A randomized controlled trial assessing the efficacy and safety of prasugrel for prevention of early saphenous vein graft thrombosis

INTRODUCTION: Aortocoronary saphenous vein graft (SVG) failure is common and associated with high morbidity. Thrombus formation may play an important role in early SVG failure. METHODS: We performed a double‐blind, randomized trial at four centers. Patients were randomized to prasugrel 10mg daily or placebo after coronary artery bypass surgery. Follow‐up angiography, optical coherence tomography (OCT), intravascular ultrasound (IVUS), and near‐infrared spectroscopy (NIRS) was performed at 12 months. The primary efficacy objective was the prevalence of OCT‐detected SVG thrombus. The primary safety endpoint was the incidence of Global Utilization of Streptokinase and t‐PA for Occluded Coronary Arteries (GUSTO) severe bleeding. RESULTS: The study was stopped early due to slow enrollment after randomizing 84 patients (target enrollment was 120). Mean age was 64±6 years? 98% of the patients were men. Follow up angiography was performed in 59 patients. SVG IVUS was performed in 52 patients, OCT in 53 patients, and NIRS in 33 patients. Angiographic SVG failure occurred in 29% of patients in the treatment arm vs. 36% in the control arm (p=0.78). Thrombus was identified by OCT in 52% vs. 54% of patients in the treatment vs. control arm (p>0.99). There were no differences in total SVG plaque volume or normalized SVG plaque volumes (301 [IQR (interquartile range) 219‐457] vs. 347 [IQR 203‐415] mm3, p=0.83? and 0.08 [IQR 0.06‐0.12] vs. 0.07 [IQR 0.06‐0.09] mm3/frame, p=0.20). There was no difference in lipid core burden index (1 [IQR 0‐15] vs. 0 [IQR 0‐10], p=0.48). The 1‐year Kaplan Meier incidence of major adverse cardiovascular events in the treatment group was 14.3% vs. 2.4% in the control group (log rank p=0.21), and incidence of severe bleeding was 2.4% in the treatment arm vs. 0% in the control arm (log rank p=0.32). CONCLUSIONS: Use of prasugrel was not associated with lower prevalence of SVG thrombus 12 months after coronary bypass graft surgery. Further investigation is needed into strategies to prevent early vein graft failure.