Regional coronary artery dilation response in variant angina.

We examined segmental left coronary artery responses to nitroglycerin in 17 variant angina patients and in 34 nonvariant angina patients using a quantitative angiography technique. In those patients with left anterior descending vasospasm, there was a marked exaggeration in the degree of dilation to nitroglycerin in those segments which at other times were involved with spasm. This observation was consistent when these segments were compared to (1) other left coronary segments in the same patient, (2) the same left coronary segments in nonvariant angina patients, and (3) the same left coronary segments in patients with right coronary spasm. These data suggest that a localized disorder in coronary vasomotion is present in patients with coronary spasm that is not limited to constriction but also involves increased dilation in response to nitroglycerin.