Abstract 11882: Exploring Abnormalities in Coronary Vascular Resistance Reserve as a Distinct Feature of The Hfpef Syndrome in Women

Introduction: Heart failure with preserved ejection fraction (HFpEF) is more common in women than men, but mechanisms underlying this female predominance are incompletely understood. Impaired systemic vasodilatory reserve and coronary microvascular dysfunction have been separately described as key abnormalities of HFpEF. However, the coronary vascular resistance reserve (CVRR), defined as the drop in coronary vascular resistance (CVR) from rest to peak stress, and its sex-specific nuances have not been explored in HFpEF. We sought to: (1) determine whether stress CVR differs between HFpEF and controls, and (2) assess sex differences in CVRR in HFpEF. Methods: We performed a cross-sectional study of 32 HFpEF participants and 26 controls, all without obstructive epicardial coronary artery disease. HFpEF was defined according to ESC Guidelines. Dipyridamole stress 82 Rb positron emission tomography was performed, and rest and stress CVR was calculated by dividing mean arterial pressure by coronary flow at rest and stress. Multivariable linear regression assessed (1) the association of HFpEF with stress CVR; and (2) the association of female sex with CVRR in patients with and without HFpEF. Results: Mean age was 74±7 years, 67% were women and mean LVEF was 62±5%: no difference between HFpEF and controls (P>0.05 for each). Results of the multivariable models are summarized in the Image. HFpEF was independently associated with higher global left ventricular CVR at peak vasodilatory stress. In addition, women had lower global left ventricular CVRR as compared to men, and this was unique to women with HFpEF. Results were the same for coronary-specific CVR and CVRR (analyses not shown). Conclusions: To our knowledge, this is the first study to non-invasively explore CVR and CVRR in HFpEF. Our findings suggest increased stress CVR in HFpEF, with a distinct abnormality in CVRR in women with HFpEF. Abnormal CVRR in women may contribute to the female predominance of HFpEF.