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.