Between rib and heart: extrinsic coronary artery compression in dilated cardiomyopathy

A 51-year-old woman with dilated cardiomyopathy and cardiac resynchronization therapy presented with exertional chest pain and progressive dyspnoea. Coronary computed tomography angiography demonstrated near-occlusion of the distal left anterior descending artery caused by extrinsic compression between the sixth costal arch and the enlarged left ventricle (asterisk in Panels A and B). Supplementary data online, Videos S1 and S2, respectively, demonstrate an axial stack scroll and a curved multi-planar reconstruction centerline rotation of the left anterior descending artery. Invasive coronary angiography confirmed significant luminal narrowing of the distal segment (arrowhead in Panel C). Medical therapy was optimized with the aim of reducing left ventricular dimensions. Given the subsequent improvement in symptoms, no invasive intervention on the coronary artery was performed. Extrinsic compression of the coronary arteries is uncommon and most frequently results from myocardial bridging, pulmonary trunk dilatation, or anomalous coronary origin. Compression of a coronary artery between the rib cage and the heart is exceedingly rare, with only a few cases reported to date, most occurring in the setting of marked cardiac enlargement. Although coronary catheterization refined the severity of luminal narrowing, computed tomography angiography was essential for elucidating the underlying mechanism, demonstrating extrinsic rib compression rather than intrinsic atherosclerotic disease as the cause of coronary narrowing.