Contrast Stress Echocardiography Findings in Myocardial Bridging Compared to Normal Coronary Course, With and Without Coronary Artery Disease

Myocardial bridging (MB) correlation with ischemia remains a diagnostic challenge. There is a lack of studies that have assessed MB using contrast stress echo and compared the findings with those in patients demonstrating a normal coronary course, with or without obstructive coronary artery disease (CAD).We evaluated all consecutive patients who underwent contrast stress echocardiography and coronary computed tomography angiography (CCTA) due to suspected symptoms of CAD within 3 months in Parma Hospital. Coronary computed tomography angiography served as the reference standard for detecting MB and obstructive CAD. The patients were divided into 3 groups: (1) MB and no evidence of obstructive CAD (MB group, N = 64), (2) no evidence of obstructive CAD or MB (NoCAD group, N = 135), (3) obstructive CAD without MB (CAD group, N = 68).The coronary flow velocity reserve in the LAD (CFVR-LAD) was reduced in the MB and CAD groups, measuring 1.91 ± 0.21 and 1.82 ± 0.28, respectively, whereas it was 2.27 ± 0.34 in the NoCAD group (P < .001). The MB and CAD groups exhibited a higher prevalence of reversible myocardial perfusion defects (rMPDs) compared to the NoCAD group (57.8% vs 64.7% vs 3.7%, P < .001). Reversible wall motion abnormalities were frequently observed in the CAD group and rarely found in the MB and NoCAD groups (47.1% vs 18.8% vs 4.4%, P < .001). In multivariable analyses, the presence of MB was independently associated with reduced CFVR-LAD (odds ratio = 14.55; 95% CI, 6.84-30.93; P < .001) and the presence of rMPD (odds ratio = 37.96; 95% CI, 13.49-106.84; P < .001). Patients with deep MB (>2 mm depth) and very deep MB (≥5 mm depth) exhibited significantly greater CFVR-LAD reduction and rMPD than those with superficial MB.Myocardial bridging is capable of inducing rMPD and reducing CFVR-LAD similar to obstructive CAD. The depth of the MB correlates with the abnormalities found in the stress echo evaluation. Contrast stress echo may serve as a valuable noninvasive tool for evaluating patients with MB.