Inflatable member having elastic expansion with limited range

An elongated intravascular catheter comprising:

• a) an elongated catheter shaft having proximal and distal extremities and an inner lumen extending therein;
• b) an inflatable section on the distal extremity of the catheter shaft having an interior in fluid communication with the inner lumen of the catheter shaft and exhibiting upon inflation to an internal pressure within a first pressure range substantial elastic expansion and within a second pressure range, higher than the first pressure range, very little expansion;
• and
• c) means to direct inflation fluid to the interior of the inflatable section.

An elongated dilatation catheter for angioplasty procedures comprising:

• a) an elongated catheter shaft having proximal and distal extremities and an inner lumen extending therein;
• b) an inflatable member on the distal extremity of the catheter shaft which has an interior in fluid communication with the inner lumen of the catheter shaft and which exhibits upon inflation to an internal pressure within a first pressure range a substantial elastic expansion and within a second pressure range, higher than the first pressure range, very little expansion;
• and
• c) an adapter on the proximal extremity of the catheter shaft to direct inflation fluid to the interior of the expandable tubular section through the inner lumen extending within the catheter shaft.

A method of performing an balloon dilatation procedure within a patient's vascular system comprising:

• a) providing an balloon dilatation catheter having,
• i) an elongated catheter shaft which has proximal and distal extremities and an inner lumen extending therein,
• ii) an inflatable balloon on the distal extremity of the catheter shaft which has an interior in fluid communication with the inner lumen of the catheter shaft and which exhibits upon inflation within a first pressure range a substantial elastic expansion and within a second pressure range, higher than the first pressure range, very little expansion, and
• iii) means to direct inflation fluid to the interior of the inflatable balloon through the inner lumen extending within the catheter shaft;
• b) advancing the balloon dilatation catheter into and through a patient's vasculature to a desired location therein;
• c) heating the inflatable balloon to reduce the first pressure range in which substantial elastic expansion of the inflatable member occurs;
• d) performing a dilatation procedure within the patient's vasculature at the desired location by inflating the balloon;
• and
• e) deflating the inflated balloon and withdrawing the catheter from the patient's vasculature system.

A method of performing a balloon dilatation procedure within a patient's vascular system comprising:

• a) providing a balloon dilatation catheter having,
• i) an elongated catheter shaft which has proximal and distal extremities and an inner lumen extending therein,
• ii) an inflatable member on the distal extremity of the catheter shaft which has an interior in fluid communication with the inner lumen of the catheter shaft and which exhibits upon inflation to an internal pressure within a first pressure range substantial elastic expansion and within a second pressure range, higher than the first pressure range, very little expansion, and
• iii) means to direct inflation fluid to the interior of the tubular section having the inflatable balloon through the inner lumen extending through the catheter shaft, and
• iv) an inner tubular member which is disposed within the catheter shaft, which extends at least in part within the interior of the inflatable member and which is adapted to collapse at a pressure below the pressure range in which substantial elastic expansion of the inflatable member occurs;
• b) advancing the intravascular catheter into and through a patient's vasculature over a guidewire disposed within the inner tubular member;
• c) inflating the inflatable member to a pressure which is at a sufficient level to collapse the inner tubular member about a guidewire disposed within the inner lumen and to releasably secure the guidewire therein but which is insufficient to cause substantial expansion of the inflatable balloon;
• d) advancing the intravascular catheter with the guidewire secured within the inner lumen thereof to provide increased pushability through the patient's vasculature to a desired location therein;
• e) further increasing the pressure of the inflation fluid within the inflatable balloon to a pressure within the first pressure range to perform an dilatation procedure within the patient's vasculature at the desired location;
• f) deflating the inflatable balloon to an internal pressure below the first pressure range which allows the release of the guidewire within the inner lumen;
• and
• g) withdrawing the catheter from the patient's vascular system.

A method of delivering a therapeutic fluid to an intraluminal location within a patient's body comprising:

• a) providing an elongated catheter having,
• i) an elongated catheter shaft which has proximal and distal extremities and an inner lumen extending therein,
• ii) an inflatable member on the distal extremity of the catheter shaft which has an interior in fluid communication with the inner lumen of the catheter shaft and which exhibits upon inflation to a pressure within a first pressure range substantial elastic expansion and within a second pressure range, higher than the first pressure range, very little expansion,
• iii) a porous outer tubular member which is disposed about the inflatable member and which is adapted to absorb a drug-laden or therapeutic fluid, and
• iv) means to direct inflation fluid to the interior of the tubular section having the expandable wall portion;
• b) advancing the catheter into and through a patient's body lumen to a desired location therein;
• c) inflating the inflatable member to a pressure within the first pressure range to expand the porous outer tubular member, thinning the wall thereof and driving out the therapeutic fluid absorbed therein to deliver the fluid to the desired location;
• and
• d) deflating the inflatable member and withdrawing the catheter from the patient's body lumen.

A method of performing an angioplasty procedure within a patient's arterial system comprising:

• a) providing a dilatation catheter having,
• i) an elongated catheter shaft which has proximal and distal extremities and an inner lumen extending therein,
• ii) an inflatable member on the distal extremity of the catheter shaft which has an interior in fluid communication with the inner lumen of the catheter shaft and which exhibits upon inflation within a first pressure range substantial elastic expansion and within a second pressure range, higher than the first pressure range at least in part, very little expansion, and
• iii) means at the proximal extremity of the catheter shaft to direct inflation fluid to the interior of the inflatable member;
• b) advancing the dilatation catheter into and through a patient's arterial system until the inflatable member is disposed within a stenosis to be dilated;
• c) inflating the inflatable member to a pressure within the first pressure range to substantially expand the inflatable member and thereby dilate the stenosis;
• d) deflating the inflated tubular section;
• and
• e) withdrawing the catheter from the patient's arterial system.

A method of making an inflatable dilatation member comprising:

• a) extruding a tubular product formed of an olefinic ionomer at an elevated temperature;
• b) cool the extruded tubular product after its extrusion to obtain a relatively amorphous structure therein;
• c) irradiate at least a portion of the amorphous tubular product which will form the inflatable member;
• and
• d) heat treating the portion of the tubular product which will form the inflatable member at a temperature between about 50° C. above and about 50° C. below the crystalline melting temperature.