JPH0357462A - Balloon for medical device and forming thereof - Google Patents

Abstract

PURPOSE: To form a medical balloon to minimize risk on presenting certain range of expansion by making maximum expansion dimension larger than non-extendable operation profile concurrently making expansion profile of the balloon a maximum expansion dimension selected from certain rage of the maximum expansion dimension. CONSTITUTION: A tube 32 made of material such as extrusion molded nylon or polyamide is formed out to be either a biaxial oriented balloon 33 or a modified biaxial oriented balloon 34. After a lengthwise extension operation is completed, a part of the tube 32a expands mainly radially, which causes the pressure given to the inner wall of the tube 32a by pressurized fluid to conduct a radial expansion of the balloon part 35 partitioned from a foot 37. Local heat application onto the balloon part 35 is conducted during the radial expansion on controlling the part of the expansion so that the heat is not applied to the foot 37. The range of the maximum expansion dimension of expanded profile should be at least 10% of the radial expansion, which means that the maximum expansion dimension of the balloon exceeds more than 5% of previously specified non-extended operation profile.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates in particular to a balloon for a medical device and a method and apparatus for restraining the same. More particularly, the present invention relates to medical and surgical balloons and catheters comprising them, such as those designed for angioplasty, valvuloplasty and urological applications. These balloons exhibit the ability to be tailored to have desired inflation properties for a particular end use. A particularly important inflation property is the amount or percentage of expansion or stretching beyond the unstretched dimension in which the balloon is inflated to eliminate fold wrinkles, but is not stretched. Balloons that are particularly suitable in this regard are made of nylon or polyamide tubes that are biaxially oriented into the desired balloon shape.

Catheter balloons and medical devices containing them are used in angioplasty and other medical procedures where narrow spots or obstructions in blood vessels and other body passageways are altered to increase blood flow through the obstructed area of the blood vessel. It is well known for use in surgical environments such as operations. For example, in a typical balloon angioplasty procedure, a partially occluded vascular lumen is dilated through the use of a balloon catheter passed percutaneously through the arterial system to the site of the vascular obstruction. The balloon is then inflated to dilate the vessel lumen at the site of obstruction.

Basically, a balloon catheter is a thin, flexible tube with a small inflatable balloon at desired locations along its length, such as at or near its tip. Balloon catheters are designed to be inserted into body passageways, such as blood vessel lumens, cardiac passageways, urinary tracts, etc., typically using fluoroscopic guidance.

In the past, medical device balloon materials have been found to be able to swell to a working diameter or a specified initial inflation diameter to a significant extent without substantially increasing the risk of balloon rupture or balloon rupture once the material has been reached. The balloon had a wall thickness exhibiting strength and flexibility to allow for. Balloons of these materials can be characterized as substantially non-stretchable balloons that cannot be stretched, inflated, or conformed to any substantial degree beyond this working diameter. Such substantially non-stretchable balloons can be characterized as somewhat similar in properties to paper balloons, which do not inflate to any significant degree once they have been inflated to remove the entire crease. This non-extensible type of polymeric material used or proposed for use as medical balloons includes polyethylene terephthalate.

Other types of materials, such as polyvinyl chloride and cross-linked polyethylene, can be characterized as extensible in that they increase in volume or stretch as pressure is increased until they rupture.

These materials are generally elastic and/or stretchable. When such extensible materials are used as medical balloons, the working diameter or designated expanded diameter of the balloon can be exceeded due to the extensibility of the material.

Substantially non-stretchable balloons are often considered advantageous because they do not bulge significantly beyond their designated inflation diameter, thereby minimizing the potential for overinflation errors. The theory is that one need only select a balloon, such as an angiography balloon, that has an open and inflated diameter that substantially corresponds to the dilation dimension desired at the obstruction site. However, physiological vessels such as arteries are generally tapered and do not always match readily available catheter balloons. And sometimes it is desirable to be able to increase the diameter of the balloon beyond what was initially expected.

With a substantially non-stretchable balloon, such over-expansion is severely limited. On the other hand, certain non-stretchable materials from which medical balloons are made generally have relatively high tensile strength values, which are typically desirable attributes for dilating particularly tough lesions.

More easily stretchable materials, such as polyvinyl chloride, typically exhibit lower tensile strength and greater elongation than substantially non-stretchable materials, such as polyethylene terephthalate. This relatively low tensile strength increases the risk of possible balloon failure. Due to their large final elongation, the most easily inflatable materials have a wide range of validity for each particular balloon size, since the inflated working shape of the balloon, once achieved, can be further expanded to achieve additional expansion. A bulge or expansion dimension can be provided. However, this property of having a wide expansion range does not come with the risk of increasing the risk of overinflation, which can damage the vessel being treated, and the risk of overinflation is greater than would otherwise be desirable for balloons. It would have to be compensated for by using wall thickness.

Although a material such as polyethylene terephthalate is advantageous in view of its particularly high tensile strength and closely controllable bulging properties, it generally has undesirable properties other than being non-extensible. In some situations, the biaxial orientation of polyethylene terephthalate will impart excessive crystallinity to the angioplasty balloon, or the Young's modulus will simply be too high. Under such circumstances,
The balloon itself or its thicker legs have the type of low profile desired for insertion through guiding catheters and/or through the cardiovascular system, and especially through narrowed arteries to be dilated. Will not easily bend up and down to provide. Resistance to bending or flapping is a particularly difficult problem when it comes to large balloons, such as those intended for valve-shaped surgical applications.

Also, thin-walled materials such as polyethylene terephthalate have a tendency to form bin holes or exhibit other signs of weakening, especially when bent. Such tendencies require extreme care in handling to avoid accidental damage that would substantially weaken polyethylene terephthalate medical balloons. Although it is known that lower profile and more flexible balloons and balloon legs can be created by thinning the walls, polyethylene terephthalate balloons made in this way become extremely brittle and do not have the desired integrity. and would not be able to withstand insertion through the cardiovascular system without hole formation and/or rupture.

Materials such as polyethylene terephthalate do not readily accept drug or degreaser coatings, which are desirable in many applications. Polyethylene terephthalate materials are difficult to fuse, whether by heat bonding or with known biocompatible adhesives.

With the present invention, these undesirable and/or disadvantageous properties of substantially non-stretchable medical balloons, such as those made from polyethylene terephthalate materials, are significantly eliminated. At the same time, many of the benefits of these types of materials are provided or approached. Additionally, the present invention offers many of the advantages of more resilient materials such as polyvinyl chloride, but with the disadvantages of relatively low tensile strength and the potential for excessive distensibility, which can lead to excessive distension of vessels, etc. Realize without sex.

In summary, the present invention provides a limited working or fully inflated but unstretched expansion profile for the balloon to be capable of inflation to a desired extent that is responsive to the specific demands of the balloon device, but within limits. Forming and providing catheters and medical catheter balloons made of materials with and generally controlled expansibility achieves these objectives and provides beneficial properties along these lines. The present invention provides proper axial stretching,
This includes the use of optional materials, such as nylon or polyamide materials, which are shaped into bi-orientated balloons in a shaping device by radial expansion and heat treatment operations.

A general object of the present invention is to provide an improved apparatus and method for styling medical balloons.

Another object of the present invention is to provide an improved apparatus and method for shaping medical balloons that exhibit controlled expansion at high pressures.

Another object of the present invention is an improved apparatus and method for shaping medical balloons that provides a certain range of expansion while minimizing the risks that may be associated with such flexibility. The goal is to provide the following.

Another object of the present invention is to provide an improved angioplasty catheter balloon forming method and apparatus that is particularly suitable for forming tubes of materials such as nylon or polyamide into catheter balloons.

Another object of the present invention is to provide an improved means and method for biaxially orienting relatively poor quality tubing into a biaxially oriented medical balloon.

Another object of the present invention is to provide improved apparatus and methods for forming balloon catheters that are easily coated with materials such as lubricants and others useful for administration in conjunction with balloon catheters. It is to be.

Another object of the present invention is to provide an improved apparatus and method for forming balloons that exhibit a desirable combination of strength and flexibility.

Another object of the present invention is to provide an improved apparatus and method for displaying medical balloons that exhibit the ability to be easily fused to other components.

These and other objects, features and benefits of the present invention will be clearly understood upon consideration of the following detailed description.

FIG. 1 is a partially sectional front view of a balloon catheter having a typical structure used in a vascular procedure.

Figures 2a, 2b, 2c, 2d and 2e are front views of the tube as it is progressively processed to be transformed into a medical balloon according to the invention.

FIG. 3 is a cross-sectional view of a preferred apparatus for carrying out the process steps shown in FIGS. 2a, 2b, 2c, 2d and 2e.

FIG. 4 is a plot of balloon size versus balloon inflation pressure for balloons made of various materials, including nylon balloons designed to provide different radial inflation properties.

Figures 5 and 6 are plots illustrating the function of heat fixation on adjustability.

FIG. 7 is a plot illustrating the function of hoop expansion ratio on adjustability.

An exemplary catheter is designated generally by the reference numeral 21 in FIG. Catheter 21 includes a catheter tube 22 having a proximal end 23 and a distal end 24 . A guide catheter 25 is also shown. Medical balloon 22 is shown secured to a distal portion of catheter tube 22 in a position over one or more openings 27 through the catheter tube. Extending through the lumen of catheter tube 22 is an inner elongated body 28 having a proximal end 29 and a distal end 31 . The inner body 28 has an inner surface, depending on whether it is merely a guiding function or whether it is also intended to provide capabilities such as inserting substances into the bloodstream or measuring parameters of blood flow. The body can be solid or have a lumen depending on the function to be achieved.

With the exception of balloon 26, these various components perform functions generally recognized in the art. Typically, with the aid of guide catheter 25, inner body 2 and catheter tube 22 are inserted into the cardiovascular system until the balloon is located at the site of occlusion. At this stage, balloon 26 is typically collapsed and collapsed and has an outer diameter smaller than the inflated diameter shown in FIG. 1, such that balloon 26 generally overlaps around catheter 22. Once the balloon is maneuvered to the occlusion site, pressurized fluid is passed through the opening and inserted from the proximal end 23 of the catheter tube 22 for inflation of the balloon 26. This means that it has a relatively smooth outer surface or working profile to apply a radially outwardly directed force at a desired location within the body to achieve the desired result of lesion dilatation, occlusion reduction, or similar procedure. Inflate balloon until ready to serve. According to an important aspect of the present invention, greater pressure transmission to the inner surface of balloon 26 is directed outwardly in the actual radial direction of balloon 26 beyond its working profile, as shown in phantom in FIG. Allows the outer surface of balloon 26 to transmit additional forces, including movement, to the lesion or otherwise.

Figures 2a, 2b, 2c, 2d and 2e show the tube 3, which is an extruded material such as nylon or polyamide.
2 to a biaxially oriented balloon 33 or a modified biaxially oriented balloon 34. Either balloon 33 or 34 has the ability to inflate to an initial unstretched or working profile and then to a limited and/or controlled degree beyond that by application of greater pressure. Balloons 33 and 34 each include a balloon portion 35.36 and a leg portion 3738. The leg parts 37, 38 are the parts where the balloon is fixed to the tube of the catheter 2l. In an exemplary application, tube 32 is extruded to have a diameter that is approximately 1/4 of the diameter intended for the balloon. This extruded tube 32 also has a nominal wall thickness on the order of 6 to 12 times closer to the desired wall thickness of the balloon 33,34.

Figure 2b illustrates tube 32a after it has been axially oriented or stretched to about three times its original length. This stretching or drawing operation is carried out at about room temperature and is typically allowed to proceed until it is stretched to the point where it exhibits appreciable resistance to further stretching. Typically, this tensile force is greater than the yield point of the particular tube 32, but less than the ultimate longitudinal tensile strength of the selected material. Generally speaking, this axial stretching operation is performed until the wall thickness of tube 33a is about half the wall thickness of tube 32 and/or the diameter of tube 32a is about half to 40% of the outside diameter of tube 32. It will be carried out until the end. The actual stretched length is typically the original tube 3
The length can be about twice to about four times the length of 2. The actual stretching of tube 32 can be performed by simply stretching tube 32 axially or by pulling or pulling tube 32 through a sizing die.

Figure 2c illustrates the steps performed after the longitudinal orientation operation of Figure 2b is completed. This is tube 32a
A biaxially oriented step in which a portion of the balloon expands primarily radially, thereby separating the balloon portion 35 from the leg portions 37. This biaxial orientation is effected by pressure applied to the inner wall of tube 32a by pressurized fluid. Typically, balloon portion 35 will have an outer diameter on the order of about six times the outer diameter of tube 32a. The pressurized fluid may include a gas such as blended air, nitrogen or argon.

Liquids such as water or alcohol could also be used if they do not cause residual fluid problems in the balloon. Generally speaking, the larger the balloon, the faster the inflation fluid flow rate will be. Examples of heart balloons that generally fall into typical orders of magnitude are those designed for use in coronary arteries, those designed for use in peripheral arteries, and those used in heart valves. This is a valve-shaped surgical balloon.

Other balloons include urethral shaped balloons for dilating the prostatic urethra.

The operation illustrated in FIG. 2c is facilitated by controlling the location at which biaxial orientation occurs. An advantageous method of achieving this result is that during radial inflation the balloon portion 35
Second, heat can be applied locally while avoiding heat to be applied to the legs 37.

The temperature increase in such a localized area will cause the nylon at that location to
This will lower the yield point of polyamides and the like, thereby facilitating biaxial orientation in this selected area. As an example, the temperature at which this step is carried out can typically be between about 35°C and perhaps 90°C, with the optimum temperature depending somewhat on the particular materials used.

Means are provided for controlling the inflation or radial orientation of tube 32a and its conformation to balloon portion 35 and legs 37. This can be accomplished by controlling and monitoring conditions and/or expansion locations within the molding equipment. Exemplary means in this regard are included in certain devices described herein. Otherwise, this function can be accomplished by tightly controlling the rate of fluid passage and monitoring its pressure. For example, for valvuloplasty balloons, the following approach can be taken.

Approximately 0. 140 inches (0.3556cr
n) diameter and 0. 0 0 6 inches (0.015
A vertically oriented tube having a wall thickness of 24 marks) is sealed and a liquid such as water is pumped into the tube at a rate of about 2 ml/min. With a tube of this size and at this rate, the balloon inflation is about 300 ps
i (2 1. ikg/cn) gauge and approximately 150 ps i (10
．． 5 5kg/c+fl) gauge. Expansion continues in this manner until a molding with the desired balloon shape is obtained, which can be observed by a significant pressure increase. Pumping is approximately 180 to 200 psi (12.7
or 1 4. This continues until a pressure of 0 kg/c+f) is reached.

This pressure condition can be maintained if desired.

A satisfactory balloon can be dimensionally stabilized near its biaxially oriented shape and dimensions by proceeding with the method including the steps shown in Figure 2c and then maintaining the elevated temperature until the selected material is heat set. , by heat setting or thermoforming. The sI1 node flexibility achieved according to the present invention is a function of the specific heat setting conditions.

The fixed temperature can be varied depending on the type of material used, wall thickness and processing time. Typical fixing temperatures are about 100°C to about 160°C for nylon materials, and typical processing times are about 1 minute to about 4 minutes.

Such a balloon 33 has an inflation hump 3 found in the area generally extending between the legs 37 and the working surface of the balloon portion 35.
9. These expansion nubs, which can also be described as knots, grooves, ribs, beading, etc., are believed to result from unbalanced expansion or orientation of the material, such as nylon, in this area. When it is desired to minimize the presence of these inflation bumps 39 on the balloon,
A secondary longitudinal orientation with radial direction followed by secondary radial expansion can proceed for the non-heat set balloon and are illustrated in FIGS. 2d and 20.

With respect to FIG. 2d, the balloon 33 of FIG. 2C, which is not heat set, is again typically vertically oriented by passing an axially directed force greater than the yield point but less than the ultimate tensile strength of the balloon 33. Oriented. If desired, this axial force can be substantially the same magnitude as the axial force applied in the operation shown in Figure 2b.

Biaxial orientation is then performed, for example, by introducing pressurized fluid into the balloon lumen to produce the balloon 34 shown in FIG. 2e. This operation is performed on balloon part 3.
6. It is often preferred to carry out within the mold cavity in order to achieve careful shaping of the leg portions, and generally the tapered connecting surfaces therebetween if desired. The resulting modified balloon 34 typically has a significant inflation gap 39.
and will have a uniformly oriented transient spacing between balloon portion 36 and leg portion 38. This additional longitudinal expansion or stretching substantially eliminates areas of non-oriented material.

Regardless of whether a manipulation is used to shape balloon 33 or a manipulation to shape balloon 34 is continued, the shaped balloon 33.34 is preferably pressurized to fix its inflated dimension. Balloons 33, 34 are hung onto the heat set stent which is heated. Setting is typically carried out at temperatures above 85° C., typically up to the melting point of the balloon material depending somewhat on the actual material and balloon dimensions and thickness. For example, a typical fixation temperature for nylon 12 is 120° C. for 1 minute. With this heat treatment, the balloon will maintain its shape and most of its expanded dimensions, typically about 95% or more when cooled. Preferably, the balloon remains pressurized until it has completely cooled. If this heat-setting operation is not used, the balloon will quickly deflate to about 40 to 50% of its blown or biaxially oriented dimensions in the mold.

Particularly with regard to this heat-setting operation, an important requirement is the use of thermoformable materials. A material is thermoformable if it can be thermally shaped into another shape. Nylon is a thermoformable plastic.

It can be heated to a temperature below its melting point and formed into other shapes and/or
or can be deformed or molded to take on dimensions. When cooled, the thermoformable material retains its new shape and/or dimensions. This operation can be virtually repeated. In contrast, thermosetting materials such as natural latex rubber, cross-linked polyethylene or silicone rubber
Once cured, it is crosslinked to its size and/or shape and can no longer be heat deformed. Also, biaxially oriented polyethylene terephthalate has a tendency to crystallize and lose the thermal stability typical of non-biaxially oriented polyethylene terephthalate. When a biaxially oriented nylon balloon is heated at a predetermined high temperature, for example about 80° C., for an extended period of time and then cooled, it is heat formed into a balloon shape. If the balloon is reheated above this temperature, it will reshape into a balloon with a different shape.

FIG. 3 illustrates a molding apparatus suitable for molding the medical balloons discussed herein. This device transforms the parison 41 into a balloon for medical instruments and the like. The apparatus includes means for achieving longitudinal stretching, biaxial orientation, heating and cooling, and for monitoring radial expansion or biaxial orientation, all of which are implemented using hard circuitry, microprocessors, or other computerized It can be conveniently controlled by a control device. These controlled parameters can thus be precisely set and easily varied to provide optimal conditions for shaping a particular balisong into a balloon with the specific dimensions and properties desired. Certain parameters are provided herein that are typical for balloon materials such as nylon, and it is understood that these parameter values can be varied as needed for the particular material being shaped into the balloon. Will.

The illustrated apparatus has the ability to perform different steps on multiple balloon sections of the parison as it passes through the apparatus, generally simultaneously. This is particularly useful due to variations in thickness and other attributes of each batch of tubing used as balisong 41.

The device includes a series of elements suitably mounted with respect to each other, for example along a slide rail 42. Sometimes movement of some of these elements is effected by suitable means, such as a piston assembly (not shown), according to generally known principles and construction.

A source of pressurized fluid 43 is arranged to introduce pressurized fluid into the end portion of the parison in cooperation with one or more regulators 44 according to well-known principles.

One or more valves 45 also help control the flow rate and volume of pressurized fluid within parison 41. Gripper assemblies 46 and 47 are provided for engaging different locations of balisong 41. Preferably an intermediate gripper assembly 48 is also provided. One or more cooling chambers 51.52, 53.54 are also preferably provided. These are particularly useful as a means of thermally isolating the various assemblies of the device from each other. In addition, the free professional one biaxial orientation chamber or the mold 55 and the molding chamber 56
Also included.

Preferably, means are provided for controlling and/or varying the temperature of these various chambers, for example between about 0°C and about 150°C or more. The illustrated assembly in this regard includes a suitable fluid population 57 and a jacket for containing thermal fluid pumped into and out of fluid outlet 58.

Heat fluid into each fluid jacket}61.62,63.64,6
5.66, an O-ring 59 or the like is provided.

In use of the illustrated apparatus, the balisong 4l is first fed or routed through the apparatus, typically between gripper assemblies 46 and 47. The pad 68 of the gripper assembly 47 moves inward and grips the downstream end of the balisong 41.
The slits are squeezed together, preferably at this time engaging the parison to the extent that it heat seals it. Generally at the same time, the pad 67 of the gripper assembly 46 holds the parison 41 of the apparatus to the extent that it prevents movement of the parison 41 with respect to the pad 67, but still allows flow of pressurized fluid therethrough when desired. engages at an upstream position.

Gripper assembly 47 then gripper assembly 4
in the downstream direction until the total length of the parison fixed between 6 and 47 is stretched or oriented not less than two times its length to about four times its length, typically about three times its unstretched length. Move (to the right as shown in Figure 3).

The free pro-biaxial orientation chamber 55 is then heated by passing heated thermal fluid into the fluid jacket 62. Cooling chambers 51, 52, or other suitable means provide thermal isolation such that heat from fluid jacket 62 is applied substantially only to the entire length of the parison within free pro-biaxial orientation chamber 55.

The temperature of this particular part of the balisong is
and approximately 70°C and 120°C depending on desired balloon properties.
or higher. The pressurized fluid in the parison 41 from the source 43 then passes through the entire length of the parison between the gripper assemblies 46 and into the length of the parison in the free blow chamber 55.

If desired, the gripper assembly 4 can be used to limit this particular pressure application to the portion of the parison 41 upstream of the gripper assembly 48.

The primary purpose of the free pro-biaxial orientation chamber 55 is to radially inflate that portion of the parison 4l into the balloon 33, as generally shown in FIG. 2C. It is often desirable to precisely control the amount of biaxial orientation, and means are provided to do so. This means, illustrated in FIG.
Contains 9. Balloon 3 with insert 69 inflated
3, it moves the air or metal to the left as shown in FIG. 3 until it reaches a suitable switch etc. (not shown) that signals that the desired degree of biaxial orientation has been achieved. It moves against a spring (not shown). At this time, a step is taken to interrupt the biaxial orientation. This typically increases the heated thermal fluid within fluid jacket 62 by approximately 1
cooling by a thermal fluid having a cooler temperature of 0° C. or somewhat lower or higher depending on the particular parison 41 and the particular properties desired.

The pressure applied to the balloon portion 33 is then removed, for example by allowing the balloon to vent through valve 45 after it has cooled. If used, the gripper assembly 48 is released and the balloon portion 43 is moved from the free blow biaxial orientation chamber 55 into the forming chamber 56 by movement of the downstream end portion of the balisong by the gripper assembly 47.

This typically accomplishes the longitudinal force orientation step illustrated in Figure 2d at the same time. Once this position is taken, a pressurized fluid is pumped into that portion of the parison that is within the shaping chamber 56 and cools this portion of the parison from about 70'C to just below the melting point, e.g. Thermal fluid is supplied to the fluid jacket 65 for reheating the balloon to an elevated temperature and higher depending on the desired properties of the balloon.
be led inside.

Generally speaking, the temperature inside the molding chamber 56 is the same as that of the free blow chamber 5.
It is usually advantageous to apply a pressure to the inner wall of the balisong in the cutting chamber 56 that is higher than the temperature applied to the molding chamber 5 and at the same time equal or lower than the pressure prevailing in the free blowing chamber 55. For example, when the material is nylon, the free blow chamber 5
The temperature inside 5 is a little higher than the environment, preferably about 30-6
0"C, although the temperature within the chamber 56 may be at the upper end of this range or above if necessary. Exemplary pressures may be within the range of 1
The pressure may be on the order of 0 atmospheres and more than twice that pressure in the free blow biaxial orientation chamber 55. The exact pressure is determined by the material of the balloon to be restrained, and by wall thickness and hoop stress.

By applying heat to the modified biaxially oriented balloon 34 within the shaping chamber 56, the balloon 34 is thereby thermally shaped and the heat set in this regard raises the temperature of the thermoplastic while it is under inflation stress. including rising to Thereafter, the thermal fluid within the fluid jacket 65 is
A cooling fluid is exchanged to substantially maintain the size and shape of the balloon 34 formed within the molding chamber 56.

After the pressure is released, the balloon is removed from the device.

Thereafter, the balisong thus shaped is used as a catheter 2.
The balloon 26 is cut generally along lines A and B shown in FIG. 2e to form the balloon 26 for strapping to a medical device such as 1.

It will be appreciated that the parison contains balloons that are in various stages of their formation as they pass through the device. Preferably, this is carried out in a somewhat reversed manner as follows. Free blow room 55
After the initial stretching and formation of the balloon 33 in the chamber, this device is used such that a portion of the balisong in the shaping chamber 56 is radially expanded prior to inflation in the free blow chamber 55, which is generally It occurs as follows. Molding chamber 56 is heated and pressurized to form balloon 34 as described herein. Gripper assembly 48 then closes the balisong between chambers 55 and 56. The free blow chamber 55 is then heated to a force U and the biaxial orientation is carried out as described herein to shape the balloon 33.
3 is moved to the precept room 56 and the process is essentially repeated.

It should be understood that the balloon can be created entirely within the shaping chamber 56 without free blowing in the chamber 55. However, balloons made in this manner may exhibit multiple humps.

Regarding fluids suitable for use in the device, it is typically advantageous for the pressure source 43 to provide a fluid that does not require extra processing to remove from the inner surface of the final medical device balloon 26. What must be taken into consideration in this regard is fluid moisture and ease and safety of fluid disposal. A particularly suitable fluid is pressurized nitrogen gas. Regarding the fluids used within the jackets 6I-66, it is typically best to use fluids that are in a liquid state at whatever operating temperature is required for the device. Preferably, the fluid maintains a generally consistent viscosity throughout the operating range to avoid the onset of solidification, crystallization, etc. that alters the properties of the thermal fluid at low processing temperatures.

As for the materials from which balloons and balisongs are made, they are typically nylon and polyamide. Preferably, these materials are amorphous in nature, but have sufficient crystallinity to be biaxially oriented under the conditions provided by the present invention. The material must also have substantial tensile strength, be resistant to bin hole formation after folding and unfolding, and generally be scratch resistant. The material must have an inherent viscosity that allows blowing at elevated temperatures. A typical intrinsic viscosity range preferred for nylon or polyamide materials according to the present invention is about 0. 8 to about 1.5, with about 1.3 being particularly preferred. It is desirable that the material also have fairly good moisture resistance. It has been found that nylon 12 type materials possess these beneficial properties. Other exemplary nylons include nylon 11, nylon 9, nylon 69 and nylon 66.

Furthermore, with regard to the intrinsic viscosity of nylon or polyamide materials, it is believed that such materials are generally able to maintain their intrinsic viscosity during extrusion and through final balloon formation. Furthermore, other materials such as polyethylene terephthalate previously used in medical balloon shapes do not exhibit this intrinsic viscosity maintenance, and the intrinsic viscosity of the pellet material decreases substantially during extrusion, resulting in biaxially oriented It has been found that polyethylene terephthalate balloons result in lower intrinsic viscosity than the polyethylene terephthalate pellets from which they are based. Additionally, it is believed that high balloon intrinsic viscosity reduces the likelihood of bottle holes occurring in the final formed balloon.

Regarding the nylon or boria trichloride materials that can be used in accordance with the present invention, they can be bonded by epoxy adhesives, urethane adhesives, cyanoacrylates, and other adhesives suitable for nylon, etc., and also by hot melt bonding,
It can be joined to the catheter 21 by ultrasonic welding, heat fusion, or the like. Additionally, these balloons can be attached to catheters by mechanical means such as tap fittings, shrink fittings, threads, and the like. Nylon or polyamide materials can also be provided in reinforced form with linear materials such as KevIer or ultra-high tensile strength polyethylene. This polymeric material used is a pharmaceutical material such as hevarin,
and a non-thrombogenic lubricant such as polyvinylpyrrolidone. In addition, this polymeric material can be loaded with radiopaque media such as barium sulfate, bismuth carbonate, iodine-containing molecules, and other additives such as plasticizers, extrusion lubricants, pigments, antioxidants, etc. can.

The nylon or polyamide used in accordance with the present invention is flexible enough to allow large wall thicknesses even in the leg areas, but can be folded onto itself for insertion into a body cavity or guiding catheter. It still provides a stackable structure.

These nylons or polyamides, when bicyclically oriented and shaped into balloons as discussed herein, have approximately 15.0
00 to about 35, (100psi (I O
5 4.5 to 2 4 6 0 kg/cm2)
, preferably about 20,000 to about 32,000p
s i (1 4 0 6 to 2249.6 kg/
d) has a calculated tensile strength of

Materials according to the present invention form medical device balloons that exhibit an initial unstretched or unstretched state or the ability to inflate to working dimensions upon application of an applied pressure. They also have the ability to further inflate so as to be stretched beyond that state in a controlled and limited manner. The degree of such stretching or stretching can be designed within limits as required. In other words, the balloon according to the invention allows for some growth due to higher pressure than is necessary to simply fill the balloon, but this additional length or expansion is not substantial enough that there is a risk of overinflation. Not the point.

The material according to the invention must be glH fiff capable of being generally stretched beyond its unstretched or working dimensions during balloon molding. This percentage depends on the conditions under which the balisong is processed into balloons. Suitable materials according to the invention can be adjusted to cover values within at least the 10 percent point of radial expansion. Some materials, including certain nylons, can exhibit a 25 or 30 percentile ffff range, and e.g.
% or less, and as high as about 30% or more.

To demonstrate this situation, angiomorphic balloons of different materials were tested: polyvinyl chloride, cross-linked polyethylene, polyethylene terephthalate, and nylon. These data are reported graphically in FIG.

The wall thickness was varied depending on the properties of the material to form a workable balloon. The polyethylene terephthalate balloon (B) had a wall thickness of 0.010 mm. The polyvinyl chloride balloon (C) is 0. The balloon had a wall thickness of 0.064 m and the polyethylene balloon (D) had a wall thickness of 0.058 m. Data for balloons C and D are Th
e American Journal of Cards
iology, January 1986 issue, “Eff
ect ofInflation Pressure
on Coronary Angioplasty Ba
Although these tests were conducted at ambient conditions, the remaining balloons in Figure 4 were tested at 37°C. Nylon Balloons (A)
One has a wall thickness of 0.013m and a hoop expansion ratio of 5.
I had 2. Another nylon balloon (E) had a wall thickness of 0.0 (18 mm) and a hoop expansion ratio of 4.3. It is a function of the hoop inflation ratio, defined as the quotient of the average balloon diameter divided by the average diameter.

FIG. 4 plots the relative pressure of fluid applied to various vascular surgical catheters versus the percentage increase in balloon dimension (such as diameter or radius) above its working dimension, defined as "0".

A pliable material such as polyvinyl chloride will gradually lengthen as pressure is increased, and will have some limit before further inflation ceases after the working dimension is reached and before the balloon's rupture limit is reached. It would be acceptable to allow additional pressure increases. In such materials,
A small increase in relative pressure (compared to the materials in plots A and B) significantly increases balloon size. Materials such as polyethylene terephthalate (PET) swell to their working dimensions, but do not exceed them to a large degree as do the other curves plotted.

The nylon or polyamide material shown by the curve path exhibits a relatively long and flat curve in FIG. 4, indicating that it will continue to expand slowly with the application of relatively small additional increments of inflation pressure. Once the unstretched inflation profile or working size is reached, the designed nylon balloon has adequate extensibility or pliability to allow it to jump to other inflated profiles. Although a polyethylene balloon with curve D initially inflates to the same extent as a curve nylon balloon E, this nylon balloon can withstand greater inflation pressures without bursting than a polyethylene balloon with curve D or a polyvinyl chloride balloon with curve C. . This is particularly significant considering that Curve E nylon balloons have a substantially thinner wall thickness. Based on data such as that shown in FIG. 4, it is possible to predict the compliant inflation associated with the added inflation pressure. The balloon according to the present invention is capable of exhibiting this lengthening property such that it expands radially from a low rate of about 5% beyond its working dimension to a high rate of about 35% or more of its working dimension.

As previously observed, balloon inflation controllability is a function of heat setting conditions and hoop expansion ratio for the balloon material according to the invention. For such materials, increasing the heat set temperature increases the finished balloon size at a given inflation pressure and reduces the shrinkage that typically occurs after sterilization such as standard ethylene oxide processing.

The amount of hoop inflation applied to the balisong during processing has a significant effect on the amount of inflation that the finished balloon will exhibit.

Figures 5 and 6 illustrate the effect of varying heat set conditions on the finished balloon expandability. This heat setting is achieved when the two-wheel oriented balloon is heated to a temperature above the glass transition temperature of the balloon material and cooled below the glass transition temperature. For materials like nylon or polyamide, about 90 to 180
℃ has excellent heat setting ability. The glass transition temperature is below this heat set temperature and may be within the range of 20 to 40°C.

The balloon exhibits good flexibility at body temperature, which facilitates balloon insertion and maneuverability during use, for example.

Figure 5 shows the different heat sets. The expansion plots of four tests at 37° C. are given for essentially identical nylon balloons except that they were exposed to m degrees. In each case, the balloon is subjected to a heating/cooling cycle for 2 minutes, cooling to room temperature. Each balloon was then subjected to ethylene oxide sterilization. Curve F was subjected to a heat set temperature of 120°C and curve G
was 130°C, curve H was 140″C, and curve II was 150°C. It will be appreciated that these curves illustrate the different expansion properties and the type of accommodation so obtained.Curves J and K are for balloons that were heat set at 100°C, but Curve J balloons were sterilized but Carp K balloons were not. Similarly, Curves L and M are both 14
Heat set at 0'C, curve L shows the case with sterilization, and curve M shows the case without sterilization.

The relationship between balloon adjustability and hoop inflation ratio is shown in FIG. Three non-sterile nylon balloons with different hoop inflation ratios were tested by inflating them to rupture at 37°C. A relatively high hoop inflation ratio (curve N) of 4.9 gave about 7% balloon inflation (safely without bursting). 3.7 hoop expansion ratio (curve 0) is approximately 23%
The balloon inflation ratio is 3.3 (curve P).
gave an expansion ratio of about 36%.

Additionally, nylon or polyamide balloons according to the present invention provide controlled inflation properties and do so without bursting without the large wall thicknesses required with other materials such as polyvinyl chloride or polyethylene. withstand the pressure exerted on it. This thin wall thickness of the nylon balloon allows the balloon to enter small vessels, lesions, and/or catheters. A suitable balloon according to the present invention is approximately 0.00 (12 inches)
5 (18 cm ) to 0.0 (12 inches (0.005
(18 cm) shell or wall thickness. An exemplary preferred thickness range is from about 0.00 (14) to about 0.001 inch (0.001016 to 0.001 inch).
0 (1254 CI1+).

Materials such as nylon are softer and more flexible at body temperature, the operating temperature, than other balloon materials such as polyethylene terephthalate, which has a glass transition temperature much higher than body temperature. For at least some nylons, the glass transition temperature is close to body temperature, and nylon balloons generally have increased flexibility and softness even after the types of treatments described herein, including thermoforming, etc. Demonstrate non-quality properties. This allows nylon balloons to be in a glass transition state when they are in the body, whereas this is not the case for many other materials that can be used as medical balloon materials.

Nylon balloons exhibit the property that when they burst, the diameter of the balloon decreases, thereby facilitating removal from the body. It is believed that this reduction occurs due to stress relaxation of the material which appreciably reduces the dimensions of the balloon. Other materials such as polyethylene terephthalate are not known to exhibit this advantageous property. A disadvantageous property characteristic of polyethylene terephthalate medical balloons is that they produce large material wrinkles during sterilization, which wrinkles even at body temperature.
This continues until a very high inflation pressure of the order of psi (14.06 kg/cd) is applied. When nylon or polyamide balloons are sterilized, there is little if any material wrinkling, and these
It virtually disappears at low inflation pressures of the order of s i (0.5 6 2 4 kg/c+f).

4. Nylon material is suitable for use with parisons for a considerable period of time. It exhibits desirable stability during processing in that it does not absorb excess moisture from the environment when left uncovered. Materials such as polyethylene terephthalate will degrade due to environmental moisture if the parison is not stored in a protective bag or the like prior to biaxial orientation.

It will be understood that the embodiments of the invention described are merely some illustrations of the principles of the invention as they apply. Numerous modifications can be made by those skilled in the art without departing from the true spirit and scope of the invention.

[Brief explanation of drawings]

Fig. 1 is a partially sectional front view of a balloon catheter suitable for blood vessel shaping; Figs. 2a, 2b, 2c, 2d and 2e are front views showing steps for shaping the medical balloon of the present invention; The figure is a sectional view of the apparatus for balloon molding,
Figure 4 is a graph showing the relationship between inflation pressure and dimensions of balloons made of various materials, Figures 5 and 6 are graphs showing the relationship between heat setting conditions and balloon expansion properties, and Figure 7 is a graph showing the relationship between balloon expansion and inflation. It is a graph showing the relationship between the ratio and the expandability of the balloon. 2■ is a catheter, 26 is a balloon, 41 is a parison,
43 is a pressurized fluid source, 46, 47. 18 is a glissopa assembly, 42 is a lenore, 55 is a free pro-biaxial orientation chamber, 56 is a blow control chamber, 61, 62, 63, 64, 65
．． 66 is a jacket.口●(140 (+!++.1 Law procedural amendment 1990 Patent Application No. 127 (126 No. 2. Title of invention Balloon for medical devices and its molding 3. Person making the amendment Relationship to the case Name of patent applicant Name: Cordis, Corporation 4. Spontaneous by the agent 6. Increased number of claims due to amendment 1 (17. Scope of claims to be amended, detailed description of the invention Contents of amendment) The scope of claims is as follows: Amend: ``(1) Inflating at least a portion of a length of tubing of nylon or polyamide material with a pressurized fluid to at least double its outer diameter, in the form of a balloon for a medical device. a balloon comprising a tube shaped into a balloon during a shaping operation, said balloon having an unstretched working profile having a predetermined dimension that swells without significant stretching thereof, and said balloon having a non-stretched working profile during use. an inflation profile having a maximum inflation dimension at which the balloon is stretched without bursting, the maximum inflation dimension being greater than the predetermined dimension of the unstretched working profile; The balloon is characterized in that the balloon is configured to have a maximum inflation dimension selected from a range of maximum inflation dimensions that are a function of processing conditions of the balloon. The first one exhibiting glass transition properties as in its glass transition state.
term balloon. (3) the balloon has a pressure of at least about 15,000 psi;
Term 1 or Term 2 balloon having a calculated tensile strength of (1054.5 kg/Cli!). (4) The balloon according to any one of clauses 1 to 3, wherein the range of the maximum inflation dimension of the inflation profile is at least the 10% point of radial expansion. (5) The balloon according to any one of paragraphs 1 to 3, wherein the maximum inflation dimension of the balloon is 5% or more in excess of the predetermined dimension of the non-stretched working profile. (6) The balloon of any one of paragraphs 1 through 3, wherein the maximum inflated dimension of the balloon has a radius that exceeds the unstretched working dimension by 5% to about 30% or more. (7) The nylon or polyamide balloon is about 0.
The balloon of any one of clauses 1 through 6 having an intrinsic viscosity of 8 to about 1.5. (8) The balloon according to any one of items 1 to 7, wherein the balloon material is nylon 12. (9) the balloon is stretched axially at about room temperature to provide a stretched tube prior to inflation of the length of the tube, and the balloon is stretched radially at an elevated temperature above room temperature; manufactured by a process that involves inflating
After said radial expansion operation, the radially expanded section is cooled to at least about room temperature, the cooled section is further stretched axially to provide a stretched section, and the bowed section is heated. The balloon according to any one of paragraphs 1 to 8, which is made by inflating the balloon, and then thermally shaping the inflated and further stretched part into a balloon. 00) the balloon is stretched to provide a predetermined balloon inflation ratio which is the ratio of the average diameter of the balloon to the average diameter of the thermally shapeable tube before inflation; 9. The balloon of any one of clauses 1 through 8, wherein the selected maximum inflation dimension is a function of the hoop inflation ratio. (11) The process further includes heat setting the balloon after expansion by raising it to a temperature above the glass transition temperature of the nylon or polyamide material and cooling it to a temperature below the glass transition temperature. Item 10 balloon. (12) The balloon of item 11, wherein the glass transition temperature is approximately equal to human body temperature. Mark G. Said balloon is subjected to radial inflation at least twice, said balloon having a first substantially knob-free expansion.
Balloon for either term or 2. (14) A catheter body; and a balloon member disposed along the length of the catheter body, the balloon member being the balloon described in Items 1 to I3 above, and the balloon member being a balloon. a medical device catheter having a diagonal profile having an outer diameter approximately equal to the outer diameter of the catheter body. (+5) The maximum inflated diameter of the balloon member is a function of a hoop inflation ratio of the balloon member, where the hoop inflation ratio is an approximate ratio of the predetermined balloon diameter to the diameter of the tube before radial inflation. The 14th which is the ratio
Nuchal catheter. 00 The maximum inflation diameter exceeds the predetermined balloon diameter by 30% or more.
Section 4 or Section 15 catheter. (17) The catheter of paragraph 14 or paragraph 15, wherein the maximum inflation diameter exceeds the predetermined balloon diameter by 5% to 40% or more. (18) The catheter according to any one of Items 13 to 17, wherein the balloon member material has an intrinsic viscosity of about 1.3. (19) stretching lengthwise to form a stretched tube a length of a tube made of material having an initial diameter and which can be adjusted by this step; radially inflating the tube into a balloon member, said balloon member having an unstretched working diameter and a hoop inflation ratio, said hoop inflation ratio being said unstretched working diameter to said initial tube diameter; wherein the radial inflation step has a maximum inflation diameter at which the balloon member is stretched without rupturing during inflation, and wherein the maximum inflation diameter increases in a manner inversely proportional to the inflation ratio; A method for determining the inflation characteristics of a medical device balloon. 1(20) The method of clause 19, wherein the hoop expansion ratio is from about 3 to about 6. (21) heat setting the balloon member by increasing the temperature of the balloon member to a heat setting temperature above the glass transition temperature of the tube material and then cooling the balloon member to a temperature below its glass transition temperature; 21. The method of claim 19 or claim 20, wherein the heat setting step adjusts the balloon member such that the maximum expanded diameter increases in a manner directly proportional to the heat setting temperature. (22) The heat setting temperature is about 90°C to about 1
The method of paragraph 21, wherein the temperature is 80°C. (23) The method of item 21 or item 22, wherein the glass transition temperature is approximately equal to human body temperature. (24) The method according to any one of Items 21 to 23, wherein the temperature below the glass transition temperature is approximately equal to room temperature. (25) The radial expansion step is followed by stretching the length and longitudinally extending to form a radially expanded section and modifying the stretched and radially expanded section. 25. The method of any one of paragraphs 19 through 24, including the steps of inflating the profile and dimensions, and setting the modified profile and dimensions to form a bar loop. 26. The method of claim 25, wherein the step of inflating the radially expanded portion includes controlling it within a mold cavity. (27) A balloon for a medical device, comprising a tube of nylon or polyamide material radially inflated to a predetermined balloon size, the balloon having an outer diameter approximately equal to the outer diameter of the medical device. the balloon further has an unstretched expanded dimension when the balloon is inflated to the predetermined balloon dimension, and the balloon has a diameter greater than the predetermined balloon diameter. wherein the balloon is made of a material other than a nylon or polyamide material and has a tensile strength greater than a medical device balloon having an expanded profile exhibiting a stretched dimension when stretched to a profile having a stretched dimension; Balloon for medical equipment featuring (28) The balloon of clause 27, wherein the stretched diameter exceeds the predetermined balloon dimension by a limited and controlled amount. (29) The balloon of Clause 27, wherein the stretched diameter exceeds the predetermined balloon dimension by about 30% or more. (30) The balloon of item 27, wherein the stretched diameter is about 5% to about 30% greater than the predetermined balloon dimension. (31) The nylon or nylon material is nylon 1
2. The balloon according to any one of Items 27 to 31, which is 2. (32) said nylon or polyamide tube is sequentially subjected to an axial stretch, a radial expansion with a pressurized fluid, a second axial stretch, a second radial expansion with a pressurized fluid at room temperature; 32. The balloon according to any one of clauses 27 to 31, wherein the balloon is substantially free of an inflation hump. (33) a second balloon in which the balloon is an angioplasty balloon;
A balloon according to any one of Items 7 to 32. (34) said expanded diameter is the maximum expanded diameter that the balloon can be expanded to without bursting, said maximum expanded diameter exceeds said predetermined balloon dimension, and said balloon tubing is The diameter is adjustable so that the diameter is selected within a certain range of maximum expanded diameter when the balloon is inflated, and the maximum expanded expanded diameter of the balloon is selected within the maximum expanded diameter value range. The balloon according to any one of Items 27 to 33. (35) said maximum stretched diameter value range is a function of a balloon hoop inflation ratio, said hoop inflation ratio being approximately equal to the ratio of said predetermined balloon diameter to said tube diameter before radial inflation; 34 balloons. (36) The nylon or polyamide material is about 1.3
The balloon according to any one of Items 27 to 35, having an intrinsic viscosity of . (37) The balloon has a pressure of about 15,000 psi to about 30,000 psi.
5kg/c+fl or 2109 kg/cff
The balloon according to any one of items 27 to 36, having a tensile strength of l). (38) comprising: a catheter body; and a balloon disposed along the length of the catheter body; 2. 3. 4. 5. 6. A medical catheter, wherein the balloon is the balloon according to any one of items 27 to 37. ” Specification page 10 No. 2
``biaxial orientation'' in line 3 on page 40 and line 4 on page 52 is corrected to ``ostentatious''. The words "biaxially oriented" in page 16, line 19, page 21, line 20, and page 47, line 20 are deleted. Page 17, line 20 (first time), page 22, line 1, 2
Page 3, line 19, page 32, line 16, page 34, lines 5 and 9, page 35, line 2, page 36, line 6, page 37, lines 6-7 and line 11 Delete "biaxial orientation". Page 17, line 20 (second time), page 23, lines 19-20
line, page 24, line 16, page 25, line 3, page 28, line 4
lines, page 30, lines 18 and 20, page 35, lines 5, 10, and 14, and page 38, lines 17 to 1
Correct "biaxial orientation" in line 8 to "radial expansion". "Delete orientation or j" on page 22, line 17. Correct "orientation" on page 23, line 15, page 25, line 20, and page 27, line 13 to "enlarge". Delete "F or orientation" on page 27, line LO. Insert "contraction" next to "radial direction" on page 27, line 13. ``Or radial orientation'' on page 25, line 8 is deleted. On page 28, line 13, "j oriented to" is corrected to "na". Correct "two wheels oriented" in line 9 of paragraph 30 of the same sentence to "discussed here." The phrase "or oriented" in the third line of page 34 is deleted. The phrase "biaxially oriented and" on page 42, line 17 is deleted.

Claims (28)

[Claims] (1) Inflating at least a portion of a length of biaxially orientable tubing made of nylon or polyamide material with a pressurized fluid to at least double the outside diameter of the balloon for a medical device; a tube formed into a balloon during a biaxial orientation operation comprising: said balloon having a non-stretched working profile having a predetermined dimension that bulges without significant stretching thereof; and said balloon ruptures during inflation. an inflation profile having a maximum inflation dimension at which the balloon is stretched without stretching, the maximum inflation dimension being greater than the predetermined dimension of the unstretched working profile; The balloon is configured to have a maximum inflation dimension selected from a range of maximum inflation dimensions that are a function of processing conditions. (2) The balloon exhibits glass transition properties such that the balloon is in its glass transition state at human body temperature.
term balloon. (3) the balloon has a pressure of at least about 15,000 psi;
The balloon of the first term has a calculated tensile strength of (1054.5 kg/cm^2). (4) The balloon of clause 1, wherein the range of the maximum inflation dimension of the inflation profile is at least the 10% point of radial expansion. (5) The balloon of item 1, wherein the maximum inflation dimension of the balloon is 5% or more in excess of the predetermined dimension of the unstretched working profile. (6) The balloon of paragraph 1, wherein the maximum inflated dimension of the balloon has a radius that exceeds the unstretched working dimension by 5% to about 30% or more. (7) the nylon or polyamide biaxially oriented balloon has an intrinsic viscosity of about 0.8 to about 1.5;
term balloon. (8) The balloon of item 1, wherein the balloon material is nylon 12. (9) the biaxially oriented balloon is biaxially oriented at about room temperature to provide a stretched tube of the length of the biaxially oriented tube, and the stretched tube is heated at an elevated temperature above room temperature; fabricated by a process that includes biaxially expanding the biaxially oriented section, after said biaxially oriented operation, cooling the biaxially oriented section to at least about room temperature and further stretching the cooled biaxially oriented section. 2. A balloon according to claim 1, which is made by stretching the balloon axially to provide the desired shape, heating and inflating the stretched section, and thermoforming the inflated stretched section into a balloon. (10) The biaxially oriented balloon stretches the length of the biaxially oriented tube and has a balloon expansion ratio that is the ratio of the average diameter of the balloon to the average diameter of the thermoformable tube. 2. The balloon of claim 1, wherein the balloon is manufactured by a process comprising biaxially expanding a stretched tube to provide an expanded tube, wherein the selected maximum expansion dimension is a function of the hoop expansion ratio. (11) further heat setting the biaxially oriented balloon by raising the temperature to a temperature above the glass transition temperature of the nylon or polyamide material and cooling it to a temperature below the glass transition temperature; The balloon of paragraph 1 manufactured by a process comprising: (12) The balloon of item 11, wherein the glass transition temperature is approximately equal to human body temperature. (13) a catheter body; and a balloon member disposed along the length of the catheter body, the balloon member comprising a thermoformable nylon material or biaxially oriented to provide a predetermined balloon diameter. made of a polyamide material tube, the balloon member having a collapsed profile such that the outer diameter of the balloon is approximately equal to the outer diameter of the catheter body; the balloon member has an expanded maximum inflation dimension that allows the balloon to be stretched without bursting during inflation, and the maximum inflation diameter is greater than the predetermined balloon diameter. and the tubing material of the balloon member is selected such that the maximum inflated diameter is within a range of maximum inflated diameters that are a function of the hoop inflation ratio of the balloon member, the hoop inflation ratio being two. A dilation catheter that is approximately the ratio of the predetermined balloon diameter to the diameter of the tube before axial orientation. (14) The maximum inflation diameter exceeds the predetermined balloon diameter by 30% or more.
Section 3 dilatation catheter. (15) The dilatation catheter of item 13, wherein the maximum inflation diameter exceeds the predetermined balloon diameter by 5% to 40% or more. (16) The dilatation catheter of paragraph 13, wherein the nylon or polyamide material is nylon 12. (17) The dilation catheter of paragraph 13, wherein the balloon member material is nylon 12 having an intrinsic viscosity of about 1.3. (18) An expansion balloon comprising a length of tubing of thermoformable material biaxially oriented to a predetermined balloon diameter, the expansion balloon having an outer diameter of an element of the medical device. having a collapsed profile approximately equal to the outer diameter, the dilatation catheter further having an unstretched inflated working diameter at which the dilatation balloon inflates to its predetermined balloon diameter; the inflation balloon has a maximum expanded diameter that can be inflated without bursting, the maximum expanded diameter being greater than the predetermined balloon diameter; The expansion balloon is adjustable so that the biaxial orientation can be selected within a certain range, and the maximum expanded diameter of the expansion balloon is selected within the range of maximum expanded diameter values. balloon. (19) the dilatation balloon has a diameter of at least about 15,000
The dilatation balloon of item 18 having a calculated tensile strength of psi (1054.5 kg/cm^2). (20) The dilatation balloon of paragraph 18, wherein the maximum stretched diameter exceeds the predetermined balloon diameter by about 30% or more. (21) The dilation balloon of clause 19, wherein the maximum stretched diameter is about 5% to about 40% or more greater than the predetermined balloon diameter. (22) The dilatation balloon of paragraph 18, wherein the balloon undergoes at least two biaxial orientations, and the dilatation balloon is substantially free of dilatation humps. (23) stretching lengthwise to form a length-stretched tube of a biaxially orientable tube made of material having an initial diameter and adjustable by this step; radially inflating the stretched tube into a balloon member, the balloon member having an unstretched working diameter and a hoop inflation ratio, the hoop inflation ratio being the unstretched working diameter to the initial tube diameter; an approximate ratio of working diameters, the biaxial orientation step having a maximum inflation diameter at which the balloon member is stretched without bursting during inflation, and the maximum inflation diameter increasing in a manner inversely proportional to the inflation ratio; A method of adjusting the inflation properties of a medical device balloon. (24) A 23rd embodiment in which the hoop has an expansion ratio of about 3 to about 6.
Section method. (25) heating the balloon member by increasing the temperature of the balloon member to a heat set temperature above the glass transition temperature of the biaxially orientable tubing material and then cooling the balloon member to a temperature below its glass transition temperature; 24. The method of claim 23, comprising setting the balloon member such that the maximum inflated diameter increases in a manner directly proportional to the heat setting temperature. (26) The heat setting temperature is about 90°C to about 18°C.
The method of paragraph 25, wherein the temperature is 0°C. (27) The method of item 25, wherein the glass transition temperature is approximately equal to human body temperature. (28) The method of item 25, wherein the temperature below the glass transition temperature is approximately equal to room temperature.