Sirolimus eluting stent in the treatment of atherosclerosis coronary artery disease.

Stent implantation represents the most commonly performed percutaneous coronary intervention nowadays. However, instent restenosis due to exaggerated neointimal hyperplasia remains a problem to overcome. Neointimal hyperplasia is a vascular response to stent injury; it mainly consists of smooth muscle cells proliferation. The underlying molecular mechanisms of restenosis were explained in this review article. Recently, drug-eluting stent has been proposed as a potential method to prevent instent restenosis. Animal studies have confirmed safety and efficacy of sirolimus-eluting stent implantation in vivo. The FIM trial, which was the first clinical study on sirolimus-eluting stent in de novo lesions, has shown an astonishing 0% restenosis rate. The RAVEL trial was the first prospective, double-blind, multi-center trial that randomized 238 patients at 19 institutions with de novo lesions into sirolimus-eluting versus bare Bx velocity stent. Six-month binary restenosis rate in the sirolimus-group was again 0% compared to 26.6% in the control group. Angiographic late loss and major cardiac event were also significantly lower in the sirolimus-group. The SIRIUS trial is an ongoing study conducted in 53 US centers that randomized 1100 patients with de novo lesion into sirolimus-eluting and bare stents. Preliminary results also showed a significant reduction in binary restenosis, late loss and repeat revascularization rates. Apart from de novo lesions, early experience of sirolimus-eluting stent implantation for instent restenosis in non-randomized study was also promising, achieving a single-digit repeat restenosis rate. As compare with standard coronary stent, a sirolimus-eluting stent shows considerable promise for the prevention of neointimal proliferation, restenosis and associated clinical events.