Introduction: Coronary microvascular dysfunction (CMD) has been proposed as a pathophysiological mechanism in heart failure with preserved ejection fraction (HFpEF). Elevated left ventricular end-diastolic pressure (LVEDP) is often present in patients with CMD. Hypothesis: We hypothesized that CMD-mediated impairment in LV relaxation may contribute to elevated LVEDP. Methods: Women (n=253; age 53.6 ± 11.5) with signs and symptoms of ischemia and no obstructive coronary artery disease underwent invasive coronary functional testing (CFT) for measurement of resting LVEDP, coronary flow reserve to adenosine, change in coronary blood flow and coronary artery diameter to acetylcholine, and diameter change to nitroglycerin. A subset (n=208) had rest-stress CMR at mean 47 days from CFT. Two sample t-test, Fisher’s exact test and Spearman correlation were performed. Results: All women had normal LVEF and no significant valvular disease. Mean LVEDP was 14.4±5.0 mmHg, with 150 women (59%) having LVEDP >12 mmHg. Comorbidities and medications were similar between groups ( Table ). LVEDP correlated with body mass index (BMI) (r=0.324, p<0.001), systolic (r=0.176, p=0.01) and diastolic systemic blood pressure (r=0.13, p=0.059) at time of CFT, as well as with time to peak filling rate (r=0.13, p=0.050), a CMR measure of diastolic function. LVEDP did not relate to invasive CFT measures nor CMR myocardial perfusion reserve index. LVEDP also did not correlate with CMR measures of LV function or structure, adjusted for body-surface area. Conclusions: Among women with suspected CMD, elevated resting LVEDP is prevalent and associated with higher BMI and systemic blood pressure. There were no significant associations between LVEDP and measurements of CMD in this cross-sectional analysis. Further analyses are underway to evaluate whether raised LVEDP initially from hypertension and obesity may lead to CMD, myocardial ischemia, structural impairment and development of HFpEF.