Maximal acetylcholine dose of 200 μg into the left coronary artery as a spasm provocation test: comparison with 100 μg of acetylcholine.

As a spasm provocation test of acetylcholine (ACH), incremental dose up (20/50/100 μg) into the left coronary artery (LCA) is recommended in the guidelines established by Japanese Circulation Society. Recently, Ong et al. reported the ACOVA study which maximal ACH dose was 200 μg in the LCA. We compared the angiographic findings between ACH 100 μg and ACH 200 μg in the LCA and also examined the usefulness and safety of ACH 200 μg in Japanese patients without variant angina. As a spasm provocation test, we performed intracoronary injection of ACH 200 μg after ACH 100 μg in 88 patients (55 males, 68.4 ± 11.7 years old) including 59 ischemic heart disease (IHD) patients and 29 non-IHD patients. Positive spasm was defined as >99 % transient stenosis (focal spasm) or 90 % severe diffuse vasoconstriction (diffuse spasm). Positive spasm by ACH 200 μg was significantly higher than that by ACH 100 μg (36 pts: 40.9 % vs. 17 pts: 19.3 %, p < 0.01). Diffuse distal spasm on the left anterior descending artery was more recognized in ACH 200 μg than in ACH 100 μg (30.7 vs. 13.6 %, p < 0.01). In 29 rest angina patients, positive spasm by ACH 200 μg (19 pts) was significantly higher than that by ACH 100 μg (7 pts) (65.5 vs. 24.1 %, p < 0.01). No serious irreversible complications were found during ACH 200 μg. Administration of ACH 200 μg into the LCA was safe and useful. We may reexamine the maximal ACH dose into the LCA.