Abstract 17990: Ectopic Fat is Associated With Gender-specific Reductions in Left Ventricular Myocardial Perfusion Index During Dobutamine Stress

Abstract

Background: Obesity and visceral adiposity are increasingly recognized risk factors for cardiovascular disease. Visceral fat may reduce myocardial perfusion by impairing endothelial function. Accordingly, we evaluated the association of visceral fat and quantitative myocardial perfusion during peak dose dobutamine stress using MRI. Methods: We evaluated MRI myocardial perfusion index (MPI) in 59 individuals at risk for their first episode of symptomatic heart failure with a left ventricular (LV) ejection fraction >45% and no MRI evidence of previous myocardial infarction or inducible ischemia. MPI was calculated after the first pass of gadolinium (by dividing the upslope of the signal intensity over time curve of the mid LV septum by the upslope of the LV cavity blood curve) after dobutamine and atropine were administered to achieve 80% of the maximum predicted heart rate response for age. Pericardial, subcutaneous (SQ), intraabdominal (IA) and retroperitoneal (RP) fat volumes were quantified using validated MRI techniques. All analyses were blinded to participant identifiers. Pearson’s coefficients were determined and a p-value of < 0.05 was considered significant. Results: Participants averaged 66 ± 7 years in age; 34% were men, 27% African American, 43% diabetic, and 93% were hypertensive. Overall, pericardial, IA, and RP fat were negatively associated with MPI (Table). No fat depots were associated with reduced MPI in men. However pericardial (r=-0.57, p=0.02), IA (r=-0.34, p=0.04) and SQ fat (r=-0.42, p=0.01) were all negatively associated with MPI in women. Conclusions: Higher pericardial, IA and RP fat volumes are associated with reduced LV myocardial perfusion at peak dobutamine stress in women. These findings suggest visceral fat may contribute to abnormal microcirculatory coronary arterial perfusion syndromes, explaining why some women may exhibit more anginal symptoms despite typically lower grade coronary artery stenoses than men.