Expandable introducer sheath

Abstract

The present invention comprises a method and device for providing an expandable introducer sheath. The method of employing the inventive device comprises inserting an elongate flexible tubular sheath into a vessel (with a proximal end of the sheath extending proximally outward through the skin), to slidably receive intravascular devices. When a larger size introducer sheath is desired, the sheath is manipulated while still in the vessel to expand its inner diameter to a larger size. In one embodiment, the sheath is made of a shape-memory polymer and is manipulated by inserting a heated mandrel (with an outer diameter larger than the inner diameter of the sheath) within the sheath to cause the sheath to expand to an inner diameter at least approximately equal to an outer diameter of the mandrel. The shape-memory polymer material ensures that the sheath will retain its expanded inner diameter. Alternatively, the sheath is formed from a telescoping multi-tubular arrangement of progressively larger tubes. In any case, insertion of the inventive sheath into the skin requires only a single small puncture which is then only expanded as needed while the sheath remains in place.