Abstract 16186: Intravascular Ultrasound-guided Surgical Unroofing in Symptomatic Patients With Myocardial Bridging of the Left Anterior Descending Artery

Abstract

Introduction: Myocardial bridging (MB) has been shown to cause significant clinical symptoms or adverse cardiac events in patients with no obstructive coronary artery disease. In contrast to medical therapy or stent placement with controversial efficacy, surgical unroofing (supra-arterial myotomy) of MB is considered to directly address the pathology with durable normalization of the altered hemodynamics. In this context, preoperative IVUS assessment can provide a precise map of the MB to guide the unroofing procedure, but it remains unclear if any IVUS parameter is related to the efficacy of this treatment. Methods: We evaluated 94 consecutive patients who underwent MB unroofing with serial (preoperative and 6-month follow-up) angina assessments using the Seattle Angina Questionnaire (SAQ). The primary outcome was the SAQ summary score, obtained by averaging the scores of physical limitation, angina frequency, and quality of life. Preoperative IVUS determined total MB length, halo thickness, arterial compression rate, maximal plaque burden upstream of MB, and septal branches originating in the tunneled LAD segment. Results: In all cases, preoperative IVUS successfully offered a geographic MB map with quantitative characteristics: MB length = 27.5 (20.2 to 40.3) mm, halo thickness = 0.54 (0.41 to 0.75) mm, arterial compression rate = 34 (26 to 43)%, and plaque burden = 34 (20 to 46)% [median (range) for all]. MB unroofing resulted in significant symptomatic improvements across all scales of SAQ (p<0.001 for all) as well as the SAQ summary score (Figure), without any death or major complications. No significant correlation was observed between the preoperative IVUS parameters and the change in SAQ summary score after the surgery. Conclusions: IVUS-guided surgical unroofing safely and effectively achieved significant symptomatic improvements in patients with MB, regardless of the morphologic or morphometric MB characteristics assessed by preoperative IVUS.