Relationship between epicardial fat and coronary microvascular dysfunction

Background: Coronary microvascular dysfunction (CMVD) is often suggested in patients with typical chest pain and abnormal stress test results that are indicative of myocardial ischaemia, in whom coronary angiography fails to show fixed stenosis in epicardial coronary arteries. The efficacy of pharmacologic treatment on clinical outcome remains to be determined. Aim: To determine the relationship between CMVD and epicardial fat thickness (EFT). Methods: A case-controlled study was conducted on 124 patients, aged 40-91 years. A matched set of 62 symptomatic and 62 asymptomatic patients underwent an exercise electrocardiogram and transthoracic echocardiography. Coronary angiography was performed in patients with abnormal exercise test results. Patients without coronary artery disease were considered for the study. EFT was measured by transthoracic echocardiography in all patients. Results: EFT was significantly higher in patients with positive exercise test results (but normal epicardial coronary arteries) compared to patients with negative exercise test results (p < 0.001). Additionally, the HDL-cholesterol level was significantly lower in patients with positive exercise test results (but normal epicardial coronary arteries) compared to patients with negative exercise test results (p < 0.0001). Conclusions: Patients with increased EFT are at an increased risk for developing angina, recurrent hospitalisation and adverse outcomes, even with normal epicardial coronary arteries.