Influence of carvedilol and propranolol on coronary blood flow

Summary

A total of 17 patients with angiographically proven coronary artery disease and at least one stenosis blocking ≥ 70% of the left anterior descending or circumflex artery were included in a double-blind, randomized study. They received either 5 mg carvedilol or 6 mg propranolol intravenously. Heart rate, aortic pressure, mean coronary sinus pressure and coronary flow (thermodilution) were measured and coronary resistance and the rate-pressure product were calculated before and 25 min after injection. Carvedilol significantly (P < 0.05) lowered the heart rate (mean, 76 to 69 beats/min), aortic pressure (mean, 153/80–135/72 mmHg), rate-pressure product (mean, 117–93 mmHg/min), and coronary flow (mean, 114–94 ml/min). Coronary resistance (mean, 0.97–1.07 mmHg × min/ml) and coronary flow related to the rate-pressure product (mean, 1.0–1.02 ml/mm Hg) showed no significant change after carvedilol treatment. Propranolol lowered the heart rate (mean, 76–64/min;P < 0.05) and rate-pressure product (mean, 109–96 mm. Hg/min; not significant). Aortic pressure (mean, 145/72–147/74 mmHg), coronary flow (mean 109–101 ml/min), coronary resistance (mean, 1.1–1.2 mmHg × min/ml), and coronary flow related to the rate-pressure product (mean,1.12–1.19 ml/mmHg) showed no significant change after propranolol administration. Following single application, carvedilol lowered the rate-pressure product more markedly than did propranolol on account of its acute blood-pressure-lowering effect. No differences in the hemodynamic effects of carvedilol and propranolol were found. Neither drug seems to influence the adaption of coronary flow to myocardial oxygen demand.