Safety and Usefulness of Intracoronary Acetylcholine 200 μg Into the Left Coronary Artery as Vasoreactivity Testing: Comparisons With Intracoronary Acetylcholine Maximum 100 μg.

OBJECTIVES

We retrospectively analyzed the usefulness and safety of intracoronary acetylcholine (ACh) 200 μg into the left coronary artery (LCA) as vasoreactivity testing compared with intracoronary ACh 100 μg.

METHODS

We recruited 1433 patients who had angina-like chest pain and intracoronary ACh testing in the LCA, including 1234 patients with a maximum ACh 100 μg and 199 patients with a maximum ACh 200 μg. ACh was injected in incremental doses of 20/50/100/200 μg into the LCA. Positive spasm was defined as ≥ 90% stenosis, usual chest pain, and ischemic electrocardiogram (ECG) changes.

RESULTS

The incidence of coronary constriction ≥ 90%, usual chest pain, and ischemic ECG changes with a maximum ACh of 100 μg was markedly higher than that with a maximum ACh of 200 μg. The frequency of unusual chest pain in patients with a maximum ACh of 200 μg was higher than that in those with a maximum ACh of 100 μg (13% vs. 3%, p < 0.001). In patients with rest angina, positive spasm of maximum ACh 100 μg was significantly higher than that of maximum ACh 200 μg, whereas there was no difference regarding positive spasm in patients with atypical chest pain between the two ACh doses. Major complications (1.38% vs. 1.51%, p = 0.8565) and the occurrence of paroxysmal atrial fibrillation (1.81% vs. 2.63%, p = 0.6307) during ACh testing in the LCA were not different between the two maximum ACH doses.

CONCLUSIONS

Intracoronary ACh 200 μg into the LCA is clinically useful and safe for vasoreactivity testing when intracoronary ACh 100 μg dose not provoke spasms.