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Restenosis in Drug-Eluting Stents
Abstract & Commentary
Synopsis: The pattern of restenosis in sirolimus-eluting stents is focal and mainly inside the stent.
Source: Colombo A, et al. Circulation. 2003;107: 2178-2180.
Early trials with short sirolimus-eluting stents (RAVEL) showed no restenosis. A subsequent trial dealing with longer lesions (SIRIUS) showed restenosis in 9%, and most of the restenosis was at the edges or in the gap in the stent and was focal. This report details restenosis following the implantation of sirolimus-eluting stents in 735 lesions in 368 unselected consecutive patients. Mean lesion length was 17 mm, and mean stent length was 28 mm. Angiography was performed in 24 patients who returned in an average of 4 months with symptoms suggestive of myocardial ischemia; 21 also had positive stress tests. Angiographic restenosis was seen in 11 of these 24 patients in 14 stented segments. The pattern in all 14 was focal and multifocal in 6, and inside the stent. One patient also had stent margin restenosis. Colombo and colleagues concluded that the pattern of restenosis in sirolimus-eluting stents is focal and mainly inside the stent.
Comment by Michael H. Crawford, MD
There are several interesting points brought out by this experience by highly skilled operators in unselected patients. First, the incidence of symptom-driven angiographic restenosis is not zero. It was 3% of patients and 2% of lesions treated. However, it is also not 9%, probably because the operators fully covered the lesions. Second, restenosis is focal and largely inside the stent. Possible explanations include underexpansion of the stent, nonuniform coating or release of drug, and complex lesions, which may influence drug delivery. Finally, it is clear that the current drug-eluting stents do not completely eliminate in-stent restenosis as was once hoped. Better stent technology, better delivery systems, or other approaches need to be pursued before we can deliver on the promise to revolutionize revascularization as we know it.
Dr. Crawford is Professor of Medicine, Mayo Medical School; Consultant in Cardiovascular Diseases, and Director of Research, Mayo Clinic, Scottsdale, AZ.