Myocardial bridging is significantly associated to myocardial infarction with non-obstructive coronary arteries

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a common disorder characterized by the presence of clinical criteria for acute myocardial infarction in the absence of obstructive coronary artery disease on angiography. We aim to investigate the relationship between myocardial bridging (MB) and MINOCA.

An observational retrospective study was conducted on 15 036 patients who had been referred for coronary angiography and who fulfilled the Fourth Universal Definition of Myocardial Infarction. The study population was divided into ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) patients, from which we defined two main groups: the MINOCA group and the coronary artery disease (CAD) group. Statistical analyses were carried out by using SPSS, version 20. The prevalence of angiographic MB among the groups was significantly greater in the MINOCA group (2.9% vs. 0.8%). MINOCA accounted for 14.5% of spontaneous myocardial infarction, and the clinical presentation was more frequently NSTEMI rather than STEMI (84.3% vs. 15.7%). After adjusting for confounders, multivariate analyses showed a positive association between MB and MINOCA [odds ratio = 3.28, 95% CI (2.34; 4.61) P < 0.001]. Cardiovascular risk factors were less common in the MINOCA population, which was younger and more often female.

MB is a risk factor for MINOCA. Because MB prevalence differed significantly between the controls (CAD group) and cases (MINOCA group), which were positively associated to MB, it seems likely that MB would be a potential cause of MINOCA. Investigations for MB in MINOCA cases and especially in NSTEMI patients seem necessary.