Relation of coronary arterial spasm to sites of organic stenosis.

Among 63 patients with Prinzmetal's variant angina, coronary arterial spasm responsible for attacks of variant angina was documented arteriographically in 9 patients. In each observed episode (11 attacks in nine patients), coronary spasm producing myocardial ischemia occurred at and was superimposed on a site of preexisting organic stenosis. Measurements of normal portions of "spastic" and "nonspastic" vessels suggested a generalized uniform constriction of all major coronary arteries during attacks, with "spasm" limited to the site of an organic lesion in most cases. In two cases the magnitude of constriction in all vessels was consistent with generalized coronary hypercontractility or spasm. Among 104 patients with organic coronary artery disease and documented single vessel coronary spasm (foregoing 9 patients combined with 95 others from published reports), there were 70 patients with essentially single vessel organic coronary disease in 90 percent of whom the spasm involved the diseased vessel. Of 60 cases abstracted from the literature in which the relation of coronary spasm to the site of organic disease was described, 88 percent had the spasm causing ischemia localized to the site of an organic lesion. Hypotheses attempting to describe the pathophysiologic aspects of coronary spasm in variant angina must account for the intimate association of spasm with sites of organic stenosis in the majority of cases.