Variant angina pectoris. Role of coronary spasm in the development of fixed coronary obstructions.

Abstract

It has been suggested that recurring coronary artery spasm may lead to the development of fixed atherosclerotic coronary obstructions. We studied 10 patients with typical Prinzmetal's variant angina in whom the disease remained active for years and in whom occlusive coronary spasm occurred reproducibly at the same arterial site during repeat coronary arteriography (25 +/- 12 months after initial angiography). At initial evaluation, four patients had significant (greater than or equal to 50% fixed coronary diameter reduction) one-vessel coronary artery disease, and six had nonsignificant disease. Spasm developed at stenotic sites (20-65% diameter reduction) in nine patients and at an angiographically normal site in one patient. Progression of coronary disease was assessed in 62 segments: 10 spastic (of which nine were stenotic) and 52 nonspastic (eight stenotic and 44 angiographically normal), using computerized arteriography. Mean diameters (millimeters) of spastic segments, nonspastic stenoses, and angiographically normal nonspastic segments were not significantly different at first and second arteriograms (1.52 +/- 0.14 versus 1.43 +/- 0.21, 1.32 +/- 0.17 versus 1.12 +/- 0.23, and 2.40 +/- 0.12 versus 2.42 +/- 0.12, respectively). Stenosis progression (from 65% diameter reduction to total occlusion) occurred in one patient at a spastic site and in two at nonspastic sites (from 34% to 65% and from 84% to 100%). Complicated stenoses suggestive of plaque fissuring were not observed during the study. In patients with chronic Prinzmetal's variant angina without myocardial infarction, stenosis progression was not frequently observed at spastic sites despite the recurrence of focal coronary spasm over relatively long periods of time.