| 摘要 |
A preformed guidewire particularly well-suited for use in percutaneous medical procedures, such as transcatheter aortic valve replacement, includes an inner corewire of discontinuous, tapered stiffness that is surrounded along a portion of its length by a flexible, outer casing of uniform cross-section, such as a tightly wound, stainless steel, spring coil wire. The inner corewire is constructed of a shape-memory material, such as a nickel-titanium alloy, that is preformed into an encircled S-shaped configuration in its atraumatic distal region. Specifically, the distal region includes an enlarged, stiffened, proximate segment that encircles a smaller, more flexible, distal segment. As a feature of the invention, the distal and proximal segments project along fixed-radial arcuate paths that extend in opposite directions from one another. As a result, the distal region is optimally configured to limit the risk of trauma to the immediate site of treatment when inserted through a straightened guide catheter. |
