Unavoidable Stent Extension Into the Bridged Segment During Percutaneous Coronary Intervention for Myocardial Bridging: A Focused Review of Mechanisms, Pitfalls, and Treatment Strategies

Myocardial bridging (MB) is usually managed medically, and percutaneous coronary intervention (PCI) is generally avoided for isolated bridging. In clinical practice, however, stent extension into a bridged segment may be difficult to avoid when proximal left anterior descending (LAD) disease reaches the bridge entrance, LAD chronic total occlusion obscures distal bridge involvement, diffuse disease leaves no bridge-free landing region, or bailout coverage is required for edge dissection or procedural instability. Once implanted within the bridge, a stent is exposed to repetitive extrinsic compression, caliber mismatch, dynamic deformation, and abnormal local shear, creating a substrate for restenosis, deformation, fracture, perforation, and target lesion failure. This focused review addresses unavoidable bridged-segment stenting as a distinct PCI scenario rather than as a general review of myocardial bridging. We summarize lesion-bridge patterns, anatomic and physiologic mechanisms, the role of coronary computed tomography angiography (CCTA), intravascular ultrasound (IVUS)/optical coherence tomography (OCT), and invasive physiology in procedural planning, and practical strategies to minimize metal burden and optimize stent-edge placement. We also examine drug-coated balloons, surgical unroofing, coronary artery bypass grafting (CABG) in selected anatomy, and emerging bioadaptor technology, while explicitly distinguishing established clinical evidence from limited observational data and hypothesis-generating concepts.