Elastic recoil of coronary stents: A comparative analysis

Minimum elastic recoil (ER) has became an essential feature of new coronary stents when deployed in artheromatous lesions of various morphologies, the ER of coronary stent might be an important component of 6-month restenosis rate by minimizing the luminal loss. We evaluated the intrinsic ER of 23 c oronary stents with a mechanical test bench. The amount of ER for one size of stent (3.0 mm) was quantified using a 3D optical contactless machine (Sm artscope MVP, Rochester, NY). The stents were expanded on their own balloon for the precrimped stents; the uncrimped stents were expended using identi cal 3.0-mm balloons. Two types of measurements were done without exterior s tress and with a 0.2-bar exterior stress, directly on the stent at the end of balloon expansion, immediately after balloon deflation, and then 30 min, 60 min, and 120 min after. ER ranged from 1.54% +/- 0.81% (Bestent BES 15) to 16.51% +/- 2.89% (Paragon stent) without stress (P < 0.01) and from 2.3 5% +/- 1.14% (Bestent BES 15) to 18.34% +/- 2.41% (Cook GR2) under 0.2-bar pressure (P < 0.0001). Furthermore, there was a significant reduction betwe en the mean result of tubular stents (TS) and coil stents (CS). The results of in vitro mechanical tests may confirm strongly the interest of a minimu m ER in the prevention of the 6-month restenosis. (C) 2000 Wiley-Liss, Inc.