Interplay between myocardial bridging and coronary spasm in patients with myocardial ischemia and non-obstructive coronary arteries: Pathogenic and prognostic implications

BACKGROUND: Myocardial bridging (MB) may represent a cause of myocardial ischemia in patients with non-obstructive coronary artery disease (NOCAD). Herein, we assessed the interplay between MB and coronary vasomotor disorders, also evalu-ating their prognostic relevance in patients with myocardial infarction and non-obstructive coronary arteries (MINOCA) or stable NOCAD. METHODS AND RESULTS: We prospectively enrolled patients with NOCAD undergoing intracoronary acetylcholine provocative test. The incidence of major adverse cardiac events, defined as the composite of cardiac death, non-fatal myocardial infarc-tion, and rehospitalization for unstable angina, was assessed at follow-up. We also assessed angina status using Seattle Angina Questionnaires summary score. 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 and a positive acetylcholine test coexisted more frequently in patients with MINOCA versus stable NOCAD. MB was an independent predictor of positive acetylcholine test and MINOCA. At follow-up (median, 22 months; interquartile range, 13–32), patients with MB had a higher rate of major adverse cardiac events, mainly driven by a higher rate of hospitalization attributable to angina, and a lower Seattle Angina Questionnaires summary score (all P<0.001) compared with patients without MB. In particular, the group of patients with MB and a positive acetylcholine test had the worst prognosis. CONCLUSIONS: Among patients with NOCAD, coronary spasm associated with MB may predict a worse clinical presentation with MINOCA and a higher rate of hospitalization attributable to angina at long-term follow-up with a low rate of hard events.