Clinical and Hemodynamic Correlates and Prognostic Value of VE/VCO2 Slope in Patients With Heart Failure With Preserved Ejection Fraction and Pulmonary Hypertension

Abstract Background Impaired exercise capacity is one of the hallmarks of heart failure with preserved ejection fraction (HFpEF), but the clinical and hemodynamic correlates and prognostic value of exercise testing in patients with HFpEF is unknown. Methods Patients with HFpEF (left ventricular ejection fraction [LVEF] ≥45%) and pulmonary hypertension underwent cardiopulmonary exercise test (CPX) to measure maximal (peak VO 2 ) and submaximal (ventilatory equivalent for carbon dioxide [VE/VCO 2 ] slope) exercise capacity. In addition, right heart catheterization was performed. Patients were grouped in tertiles based on the VE/VCO 2 slope. Univariate and multivariate regression analyses were performed. A Cox regression analysis was performed to determine the mortality during follow-up. Results We studied 88 patients: mean age 73 ± 9 years, 67% female, mean LVEF 58%, median N-terminal pro–B-type natriuretic peptide (NT-proBNP) 840 (interquartile range 411–1938) ng/L. Patients in the highest VE/VCO 2 tertile had the most severe HF, as reflected in higher New York Heart Association functional class and higher NT-proBNP plasma levels (all P 2 slope was independently associated with pulmonary vascular resistance (PVR). Cox regression analysis showed that increased VE/VCO 2 slope (but not peak VO 2 ) was independently associated with increased mortality. Conclusion Increased VE/VCO 2 slope was associated with more severe disease and higher PVR and was independently associated with increased mortality in patients with HFpEF.