Pulmonary function impairment, exercise intolerance, and clinical outcomes in symptomatic patients with HFpEF undergoing exercise stress echocardiography

Pulmonary function impairment is common in heart failure with preserved ejection fraction (HFpEF). However, its relationships with exercise capacity, cardiovascular reserve capacity, and prognosis in HFpEF remain uncertain. We retrospectively studied symptomatic patients undergoing exercise stress echocardiography with simultaneous expired gas analysis. Cross-sectional analyses were performed to compare pulmonary function in patients with HFpEF and symptomatic controls in the cohort with available data on percent predicted vital capacity (%VC) and forced expiratory volume in 1 s (%FEV₁). Outcome assessment was also performed in a subset of patients. Among 486 patients in the cross-sectional cohort, 178 had HFpEF and 308 were symptomatic controls. Patients with HFpEF had lower %VC and %FEV₁ than controls. After adjustment for age, sex, and body mass index, lower %VC and %FEV₁ were consistently associated with reduced exercise capacity, higher echocardiographic estimates of left ventricular filling pressure (E/e') and reduced right ventricular systolic function during exercise. Prognostic analyses were performed in the HFpEF cohort with follow-up data (N = 148). There were 37 primary composite events of all-cause death or worsening heart failure over a median follow-up of 935 days. Lower %VC was associated with a higher risk of the primary composite endpoint and remained associated in multivariable models. The %FEV₁ showed a weaker but concordant association. Lower %VC and %FEV₁ were associated with reduced exercise capacity and hemodynamic derangements in the overall cohort and with worse clinical outcomes in patients with HFpEF.