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Updated: May 25, 2025
Intracoronary Acetylcholine Provocation Testing for Assessment of Coronary Vasomotor Disorders
Published on: August 18, 2016
Should the Right Coronary Artery Be Routinely Assessed During Provocative Spasm Testing?
Olivia Girolamo1,2, Rosanna Tavella1,2,3, David Di Fiore4
1Adelaide Medical School, University of Adelaide, Adelaide, SA 5005, Australia.
Insights
Routine assessment of the right coronary artery (RCA) for coronary artery spasm (CAS) is crucial. Evaluating only the left coronary artery (LCA) may miss up to one-third of CAS cases, highlighting the importance of multivessel testing.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Interventional Cardiology
Background:
- Coronary artery spasm (CAS) diagnosis often relies on invasive provocation testing using acetylcholine (ACh).
- Current protocols typically assess the left coronary artery (LCA) but often omit the right coronary artery (RCA) due to procedural complexity.
- This study investigates the prevalence of inducible CAS in both LCA and RCA during multivessel testing.
Purpose of the Study:
- To compare the incidence of inducible CAS in the LCA versus the RCA.
- To determine the proportion of CAS cases missed by assessing only the LCA.
- To advocate for routine RCA assessment in CAS provocation testing.
Main Methods:
- Analysis of a multi-institutional ANOCA database including 316 patients with suspected CAS.
- Fifty patients underwent multivessel spasm provocation testing with intracoronary ACh (LCA: 25, 50, 100 μg; RCA: 25, 50 μg).
- CAS was defined as >90% epicardial coronary artery constriction on angiography.
Main Results:
- In 50 patients undergoing multivessel testing, 40% (20 patients) had inducible CAS.
- ACh induced CAS exclusively in the LCA in 45% of cases, exclusively in the RCA in 35%, and in both vessels in 20%.
- This indicates that 35% of multivessel CAS cases were confined to the RCA.
Conclusions:
- Routine assessment of the RCA during ACh provocation testing is essential for comprehensive CAS diagnosis.
- Excluding the RCA from spasm testing may lead to underdiagnosis, potentially missing up to one-third of CAS cases.
- Multivessel spasm provocation testing, including the RCA, improves diagnostic accuracy for coronary artery spasm.
Abstract:
Background/Objectives: The diagnosis of coronary artery spasm (CAS) frequently requires invasive provocation testing, typically utilising acetylcholine (ACh). Although the left coronary artery (LCA) is routinely assessed as a part of the testing protocol, assessment of the right coronary artery (RCA) is often avoided since it requires the insertion of a temporary pacing wire. We sought to compare the prevalence of inducible CAS in the LCA and RCA, among patients with CAS undergoing multivessel spasm provocation testing with ACh. Methods: A local multi-institutional ANOCA (angina and non-obstructive coronary arteries) database was analysed, which included 316 patients with angina and suspected CAS who underwent provocation testing (single vessel n = 266, multivessel n = 50) with incremental bolus doses of intracoronary ACh (25, 50, 100 μg in the LCA; 25, 50 μg in the RCA). CAS was defined as >90% constriction of the epicardial coronary artery as assessed visually on coronary angiography. Results: In the 50 patients (55 ± 10 years, 77% female) who underwent multivessel spasm provocation testing, CAS was induced in 20 patients (40%), with ACh provoking CAS only in the LCA system in 45%, only in the RCA system in 35%, and both LCA/RCA in 20%. Conclusions: These findings demonstrate that assessing only the LCA may miss up to one-third of CAS cases. Therefore, it is essential to routinely evaluate the RCA, particularly when no inducible spasm is detected in the LCA.
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