Preventing spasm of the radial artery conduit during coronary artery bypass grafting: Nicardipine versus verapamil.

Background and aim of the study In vitro studies have shown a reduction in radial artery spasm with the use of calcium antagonists. The purpose of this study was to evaluate the efficacy of topical treatment of the radial artery conduit using either verapamil or nicardipine before the anastomoses. Methods This prospective randomized study included 131 patients, who underwent coronary artery bypass grafting surgery with the use of the radial artery as a conduit. In 65 patients, the harvested radial artery was topically treated with verapamil and in 66 patients with nicardipine. After harvesting the radial artery, the direct flow through the conduit was measured in vitro before 5-minute incubation in nicardipine or verapamil and measured again after incubation. The flow before and after incubation was compared. Postincubation flow was also compared in the two groups. After performing the anastomosis, the flow through the radial artery was measured in vivo. Results The mean flow after NaCl incubation was 19.93 +/- 12.66 mL/min and after incubation in the Ca+ channel blocker 47.16 +/- 14.58 mL/min (P < .001). No significant difference in postincubation free flow was found between verapamil (46.29 +/- 15.43 mL/min) and nicardipine (48.01 +/- 13.77 mL/min; P = .503). Conclusion Topical treatment with Ca+ channel blockers reduces radial artery spasm and significantly increases the free flow through the radial artery conduit. Nicardipine is a safe and effective alternative of verapamil in preventing spasm of radial artery conduit.