Sex Differences in Heart Failure With Preserved Ejection Fraction Pathophysiology: A Detailed Invasive Hemodynamic and Echocardiographic Analysis.

OBJECTIVES: This study sought to identify sex differences in central and peripheral factors that contribute to the pathophysiology of heart failure with preserved ejection fraction (HFpEF) by using complementary invasive hemodynamic and echocardiographic approaches.

BACKGROUND: Women are overrepresented among patients with HFpEF, and there are established sex differences in myocardial structure and function. Exercise intolerance is a fundamental feature of HFpEF; however, sex differences in the physiological determinants of exercise capacity in HFpEF are yet to be established.

METHODS: Patients with exertional intolerance with confirmed HFpEF were included in this study. Evaluation of the subjects included resting and exercise hemodynamics, echocardiography, and mixed venous blood gas sampling.

RESULTS: A total of 161 subjects included 114 females (71%). Compared to males, females had a higher pulmonary capillary wedge pressure (PCWP) indexed to peak exercise workload (0.8 [0.5 to 1.2] mm Hg/W vs. 0.6 [0.4 to 1] mm Hg/W, respectively; p = 0.001) and lower systemic (1.1 [0.9 to 1.5] ml/mm Hg vs. 1 [0.7 to 1.2] ml/mm Hg, respectively; p = 0.019) and pulmonary (2.9 [2.2 to 4.2] ml/mm Hg vs. 2.4 [1.9 to 3] ml/mm Hg, respectively; p = 0.032) arterial compliance at exercise. Mixed venous blood gas analysis demonstrated a greater rise in lactate indexed to peak workload (0.05 [0.04 to 0.09] mmol/l/W vs. 0.04 [0.03 to 0.06] mmol/l/W, respectively; p = 0.007) in women compared to men. Women had higher mitral inflow velocity to diastolic mitral annular velocity at early filling (E/e') ratios at rest and peak exercise, along with a higher ejection fraction and smaller ventricular dimensions.

CONCLUSIONS: Women with HFpEF demonstrate poorer diastolic reserve with higher echocardiographic and invasive measurements of left ventricular filling pressures at exercise, accompanied by lower systemic and pulmonary arterial compliance and poorer peripheral oxygen kinetics.