Self‐Expandable nitinol stent for cardiovascular applications: canine and human experience

Abstract

The initial experimental and clinical experience with the cardiovascular self-expandable Nitinol stent (vascular and coronary versions) is described. The stent is designed as a helical coil with two terminal balls that are used for restraining it on the delivery catheter. Upon release, the stent self-expands immediately. A temporary stent version continues with a long wire that can be removed by pulling it as a straight wire through a small profile catheter. The stent uncoils in its own groove upon removal, a relatively atraumatic procedure. The stents have been studied in dogs and in peripheral arteries in patients. The results show a transient nonocclusive proliferative response to the stent that is maximal at 3-6 mo. The removability of the permanent stent has been proven in dogs. The preliminary results in patients are encouraging and demonstrate its feasibility for permanent and potentially temporary arterial support.

Extraction of fully deployed coronary stents

“…This, unfortunately, is also a disadvantage in that it permits longitudinal compression or collapse of the stent-the so-called concertina effect. In addition, it tribution of a permanently implanted "foreign body" to restenosis and to solve the problem of stent misplacement within the target vessel [13,14], this concept has not yet proved to be clinically useful.…”

Interventional Pediatric Cardiology: State of the Art and Future Directions

“…The Wallstent, because of its thrombogenicity and intimal proliferative response, is no longer favored [156,188]. The self-expandable InStent uses thermal shape memory of Nitinol and the initial experience is encouraging [9]. The majority of experience in the pediatric practice has been with balloon expandable Palmaz-Schatz stents.…”

“…Several designs of the former stents have been tested and include Palmaz-Schatz [85,160], Roubin [155], Strecker [148,184], Wiktor [13], Freedom [199], Cordis [90], ACS multi-link [178] and others; PalmazSchatz stents are the most commonly used stents in clinical practice, to date. Among the self-expandable stents, Wallstent [156,188] and the Nitinol InStent [9] have been tested. The Wallstent, because of its thrombogenicity and intimal proliferative response, is no longer favored [156,188].…”

High Technology in Medicine: Lessons from Cardiovascular Innovations and Future Perspective

“…More flexible stents with novel design such as the BeStent13 and the Nir stent14 were developed, and various metal surface modifications were applied to give the best clinical results. Newer metals such as nitinol, a nickel and titanium alloy with thermal memory, were used to generate self-expanding stent technologies that applied the appropriate strength at body temperature 15. All these developments resulted from tight collaborations between physicians and engineers with industrial and financial support around them.…”