Copyright © 1989 by the European Society of Cardiology.
© 1989 The European Society of Cardiology
Effect of intracoronary and intravenous propranolol on human coronary arteries
Department of Internal Medicine, Medical Policlinic, Cardiology, University Hospital Zurich, Switzerland
Address for correspondence: Otto M. Hess, M.D., Medical Policlinic, Cardiology, University Hospital, Raemistrasse 100, CH-8091 Zurich, Switzerland
The effect of intracoronary and intravenous propranolol on coronary vasomotion was evaluated in 28 patients with coronary artery disease. Luminal area of a normal and a stenotic coronary vessel segment was determined at rest, during submaximal bicycle exercise and 5 min after 1·6 mg sublingual nitroglycerin administered at the end of the exercise test involving biplane quantitative coronary arteriography. Patients were divided into three groups: group 1 (n=12) served as the control group, group 2 consisted of 10 patients with intracoronary administration of 1 mg propranolol and group 3 of six patients with intravenous administration of 0·1 mg kg–1 propranolol prior to the exercise text.
In the control group there was coronary vasodilation (+23%, P<0·01) of the normal and coronary vasoconstriction (–29%, P < 0·0·01) of the stenotic vessel segment during bicycle exercise. After sublingual administration of 1·6 mg nitroglycerin there was vasodilation of both normal (+40%, P <0·001 vs rest) and stenotic (+12%, NS vs rest) vessel segments. In group 2 intracoronary propranolol was not accompanied by a change in coronary vessel area but both normal (+13%, P<0·05) and stenotic (+22%, P<0·05) vessel segments showed coronary vasodilation during bicycle exercise. After sublingual nitroglycerin there was further vasodilation of both normal (+31 %, P<0·001 vs rest) and stenotic (+45%, P<0·01 vs rest) arteries. In group 3 intravenous administration of propranolol was associated with a decrease in coronary luminal area of both normal (–24%, P 0·001) and stenotic (–31%, P<0·001) vessel segments. During dynamic exercise there was coronary vasodilation of both vessel segments when compared with the data after intravenous injection of propranolol but there was no change in luminal area (normal vessel –2%, NS vs rest; stenotic vessel –3%, NS vs rest) when compared with the resting data. After sublingual administration of 1·6mg nitroglycerin both normal (+21%, P–0·01) and stenotic (+36%, P<0·001) vessel segments showed coronary vasodilation.
It is concluded that supine bicycle exercise in patients with coronary artery disease is associated with vasodilation of the normal and vasoconstriction of the stenotic coronary arteries. Intravenous administration of propranolol is followed by coronary vasoconstriction of both normal and stenotic coronary arteries, probably due to secondary mechanisms because it is not observed after intracoronary injection of propranolol and it is overridden by bicycle exercise and sublingual nitroglycerin.
Key Words: Coronary vasomotion • quantitative coronary arteriography • bicycle exercise • intracoronary and intravenous propranolol • coronary artery disease • nitroglycerin