Frequency and importance of unprovoked coronary spasm in patients with angina pectoris undergoing percutaneous transluminal coronary angioplasty

Coronary spasm superimposed on fixed coronary artery stenosis was discovered in 14 of 74 candidates for percutaneous transluminal coronary angioplasty (PTCA). In 3 of the 14, spasm developed during PTCA and was presumably catheter-induced. Eleven of the 14, with unprovoked spasm, are the subject of this study. Three of the 11, in whom the fixed component of the mixed stenosis was subcritical were treated medically, with good results in 2 but with persistent angina pectoris and eventual myocardial infarct in 1. Nitroglycerin administered by the intracoronary route relieved spasm resistant to sublingual nitroglycerin in 1 of the 3. In 8 of the 11 with critical fixed stenosis, spasm was discovered either before PTCA (7 patients) or on follow-up (1 patient). Six of the 8 had successful PTCA, with no or mild symptoms on follow-up. Of the 2 failures, 1, uncomplicated, was followed by successful elective coronary artery bypass surgery while the other, complicated, led to successful emergency coronary artery bypass surgery, with disappearance of symptoms in both. The rate of success was similar in patients with documented unprovoked spasm (6 of 8) and patients without (39 of 63, 62%). It is concluded that (1) coronary spasm, if properly sought for, is probably not uncommon in single-vessel candidates for PTCA; (2) patients considered candidates for PTCA should have intracoronary nitroglycerin administered before PTCA; (3) in patients with critical, fixed coronary artery disease, associated spasm does not reduce the chances of successful PTCA; (4) coronary spasm may outlast the relief by PTCA of the fixed component of the mixed stenosis and requires long-term vasodilator therapy; and (5) the lack of adverse effects when PTCA is performed in patients with spasm superimposed on critical fixed single-vessel stenosis appears to justify its use for the time being.