Medical and surgical treatment of Prinzmetal's angina
John S. Schroeder, M.D.
Steven Rosenthal, M.D.
Irene Lamb, R.N.
Robert Ginsburg, M.D.
Since the pathophysiologic mechanism inducing coronary artery spasm is poorly understood, both medical and surgical therapy remain empirical. Nitroglycerin remains an extremely effective drug for relief of the anginal chest pain associated with coronary spasm and has been documented to reverse quickly the spasm that occurs spontaneously or in response to ergonovine maleate during coronary arteriography. Long-acting nitrates are also useful, but are usually not complete in their prophylactic effect because a continuous serum level of the drug is needed for it to be effective and because the spasm frequently occurs during the early morning hours. We have found that nitroglycerin paste, applied at bedtime, is frequently effective as a prophylaxis for this problem if the patient can tolerate the side effects. The problem of nitroglycerin tolerance in Prinzmetal's angina has been difficult to document, although a few patients appear to have become nitroglycerin-dependent with an increasing number of pain episodes upon sudden withdrawal of the nitroglycerin, such as at the time of surgery.
One proposed mechanism for the coronary spasm is alpha-receptor mediated coronary artery vasoconstriction, either due to excessive or unbalanced sympathetic tone. Beta blockers have been reported by Yasue et al1 to aggravate Prinzmetal's angina. This observation tends to support the concept of unopposed alpha-mediated spasm occurring when the beta-mediated vasodilation is blocked. For this reason we have used alpha blockers, both phentolamine and phenoxybenzamine, as second line drugs for difficult-to-control symptoms. These agents, in nonrandomized trials, tend to be partially effective but appear to lose their . . .