Tubular stent-type endoprosthesis for use in cardiovascular surgery is cut out from stainless steel tube and has radial force slightly greater than the elastic retraction of blood vessel in which it is implanted

摘要

Vascular stent made from stainless steel tube has crushing resistance 1.2-2 times the elastic retraction force of the vascular vessel. The stent is formed from a succession of annular segments articulated by curved sections. Stent for implanting in vascular vessel in its deployed state, aided by balloon expansion, is made by cutting stainless steel tube and, once implanted and deployed, it has crushing resistance from 1.2 times to 2 times of elastic retraction force of this vascular vessel. In case (I) of implanting the stent in coronary artery its crushing resistance in deployed state is 0.2 * 105 Pa, and in case (II) of implantation in periphery artery the crushing resistance is 0.5 * 105 Pa. The stent comprises a succession of annular segments composed of sections articulated by one or two curved connections between each two annular segments. In case (I) the length L1 of annular segment is approximately 1.4 mm, the number of connections is 1 and each segment consists of 7 sections. In case (II) the length L1 of annular segment is approximately 3.9 mm, the number of connections is 1 and each segment consists of 6 sections. Preferably each segment has the form of a coil composed of a succession of arms linked two to two by articulation zones, with each two arms linked with articulation zone forming one section, and with each arm of a segment disposed obliquely in relation to longitudinal axis, at an angle alpha above 20 deg , preferably 20-30 deg . Successive connections are preferably angularly shifted in relation to longitudinal axis of stent, forming helix path. The length L2 of each connection is preferably 1/4 of the length L1 of annular segment. The arms of two successive annular segments are preferably at the inverse alpha angle to each other, and the articulation zones of two adjacent annular segments are shifted in such way as to ensure oblique general direction of correspondent connection. The stent preferably has radio-opaque marker at each of its extremities, in form of curved piece closed around such extremity. The marker preferably has protective coating, to diminish its electric potential, or the stent extremity (or at least its part) destined to receive the marker comprise such protective coating.