Relationship between the coronary diameter and occurrence of vasospastic angina in patients with normal coronary arteries.

Coronary artery diameters were measured after various interventions in 30 patients without angina pectoris (group 1) and in 15 with angina pectoris (group 2: rest, or rest and effort angina) who had normal coronary arteries. The coronary artery diameters were significantly smaller in many coronary segments in group 2 than in group 1 during a control state, after exercise and ergonovine, but became nearly identical after isosorbide dinitrate in both groups. Patients in group 1 had diffuse narrowing but no focal vasoconstriction after ergonovine and all the segments had a diameter of more than 50% of that after isosorbide dinitrate. The change of coronary artery diameter in group 2 patients who had no vasospasm by ergonovine was the same as that in group 1. Patients in whom vasospastic angina was induced had local vasoconstriction or severe diffuse narrowing (less than 45%). These results indicate that angina pectoris patients with normal coronary arteries had an acceleration of coronary arterial basal tone, but vasospastic angina pectoris was not induced just by the general response of the coronary artery to various interventions in addition to the accentuated basal tone. For vasospastic angina to occur, local abnormal response to various interventions must be present.