Alpha-adrenoceptor-mediated coronary artery spasm
D. L. Levene and M. R. Freeman
Selective coronary arteriography performed on a 41-year-old woman with
angina pectoris demonstrated proximal stenosis of the right and left main
coronary arteries that was unaffected by nitrate therapy. To exclude
coronary artery spasm, the study was repeated, and a striking increase in
the narrowing of the right coronary artery was observed. This 90% stenosis
was virtually abolished by pretreatment with intravenously given
phentolamine hydrochloride. Prolonged alpha-adrenoceptor blockade with
phenoxybenzamine hydrochloride improved the patient's exercise tolerance
and postexercise electrocardiographic abnormalities when compared to
therapy in matched controls given placebo. These observations suggest that
alpha-adrenoceptor-mediated coronary artery spasm may mimic organic lesions
at coronary arteriography and may be a factor in the pathogenesis of angina
pectoris in some patients.
