Antiplatelet Therapy in Myocardial Bridge: Insights From the RIALTO Registry

Background: Myocardial bridge (MB) is a frequent coronary artery anomaly. The aims of this study are to describe the use of antiplatelet therapy (APT) in a cohort of patients with MB and assess its impact on ischemic and bleeding events. Methods: The RIALTO (Myocardial Bridge Evaluation Towards Personalized Medicine) registry (ID: NCT05111418) is an ambispective multicenter observational registry, enrolling patients with a clinical indication to coronary angiography and evidence of MB. The present analysis included patients with MB without any preexisting indication for APT/anticoagulant therapy according to guidelines. Patients were categorized into 2 groups: single APT or no APT based on discharge prescriptions. The primary end point was the time to first occurrence of net adverse clinical events, defined as a composite of cardiovascular death, nonfatal myocardial infarction, unplanned or elective coronary angiography, ischemic cerebrovascular events, and any bleeding. Results: Out of 486 enrolled patients with MB, 221 (mean age: 60 years, 66% male) were included in this analysis. One hundred and forty-one patients (64%) received single APT. At a median follow-up of 1661 days, patients with MB receiving single APT had a higher rate of net adverse clinical events (adjusted hazard ratio [aHR], 6.2; P=0.03), mainly driven by a higher rate of minor bleeding events (aHR, 10.58; P=0.02), with no difference regarding ischemic events. Results were consistent after 1:1 propensity-score matching sensitivity analyses. Conclusions: The prescription of single APT is common in patients with MB, and it seems to be associated with an increased risk of bleeding, in the absence of a beneficial effect on ischemic events.