Dilatation catheter with varied stiffness

• US 6,030,405 A
• Filed: 06/25/1998
• Issued: 02/29/2000
• Est. Priority Date: 04/28/1997
• Status: Expired due to Term

• Current Assignee: Agfa-Gevaert N.V.
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Zarbatany, David J., Verbeek, Maurice, Pintor, Rafael
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): Woo, Julian W.
• Application Number:
  US09/104,949
• Time in Patent Office: 614 Days
• Field of Search: 174/95, 174/96, 174/113 A, 174/110 PM, 174/110 FC, 606/191, 606/194, 604/96, 604/164
• US Class Current: 606/191
• CPC Class Codes: A61M 2025/0063 having means, e.g. stylets, mandrils, rods or wires to reinforce or adjust temporarily the stiffness, column strength or pushability of catheters which are already inserted into the human body
• CPC Class Codes: A61M 2025/0098 having a strain relief at the proximal end, e.g. sleeve
• CPC Class Codes: A61M 25/0054 with regions for increasing flexibility
• CPC Class Codes: A61M 25/104 used for angioplasty

Abstract

A dilation catheter having a balloon inflation shaft with an inflation lumen into which a stiffening wire extends and a guidewire shaft having a guide wire lumen adjacent to the balloon. The stiffening wire includes at least two stepped diameter reductions along its length to vary stiffness from a stiff proximal end providing improved pushability to a less stiff distal end providing improved trackability. A manifold at the inflation shaft proximal end includes a handle for adjusting the distance the stiffening wire extends into the inflation lumen to allow stiffness to be optimized. The handle includes a tubular flange frictionally engaging the manifold to prevent inadvertent handle movement. The balloon inflation shaft and guidewire shafts are bonded together in a manner producing an assembly having a circular cross section for improved connection to a circular balloon and improved catheter performance.

Claims

1. A method of making a substantially circular shaft having two adjacent parallel lumens therethrough, which comprises the steps of:

forming a shaft assembly by positioning first and second shafts each of which has a longitudinal lumen in an adjacent, generally parallel, relationship;

inserting a strip of material having a lower melting temperature than said shafts between said shafts and surrounding said shaft assembly with a pressure application tube that shrinks at a temperature above the melting temperature of said strip;

heating said shaft assembly to a temperature at which said strip melts and said pressure application tube shrinks;

forcing a tight fitting reshaping tube of a stiff, circular cross section, material over said shaft assembly;

heating said reshaping tube;

cooling said shaft assembly; and

removing said reshaping tube.

2. The method according to claim 1 wherein:

said reshaping tube is removed when said shaft assembly is cooled to a temperature at which said strip material is partially solidified;

forcing a second reshaping tube having a smaller diameter over said shaft assembly;

heating said second reshaping tube;

cooling said shaft assembly until said strip material is fully solidified; and

removing said second reshaping tube.

3. The method according to claim 2 wherein said reshaping tubes are formed from polytetrafluoroethylene and said strip is formed from low density polyethylene.