Patent ID: 8485969

Claim:
An apparatus for percutaneously dilating an opening in the wall of a blood vessel or other anatomic structure comprising, in combination: an elongate, introducing guide element having a proximal segment and a distal segment which meet at a juncture, said proximal segment having a first outer diameter at said juncture and said distal segment having a second outer diameter at said juncture greater than said first outer diameter thereby forming an abrupt, circumferential step comprising a proximally-facing surface such that said circumferential step creates a discrete transition between said proximal segment and said distal segment, said distal segment comprising a distal tip and an elongate portion extending from said step to said distal tip of said distal segment, said elongate portion having an outer diameter that is substantially constant over the entire length of said elongate portion and equal to said second outer diameter; and a dilator matched to said introducing guide element having an interior bore of sufficient size to permit said dilator to slide over the entire proximal segment of said introducing guide element, said dilator comprising a distal tip with an opening to said interior bore, said dilator distal tip having an inner diameter less than said second diameter and an outer diameter substantially equal to said second diameter, such that when assembled together with said dilator distal tip abutting said step, said dilator cannot pass distally beyond said step.