Prognostic value of cardiopulmonary exercise testing in heart failure with preserved ejection fraction. The Henry Ford HospITal CardioPulmonary EXercise Testing (FIT-CPX) project

Background Although cardiopulmonary exercise (CPX) testing in patients with heart failure and reduced ejection fraction is well established, there are limited data on the value of CPX variables in patients with HF and preserved ejection fraction (HFpEF). We sought to determine the prognostic value of select CPX measures in patients with HFpEF. Methods This was a retrospective analysis of patients with HFpEF (ejection fraction ≥ 50%) who performed a CPX test between 1997 and 2010. Selected CPX variables included peak oxygen uptake (VO 2 ), percent predicted maximum oxygen uptake (ppMVO 2 ), minute ventilation to carbon dioxide production slope (V E /VCO 2 slope) and exercise oscillatory ventilation (EOV). Separate Cox regression analyses were performed to assess the relationship between each CPX variable and a composite outcome of all-cause mortality or cardiac transplant. Results We identified 173 HFpEF patients (45% women, 58% non-white, age 54 ± 14 years) with complete CPX data. During a median follow-up of 5.2 years, there were 42 deaths and 5 cardiac transplants. The 1-, 3-, and 5-year cumulative event-free survival was 96%, 90%, and 82%, respectively. Based on the Wald statistic from the Cox regression analyses adjusted for age, sex, and β-blockade therapy, ppMVO 2 was the strongest predictor of the end point (Wald χ 2 = 15.0, hazard ratio per 10%, P 2 (Wald χ 2 = 11.8, P = .001). V E /VCO 2 slope (Wald χ 2 = 0.4, P = .54) and EOV (Wald χ 2 = 0.15, P = .70) had no significant association to the composite outcome. Conclusion These data support the prognostic utility of peak VO 2 and ppMVO 2 in patients with HFpEF. Additional studies are needed to define optimal cut points to identify low- and high-risk patients.