Vascular catheter

Claim 1

A vascular dilatation instrument comprising an inner tube defining a first lumen extending between an open distal end and a proximal portion, an outer tube disposed coaxially around said inner tube, having a distal end retracted a predetermined distance from the distal end of said inner tube and a proximal portion, and defining a second lumen with the outside surface of said inner tube, an inflatable member having one end attached to said inner tube and another end attached to said outer tube, and defining an interior space in fluid communication with said second lumen in the vicinity of the other end, a first opening disposed in the proximal portion of said inner tube in communication with said first lumen, and a second opening disposed in the proximal portion of said outer tube in fluid communication with said second lumen, wherein at least one of said inner tube and said outer tube includes a main body section based on a tube formed of a metal selected from the grope consisting of steel, tungsten and copper or a alloy selected from the grope of steel alloy, tungsten alloy and copper ahoy and a distal section made of a synthetic resin, the tube made of said metal or said alloy has one or more spiral slits in the distal end portion.