Patent ID: 6371928
Filing Date: 2002-04-16
Classification: A61B,A61M

Abstract:
A guidewire having a generally straight proximal section, and a distal section having a helical support section which defines a curved three dimensional profile that is diametrically larger than the diameter of the proximal section, the helical support section capable of elongation into a substantially straight profile when constrained and expansion to a wider diameter when unconstrained, the helical support section exerting an outward radial force (Wr) less than 20 lbs/in when axially extended so the diameter of the helical guide section is half the unconstrained diameter, wherein Wr is determined by the formula:(((SS)Fa&dgr;a)/(2StotRkRoR2))Â½whereinSS=the measured or calculated beam stiffness of the helical support section; Stot=the measured length of the helical support section; &dgr;a=the measured axial extension of the guide section at Â½ Ro; Fa=the applied axial force to elongate the helical support section by &dgr;a with ends of the helical guide section fixed in rotation; R=the measured average radius of the helical support section when constrained; Rk=the average measure of R less half the wire diameter; and Ro=the measured average radius of the helical support section when unconstrained.