Ergonovine-Induced Alterations in Coronary Flow Velocity Preceding Onset of Occlusive Spasm in Patients Without Significant Coronary Artery Stenoses

Abstract

This study examined serial changes in coronary flow velocity to elucidate the dynamic change of coronary circulation during coronary spasm. Twenty patients with variant angina and 27 control patients were studied. Coronary flow velocity was monitored using a Doppler guidewire following intracoronary ergonovine administration. In the control group, diastolic flow velocity either did not change or increased slightly in response to ergonovine. However, in patients with variant angina, 2 patterns of flow velocity alterations were observed. In the first pattern, flow initially increased and then suddenly decreased (16 of 20 patients). In the second pattern, flow gradually decreased (3 of 20 patients). In the remaining patient, the coronary flow alteration could not be detected because of branch spasm. When abnormally high flow velocity was defined as a 100% increase in flow after ergonovine administration within 1 minute, and abnormally low flow velocity was defined as a 50% decrease in flow to diagnose variant angina, sensitivities of 35%, 75%, and 85% were noted if flow was measured 1.0, 2.0, and 3.0 minutes after ergonovine administration, respectively. These abnormal flow velocities were observed before ischemic ST changes appeared. In conclusion, in patients with variant angina, characteristic serial changes in coronary flow velocity occur before occlusive spasm. Variant angina may be diagnosed earlier by monitoring flow velocity rather than by monitoring for ischemic electrocardiographic changes.