Patent ID: 7507229

Claim:
A braid-reinforced microcatheter having a degree of flexibility to traverse remote vascular locations and a degree of strength to withstand high pressure associated with catheter delivery of viscous liquid embolizing compositions comprising: a) a cylindrical inner layer of polymer defining a single lumen in the catheter wherein said inner layer has a proximal end and a distal end and a flexibility at its distal end greater than at its proximal end further wherein said inner layer consists essentially of a first or inner polymer layer and a second or outer polymer layer at the proximal end and said first polymer layer at the distal end and still further wherein said first polymer layer is a lubricous polymer selected from the group consisting of polytetrafluoroethylene and high density polyethylene and said second layer comprises polyimide and wherein the second layer gradually tapers to zero at the distal end wherein at least 3-5 cm of the distal end is provided with no polyimide; b) a braided wire layer over the inner layer, the braided wire layer including a distal segment of a first pic rate and a proximal segment of a second pic rate which is smaller than the first pic rate, the braided wire layer extending from the proximal end to within about 1 cm of the distal end of the catheter; c) an outer jacket surrounding the braided wire comprising a plurality of joined segments of polymers of increasing flexibility thereby having a proximal durometer higher than a distal durometer; and d) wherein the microcatheter is devoid of a balloon and wherein the microcatheter has a burst strength of from 700 to 1000 psi.