Patent Application
20150174383
The present invention relates to a catheter balloon, a catheter, and a method of manufacturing the catheter balloon.
Causes for stenotic aortic lesion are, for example, an acquired calcific or rheumatic aortic stenosis, and a congenital aortic stenosis. For example, about the calcific aortic stenosis, at the time when the lesion thereof is deteriorated, the calcification of valve cusp advances so that the valve cusp gradually hardens. As a result, the mobile scope thereof is gradually restricted to cause cardiac insufficiency. For this reason, in the case of a severe valve cusp stenosis, it is necessary to treat the stenosis by operation.
In order to treat such a disease, balloon valvuloplasty is suggested as a low-invasive treating method for spreading a valve undergoing a stenosis, such as a calcific aortic stenosis, or a rheumatic or congenital aortic stenosis. An ordinary operation for the present treating method about the calcific aortic stenosis is as follows; first, a catheter having a deflated balloon is percutaneously inserted into a vein or artery, and then the balloon is arranged inside a cardiac valve required to be treated. Next, by spreading the balloon, the valve cusp is spread to pulverize a calcific portion depositing on the valve cusp. In this way, the softness of the valve cusp is restored to improve the mobile scope. After it is confirmed that the ejection quantity of the blood flow increases, the balloon is deflated and the catheter is removed from the inside of the body.
In order to spread the valve cusp of the aorta largely, the catheter balloon used in the present treatment may be made of a highly elastic material such as latex or silicone to cause the whole of the balloon to have expansibility. By using the highly elastic material to make the balloon expansible, advantages are produced that the initial outer diameter thereof can be made small and further the flexibility thereof facilitates the invasion and advance of the balloon into the vessel. Furthermore, the balloon has an advantage that when the balloon is removed from the blood vessel, the balloon can easily be withdrawn since the outer diameter of the balloon is made small after the deflation. However, the balloon made of the high elastic material such as latex or silicone can be arbitrarily made large in diameter to cause a problem of requiring an instrument or means for precisely controlling the spread diameter of the expansible balloon.
About any existing balloon, the shape thereof is cylindrical or ovoid, and further the balloon is easily slipped in blood or on a vascular wall. Thus, the balloon is freely shifted, and there remains a problem that a considerable skill and attentiveness are required to locate the balloon at a predetermined position.
Patent document 1: JP 2005-537856 A
Thus, the present invention has been made in light of the above-mentioned problems, and an object thereof is to provide a catheter balloon, a catheter and a method of manufacturing the catheter balloon, the balloon being an expansible balloon that has a spreadable outer diameter controllable easily in treatments for a calcific aortic stenosis, rheumatic and congenital aortic stenosis and others, and that can be effectively prevented from being freely shifted and can easily be fixed at a predetermined position.
In order to attain the object, the present invention is as follows:
The catheter balloon of the present invention comprising:
a cylindrical balloon part that is made non-expansive or low-expansive; and
a band part that is wound around the balloon part and is made of an elastic material having a shorter diameter than a spread diameter of the balloon part.
According to the present invention, the balloon part is made non-expansive or low-expansive; thus, the balloon can be prevented from continuing to be inflated to be excessively largely increased in diameter as seen in an expansive balloon. Consequently, the balloon can be prevented from being excessively spread to damage tissues therearound. When the band part is wound at the center, both sides of the band part (hereinafter referred to as “shoulder parts”) form spread regions wherein the band part is not wound. When an appropriate size for valve cusp and LVOT is selected, only the shoulder parts at the both sides are spread and the band part is not spread, by spreading the balloon at the pressure or less at which the band part expands. The shoulder parts are made to form waist parts whose radii are smaller than the shoulder parts. As a result, the catheter balloon can be naturally arranged in a manner that annulus is sandwiched between the shoulder parts.
In the catheter balloon according to the present invention, the balloon part may be made of non-expansive material or low-expansive material. By adopting such a configuration, a non-expansive or low-expansive balloon can be easily manufactured.
In the catheter balloon according to the present invention, the expansion percentage of the outer diameter may be 10% or less, when the balloon part is inflated at the pressure of 0.2 atm. By adopting such a configuration, it is surely prevented from breaking the surrounding tissue due to the over-expansion of the balloon part.
In the catheter balloon according to the present invention, the balloon part may be inflated to form a substantial gourd shape with which the band part is not provided at less than a predetermined pressure, and the band part may also be inflated at the predetermined pressure or more. By adopting such a configuration, the inflated band part can dilate valve cusp to break its calcified part.
In the catheter balloon according to the present invention, the balloon part may be inflated to from a substantial gourd shape with which the band part is not provided at less than a predetermined pressure, and the band part may also be inflated to form a substantial cylindrical shape at the predetermined pressure or more. By adopting such a configuration, the band part can be spread to the same diameter as the shoulder parts to break the calcified part of valve cusp.
In the catheter balloon according to the present invention, the balloon part may be inflated to form a substantial gourd shape with which the band part is not provided at less than a predetermined pressure, and may be a gourd shape even if a pressure equal to or more than the predetermined pressure is applied. By adopting such a configuration, the possibility of the balloon part being freely shifted can be prevented at the time of breaking the calcified part of valve cusp.
In the catheter balloon according to the present invention, the material forming the inner surface of the band part and the material forming the outer surface of the balloon part may be compatible. By adopting such a configuration, the balloon part and the band part can be welded together to be fixed.
In the catheter according to the present invention, an outer tube and the catheter balloon communicated with the lumen for injecting the spreading fluid of the outer tube are comprised. With these, the catheter which has the above-mentioned effect can be provided.
The method of manufacturing the catheter balloon according to the present invention is comprising:
(1) a process of arranging a tubular band part around a tubular member made of non-expansive material or low-expansive material; and
(2) a process of heating these parts to extend the tubular member by heat and inflate it to a cylindrical shape.
According to such a manufacturing method, the catheter balloon can be manufactured in a single process. And the whole surfaces of the band part and the balloon part can be thermally welded.
The method of manufacturing the catheter balloon according to the present invention may comprise:
(1) a process of heating the tubular member made of non-expansive material or low-expansive material to extend it by heat and inflate it to a cylindrical shape.
(2) a process of attaching a expansive band to the processed cylindrical material.
In this case, the expansive band may be attached to the processed cylindrical material by adhesion bonding, thermal welding, and etc.
According to the catheter balloon, medical apparatus and the method of manufacturing the catheter balloon according to the present invention, the spreadable outer diameter of the balloon, which is expandable, can easily be controlled and further the balloon can be effectively prevented from being freely shifted in treatments for calcific, rheumatic and congenital aortic stenosis, and others. Moreover, the present invention can provide a catheter balloon, a catheter and a method of manufacturing the catheter balloon, this balloon and a balloon of this catheter being capable of being easily fixed at a predetermined position.
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Hereinafter a detailed description will be made along with the drawings about a catheter balloon 10, a catheter 100, and a method of manufacturing the catheter balloon 10 according to an embodiment.
As illustrated in
The balloon part 20 is formed in a hollow bag shape, whose middle part is formed in a cylindrical shape, and whose both ends are tapered and formed in a conical shape. The balloon itself is formed non-expansive or low-expansive, and formed not to be inflated more than a certain level even if the inside is pressurized. Various kinds of well-known materials may be used for the balloon part 20; for example, nylon, polyvinyl chloride, polyethylene, polyurethane, polyether block amide copolymer, polyethylene telephthalate, olefinic polymer such as polypropylene, or copolymer consisting of a combination thereof, and others. Preferably, non-expansive material or low-expansive material is recommended for the material forming the balloon part 20 itself. The balloon part 20 is not necessarily made of a single material, and may be a double layer consisting of different materials between an inner layer and an outer layer. The double layer balloon can be manufactured by shaping a tube manufactured by a double-layer extrusion molding. If a material compatible with a band part 30 that will be described later is used for the outer layer, for instance, it can be welded with the band part 30 so that they are easily fixed each other. By adopting the above-mentioned expansive percentage, over-spreading can be prevented. The balloon part 20 is formed in length from 30 mm to 80 mm, preferably from 50 to 70 mm, and the maximum spreading diameter is formed, preferably, from 10 mm to 25 mm. Depending on the size of the maximum spreading diameter, it can be applied to the openings of a body and other hollow organs in addition to artery and vein.
The band part 30 is an expansive ring member, which is wound around the balloon part 20 to keep a part of the balloon part 20 less than the maximum spreading diameter at a certain pressure or less, and to be expanded at the certain pressure or more. Silicone, polyurethane, other elastomer-based polymer, and others, are used accordingly for materials, however, are not limited for the materials. The thickness of the band part 30 is manufactured from 20 μm to 100 μm, preferably from 50 to 70 μm, the width is manufactured from 3 to 30 mm, preferably 5 to 15 mm, and the diameter is manufactured from 3 mm to 20 mm. The diameter must be smaller than the maximum spreading diameter of the balloon part 20.
About the catheter balloon 10 formed in the above-mentioned manner, the band part 30 keeps the diameter of a part of the balloon part 20 small. Thus, when the spreading fluid is inserted into the balloon 20 at a predetermined pressure or less, specifically at a pressure permitting a waist part 30 to be spread or inflated, or lower, only the shoulder parts 23 are being spread while the waist part keeps the initial diameter thereof. Subsequently, the spread of the shoulder parts 23 and the other reaches into an equilibrium. The spread of the shoulder parts 23 causes the balloon 20, which has been folded up, to merely open, and thus the raw material itself of the balloon 20 is not expanded. Accordingly, the shoulder parts 23 are spread even at a relatively low pressure, for example, 0.05 atm or less. However, about the band part 30, the raw material itself thereof needs to be expanded. Thus, at a low pressure, the band part 30 is hardly expanded so that the band part 30 is kept to have the pre-expansion diameter. Consequently, as illustrated in
Next, a method of manufacturing the above-mentioned catheter balloon 10 is described.
The first manufacturing method is a method of manufacturing the balloon part 20 first, and then the band part 30 is attached with the balloon part 20. As a method of manufacturing the balloon part 20, blow-forming, or stretching a tube manufactured by extrusion-forming by spreading it after heating the tube, may be used. On the other hand, a method of manufacturing the band part 30 is not particularly limited, as long as a strip-like expansive sheet is prepared. For example, stretching a tube prepared by extrusion-forming or by dipping may be adopted. When the band part 30 is fixed onto the manufactured balloon part 20, the sheet-like band part 30 may be wrapped around the balloon part 20 and fixed, or the band part 30 preformed in a ring shape, as illustrated in
The second manufacturing method is a method of forming both the balloon part 20 and band part 30 at the same time by blow-forming. First, as illustrated in
The balloon part 20 manufactured in the above-mentioned manner is arranged at the distal end of a catheter main body to be a catheter. Specifically, as illustrated in
The following will describe how to use the above-mentioned catheter for valvuloplasty. According to the Seldinger technique, the catheter 100 is introduced through a thigh, upper arm artery or left subclavian artery. Alternatively, after a surgical incision, the catheter 100 is directly inserted into an aortic valve, so that the catheter 100 can be anteogradely inserted. Hereinafter, as an example, a case will be described where at the time of a detention of the catheter balloon 10 in a transcatheter aortic valve replacement, the catheter 10 is detained in a valve cusp by an approach through a thigh. It is however needless to say that various detaining techniques are usable in accordance with the present invention.
A puncture needle is stuck into a femoral artery (or an iliac artery inside the pelvis), which is near person's groin. Thereafter, a guide wire is inserted into the blood vessel. While the guide wire is being shifted along the blood vessel, the guide wire is slipped to be inserted into the blood vessel. The guide wire is passed through the aortic valve, and then indwelled. Thereafter, while the position of the guide wire is being monitored on a roentgenoscopic screen, the balloon 10 for catheter is retrogradely advanced to a target position. Next, as illustrated in
As illustrated in the drawing 6B, a spreading fluid is introduced into the catheter balloon 10 to increase the pressure therein up to about 0.1 atm to 0.5 atm (the pressure in the balloon part 20 is made slightly higher than that outside the balloon). In this way, the balloon 20 is spread. According to this pressure, the shoulder part 23 at the proximal side of the catheter and the shoulder part 23 at the distal side are spread while the waist part 22 is not spread to keep the diameter thereof small. In this state, about the catheter balloon 10, the spreadable diameter of the shoulder parts 23 is selected into a size suitable for the valve cusp and the LVOT. For this reason, the annulus is arranged to be sandwiched between the shoulder parts 23 at both the sides, so that the waist part 22 is arranged naturally at the valve cusp. Consequently, the balloon catheter 10 can be arranged at a desired position to be prevented from being freely shifted.
Next, the pressure inside the balloon part 20 is further increased, and the spreading fluid is introduced thereinto to give a pressure in the range of 0.5 atm to 5.0 atm, preferably 1.0 atm to 3.0 atm. As a result, the waist part 22 is spread to start pushing and moving the valve cusp outward. The spread of the waist part 22 pushes and moves the valve cusp to be opened, so that its calcified part is pulverized.
As the pressure inside the balloon part 20 is further increased, the diameter of the waist part 22 is gradually increased. Thus, as illustrated in
Hereinafter, experimental results are shown about the relationship between the pressure and the outer diameter in a working example. The present example merely shows one aspect of the invention. Thus, raw material and forms usable in the present invention are not limited to the present raw materials and form. The band parts 30 which are manufactured of polyurethane as an expansive material, 9 mm in the outer diameter, and 3 mm, 5 mm, and 10 mm each in width is prepared and attached with the balloon parts 20 which are manufactured of low-expansive nylon and 15 mm in the outer diameter. By injecting a spreading fluid into the balloon part 20, a change is measured in the inner pressure of the balloon part 20 and the outer diameter of the waist part 22 and shoulder parts 23 attached with the band part 30. The measurement of the outer diameter of each of the parts is started when the pressure begins rising inside the balloon part 20 after a spreading fluid is injected. Thereafter, the pressure and the outer diameter are measured each time a predetermined amount of the fluid is injected. Because the pressure is decreasing over time due to the creep phenomenon of the expansive material of the band part 30, the pressure in stable condition is recorded after a certain amount of time has been passed. The measurement result is as follows; with the 3 mm band width, 12.6 mm at the pressure of 0.032 MPa, and 14.3 mm at the pressure of 0.150 MPa. With the 5 mm band width, 12.0 mm at the pressure of 0.024 MPa, 14.2 mm at the pressure of 0.1450 MPa, and 14.5 mm at the pressure of 0.180 MPa. With the 10 mm band width, 11.1 mm at the pressure of 0.046 MPa, 13.4 mm at the pressure of 0.156 MPa, and 14.3 mm at the pressure of 0.221 MPa. With the shoulder parts, on the other hand, 14.3 mm at the pressure of 0.046 MPa, 14.8 mm at the pressure of 0.156 MPa, and 15.1 mm at the pressure of 0.221 MPa. The graph of the results is shown in the
According to the measurement results, a higher pressure than the expansive strength of the band part 30 is necessary to expand the band part 30. However, this pressure can be changed depending on the material and size, etc. of the band part 30. The diameter of the shoulder parts 23 inflates slightly along with the pressure increase, however, non-expansive material is used and 10% or less of the inflation rate is achieved so that no big difference can be seen. While the pressure is increasing to expand the band part 30, and the shoulder parts 23 are getting close to the outer diameter, however, depending on the material or the size of the band part 30, the band part 30 cannot be the same as the outer diameter of the shoulder parts 23. It shows the slightly smaller diameter than that of the shoulder parts 23. As a result, an uneven shape of the balloon part 20 can prevent the balloon part 20 from slipping out of the valve and shifting freely.
The present invention is not limited to the above-mentioned embodiment, and a variety of embodiments can be practiced within the technical scope of the present invention.
First, the catheter balloon 10 and the catheter 100 according to the present embodiment were described through an example of a transcatheter aortic valve replacement; however, they can be applied to the valvuloplasty of a stenotic aortic valve or pulmonary valve, or for dilating all stenotic constrictions in blood vessels. They also can be applied to the pre-spread of aortic valve cusp before placing a percutaneous aortic valve or any other artificial device used for aortic valve repair, replacement or transplantation. The applicable blood vessels include all blood vessels of the body, such as coronary arteries, peripheral arteries, veins, the gullet, the trachea, enteric blood vessels, the bile duct and the uriter, etc. of the body.
As has been demonstrated in the above-mentioned embodiment, the present invention is usable for intervention operations, especially for preventing a blood clot or debris from being scattered.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-281704 | Dec 2012 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/084196 | 12/20/2013 | WO | 00 |
