Differential Incidence and Morphology of Spasm According to Coronary Arterial Location by Intracoronary Ergonovine Spasm Provocation Testing.

BACKGROUND: We reported less provoked spasm in the left circumflex artery (LCX) by acetylcholine testing compared with the left anterior descending artery (LAD) and right coronary artery (RCA), so we investigated the clinical characteristics of provoked spasm in the LCX by ergonovine (ER) testing.Methods and 
Results: We retrospectively analyzed 1,185 consecutive cases of intracoronary ER testing during 25 years. Maximal ER dose was 64 μg into the left coronary artery (LCA) and 40 μg into the RCA. Positive spasm was defined as a transient ≥90% narrowing and usual chest symptoms or ischemic ECG changes. Positive provoked spasm was recognized in 347 patients (29.3%), including 207 RCA spasms, 166 LAD spasms, and 79 LCX spasms. Spasm was provoked in the LCX significantly less than in the other vessels (P<0.001). LCX-provoked spasm was obtained in 79 patients consisting of 16 patients (20.3%) with triple-vessel spasm, 38 patients (48.1%) with double-vessel spasm and 25 patients (31.6%) with single-vessel spasm. Less than 70% patients with LCX-provoked spasm had multiple spasms, whereas approximately 60% patients had single-vessel spasm in the RCA (64.3%) or LAD (59.6%). In 25 patients with LCX single-vessel spasm, 18 patients (72.0%) had a focal spasm.
CONCLUSIONS: Under maximal ER dose of 64 μg into the LCA, LCX-provoked spasm occurred significantly less than spasm in the other vessels and less than 70% patients had multiple spasms.