Prevention of in-stent restenosis

Despite the favourable impact of stent implantation on restenosis rates for selected lesion types, in-stent restenosis remains a commonly encountered and difficult to manage entity. Histologically, in-stent restenosis appears to derive almost exclusively from neointimal hyperplasia, which appears to be more abundant following stent implantation than balloon angioplasty. The most powerful predictors of in-stent restenosis include the presence of diabetes, greater lesion length, small vessel caliber, and inadequate stent expansion. Several strategies have been proposed as a means to reduce the incidence of in-stent restenosis. Perhaps the most important among these relates to a strategy of provisional stent use, whereby stenting is undertaken only if suboptimal results are achieved following balloon angioplasty. Recent data from the EPILOG and EPILOG-stent trials suggest that the use of IIb/IIIa receptor antagonists may enhance the strategy of provisional stenting. When stents are used, adequate deployment is essential. The ability of adjunct IVUS imaging to guide proper balloon sizing during stent implantation and consequently reduce the risk of restenosis is currently the subject of randomized trials. Based on preliminary study results, intravascular radiation appears to hold great potential as a means to inhibit neointimal hyperplasia and consequently reduce the occurrence of in-stent restenosis, and large scale safety and efficacy trials are in progress. Other pharmacologic- and device-oriented strategies are likewise undergoing evaluation. In conclusion, while the availability of coronary stents has without question improved the safety and efficacy of coronary angioplasty, it remains critical that we continue to determine in an objective manner how and when best to use these devices.