CARPORT — Coronary artery restenosis prevention on repeated thromboxane antagonism. A multicenter randomized clinical trial

GR32191B is a novel thromboxane A2 receptor antagonist with potent antiaggregational and antivasoconstrictive properties. To study whether this compound is useful in restenosis prevention after coronary angioplasty, we have conducted a randomized, double blind, placebo controlled trial. Patients were randomized to receive either GR32191B, 80 mg intravenous before angioplasty and 40 mg orally for 6 months, or 250 mg intravenous aspirin before angioplasty and control for 6 months. Coronary angiograms before angioplasty, after angioplasty and at 6 months follow-up were quantitatively analyzed using an automated edge detection technique. Angioplasty was attempted in 697 patients. Failure of the procedure occurred in 47 patients (6.7%). Follow-up angiography was available in 88.5% (575 patients) of successfully treated patients. In 53 patients drug compliance was less then 80% or trial medication was discontinued for more then 3 consecutive days. Quantitative data from these patients were excluded from analysis in accordance with the protocol. Baseline clinical and angiographic parameters did not differ between the two treatment groups. Multiple matched view analysis was performed on 320 segments (261 patients) in the control group and on 316 segments (261 patients) in the active treatment group. The mean minimal luminal diameter after angioplasty was 1.77 ± 0.35 mm in the control group and 1.79 ± 0.33 mm in the treatment group. Minimal luminal diameter at follow-up angiography was 1.46 ± 0.59 mm in the control group and 1.49 ± 0.58 mm in the treatment group. The mean difference in coronary diameter between post angioplasty and follow-up angiogram was - 0.31 ± 0.54 mm in the control group and - 0.31 ± 0.55 mm in the treatment group. Clinical events during 6 months follow-up, analyzed on intention to treat basis, were ranked according to the highest category on a scale ranging from death, nonfatal myocardial infarction, bypass grafting, re-angioplasty. No significant difference in ranking was detected between the two treatment groups. Six months after angioplasty 75% of patients in the treatment group and 72% of patients in the control group were symptom free, 18% of the control group were in Canadian Heart Association class I/II versus 21% in the treated group and 8% of the control group was in Canadian Heart Association class III/IVversus 5% in the treated group. In conclusion: long term thromboxane A2 receptor blockade with GR32191B does not prevent reactive intimal hyperplasia and does not favorably influ­ence the long-term clinical course following angioplasty.