Extrinsic Compression of the Left Anterior Descending Coronary Artery by Rib in a Patient With Progressive Left Ventricular Remodeling

A 78-year-old man with a history of dilated cardiomyopathy diagnosed 5 years previously was admitted to our clinic with accelerating chest pain and dyspnea. The initial ECG showed sinus tachycardia and left bundle-branch block. Laboratory tests revealed elevated levels of troponin T (0.409 ng/mL), creatinine kinase (218 U/L), and creatinine kinase-MB isoenzyme (9.8 μg/L). The peak level of creatinine kinase-MB isoenzyme was 41.9 μg/L. Transthoracic echocardiography revealed a more progressed left ventricular remodeling in comparison with an echocardiography conducted 2 years previously. Compared with the previous study, the end-diastolic dimension of the left ventricle (LV) was increased from 68 mm to 76 mm and the LV end-diastolic volume was increased from 199 mL to 331 mL. Previously, the LV showed global hypokinesia with decreased global LV systolic function (ejection fraction=30%). The present study showed worsened regional wall motion abnormality at the territories of the left anterior descending coronary artery (LAD) with aggravated LV dysfunction (ejection fraction=23%; online-only Data Supplement Movies I and II).Coronary angiography revealed an unusual obstruction of the distal LAD (Figure 1). In the course of distal LAD, a filling defect, evident as …