Antiplatelet Therapy in Myocardial Bridge Insights From the RIALTO Registry summary

Myocardial bridge (MB) is a common congenital coronary anomaly where a coronary artery tunnels through the myocardium, causing systolic compression. This PACUPod overview examines whether single antiplatelet therapy (APT), such as aspirin, provides ischemic protection for MB patients without other indications, and how the RIALTO registry informs clinical practice. The ambispective study analyzed 221 MB patients after excluding those with established APT or anticoagulation indications, comparing mostly aspirin at discharge versus no APT over a median follow-up of 4.5 years. The primary outcome, net adverse clinical events (NACE), combined cardiovascular death, nonfatal MI, need for coronary imaging, ischemic stroke, and bleeding events. After adjustment for confounders and propensity-matching, single APT was associated with a higher NACE rate (adjusted HR 6.2, p=0.03), chiefly driven by increased minor bleeding (adjusted HR 10.58, p=0.02), with no significant reduction in ischemic events. The findings align with 2019 ACC/AHA primary prevention guidance that cautions aspirin use in the absence of established disease and challenge routine APT in MB patients. The episode discusses MB pathophysiology—ischemia largely results from mechanical compression rather than plaque rupture—and explores management implications, including prioritizing personalized risk assessment, shared decision-making, and careful medication review. Alternatives such as beta-blockers and calcium channel blockers, as well as selective surgical or stenting options for refractory cases, are considered. The role of diagnostic and functional testing (IVUS, OCT, stress imaging) in guiding therapy and avoiding unnecessary APT is highlighted, along with study limitations (observational design, residual confounding) and the need for randomized trials. Related research (e.g., ADAPTT 2023) and the broader context of coronary anomalies are discussed to emphasize individualized care rather than reflexive antiplatelet use.