Importance

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Abstract

A catheter which has resistance to collapsing when bent, and a method for producing such a catheter. The method includes (i) supporting a helical metallic coil having turns on a mandrel which has a release surface comprising a polytetrafluoroethylene (PTFE) or fluorinated ethylene propylene copolymer (FEP) tube supported on the mandrel; (ii) introducing the helical coil while supported on the mandrel into a first tube, the first tube being formed from a material which is flowable at a first elevated temperature and said first tube being received within a second tube, the second tube being heat shrinkable at a second temperature which is equal to or greater than the first temperature; (iii) heating the resulting assembly to a temperature equal to or greater than the second temperature, whereby shrinkage of the second tube causes material of the first tube to flow between turns of the coil and substantially encapsulate the coil; (iv) removing the mandrel while leaving the sheathing tube within the coil; and (v) removing the sheathing tube by tensioning the tube longitudinally of the coil. Catheters having small internal bores and very thin walls are prepared by this method. The catheter includes a first, thermo-flowed tube having a helical coil at least partially enveloped in the material of the tube. A second tube surrounds the first tube and is formed from heat shrunk material.

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First Claim