Measurement of the coronary flow velocity reserve in patients with non-alcoholic fatty liver disease

BACKGROUND/AIMS: Endothelial dysfunction is an early and reversible feature in the pathogenesis of atherosclerosis. Coronary flow velocity reserve is a noninvasive test showing endothelial function of epicardial coronary arteries and coronary microcirculatory function. This study was designed to evaluate the carotid intima-media thickness and myocardial microvascular circulation in patients with non-alcoholic fatty liver disease. MATERIALS AND METHODS: Twenty-four patients with non-alcoholic fatty liver disease and 28 healthy subjects were studied. According to the pathology of liver biopsies, patients with non-alcoholic fatty liver disease were divided into non-alcoholic fatty liver and nonalcoholic steatohepatitis groups. Coronary diastolic peak flow velocities were measured at baseline, and then dipyridamole infusion was measured by transthoracic Doppler echocardiography. The ratio of hyperemic to baseline diastolic peak velocities was calculated and the intima-media thicknesss of the carotid arteries were measured. RESULTS: Baseline average diastolic peak and diastolic mean flow velocities were similar between non-alcoholic fatty liver disease patients and healthy subjects. However, hyperemic average diastolic peak and diastolic mean flow velocities were significantly lower in the patient groups compared to those in the controls (p=0.005 and p=0.002). Coronary flow velocity reserve was 1.65 ± 0.36 and 2.67 ± 0.81 in patients and healthy subjects, respectively (p < 0.001). The intima-media thickness was similar between the patients with non-alcoholic fatty liver disease and healthy subjects. The comparison of patients with non-alcoholic fatty liver and non-alcoholic steatohepatitis within the non-alcoholic fatty liver disease group with respect to coronary flow velocity reserve and intima-media thickness yielded no statistical differences. CONCLUSIONS: The present study showed that coronary flow velocity reserve, which establishes coronary microvascular and endothelial functions noninvasively, is significantly impaired in patients with non-alcoholic fatty liver disease. The impaired coronary flow velocity reserve-like early atherosclerotic changes may have value in the prediction of coronary artery disease in patients with non-alcoholic fatty liver disease.