Choice of conduit for the right coronary system: 8-year analysis of Radial Artery Patency and Clinical Outcomes trial

Abstract

Background: Previous reports have supported the use of bilateral internal thoracic arteries to revascularize the left coronary circulation. If this becomes standardized practice, the optimal conduit for the right coronary system remains to be established. Our objective is to compare the performance of the radial artery versus the saphenous vein when used to graft the right coronary artery or its branches during an 8-year period after primary coronary artery bypass graft surgery.

Methods: The Radial Artery Patency and Clinical Outcomes study is a randomized controlled trial comparing radial artery, saphenous vein, and free right internal thoracic artery. Of the 621 patients enrolled in the study, 465 patients received a graft to the right coronary artery or its branches. The retrospectively compiled database was used to establish patency rates and clinical events among these patients.

Results: Absolute graft patency rates were as follows: radial artery, 86.9% of 68 (95% confidence interval, 76.6% to 93.1%); and saphenous vein, 81.2% of 197 (95% confidence interval, 75.1% to 86.1%). Noninferiority tests show that absolute radial patency to saphenous patency is at least 0.9526 (p = 0.025). Kaplan-Meier estimates of angiographic outcomes show no significant difference (log rank p = 0.22). Cardiac events in the right coronary territory occurred in the radial artery group (1.79%) versus the saphenous vein group (4.93%; p = 0.26). Overall mortality was 8.03% in the radial artery group versus 12.5% in the saphenous vein group (p = 0.23).

Conclusions: The radial artery patency is at least comparable to that of the saphenous vein when grafted to the right coronary artery or its branches. The paucity of clinical events in both grafts is notable. Selection of best conduit may therefore be made according to other factors.