Predictive Value of Cardiopulmonary Exercise Testing Parameters in Ambulatory Advanced Heart Failure.

Objectives: This study sought to determine cardiopulmonary exercise (CPX) predictors of the combined outcome of durable mechanical circulatory support (MCS), transplantation, or death at 1 year among patients with ambulatory advanced heart failure (HF).

Background: Optimal CPX predictors of outcomes in contemporary ambulatory advanced HF patients are unclear.

Methods: REVIVAL (Registry Evaluation of Vital Information for ventricular assist devices [VADs] in Ambulatory Life) enrolled 400 systolic HF patients, INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) profiles 4-7. CPX was performed by 273 subjects 2 ± 1 months after study enrollment. Discriminative power of maximal (peak oxygen consumption [peak VO]; VO pulse, circulatory power [CP]; peak systolic blood pressure • peak VO], peak end-tidal pressure CO [PEtCO], and peak Borg scale score) and submaximal CPX parameters (ventilatory efficiency [VE/VCO slope]; VO at anaerobic threshold [VOAT]; and oxygen uptake efficiency slope [OUES]) to predict the composite outcome were assessed by univariate and multivariate Cox regression and Harrell's concordance statistic.

Results: At 1 year, there were 39 events (6 transplants, 15 deaths, 18 MCS implantations). Peak VO, VOAT, OUES, peak PEtCO, and CP were higher in the no-event group (all p < 0.001), whereas VE/VCO slope was lower (p < 0.0001); respiratory exchange ratio was not different. CP (hazard ratio [HR]: 0.89; p = 0.001), VE/VCO slope (HR: 1.05; p = 0.001), and peak Borg scale score (HR: 1.20; p = 0.005) were significant predictors on multivariate analysis (model C-statistic: 0.80).

Conclusions: Among patients with ambulatory advanced HF, the strongest maximal and submaximal CPX predictor of MCS implantation, transplantation, or death at 1 year were CP and VE/VCO respectively. The patient-reported measure of exercise effort (Borg scale score) contributed substantially to the prediction of outcomes, a surprising and novel finding that warrants further investigation. (Registry Evaluation of Vital Information for VADs in Ambulatory Life [REVIVAL]; NCT01369407).