Masaru, O

Abstract Background Mild to moderate mitral regurgitation (MR) is a common finding in heart failure with preserved ejection fraction (HFpEF). MR is often considered to be an innocent bystander, yet little data is available regarding its implications. Aim Determine the pathophysiologic correlates of MR in HFpEF Methods We retrospectively studied 280 patients with invasively proven HFpEF. MR was absent (None or trivial) in 163 subjects (Non-MR-HFpEF), and present in 117 (MR-HFpEF; 78 mild and 39 moderate MR). 247 subjects also underwent invasive cardiopulmonary exercise testing. Results At rest, MR-HFpEF subjects displayed higher pulmonary artery pressures (PAP), PCWP, and pulmonary vascular resistance (PVR; Table). During exercise, PAP and PCWP were not significantly different among groups, but MR-HFpEF displayed reduced ability to enhance cardiac output (CO) in response to heightened metabolic demand (oxygen consumption, VO2; Figure). Baseline characteristics and haemodynamic characterization at baseline and peak exercise Baseline characteristics Non-MR-HFpEF (N=163) MR-HFpEF (N=117) p value Age 66±11 71±10 0.0002 Female (%) 56 69 0.02 AFib (%) 13 38 <0.0001 Nt proBNP 192 [66, 557] 870 [401, 2135] <0.0001 E/E' 12.3±5.5 15.6±7.2 0.0006 LVEF (%) 64±6 62±6 0.0001 RV fractional area change (%) 51±9 47±10 0.0001 Mean PA (mmHg) 25±7 28±9 0.001 Mean PCWP (mmHg) 15±5 17±6 0.0002 PVR (Woods) 2.0±1.1 2.5±1.4 0.015 CO (L/min) 5.5±1.6 4.8±1.3 0.12 Peak exercise hemodynamics Non-MR-HFpEF (N=152) MR-HFpEF (N=95) p value Mean PA (mmHg 45±10 46.5±10 0.07 Mean PCWP (mmHg) 32±6 31±6 0.6 PVR (Woods) 1.8±1.6 2.7±2.4 0.002 CO (L/min) 9.1±3 7.2±3 0.01 P value adjusted for age, gender and BMI. CO change in response to VO2 increase Conclusion The presence of even mild MR in HFpEF is associated with more adverse hemodynamics, greater pulmonary vascular dysfunction and impaired CO reserve with exercise. Further study is required to better understand the natural history and treatment for MR in HFpEF. Acknowledgement/Funding None