Epicardial adipose tissue differentiates in patients with and without coronary microvascular dysfunction.

BACKGROUND/OBJECTIVES: Coronary microvascular dysfunction (CMD) is a common disorder, leading to symptoms similar to obstructive coronary artery disease and bears important prognostic implications. Local inflammation is suggested to promote development of CMD. Epicardial adipose tissue (EAT) is a local visceral fat depot surrounding the heart and the coronary arteries, modifying the inflammatory environment of the heart. We compared EAT in patients with and without CMD. METHODS: We retrospectively included consecutive patients undergoing diagnostic coronary angiography as well as transthoracic echocardiography between March and October 2016. EAT thickness was defined as space between the epicardial wall of the myocardium and the visceral layer of the pericardium and EAT index was calculated as EAT thickness/body surface area. Logistic regression analysis was used to determine the association of EAT index with the presence of CMD. RESULTS: Overall, 399 patients (mean age 60.2 ± 14.0 years, 46% male) were included. EAT thickness was significantly higher in patients with CMD compared to patients without CMD (EAT thickness 4.4 ± 1.8 vs. 4.9 ± 2.4 mm, p = 0,048 for patients without and with CMD, respectively). In univariate regression analysis, EAT index was associated with a 30% higher frequency of CMD (odds ratio [95% confidence interval]: 1.30 [1.001-1.69], p = 0.049). Effect sizes remained stable upon adjustment for body mass index (BMI, 1.30 [1.003-1.70], p = 0.048), but were attenuated when ancillary adjusting for age and gender (1.17 [0.90-1.54, p = 0.25). The effect was more pronounced in patients >65 years of age and independent of BMI and sex (1.85 [1.14-3.00], p = 0.013). CONCLUSION: EAT thickness is independently associated with CMD and can differentiate between patients with and without CMD especially in older age groups. Our results support the hypothesis that modulation of local inflammation by epicardial fat is involved in the development of CMD.

Association of echocardiographic measures of left ventricular diastolic dysfunction and hypertrophy with presence of coronary microvascular dysfunction.

BACKGROUND: Coronary microvascular dysfunction (CMD) is a common disorder, leading to symptoms similar to obstructive coronary artery disease. We aimed to determine whether measures of left ventricular (LV) diastolic function and hypertrophy may predict presence of CMD. METHODS: We retrospectively included patients undergoing diagnostic coronary angiography and transthoracic echocardiography, excluding patients with obstructive coronary artery disease, previous revascularization therapy, moderate or severe mitral valve disease, or atrial fibrillation. The following markers of LV diastolic function and hypertrophy were assessed: E- and A-wave velocity, E-wave deceleration time, E/A- and E/E'-ratio, left atrial area, left LV mass index, LV ejection time (LVET) and mitral valve closure to opening time. Logistic regression analysis was used to determine the association of echocardiographic parameters with presence of CMD. RESULTS: From 378 patients (mean age ± SD 59.7 ± 13.6 years, 45.6% male) included, the majority had CMD (n = 293, 77.5%). Patients with CMD were older (60.5 ± 13.4 years vs. 56.9 ± 14.3 years, p = 0.03), were less frequent male (42.3% vs. 57.0%, p = 0.02), and had higher systolic blood pressure (137.9 ± 25.7 mmHg vs. 124.7 ± 25.6 mmHg, p < 0.0001). LVET was significantly associated with CMD (1.42 [1.02-1.96], p = 0.04), while a non-statistically significant link was observed for A-wave velocity and E/E'-ratio (1.39 [0.96-2.00], p = 0.08 and 1.40 [0.92-2.13], p = 0.1, respectively). For all other echocardiography-derived measures, odds ratio for the association with CMD was <1.3 per each SD increase. CONCLUSIONS: In this cross-sectional single-center cohort study, CMD was a frequent finding in patients undergoing coronary angiography for suspected obstructive coronary artery disease. LVET from transthoracic echocardiography is associated with the presence of CMD.