Background: GR32191B is a novel thromboxane A2-receptor antagonist with potent antiagregational and antivasoconstrictive properties. We have conducted a randomized, double-blind placebo-controlled trial to study its usefulness in restenosis prevention.
Methods and results: Patients received either GR32191B (80 mg orally before angioplasty and 80 mg/day orally for 6 months) or 250 mg i.v. aspirin before angioplasty and placebo for 6 months. Coronary angiograms before angioplasty, after angioplasty, and at 6-month follow-up were quantitatively analyzed. Angioplasty was attempted in 697 patients. For efficacy analysis, quantitative angiography at follow-up was available in 522 compliant patients (261 in each group). Baseline clinical and angiographic parameters did not differ between the two treatment groups. The mean difference in coronary diameter between postangioplasty and follow-up angiogram (primary end point) was -0.31 +/- 0.54 mm in the control group and -0.31 +/- 0.55 mm in the GR32191B group. Clinical events during 6-month follow-up, analyzed on intention-to-treat basis, were ranked according to the highest category on a scale ranging from death (control, six; GR32191B, four) to nonfatal infarction (control, 22; GR32191B, 18), bypass grafting (control, 19; GR32191B, 22) and repeat angioplasty (control, 52; GR32191B, 48). No significant difference in ranking was detected. Six months after angioplasty, 75% of patients in the GR32191B group and 72% of patients in the control group were symptom free.
Conclusions: Long-term thromboxane A2-receptor blockade with GR32191B does not prevent restenosis and does not favorably influence the clinical course after angioplasty.