Stent fracture, an incidental finding or a significant marker of clinical in‐stent restenosis?

Abstract

SF proved to be associated with angiographically-documented clinical ISR. Although the exact mechanism is unknown, factors that appear to play a negative role in SF include vessel tortuosity, use of SES and overlapping stents. Larger stent diameter was protective. Further studies are needed to better define the factors important in the mechanism of SF.

Micro-scale testing and micromechanical modelling for high cycle fatigue of CoCr stent material

“…[1][2][3]. Fractures were previously concealed by growth of neointima over stent struts and often went unnoticed as the tissue-growth provided support at the site of the fracture and provided coverage from the blood flow [4,5].…”

Very delayed coronary stent fracture presenting as unstable angina: A case report

“…The rigid, and closed cell design of the sirolimus eluting stent results in greater straightening of the vessel thereby subjecting the stent to greater forces during the cardiac cycle [1,10]. …”

“…The introduction of drug-eluting stents has marked a new era in the field of interventional cardiology with significant reduction in the incidence of restenosis as well as repeat revascularization [1,2]. Although drug-eluting stents has become the standard of care for percutaneous coronary intervention, the occurrence of late stent thrombosis has raised concern over their long-term safety.…”

Direct Microscopic Observation of Striations in a Fractured Section of a Sirolimus-Eluting Stent (Cypher Bx Velocity) Indicates Induction of Stent Fracture by Continuous Shear Stress

“…Thus, patients implanted with SES should be carefully observed, particularly those with a high likelihood of having fracture in the SES. [1][2][3][4][5][6][7] Furthermore, since the structure of the Cypher Select+ ® (approved in February 2010 in Japan) was modified to withstand shear stress through extension of the flex segment with an oblique angle, the incidence of SF and the long-term clinical and angiographic outcomes as well as outcomes of MSCT after implantation with Cypher Select+ ® should be estimated. All 7 flex segments linking the cells (radial-strength segments) were found to be fractured ( Figure 3A).…”

“…Additionally, previous reports suggest that shear stress induced by coronary movement and hinge motion, SES length and overlap, tortuosity of the right coronary artery (RCA), interval after stent placement, small stent diameter, lack of stent protection by the neointima, and changes in angulation after SES placement are factors related to SF. [1][2][3][4][5][6][7] However, the direct outcome of continuous shear stress, which causes fracture of the stainless steel-based platform of the SES after placement in native coronary arteries, is not fully understood.…”