The interplay between myocardial bridging and coronary spasm in patients with myocardial infarction and non-obstructive coronary arteries: pathogenic and prognostic implications

Type of funding sources: None.

Myocardial bridging (MB) is associated with endothelial dysfunction and may represent a cause of angina in patients with non-obstructive coronary artery disease (NOCAD).

 Herein, we assessed the interplay between MB and coronary vasomotor disorders, evaluating also their prognostic relevance in patients with myocardial infarction and non-obstructive coronary arteries (MINOCA) or stable NOCAD.

We prospectively enrolled consecutive NOCAD patients undergoing intracoronary acetylcholine provocative test to assess the presence of epicardial or microvascular spasm in patients with suspected angina or MINOCA. Myocardial bridging was diagnosed by coronary angiography. The incidence of major adverse cardiac events (MACE), defined as the composite of cardiac death, non-fatal MI and rehospitalisation for unstable angina, was assessed at follow-up. We also assessed angina status using Seattle Angina Questionnaires (SAQ).

We enrolled 310 patients (mean age 60.6 ± 11.9; 136 [43.9%] men; 169 [54.5%] stable NOCAD and 141 [45.5%] MINOCA). MB was found in 53 (17.1%) patients. MB was an independent predictor of spasm and MINOCA (p < 0.05). At follow-up (median 22 months, interquartile range [13-32]), patients with MB had a higher rate of MACE and a lower SAQ score (all p < 0.001) compared with patients without MB. The rate of MACE was considerably higher in patients with both spasm and MB than in the remaining patients (12/42 [28.6%] vs. 13/268 [4.8%], p < 0.001).

Among patients with NOCAD coronary spasm associated with MB predicts a worse clinical presentation with MINOCA and a worse clinical outcome at medium-long term follow-up, thus identifying a high-risk subset of patients with MB with relevant therapeutic implications.

MB and clinical outcomes