Distinguishing between ischemic and non-ischemic dilated cardiomyopathy based on non-invasive ultrasonic evaluation of peripheral arteries

Abstract

Background Recently, high-frequency transducers have been introduced in echocardiography laboratories to non-invasively evaluate peripheral arteries. Our aim was to assess the usefulness of these non-invasive vascular ultrasonic techniques in differentiating between ischemic and non-ischemic dilated cardiomyopathy. Methods Forty patients with dilated cardiomyopathy of uncertain origin who underwent echocardiographic examination were studied. In all patients, carotid, femoral, and brachial arteries were scanned using high-frequency transducers in order to detect atherosclerotic plaques and to measure intima-media wall thickness. Also, flow-mediated vasodilation was measured at the brachial artery. Results Of the 40 patients studied, 24 (60%) had significant coronary lesions. In patients with ischemic cardiomyopathy, carotid plaques were found more frequently (79% vs. 25%, p=0.001), and intima-media wall thickness was higher in carotid (1.14±0.23 vs. 0.84±0.20 mm, <0.001), femoral (1.21±0.15 vs. 0.90±0.17 mm, p<0.001), and brachial (0.85±0.11 vs. 0.68±0.12, p<0.001) arteries. Carotid intima-media thickness of 1 mm or more was 83% sensitive and 69% specific for the diagnosis of ischemic cardiomyopathy. The highest diagnostic accuracy for any isolated vascular finding was obtained for femoral intima-media thickness greater than 1.1 mm (83% sensitivity, 88% specificity) and for brachial intima-media thickness greater than 0.7 mm (88% sensitivity and 81% specificity). The highest sensitivity (92%) was obtained for the presence of 1 or more vascular findings, and the highest specificity (94%) for 3 or more vascular findings. Conclusion Non-invasive assessment of peripheral arteries is of help in differentiating between ischemic and non-ischemic dilated cardiomyopathy. These ultrasonic techniques should be considered as complementary examinations in the evaluation of patients with dilated cardiomyopathy in echocardiography laboratories.