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Myocardial bridging increases the risk of coronary spasm
Hiroki Teragawa1, Yukihiro Fukuda, Keiji Matsuda
1Department of Medicine and Molecular Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan. hteraga@hiroshima-u.ac.jp
Insights
Myocardial bridging (MB) increases the likelihood of coronary artery spasm. This study found that patients with MB experienced more frequent coronary spasms, suggesting MB is a risk factor for spasm-induced cardiac events.
Area of Science:
- Cardiology
- Vascular Medicine
- Cardiac Electrophysiology
Background:
- Myocardial bridging (MB) is linked to cardiac events, but its role in coronary artery spasm remains unclear.
- Investigating the association between MB and coronary spasm is crucial for understanding cardiac event etiology.
Purpose of the Study:
- To determine if patients with myocardial bridging have an increased likelihood of experiencing coronary artery spasm.
- To explore the relationship between MB and coronary spasm in patients presenting with chest pain.
Main Methods:
- A spasm-provocation test using acetylcholine was administered to 114 Japanese patients with chest pain.
- Myocardial bridging was identified by a >15% systolic diameter reduction in coronary arteries.
- Coronary spasm was confirmed by >50% diameter reduction and ST-segment changes.
Main Results:
- Myocardial bridging was present in 36% of patients, predominantly in the mid-left anterior descending artery.
- Patients with MB showed a significantly higher incidence of coronary spasm (73%) compared to those without MB (40%).
- MB was identified as an independent predictor of coronary spasm (OR: 3.478, p=0.0088).
Conclusions:
- Myocardial bridging is associated with an increased risk of coronary artery spasm.
- Coronary spasm may be a direct cause of cardiac events in patients with myocardial bridging.
Background:
Myocardial bridging (MB) has been associated with cardiac events. Whether coronary spasm is one factor contributing to those events is unknown.
Hypothesis:
This study investigated whether the likelihood of coronary spasm is increased in patients with MB.
Methods:
A spasm-provocation test was performed by infusing acetylcholine into the left coronary artery in 114 Japanese patients with chest pain. The test result was defined as positive when the diameter of the coronary artery was reduced by > or = 50% and ST-segment changes were documented. Myocardial bridging was defined as a > 15% reduction in coronary arterial diameter during systole after intracoronary injection of nitroglycerin.
Results:
Myocardial bridging was identified in 41 patients (36%) and was located in the mid-segment of the left anterior descending coronary artery (LAD) in all patients. Patients with MB experienced coronary spasm more frequently than patients without MB (MB+: 73%; MB-: 40%, p = 0.0006). Furthermore, among patients with a positive spasm-provocation test, coronary spasm occurred more frequently in the mid-segment of the LAD in patients with MB than in those without MB (MB+: 73%; MB-: 45%, p = 0.0259). Multivariate regression analysis demonstrated that MB was a predictor of coronary spasm (odds ratio: 3.478, p = 0.0088).
Conclusions:
These results suggest that MB increases the risk of coronary spasm and that coronary spasm may be the proximate etiology of cardiac events associated with MB.