Safety of Provocative Testing With Intracoronary Acetylcholine

Jun 14, 2022
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Authors:
Takahashi T, Samuels BA, Li W, et al., on behalf of the Microvascular Network.
Citation:
Safety of Provocative Testing With Intracoronary Acetylcholine and Implications for Standard Protocols. J Am Coll Cardiol 2022;79:2367-2378.
Summary By:
Bina Ahmed, MD, FACC

Quick Takes

  • This important meta-analysis reports on safety of provocative testing using intracoronary acetylcholine. Overall rates of major complications were very low (pooled incidence, 0.5%).
  • No deaths were reported.
  • Findings from this study lay the groundwork for developing a standardized protocol for provocative testing to diagnose epicardial and microvascular spasm, and to assess endothelial function.

Study Questions:

What is the safety of provocative testing using intracoronary acetylcholine (ACh) and subgroup differences in procedural risks based on ethnicity, diagnostic criteria, and provocation protocols?

Methods:

PubMed and Embase were searched in November 2021 to identify original articles reporting procedural complications associated with intracoronary ACh administration. The primary outcome was the pooled estimate of the incidence of major complications including death, myocardial infarction, ventricular tachycardia/fibrillation, and shock.

Results:

A total of 16 studies with 12,585 patients were included in the meta-analysis. The overall pooled estimate of the incidence of major complications was 0.5% (95% confidence interval [CI], 0.0%-1.3%) without any reports of death. Exploratory subgroup analyses revealed that the pooled incidence of major complications was significantly higher in the studies that followed the contemporary diagnosis criteria for epicardial spasm defined as ≥90% diameter reduction (1.0%; 95% CI, 0.3%-2.0%) but significantly lower in Western populations (0.0%; 95% CI, 0.0%-0.45%). The rate of positive epicardial spasm and the incidence of major complications were similar between provocation protocols using the maximum ACh doses of 100 mg and 200 mg.

Conclusions:

Intracoronary ACh administration for the contemporary diagnosis of epicardial and microvascular spasm is a safe procedure. Moreover, excellent safety records are observed in Western populations primarily presenting with myocardial ischemia and/or infarction with nonobstructive coronary arteries. This study will help standardize ACh testing to improve clinical diagnosis and ensure procedural safety.

Perspective:

This important meta-analysis reports on safety of provocative testing using intracoronary ACh. Overall rates of complications were very low (pooled incidence, 0.5%). Importantly, no deaths were reported. Though there appeared to be a signal for increased complications in Asian populations, the results may be confounded by differences in protocol and indication for testing in those populations. Overall, findings from this study lay the groundwork for developing a standardized protocol for provocative testing when indicated.

Clinical Topics: Arrhythmias and Clinical EP, Stable Ischemic Heart Disease, SCD/Ventricular Arrhythmias, Chronic Angina

Keywords: Acetylcholine, Angina Pectoris, Cardiology Interventions, Coronary Vasospasm, Diagnostic Techniques and Procedures, Microvascular Angina, Myocardial Infarction, Myocardial Ischemia, Spasm, Tachycardia, Ventricular, Ventricular Fibrillation


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