Background Studies have reported benefit of oral therapy with the phosphodiesterase inhibitor, trapidil, in reducing restenosis after coronary angioplasty. Coronary stenting is associated with improved late outcome compared with balloon angioplasty, but significant neointimal hyperplasia still occurs in a considerable proportion of patients. The aim of this study was to investigate the safety and efficacy of trapidil 200mg in preventing in-stent restenosis.
Methods Patients with a single native coronary lesion requiring revascularization were randomized to placebo or trapidil at least 1h before, and continuing for 6 months after, successful implantation of a coronary Wallstent. The primary end-point was in-stent neointimal volume measured by three-dimensional reconstruction of intravascular ultrasound images recorded at the 6 month follow-up catheterization.
Results Of 312 patients randomized at 21 centres in nine countries, 303 (148 trapidil, 155 placebo) underwent successful Wallstent implantation, and 139 patients (90%) in the placebo group and 130 (88%) in the trapidil group had repeat catheterization at 26±2 weeks. There was no significant difference between trapidil and placebo-treated patients regarding in-stent neointimal volume (108·6± 95·6mm3vs 93·3±79·1mm3;P=0·16) or % obstruction volume (38±18% vs 36±21%;P=0·32), in angiographic minimal luminal diameter at follow-up (1·63±0·61mm vs 1·74±0·69mm;P=0·17), restenosis rate (31% vs 24%;P=0·24), cumulative incidence of major adverse cardiac events at 7 months (22% vs 20%;P=0·71) or anginal complaints (30% vs 24%;P=0·29).
Conclusion Oral trapidil 600mg daily for 6 months did not reduce in-stent hyperplasia or improve clinical outcome after successful Wallstent implantation and is not indicated for this purpose.