GB2025233A

GB2025233A - Guiding catheter assembly and catheter assembly and a combination thereof and methods for making the same

Info

Publication number: GB2025233A
Application number: GB7914116A
Authority: GB
Original assignee: Advanced Catheter Systems Inc
Current assignee: Advanced Catheter Systems Inc
Priority date: 1978-04-24
Filing date: 1979-04-23
Publication date: 1980-01-23
Also published as: CA1142835A; GB2102680B; CH644523A5; CH638991A5; CH644522A5; DE2916097A1; GB2102680A; DE2954452C2; DE2954391C2; GB2025233B; DE2916097C2

Abstract

A catheter assembly for angioplasty comprises a novel guiding catheter and a novel dilating catheter. The guiding catheter comprising an inner, flexible low friction tube (22) tightly encased in a heat-shrunk flexible tube (23), and is bent, (27), (28) or (29) adjacent to its tip. The dilating catheter comprises an inner catheter tube (37) loosely encased by and sealed by heat shrinking at its tip to an outer tube (38) having an inflatable balloon-like portion (43) towards its tip. The proximal ends of the guiding catheter, and each tube of the dilating catheter are provided with connection fittings (31), (86), (66). <IMAGE>

Description

SPECIFICATION Guiding catheter assembly and catheter assembly and a combination thereof and methods for making the same The invention relates to catheter assemblies. As disclosed in the following three references: 1. Grüntzig,A.: Die perkutanetransluminale Rekanalisation chronischer Arterienverschlusse mit einer neuen Dilationstechnik; p. 50. Baden-Baden 1977.

2. Grüntzig, A., H. H. Riedhammer, M. Turina, Rutishauer W. Verh. Dtsch. Ges. Kreislaufforschg.

1976. 42 282.

3. Grüntzig, A., R. Muler, E. Hanna, Turina M.

Abstracts Circulation. 1977 56 84.

a technique has been developed for percutaneous transluminal coronary angioplasty. This technique consists of a catheter system introduced via the femoral artery under local anesthesia. A preshaped guiding catheter is positioned into the orifice of the coronary artery and through this catheter a second dilation catheter is advanced into the branches of the coronary artery. The dilation catheter has an elliptical-shaped distensible balloon portion near the tip which can be inflated and deflated. After traversing the stenotic lesion of the coronary artery, the distensible portion is inflated with fluid which compresses the atherosclerotic material in a direction generally perpendicular to the wall of the vessel thereby dilating the lumen of the vessel.Peripheral arterial lesions treated by this technique have demonstrated by morphological studies that the atheroma can be compressed leaving a smooth luminal surface noted at the time of restudy. The patency rate two years following dilation of iliac and femoropopliteal atherosclerotic lesions was greater than 70%. The continued success of this technique could greatly widen the horizons for coronary angiography and provide anothertreatmentfor patients with angina pectoris.

The guiding and dilating catheters utilised by Grüntzig in his work have been more or less hand made. They have been difficult and expensive to fab ricate and for that reason it has been very difficult to obtain an adequate supply of the same. There is therefore a need for a new and improved guiding and dilation catheter and method for making the same.

To perform coronary percutaneous transluminal angioplasty, vascular guiding and dilating catheters must be provided. The present invention provides a guiding catheter assembly comprising an inner tubular member formed of a material which has a low coefficient of friction, an outertubular member lightly encasing the inner tubular member, said outer tubular member being formed of a more rigid, flexible material than the inner tubular member, a fitting mounted on the proximal end of the pair of members to permit access to the passage in the first tubular member, the first and second tubular members having proximal and distal ends, the distal end of the assembly having a bend therein.

The rigidity of the outer member can be chosen such that the guiding catheter assembly has sufficient rigidity so that it can be readily manouevered in use.

Preferably, the outer member of the guiding catheter assembly utilises heat-shrinkabletubing in the form of an irradiated modified polyolefin for providing the rigidity required.

The present invention also provides a combination of such a guiding catheter and dilating catheter assembly comprising a flexible tubular member and inflatable balloon-like portion formed in the tubular member near the distal end thereof and a fitting mounted on the proximal end thereof, the tubular member of the dilating catheter assembly being disposed within said guiding catheter assembly.

The invention includes a dilating catheter assembly, comprising a tubular member formed of a heatshrinkable flexible material and having a balloonshaped portion formed adjacent one end (distal) and a fitting carried by the other end (proximal) permitting the introduction of a radiographic contrast liquid for inflating said balloon.

The invention also includes a dilating catheter assembly, comprising a firstflexibletubular member serving as an inner catheter, a second flexible tubular member coaxially encasing said first tubular member, said second tubular member having a balloon-shaped portion formed therein adjacent one end (distal) and a fitting carried by the other end for permitting the introduction of fluid through the first tubular member and for permitting insertion of a fluid for inflating and deflating the balloon portion of the second tubular member.

The invention also provides a method for forming a guiding catheter assembly, which method comprises providing a first tubular member formed of material having a low coefficient of friction, providing a second tubular member formed of a heatshrinkable material, inserting the first tubular member into the second tubular member, applying heat to the second tubular member to cause it to tightly encase the first tubular member to provide a guiding catheter assembly with sufficient rigidity to permit manouevering of the same.

The invention also provides a method for forming a dilating catheter assembly, comprising providing first and second tubular members formed of a heatshrinkable flexible material, the second tubular member having a diameter greater than that of the first tubular member, heating a portion of the second tubular member adjacent the one end to a temperature above a predetermined temperature and introducing a fluid under pressure to cause expansion of said portion to form a balloon-like portion and cooling the same while under pressure to maintain a balloon-like portion in said second tubular member, inserting a mandrel into the first tubular member, heating the first tubular member to shrink it onto the mandrel, inserting thefirsttubular memberwith the mandrel therein into the second tubular member, heating the end of the second tubular member adja cent the balloon-like portion to cause it to shrink onto the first tubular member with the mandrel therein to form an adhesive-free seal between the ends of the first and second tubular members, removing the mandrel from the first tubular member, and providing fittings on the unsealed ends of the first and second tubular members which fittings are in communication with the passage in the first tubular member and in communication with the passage in a second tubular member extending into the balloon-like portion.

Similarly, the invention also provides a method for forming a dilating catheter assembly, comprising providing first and second tubular members formed of a flexible material, the second tubular member having a diameter greater than that of the first tubular member, heating a portion of the second tubular member adjacent one end to a temperature above the crystalline melting point and introducing a fluid under pressure to cause expansion of said portion to form a balloon-like portion, cooling the same while under pressure to maintain a balloon-like portion in said second tubular member, inserting the first tubular member into the second tubular member so it extends through, forming a fluid-tight seal between the ends of the first and second tubular members adjacent the balloon-like portion, and providing a fitting on the other ends of the first and second tubular members with passages which are in communication with the passage within the first tubular member and the second tubular member and in communication with the balloon-like portion.

Preferably, the balloon-like portion is formed integral with one of the tubular members forming the dilating catheter assembly.

By techniques hereafter specifically described the balloon can be readily and reliably formed.

Preferably, heat-shrinkable tubing is used for the formation of the balloon andforforming.thepas- sage leading to the balloon.

It is to be understood that the term "heatshrinkable" includes where the context requires it the term "heat-shrunk".

Preferably, the tubular members of the dilating catheter are formed of an irradiated modified polyolefin tubing.

Preferably, the dilating catheter includes inner outer coaxial tubular members and a distal pressure seal is formed between the inner and outer tubular members solely by heating the out tubular member.

The invention will be illustrated by the following description in which preferred embodiments are set forth in detail in conjunction with the accompanying drawings.

Figure 1 is a perspective view of a dilator, a guid ing catheter assembly, a dilating catheter assembly and a balloon flushing tube and showing the manner in which they are used with respect to each other and incorporated into assemblies for performing coronary percutaneous transluminal angioplasty.

Figure 2 is a cross-sectional view taken along the line 2-2 of the guiding catheter assembly, Figure 3 is a cross-sectional view taken along the line 3-3 of the dilating catheter assembly, Figure 4 is a cross-sectional view taken along the line 44 of the dilating catheter assembly, Figure 5 is a cross sectional view taken along the line 5-5 of Figure 4, Figures 6A and 6B are taken along the line 6-6 of Figure 5 and showthe balloon in inflated and deflated conditions respectively, Figures 7A, 7B, XC and7D illustrated the steps utilised in one method for forming the balloon from the irradiated modified polyolefin tubing utilised forthe dilating catheter assembl'y, Figures 8A and 8B blustrate the steps in another method utilised forformingthe balloon on the outer catheter of the dilatingqcatheter assembly, Figures 9A and 9B show the steps utilised in the method for forming thsiknescatheter of the dilating catheter assembly.

Figures 10A and 10B showthe steps in the method of inserting the inner tubular member into the outer tubular member having a balloon formed therein and shrinking the distal end of the outer tubular member onto the distal endrof the inner tubular member to provide an air-tightadhesive4ree seal and providing a flow passagethrough which fluid can be introduced into the balloon for inflating the same and withdrawing it from the balloon for deflating the same.

The guiding catheter assembly 21 shown in Figure 1 consists of first and second coaxial tubular members 22 and 23. The first tubular member is formed of a material which has an extremely low coefficient of friction as for example TFE Teflon (a tetrafluoroethylene polymer) having a coefficient of friction of approximately .02. For the material for the first, tubular member, the coefficient of friction can range from as low a value as possible to .05. It is also desirable that the material utilised for the first tubular member have a certain amount of flexibility.

Thefirsttubular member has a guiding passageway 24 having an internal diameter; of approximately .094 of an inch. It also can have a suitable wall thickness preferably in the vicinity of.OQ# of .0Q & f an inch. However, these dimensions can vary within the range of approximately +15% and stillilje satisfactory.

Although TFE Teflon (Registered Trade Mark) utilised for the first tubu larmember was very desirable because it had a very low coefficient of friction, it was found, however that itwas too flexible to serve as a guiding catheterfbecause itcould not be properly manipulated in the body of the patient It is for this reason that thssecood tubular member 23 is provided. This second tubular member is formed of a heat-shrinkablei#rndiated modified polyolefin such as RNF-100 type supplied by Raychem Corporation of Menlo Park, CialífornEia. The heatshrinkabletubing selected had ataihternai diameter of .120 of an inch which was of a sufficient size so that the first tubular member could be readily inserted into the same.The second tubular member of the assembled first and second tubular members 22 and 23 was then progressively heated along its length in a suitable manner such as by a hot air tool to a suitable temperature as for example 1200Cto cause the second or outer tubular member 23 to shrink in a manner well known to those skilled in the art so that it forms a skin-tight fit with respect to the first tubular member 22. Alternatively this can be accomplished by passing the assembled first and second tubular members through a cylindrical heating unit to cause progressive heating of the second tubular member.

The assembly is provided with proximal and distal ends 25 and 26. The distal end is provided with bends to form a shape identical to the standard coronary catheter. A left coronary guiding catheter is formed by providing two bends 27 and 28 of approximately 120-150 (proximal) and 60-90 (distal) each in the same direction to provide the bends which are shown in Figure 1 for a left coronary artery. As soon as the bends 27 and 28 have been formed, the distal end can be cut off to the desired length and thereafter, the distal end can be sanded or smoothed in a suitable manner. An annular recess 30 is formed on the extreme distal end of the tubular member 23. For a right coronary guiding catheter a single bend 29 as shown by the broken lines in Figure 1 can be provided.

An attachment or fitting 31 is secuted to the proximal end of the first and second tubular member in a suitable manner. The attachment or fitting 31 is in the form of a female Luer fitting or attachment hav ing a metal cylindrical extension 32 on which there is crimped a metal band 33. The first or inner tubular member 22 is inserted into the cylindrical extension 32 and the second or outer tubular member 23 is slipped over the cylindrical extension 32 and the band 33. A sleeve 34 also formed of a similar heatshrinkable tubing is thereafter slid over the outer or second tubular member 23 and the fitting 31.The sleeve 34 is then heated to a suitable temperature as for example 120 C to cause it to shrink over the fitting 31 and also over the proximal end of the first and second tubular members 22 and 23 to form an excellent leakproof adhesive-free connection between the parts.

The material which is utilized for the second tubular member 23 has a substantially higher coefficient of friction than the material utilized for the first tubular member 22. However, this is not objectionable since the second tubular member will be inserted into the blood vessel over a wire in a standard percutaneous technique and thus will be lubricated by the blood in the vessel. The use of the guiding catheter assembly will be described in conjunction with the dilating catheter assembly hereinafter described.

The guiding catheter assembly 21 has a suitable length which is tailored to the purpose for which it is used. As for example, when utilizing the same for doing coronary percutaneous transluminal angioplasty on adults, a length of 95-110cm. is utilized.

The dilating catheter assembly 36 as shown in Figure 1, consists of first and second tubular members 37 and 38. The first and second tubular members 37 and 38 are formed of heat-shrinkable tubing of the type hereinbefore described manufactured by Raychem Corporation of Menlo Park, California. The first tubular member 37 is provided with a flow passage 39 extending the length of the same. The first tubular member 37 is coaxially disposed within the second tubular member in such a manner so that the second tubular member surrounds the first tubular member. The combined first and second tubular members 37 and 38 have a proximal end 41 and a distal end 42. The second tubular member 38 has formed therein a balloon-like portion near the distal end 42 of the first and second tubular members 37 and 38.An annular flow passage 44 is formed between the second tubular member 38 and extends from the proximal end into the balloon-like portion 43 to permit the introduction of fluid into the balloon-like portion 43 for inflating the balloon-like portion and for withdrawing fluid from the same for deflating the balloon-like portion.

The method by which the assembly consisting of the first and second tubular members 37 and 38 with the balloon-like portion 43 and the passages 39 and 44 formed therein can be seen by reference to Figures 7Athrough 7D. The second tubular member 38 has an initial inside diameter of 0.065 inches and an initial outside diameter of 0.085 inches. As is well known to those skilled in the art, the manufacture of heat-shrinkable tubing is accomplished by extruding a modified polyolefin to a predetermined size and utilizing high energy ionizing radiation to cause cross-linking of the polymer chains to occur. Thereafter, the tubing is expanded to a suitable ratio such as 2:1. A mandrel 46 in the form of a Teflon tube is inserted into the tubular member 38 as shown in Figure 7A.The member38 is then progressively heated as shown in Figure 7B to shrinkthe member 38 down onto the mandrel 46 so that it has an inside diameter of approximately .058 inches and an outside diameter of .072 inches with a wall thickness of .007 inches. The steps shown in Figures 7A and 7B are only carried out to provide a tubular member 38 of the desired size. Alternatively this can be accomplished by producing initially a heat-shrinkable tubing of the desired size. The mandrel 46 is withdrawn to the position shown in Figure 7C and another mandrel 47 in the form of a Teflon tube having an outside diameter of .054 inches is placed in the distal end 42.

The mandrel 46 extends substantially the entire length of the second tubular member 38 which can have a suitable length ranging from 105 to 120 cm.

The mandrel 47 is spaced from mandrel 46 to provide a space 49 through which the balloon-like portion 43 is to be formed. The other mandrel 47 serves as a support for supporting the distal end of the second tubular member 38. The second tubular member 38 is then heated to a suitable temperature as for example 120 C. in the vicinity of the ends of the mandrels 46 and 47 facing the space 49 to shrink those portions of the second tubular member 38 onto the mandrels 46 and 47 to form air-tight seals.

The portion of the member 38 encircling the space 49 is then heated until the material reaches a temperature beyond its crystalline melting point. With the mandrel 46 clamped shut at its proximal end, fluid under pressure is introduced by suitable means such as a syringe (not shown) through the passage 51 into the space 49 in the tubular member 38 to cause the tubular member to expand to form the balloon-like portion 43 as shown in Figure 7D. By way of example, air under pressure of 4 to 5 p.s.i. was utilized to form the balloon-like portion 43. Other fluids can be utilized if desired.

The balloon-like portion 43 is formed by expanding that portion of the tubing 38 surrounding the space 49 to its elastic limit which generally corresponds to a ratio of 4 or 5 to 1 from the original extruded irradiated tubing size prior to the initial expansion.

The balloon-like portion 43 thus formed preferably has dimensions ranging in length from approximately 1 to 2 centimeters and an outside diameter ranging from .120 to .140 inches and a wall thickness ranging from .002 to .004 inches.

Alternatively the balloon-like portion 43 can be formed as shown in Figures 8A and 8B. As shown therein, the mandrel 46 can be removed and amother mandrel 53 having holes 54 inserted into the distal end. Heat is then applied to the tubular member on opposite ends of the holes 54to shrink the tubular member 38 so that it forms air tight seals with the mandrel 38. The proximal end of the member 38 is clamped and air is introduced into the distal end after the member 38 has been heated in the vicinity of the holes to a temperature beyond the crystalline melting point and a balloon-like portion 43 is formed in the manner hereinbefore described.

Thereafter, the mandrel 53 can be removed.

The balloon-like portion is permitted to cool to room temperature while the pressure is maintained in the balloon so that the temperature of the material falls below its crystalline melting point to thereby retain a semi-permanent balloon-like portion 43 within the second tubular member adjacent the distal end thereof. After the balloon-like portion has been sufficiently cooled, the Teflon mandrels 46 and 47 are removed to provide a second or outer sheath.

The first or inner tubular member 37 is formed by taking a tube of heat-shrinkable tubing of the type hereinbefore described having an outside diameter of 0.05 and having an inside diameter .030 having a suitable length as for example approximately 110 cm. and placing within the same a Teflon coated guide wire (or a Teflon mandrel) 56 having an outside diameter of 0.021 inches as shown in Figure 9A.

The first tubular member 37 with the guide wire 56 therein which serves as a mandrel is heated to a suitable temperature as for example 125 C. and stretched to cause the first tubular member 37 to shrink down onto the guide wire 56 as shown in Figure 9B.

The assembly which is shown in Figure 9B is then taken and inserted intothe outer sheath ortubular member 38 which is shown in Figure 10A. It extends beyond both ends of the outer sheath and passes through the balloon portion 43. The balloon-like portion 43 is then covered with a cover 59 of a suitable type such as aluminum foil for protecting the balloon-like portion 43 from heat. Thereafter, the portion of the second tubular member 38 from the balloon-like portion 43 to the distal end is heated to a suitable temperature as for example 125 C. to cause the outer tubular member 38 to shrink tightly onto the first tubular member 37 with the Teflon guide wire or mandrel 56 therein to provide a fluid tight adhesive-free seal between the first and second tubular members 37 and 38.After the material has cooled, the mandrel 56 is removed to provide the construction hereinbefore described that is, a first tubular member 37 with a flow passage 39 therein and a second tubular member38 coaxial with tubular member 37 with an annular flow passage 44 therein extending from the proximal end into the balloon portion 43.

The proximal ends of the first and second tubular members 37 and 38 as shown in Figure 3 are inserted into an adapter body 66. The body 66 is formed of a suitable material such as metal and is provided with a centrally disposed bore 67 which opens through a female Luer type fitting 68. The adapter body 66 is also provided with a threaded cylindrical projection 69 and a generally conical portion 72 which projects beyond the threaded projection 69. The adapter body 66 is provided with a side arm 76 which is provided with a cylindrical bore 77 that extends into the bore 67 at a suitable angle as for example an angle of approximately 309 A well 78 is formed in the side arm 76 and is provided with an internally threaded portion 79 and a conical-shaped recess 81. As shown particularly in Figure 3, the first or innertubular member37 is placed in contact with a fitting 86.The fitting 86 is provided with a cylindrical bore 87. As can be seen, the fitting 86 is in the form of a conventional female-type Luer fitting. The fitting 86 is provided with a threaded projection 88 which engages the internal threads 79. It is also provided with a conical projection 89 which is adapted to seat against the conical recess 81.

In the construction shown in Figure 3, the inner tubular member 37 is brought into engagement with the inner end of a conical bore 91 provided in the threaded portion 88 and the conical portion 89 of the fitting 86 and is thus in communication with the cylindrical bore 87. Suitable means is provided for maintaining the flow passage 39 in the first tubular member 37 in communication with the conical bore 91 and consists of a heat-shrinkable tubular member 92 which is secured to the proximal end of the first tubular member 37. Member 92 is provided for the purpose of reinforcing the proximal end of the tubular member 37. Another heat-shrinkable tubular member 93 which has a flared outer end is shrunk onto the tubular member 92 and is fitted onto the conical projection 89 and is firmly held in place by threading of the fitting 86 into the side arm 76.

A heat shrinkable tubular member 96 having a flared outer end is secured to the proximal end of the second tubular member 38. The flared outer end of the tubular member 96 is then positioned over the conical portion 72 of the adapter body 66 and is held in place by a collar 97 which is provided with a well 98 having an internally threaded portion 99 and a conical recess 101 against which the conical projection 72 is adapted to seatto firmly grip the flared portion of the tubular member 96.

First and second syringes 1Q6 and 107 are adapted to be placed in the fittings 86 and 68 as shown particularly in Figure 1. The syringes 106 and 107 are of a conventional type and therefore will not be described in detail.

After the fittings hereinbefore described have been provided on the proximal end of the first and second tubular members 37 and 38, the distal end can be cut to the proper length and then ground to provide a smooth tapered distal end.

The balloon flushing tube 111 which is also shown in Figure 1 consists of a long tubular member 112 formed of a suitable material such as stainless steel in length 36 to 40 inches. By way of an example, it can have an outside diameter of .020 inch and an internal diameter of 0.10 inch. The tubing 112 has its proximal end connected to a conventional female Luer-type fitting 113 formed of a suitable material such as aluminum. The tubular member 112 can be secured to the fitting 113 by soldering or by a crimp fit.

A dilator 116 which is shown in Figure 1 is of a conventional type and consists of a flexible tube 117 formed of plastic and having a tapered distal end 118 having an outside diameter of .080 inches and an inside diameter of .040 inches. A female Luer-type fitting 119 is secured to the proximal end of the tube 117. A flexible Teflon coated guide wire 121 of a conventional type with an outside diameter of .038 inches is adapted to be inserted through the dilator 116 as shown.

Use of the guiding catheter 21, the dilating cathe- ter 36 and the balloon flushing tube 111 can now be briefly described as follows. Let it be assumed that it is desired to utilize these devices with a middle-aged patient who has been identified as having a significant narrowing in one of the coronary arteries as for example the left anterior descending coronary artery i.e. the proximal portion of that vessel for which a coronary transluminal dilation is considered advisable.

The patient is brought into a sterile environment and is prepared by sterilizing one of the groins. In preparation for operating upon the patient, the dilating catheter assembly 36 is checked. Normally, the dilating catheter assembly 36 would be supplied with the balloon flushing tube 111 in place. However if this is not the case, the balloon flushing tube 111 can be inserted through the passage 44 until it enters into the balloon 43. A syringe (not shown) filled with a radiographic contrast liquid inserted into the fitting 113 and the fluid is introduced into the balloon 43 to fill the balloon at the same time to flush out any air bubbles which may exist in the balloon or in the passage or lumen 44 leading to and from the balloon.The balloon flushing tube 111 can then be removed and as soon as it is removed, a syringe 107 is placed in the fitting 68 and is filled with a radiographic contrast liquid. The operations thus far described have taken place outside the body of the patient. Before inserting the dilating catheter assembly 36 into the body, the inflation and deflation of the balloon 43 can be readily checked merely by operating the syringe 107. A conventional pressure gauge and pressure regulator 115 are provided associated with the syringe 107 so that one can ascertain and limit the pressure being applied to the balloon 43 to approximately 45 to 80 psi.

When this has been accomplished, the guiding catheter 21 can be inserted into the patient in a standard percutaneous technique. The guiding catheter 21 has been designed so that it can enter into one of either the right or left femoral arteries. In such a technique, a needle is inserted into the femoral artery and the Teflon covered guide wire 121 is inserted through the needle and through the femoral artery into the aorta. The movement of the guide wire and positioning thereof is observed with conventional fluoroscopic techniques. It is positioned so that its tip is generally at the level of the diaphragm of the patient which is essentially half way up the aorta. The dilator 116 is positioned in the guiding catheter assembly 21 so that the flexible tapered tip 118 projects from the distal end of the guiding catheter assembly 21.

The distal end of the guiding catheter assembly 21 is then straightened out and the dilator and the guiding catheter 21 are passed over the guide wire which is already in place and is then introduced into the femoral artery. The guiding catheter is then passed along the guide wire using the guide wire as a guide to the descending aorta or arch of the aorta. During the time that the guiding catheter assembly is being inserted, the operation is under continuous fluoroscopic control. The dilator carried by the end of the guiding catheter assembly is radiopaque and therefore can be easily visualized radiographically. The guiding catheter is inserted until the distal end of the catheter is at the desired point which will generally be in the ascending portion of the aorta several centimeters from the coronary artery ostium.As soon as the guiding catheter assembly has reached this position, the guide wire and the dilator can be removed from the guiding catheter and the guiding catheter will be aspirated to remove any debris then flushed with radiopaque contrast medium. Thereafter, the catheter can be flushed with a saline solution or contrast medium.

As soon as entry into the blood vessel has been accomplished as hereinbefore described with the guiding catheter assembly 21, the patient can be given intravenous heparin in a standard dose to act as an anticoagulant and to prevent any abnormal thrombosis or blood clot formation on the catheter or in the areas of catheter entry. The guiding catheter assembly 21 can then be filled with a radiographic contrast material such as Renographin 76 and the catheter can be advanced until it engages into the left main coronary ostium which is the artery to be utilized. The positioning of the guiding catheter can be confirmed by one or more injections of the contrasting liquid into the coronary vessel in which fluoroscopic observations are taking place.

As soon as it has been ascertained that the guiding catheter assembly 21 has been properly positioned in the coronary ostium, the dilating catheter assembly 36 can be inserted. To insert the dilating catheter, the balloon 43 is completely deflated as shown in Figure 6B. When it is deflated, it may assume the position shown by broken lines in Figure 6B so that the dilating catheter assembly 36 can be readily inserted into the guiding catheter assembly 21.As hereinbefore explained, since the guiding catheter assembly 21 is formed of a first tubular member which is formed of a material having a low coefficient of friction, it is possible to push the dilating catheter assembly 36 through the entire length of the guiding catheter assembly 21 so that it will protrude out of the distal tip of the guiding catheter assembly by suitable distance such as 5 or 6 cm. and protrude into the left main coronary orifice.

Initially the balloon 43 is positioned in one of the closest portions of the vessel the aorta and then gradually under fluoroscopic control is advanced to the point where the narrowing has been previously documented to exist The balloon is then appropriately positioned in the narrowed portion.

Although it should be possible in all cases to be able to insert the dilating catheter 36 into the guiding catheter assembly without the help of a guide wire, a small guide wire can be utilized if desired. If such is the case, a small guide wire can be inserted through the sidearm 76 and through the first tubular member 37 so it extends just to the distal portion of the dilating catheter assembly 36 or slightly beyond it. If such guide wire is utilized, after the dilating catheter assembly 36 is in position, the small guide wire can be removed and the syringe 106 having a radiographic contrast liquid therein can be mounted on the side arm 76 and small injections of the contrasting liquid can be introduced intothefirstinnertubular member 37 through the passage 39 to document the position of the distal end of the dilating catheter assembly 36.If desired, the guide wire can be reinserted at any time to be used as an aid in guiding the dilating catheter into the vessel that has previously demonstrated that it is subject to a stenosis or narrowing. As soon as it has been established that the balloon 43 has been positioned within the stenosis, pressure can be applied by the use of the hand syringe 107 to inflate the balloon to a suitable pressure as for example from 3 to 5 atmospheres. The inflation of the balloon can be visualized radiographically because the balloon is filled with a radiographic contrast liquid. By way of example, the balloon would be inflated for a period ranging from 2 to 5 seconds and then deflated rapidly and removed from the stenosis at which time a second coronary contrast injection can be made either through the guiding catheter itself orthrough the passage 39 of the inner catheter 37.

As far as can be ascertained, the inflation of the balloon causes dilation of the material deposited in the wall of the vessel by causing elongation of the material along the wall and compressing of the material against the wall so that the end result is an increased blood vessel lumen size with increased blood flow to provide an improved oxygen delivery to the jeopardized portion of the heart muscle or myocardium.

The procedure can be repeated as many times as deemed necessary either on the same site or at a stenosis or narrowing in a second vessel. As soon as the necessary dilations have been completed, the dilating catheter assembly 36 can be removed.

Thereafter, the guiding catheter assembly 21 can be removed merely by pulling it out of the femoral artery. As soon as the guiding catheter has been removed, the groin is held firmly to prevent any ble eding until clotting has been accomplished. The patient can then be returned to his room and instructed to remain at bed rest with the legs straight and flat for approximately six hours after which normal routine activity can be undertaken by the patient.

It should be appreciated that if desired, a dilating catheter assembly 36 can be provided which only utilizes a single tubular member with a balloon near its distal end. When this isthe case, the first tubular member 37 can be omittedf and the tubular member which is utilized can be shrunk down to the final desired size onto mandrels priortoformation of the balloon portion.

It is apparent from theforegoingthatthere has been provided a vascular dilating catheter and an assembly thereof and method for making the same which makes it possible to fabricate the same utiliz ingzquantity production techniques. The construction of the guiding catheter assembly and the dilating catheter assembly is such that the methods utilized take advantage of heat-sh?inkabletubing. The guiding catheter assembly has an interior surface which has a very low coefficient of friction so that the dilating catheter assembly can be readily inserted therethrough. In addition, the guiding catheter assembly has sufficient rigidity so that it can be readily manuevered. The dilating catheter assembly is provided with a balloon which is formed integral therewith which can be readily inflated and deflated through an annular passage independently from fluid infusion or pressure measurements through the inner catheter.

Claims

1. A guiding catheter assembly, comprising an inner tubular member formed of a material which has a low coefficient of friction, an outer tubular member lightly encasing the inner tubular member, said outer tubular member being formed of a more rigid, flexible material than the inner tubular member, a fitting mounted on the proximal end of the pair of members to permit access to the passage in the first tubular member, the first and second tubular members having proximal and distal ends, the distal end of the assembly having a bend therein.

2. A guiding catheter assembly as claimed in claim 1,wherein said inner tubular member is formed of a tetrafluoroethylene polymer.

3 A guiding catheter assembly as claimed in claim 1 or claim 2, wherein saidoutertubular member is formed of a heat-shrinkable plastic

4 A guiding catheter assembly as claimed in any preceding claim, wherein thedistali end of the outer tubular member is providedlwith an annular recess.

5. A guiding catheter assembly substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 Of the accompanying drawings.

6. A combination of guiding catheter assembly as claimed in any preceding claim and a dilating catheter assembly, the dilating catheter assembly comprising a flexible tubular member, an inflatable balloon-like portion formed in the tubular member near the distal end thereof and a fitting mounted on the proximal end thereof, the tubular member of the dilating catheter assembly being disposed within said guiding catheter assembly.

7. A combination as claimed in claim 6, wherein the tubular member of the dilating catheter assembly is formed of a flexible heat-shrinkable material.

8. A combination as claimed in claim 6 or claim 7, further comprising means for inflating and deflating the balloon-like portion with radiographic contrast liquid.

9. A combination as claimed in any one of claims 6 to 8, wherein the dilating catheter assembly comprises an inner flexible tubular member, serving as an inner catheter, which is encased by and sealed at the distal end to the said tubular member having a balloon-like portion, the fitting at the proximal end allowing the introduction of fluid selectively into the inner catheter or into the encasing tubular member to inflate the balloon-like portion.

10. A combination as claimed in claim 9, wherein both tubular members of the dilating catheter assembly are formed of heat-shrinkable material.

11. A combination as claimed in claim 10, wherein the distal end of the tubular member having the balloon-like portion is heat-shrunk onto the distal end of the innercatheterto provide a fluid-tight, adhesive-free, seal.

12. A combination of a guiding catheter assembly and a dilating catheter assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

13. A method for forming a guiding catheter assembly, which method comprises providing a first tubular member formed of material having a low coefficient of friction, providing a second tubular member formed of a heat-shrinkable material, inserting the first tubular member into the second tubular member, applying heat to the second tubular member to cause it to tightly encase the first tubular member to provide a guiding catheter assembly with sufficient rigidity to permit manouevering of the same.

14. A method for forming a guiding catheter substantially as hereinbefore described with reference to Figures 1 to 3 of the accompanying drawings.

15. A dilating catheter assembly, comprising a tubular member formed of a heat-shrinkable flexible material and having a balloon-shaped portion formed adjacent one end (distal) and a fitting carried by the other end (proximal) permitting the introduction of a radiographic contrast liquid for inflating said balloon.

16. A dilating catheter assembly, comprising a first flexible tubular member serving as an inner catheter, a second flexible tubular member coaxially encasing said first tubular member, said second tubular member having a balloon-shaped portion formed therein adjacent one end (distal) and a fitting carried by the other end for permitting the introduction of fluid through the first tubular member and for permitting insertion of a fluid for inflating and deflating the balloon portion of the second tubular member.

17. An assembly as claimed in claim 16 in which the first and second tubular members are formed of a heat-shrinkable plastic.

18. An assembly as claimed in claim 17, wherein the distal ends of the first and second tubular members are formed to provide a fluid-tight adhesive-free seal.

19. An assembly as claimed in any one of claims 16 to 18, wherein the first and second annular - members are formed so that an annular flow pas sage extends from the proximal ends to the balloon.

20. An assembly as claimed in any one of claims 16 to 19, in which the balloon portion is integral with the second tubular member.

21. An assembly as claimed in claim 20 in which the balloon portion has a wall thickness substantially less than the wall thickness of the second tubular member.

22. A dilating catheter assembly substantially as hereinbefore described with reference to and as illustrated in any of Figures 3 to 10B of the accompanying drawings.

23. A method for forming a dilating catheter assembly, comprising providing first and second tubular members formed of a heat-shrinkable flexible material, the second tubular member having a diametergreaterthan that of the first tubular member, heating a portion of the second tubular member adjacent one end to a temperature above a predetermined temperature and introducing a fluid under pressure to cause expansion of said portion to form a balloon-like portion and cooling the same while under pressure to maintain a balloon-like portion in said second tubular member, inserting a mandrel into the first tubular member, heating the first tubular member to shrink it onto the mandrel, inserting the firsttubular memberwith the mandrel therein into the second tubular member, heating the end of the second tubular member adjacent the balloon-like portion to cause it to shrink onto the first tubular member with the mandrel therein to form an adhesive-free seal between the ends of the first and second tubular members, removing the mandrel from the first tubular member, and providing fittings on the unsealed ends of the first and second tubular members which fittings are in communication with the passage in the first tubular member and in communication with the passage in a second tubular member extending into the balloon-like portion.

24. A method for forming a dilating catheter assembly, comprising providing first and second tubular members formed of a flexible material, the second tubular member having a diameter greater than that of the first tubular member, heating a portion of the second tubular member adjacent one end to a temperature above the crystalline melting point and introducing a fluid under pressure to cause expansion of said portion to form a balloon-like portion, cooling the same while under pressure to maintain a balloon-like portion in said second tubular member, inserting the first tubular member into the second tubular member so it extends through, forming a fluid-tight seal between the ends of the first and second tubular members adjacent the balloon-like portion, and providing a fitting on the other ends of the first and second tubular members with passages which are in communication with the passage within the first tubular member and the passage between the first tubular member and the second tubular member and in communication with the balloon-like portion.

25. A method as claimed in claim 24, wherein the first and second tubular members are formed of a heat-shrinkable material and wherein the formation of the seal between the distal ends of the first and second tubular members is accomplished by heat shrinking the second tubular member onto the first tubular member.

26. A method of forming a dilating catheter assembly substantially as hereinbefore described with reference to the accompanying drawings.

27. In a combination of a guiding catheter asse mbly and a dilating catheter assembly, a g#uiding catheter assembly comprising a first tubular member formed of a material which has a low coefficient of friction, a second tubular member encasing said first tubular member so that the first tubular member fits tightly in the second tubular member, said second tubular member being formed of a material which is flexible but which has a greater rigidity than said first tubular member so asto provide the guiding catheter with the desired rigidity to permit manouevering of the same, said combined first and second tubular members having proximal and distal ends and a fitting mounted on the proximal end, the dilating catheter assembly comprising a tubular member formed of a flexible heat-shrinkable material, said tubular member having proximal and distal ends and inflatable balloon-like portion formed integral with the tubular member near the distal end thereof, a fitting mounted on the proximal end, said dilating catheter assembly being disposed within said guiding catheter assembly and means for inflating and deflating said balloon with the radiographic contast liquid.

28. In a guiding catheter assembly, a first tubular member formed of a material which has a low coefficient of friction and having a guide passageway extending therethrough, a second tubular member encasing said first tubular member so that the first tubular member fits tightly in said second tubular member, said second tubular member being formed of a material which is flexible but which has a greater rigidity than said first tubular member so as to provide a catheter assembly with the desired rigidity to permit manouevering of the same, the first and second tubular members having proximal and distal ends, the distal ends having a bend therein and a fitting mounted on the proximal ends to permit access to the passage in the first tubular member.

29. In a dilating catheter assembly, a tubular member formed of a heat-shrinkable flexible material and having proximal and distal ends, said tubular member having a balloon-shaped portion formed adjacent the distal end and a fitting carried by the proximal end permitting the introduction of a radiographic contrast liquid for inflating said balloon.

30. In a dilating catheter assembly, a first tubular member formed of a flexible material and serving as an inner catheter, a second tubular member, said second tubular member being formed of a flexible material and encasing said first tubular member so that said first and second tubular members are coax ially aligned, said first and second tubular members having proximal and distal ends, said second tubular member having a balloon-shaped portion formed therein adjacent the distal end and a fitting carried by the proximal end for permitting the introduction of fluid through the first tubular member and for permitting insertion of a fluid for inflating and deflating the balloon portion of the second tubular member.