft 18 is provided with an X-ray opaque contrast marker 26 at two locations separated from each other in the length direction. The contrast markers 26, 26 are arranged at positions corresponding to both ends of the central portion 30 of the balloon 14, which will be described later, so that the position of the balloon 14 can be grasped under fluoroscopy.

Further, the balloon 14 is provided so as to cover the outer periphery of the protruding portion of the inner shaft 18 from the outer shaft 16. The balloon 14 is made of, for example, a resin film formed of a polyamide elastomer, and has a tubular shape as a whole in an expanded state. The balloon 14 has both axially constricted ends, the proximal end of the balloon 14 is anchored to the distal end of the outer shaft 16, and the distal end of the balloon 14 is to the distal end of the inner shaft 18. It is stuck. As a result, each opening at the proximal end and the distal end of the balloon 14 is closed by the shaft 12, and the balloon 14 has a hollow structure having a pressure regulating space 28 inside. The pressure regulating space 28 of the balloon 14 communicates with the pressure regulating lumen 20 of the outer shaft 16 and the internal pressure can be controlled by a pump (not shown) indirectly or directly connected to the proximal end of the outer shaft 16. ing. A known connector (not shown) may be provided at the proximal end of the outer shaft 16, for example, the pump may be indirectly connected to the outer shaft 16 via the connector and external through the connector. Injection of a contrast agent into the distal end of the shaft 16 may be possible. The inner diameter of the outer shaft 16 is larger than the outer diameter of the inner shaft 18, and the distal opening of the pressure adjusting lumen 20 of the outer shaft 16 is opened to the pressure adjusting space 28 of the balloon 14.

More specifically, the inflated balloon 14 has a cylindrical central portion 30 forming the middle in the axial direction (vertical direction in FIG. 1) and a proximal end side forming the proximal end side with respect to the central portion 30. A substantially conical proximal portion 32 having a small diameter toward the tip and a substantially inverted conical distal portion 34 forming a tip side from the central portion 30 and having a small diameter toward the tip are integrally provided. ing. The proximal end of the proximal portion 32 is overlapped and fixed to the outer peripheral surface of the outer shaft 16, and the distal end of the distal portion 34 is overlapped and fixed to the outer peripheral surface of the inner shaft 18.

In the inflated balloon 14, the central portion 30 has a tapered shape in which the outer diameter gradually increases from the distal side 36 toward the proximal side 38. Therefore, in the central portion 30, the outer diameter R1 of the proximal side 38 is made larger than the outer diameter R2 of the distal side 36. The outer diameter R1 of the proximal side 38 of the central portion 30 is preferably set within the range of 1.2 to 6.3 mm, preferably within the range of 2.4 to 5.4 mm. The outer diameter R2 of the distal 36 of the central portion 30 is set within the range of 1.0 to 3.5 mm, preferably within the range of 2 to 3 mm. The outer diameter R1 of the proximal side 38 is set within the range of 1.2 to 1.8 times the outer diameter R2 of the distal side 36. The outer diameter R1 of the proximal side 38 is preferably increased by 1 to 2 mm with respect to the outer diameter R2 of the distal side 36.

In the inflated balloon 14, the outer diameter R2 of the distal side 36 of the central portion 30 is preferably 3 mm or less, and in that case, the outer diameter r1 of the outer shaft 16 is preferably 0.5 mm. As mentioned above, it is more preferably 0.9 mm or more. For the outer diameter r1 of the outer shaft 16 and the outer diameter r2 of the inner shaft 18, for example, a combination of 0.5 mm and 0.2 mm, 1 mm and 0.6 mm, 2 mm and 1 mm, and the like can be adopted. The distance from the outer peripheral surface of the inner shaft 18 to the outer peripheral surface of the proximal side 38 of the balloon 14 is set to, for example, 0.3 mm, 1.5 mm, 2.6 mm, or the like.

The length dimension L0 of the central portion 30 is set within the range of 15 to 25 mm, for example, 20 mm. The length dimension L0 of the central portion 30 is made larger than the length dimension L1 of the proximal portion 32 and the length dimension L2 of the distal portion 34, and preferably the length dimension L1 and the distal portion of the proximal portion 32. It is made larger than the sum of the length dimensions L2 of the portion 34. In the balloon 14 of the present embodiment, the length dimension L0 of the central portion 30 is preferably 50% or more, preferably 60% or more of the length dimension L of the entire balloon 14. As a result, the central portion 30 exerting a dilating force on the stenotic lesion of the pulmonary artery P (see FIG. 2) is secured long with respect to the total length of the balloon 14, and efficient treatment of the stenotic lesion may be possible. The length dimension L of the entire balloon 14 is preferably set within the range of 20 to 35 mm.

On the outer peripheral surface of the central portion 30, the taper angle θ0 with respect to the central axis A is substantially constant from the distal side 36 to the proximal side 38. Further, the inner peripheral surface of the central portion 30 has a taper angle with respect to the central axis A substantially constant from the distal side 36 to the proximal side 38. Therefore, the cross-sectional center line extending in the length direction of the central portion 30 has a taper angle with respect to the central axis A substantially constant from the distal side 36 to the proximal side 38. The taper angle θ0 of the outer peripheral surface of the central portion 30 is preferably set within the range of 2 to 5 degrees.

In the central portion 30, the thickness dimension t1 of the proximal side 38 is made smaller than the thickness dimension t2 of the distal side 36. Since the outer peripheral surface and the inner peripheral surface of the central portion 30 of the present embodiment each have a substantially constant taper angle, the thickness is gradually reduced from the distal side 36 to the proximal side 38 at a substantially constant ratio. It has become. The minimum thickness dimension t1 of the proximal side 38 is preferably set within the range of 20 to 50 μm. The maximum thickness dimension t2 of the distal side 36 is preferably set within the range of 50 to 70 μm.

When designing the balloon 14, the continuous portion between the central portion 30 and the proximal portion 32 may be designed as a cross-sectional shape curved in an arc shape, but is preferably designed as a square cross-sectional shape. To. Similarly, the continuous portion of the central portion 30 and the distal portion 34 is also preferably designed as a square cross-sectional shape. In the inflated balloon 14, it is desirable that both the continuous portion between the central portion 30 and the proximal portion 32 and the continuous portion between the central portion 30 and the distal portion 34 have a square cross-sectional shape. It can be rounded due to the expansion of the balloon 14.

The proximal portion 32 of the balloon 14 has a smaller diameter toward the proximal side at a taper angle θ1 that is substantially constant with respect to the central axis A. The distal portion 34 of the balloon 14 has a smaller diameter toward the distal side at a substantially constant taper angle θ2 with respect to the central axis A. The taper angle θ1 of the proximal portion 32 is preferably larger than the taper angle θ2 of the distal portion 34. The size of the taper angle θ1 of the proximal portion 32 and the size of the taper angle θ2 of the distal portion 34 are both larger than the size of the taper angle θ0 of the central portion 30. The magnitude of the taper angle θ1 of the proximal portion 32 is preferably set within the range of 5 to 45 degrees. The magnitude of the taper angle θ2 of the distal portion 34 is preferably set within the range of 3 to 30 degrees.

Further, the length dimension L1 of the proximal portion 32 is preferably smaller than the length dimension L2 of the distal portion 34. The length dimension L1 of the proximal portion 32 is preferably set within the range of 3.0 to 4.5 mm. The length dimension L2 of the distal portion 34 is preferably set within the range of 3.5 to 5.0 mm. The length dimension L1 of the proximal portion 32 and the length dimension L2 of the distal portion 34 are, for example, 3.0 mm and 3.5 mm, 3.5 mm and 4.0 mm, 4.0 mm and 4.5 mm, and 3.0 mm. And 5.0 mm or the like.

The maximum outer diameter of the proximal portion 32 (outer diameter of the distal end of the proximal portion 32) R1 is made larger than the maximum outer diameter of the distal portion 34 (outer diameter of the proximal end of the distal portion 34) R2. ing.

The balloon 14 has a guaranteed pressure resistance value of 16 atm or less, which indicates the maximum pressure allowed in the pressure regulating space 28. More preferably, the guaranteed pressure resistance value of the balloon 14 is 14 atm or less. The guaranteed pressure resistance value of the balloon 14 is presented to the user in a clearly recognizable manner. Specifically, for example, the user can grasp the pressure resistance guarantee value of the balloon 14 by writing on the attached document or package of the tapered balloon catheter 10, marking on the tapered balloon catheter 10 itself, or the like. It is desirable that the balloon 14 has a therapeutic pressure of 12 atm or more and 16 atm or less for dilating the stenotic lesion of the pulmonary artery P. By setting the minimum pressure in the balloon 14 at the time of treatment to 12 atm or more, the stenotic lesion of the pulmonary artery P can be effectively expanded.

The tapered balloon catheter 10 having such a structure is not shown in the pulmonary artery P in which the contracted balloon 14 in which the liquid in the pressure regulating space 28 is discharged is wound or folded around the shaft 12. It is inserted into a guiding catheter. In the balloon 14 of the present embodiment, the length dimension L2 of the distal portion 34 is larger than the length dimension L1 of the proximal portion 32, and the maximum outer diameter R2 of the distal portion 34 is the maximum outer diameter of the proximal portion 32. It is made smaller than R1, and in the balloon 14, the taper angle θ2 of the distal portion 34 is made smaller than the taper angle θ1 of the proximal portion 32. As a result, in the balloon 14 in a state of being wound or folded around the inner shaft 18, the rate of change in the outer diameter dimension from the tip to the proximal end side at the distal end portion is small, and the balloon 14 is used as a guiding catheter. The resistance during insertion is reduced, making it easier to insert into a guiding catheter.

Then, the distal end of the tapered balloon catheter 10 on which the balloon 14 is arranged is projected from the distal opening of the guiding catheter, and the contracted balloon 14 is inserted into the stenotic lesion of the pulmonary artery P. A liquid is sent into the pressure-regulating space 28 to pressurize the pressure-regulating space 28 to a predetermined pressure, and the balloon 14 is inflated. As a result, the stenotic lesion of the pulmonary artery P is expanded by the balloon 14, and the blood flow of the pulmonary artery P is restored. Since the balloon 14 folded in a contracted state has a small rate of change in the outer diameter of the tip portion as described above, resistance is suppressed even when it is inserted into a stenotic lesion, and it is easy to insert it into a stenotic lesion. To.

Since the flexible balloon 14 made of polyamide elastomer is softer than a balloon made of polyamide even in a contracted state such as when folded, it has low resistance and is easy to insert when it is inserted into a guiding catheter or a stenotic lesion. ..

Since the pressure resistance guarantee value of the balloon 14 of the taper balloon catheter 10 is 16 atm or less, the pressure adjusting space 28 can be pressurized up to 16 atm. For example, in a balloon catheter used for coronary angioplasty of the heart, the guaranteed pressure resistance value of the balloon may be about 24 atm, and the guaranteed pressure resistance value of the tapered balloon catheter 10 is larger than the guaranteed pressure resistance value of the balloon catheter for coronary arteries. Is set low to. One of the reasons why the guaranteed pressure resistance value of the tapered balloon catheter 10 can be set low in this way is that the stenotic lesion of the pulmonary artery P is often caused by the organizing of the thrombosis, and high-pressure dilation such as calcified lesion. It can be mentioned that the force required for dilation of the stenotic lesion may be smaller than that of the stenotic lesion of the coronary artery. The balloon 14 does not need to be inflated until the internal pressure reaches the guaranteed pressure resistance value. For example, it was confirmed by contrast enhancement that the stenotic lesion was sufficiently expanded before the pressure inside the balloon 14 was increased to the guaranteed pressure resistance value. In this case, the pressure increase in the balloon 14 may be stopped at a pressure smaller than the guaranteed pressure resistance value.

Based on the above-mentioned circumstances peculiar to the pulmonary artery, the guaranteed pressure resistance value of the balloon 14 is set low, so that the distal side 36 of the balloon 14 at the time of expansion is strongly applied to the inner peripheral surface of the pulmonary artery P. It can be prevented from being pressed. Since the pulmonary artery P is tapered toward the periphery with a relatively large taper angle, when the distal side 36 of the balloon 14 is strongly pressed against the inner peripheral surface of the pulmonary artery P, it is close to the balloon 14. A relatively large reaction force toward the position may act, causing unintended movement of the balloon 14 due to slippage. The tapered balloon catheter 10 limits the maximum value (guaranteed pressure resistance) of the internal pressure of the balloon 14 to a relatively small value, thereby preventing the distal side 36 of the balloon 14 from being strongly pressed against the inner peripheral surface of the pulmonary artery P. Therefore, by preventing the balloon 14 from sliding and inflating the balloon 14 in a state of being positioned with high accuracy with respect to the stenotic lesion, the stenotic lesion can be efficiently expanded.

The flexible balloon 14 formed of the polyamide elastomer can be inflated at a relatively low pressure, and even if the guaranteed pressure resistance value is set low as described above, the expansion rate of the balloon 14 can be sufficiently secured. It can effectively spread the stenotic lesion.

Further, the balloon 14 has a shape in which the central portion 30 that dilates the stenotic lesion is pressed against the inner peripheral surface of the pulmonary artery P preferentially over the distal side 36 on the proximal side 38. That is, the length dimension L0 of the central portion 30 is set within the range of 15 to 25 mm, the outer diameter R2 of the distal side 36 is set within the range of 1.0 to 3.5 mm, and near. The outer diameter R1 of the position side 38 is set within the range of 1.2 to 1.8 times the outer diameter R2 of the distal side 36. As a result, the inflated balloon 14 is strongly pressed against the inner peripheral surface of the pulmonary artery P on the proximal side 38 rather than the distal side 36, and the sliding movement toward the proximal side of the balloon 14 is suppressed. .. In the present embodiment, since the outer peripheral surface of the central portion 30 of the balloon 14 has a substantially constant taper angle θ0, for example, the stenotic lesion of the pulmonary artery P can be effectively expanded by the entire central portion 30.

The taper angle θ0 of the outer peripheral surface of the central portion 30 of the balloon 14 is slightly larger than the taper angle of the inner surface of the pulmonary artery P, and is set to, for example, 2 degrees or more. As a result, the balloon 14 is strongly pressed against the inner surface of the pulmonary artery P on the proximal side 38 rather than the distal side 36 of the central portion 30, and the sliding movement of the balloon 14 to the proximal side is suppressed. Further, the taper angle θ0 of the central portion 30 is set to, for example, 5 degrees or less, so that the contact reaction force acting on the balloon 14 when pressed against the inner surface of the pulmonary artery P is proximal in the axial direction. The magnitude of the directed component is suppressed, and the balloon 14 is suppressed from slipping proximally.

When the proximal 38 of the balloon 14 is pressed against the inner peripheral surface of the pulmonary artery P more strongly than the distal 36, not only the central portion 30 of the balloon 14 but also a portion of the proximal portion 32 of the balloon 14 is the pulmonary artery P. It may be pressed against the inner peripheral surface of the stenotic lesion. Then, as shown in FIG. 2, the contact reaction force F due to the contact with the inner peripheral surface of the stenotic lesion of the pulmonary artery P acts on the proximal portion 32. The contact reaction force F acting substantially orthogonally to the proximal portion 32 includes an axial component force f, and the component force f acts distally to the balloon 14. As a result, the component force of the proximal contact reaction force acting on the central portion 30 and the distal portion 34 of the balloon 14 by pressing against the pulmonary artery P is offset and reduced by the component force f. , The displacement due to the proximal slip of the balloon 14 is suppressed. In the present embodiment, since the taper angle θ1 of the proximal portion 32 is larger than the taper angle θ2 of the distal portion 34, the axial component force f of the contact reaction force F in the proximal portion 32 is , The contact reaction force at the distal portion 34 can be exerted more efficiently than the axial component force, and the proximal slip of the balloon 14 is effectively suppressed. Further, since the taper angle θ1 of the proximal portion 32 is larger than the taper angle θ0 of the central portion 30, a component force f toward the distal side acts on the central portion 30 in the proximal portion 32. It is applied more efficiently than the proximal component force to prevent the balloon 14 from slipping proximally.

In the present embodiment, since the cross-sectional shape of the balloon 14 at the continuous portion (boundary portion) of the central portion 30 and the proximal portion 32 is a corner shape, the continuous portion is an anchor that is caught in the stenotic lesion of the pulmonary artery P. The action can also prevent the balloon 14 from slipping. The anchoring action can be exerted even if the continuous portion of the central portion 30 and the proximal portion 32 is rounded due to the expansion of the balloon 14 and is not strictly angular.

By setting the axial length dimension L of the balloon 14 to 20 to 35 mm, it is possible to arrange the balloon 14 for a stenotic lesion of the pulmonary artery P having a short length dimension without causing the balloon 14 to protrude significantly. Therefore, the proximal side 38 and the proximal portion 32 of the central portion 30 of the balloon 14 can be pressed against the organic stenotic lesion to suppress the proximal sliding movement of the balloon 14.

Since the thickness dimension t1 of the proximal side 38 of the central portion 30 of the balloon 14 is smaller than the thickness dimension t2 of the distal side 36, the proximal side 38 is distal when the balloon 14 is inflated. It swells preferentially over the side 36 and is pressed against the inner peripheral surface (stenosis lesion) of the pulmonary artery P. In particular, by setting the minimum thickness dimension t1 of the proximal side 38 of the balloon 14 to 20 to 50 μm, the preferential expansion of the proximal side 38 is effectively realized, and the durability of the proximal side 38 is also ensured. can do. Since the internal pressure of the balloon 14 is limited to 16 atm or less, the thinned proximal side 38 is not excessively dilated, the balloon 14 is prevented from rupturing, and the pulmonary artery by the proximal side 38 is prevented. Overexpansion of P is also prevented. In the figure, the thickness dimension of the balloon 14, the rate of change in thickness, and the like are exaggerated for the purpose of facilitating understanding. Further, the thickness of the shaft 12 and the contrast marker 26 are also exaggerated in the drawing.

Further, in the present embodiment, the outer diameter R2 of the distal side 36 of the balloon 14 is set to 3.5 mm or less, and the outer diameter r1 of the shaft 12 is set to 0.5 mm or more, so that the outer diameter of the balloon 14 is set to 0.5 mm or more. A relatively thick shaft 12 is adopted. Therefore, for example, when the tapered balloon catheter 10 is inserted into the guiding catheter to deliver the balloon 14 to the stenotic lesion, excellent pushability is exhibited and the balloon 14 can be easily inserted into the stenotic lesion.

FIG. 3 shows the distal end of a tapered balloon catheter 40 as a second embodiment of the present invention. In the following description, the members and parts substantially the same as those in the first embodiment are designated by the same reference numerals in the drawings, and the description thereof will be omitted.

The taper catheter 40 includes a balloon 42 at the tip of the shaft 12. The balloon 42 has a smooth curved shape in which the continuous portion (boundary portion) of the central portion 30 and the proximal portion 32 and the continuous portion of the central portion 30 and the distal portion 34 are not angular but smooth in the vertical cross section shown in FIG. It is said that. Further, the proximal portion 32 and the distal portion 34 have a curved shape that is convex toward the outer periphery in the vertical cross section, and are smoothly continuous with the central portion 30. The central portion 30 may have a linear tapered shape having a substantially constant tilt angle in the axial direction in the vertical cross section, or may have a curved tapered shape in which the tilt angle continuously changes in the axial direction. May be good.

If the balloon 42 having such a smoothly continuous outer surface is adopted, the continuous portion between the central portion 30 and the proximal portion 32 and the central portion 30 and the distal portion 34 in the folded state of the balloon 42 are adopted. It is difficult for horns to form in the continuous part, and when it is inserted into a pulmonary artery stenosis lesion or a guiding catheter, resistance due to catching or rubbing is suppressed, and excellent insertion into the stenosis lesion and excellent storability in the guiding catheter. Is realized.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited by the specific description thereof. For example, the taper angle of the outer peripheral surface of the central portion 30 of the balloon 14 is preferably substantially constant, but may be gradually or stepwise changed in the length direction.

It is desirable that the thickness dimension of the balloon 14 gradually decreases from the distal side 36 toward the proximal side 38, but for example, in the central portion 30, only the proximal side 38 is thinner than the other portions. The other portion including the distal side 36 may be thicker than the proximal side 38 and may have a substantially constant thickness.

The taper angle θ1 of the proximal portion 32 may be the same as the taper angle θ2 of the distal portion 34, or may be smaller than θ2. Further, the length dimension L1 of the proximal portion 32 may be the same as the length dimension L2 of the distal portion 34, or may be larger than L2.

10 Tapered balloon catheter (first embodiment)
12 Shaft 14 Balloon 16 Outer shaft 18 Inner shaft 20 Pressure control lumen 22 Tip tip 24 Guide wire lumen 26 Contrast marker 28 Pressure control void 30 Central part 32 Proximal part 34 Distal part 36 Distal side 38 Proximal side 40 Tapered balloon Catheter (second embodiment)
42 Balloon A Central axis P Pulmonary artery

Claims (4)

A tapered balloon catheter with a balloon used to treat the pulmonary artery.
The central portion of the balloon in the length direction has a tapered shape in which the outer diameter gradually increases from the distal side to the proximal side.
The length dimension of the central portion is set within the range of 15 to 25 mm, and the length dimension is set within the range of 15 to 25 mm.
The outer diameter on the distal side is set within the range of 1.0 to 3.5 mm.
The outer diameter on the proximal side is set within the range of 1.2 to 1.8 times the outer diameter on the distal side.
The thickness dimension on the proximal side is smaller than the thickness dimension on the distal side, and
A tapered balloon catheter having a guaranteed pressure resistance of 16 atm or less. The tapered balloon catheter according to claim 1, wherein the central portion has a substantially constant taper angle. According to claim 1 or 2, the outer diameter of the distal side in the central portion is 3.0 mm or less, and the outer diameter of the shaft provided with the balloon in the distal portion is 0.5 mm or more. The tapered balloon catheter described. The tapered balloon catheter according to any one of claims 1 to 3, wherein the material of the balloon is a polyamide elastomer, and the minimum thickness dimension on the proximal side is set within the range of 20 to 50 μm.

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