Combining the ventilatory response to exercise and peak oxygen consumption is no better than peak oxygen consumption alone in predicting mortality in chronic heart failure

Background: A low peak oxygen uptake (pV O 2 ) and steep V E /V CO 2 slope are independently associated with a worse prognosis in patients with chronic heart failure (CHF). We wished to confirm whether combining these variables as a ratio would lead to a more accurate predictor of prognosis than using either alone. Methods: 388 CHF patients completed a treadmill‐based cardiopulmonary exercise test (CPET) to volitional exhaustion using a modified Bruce protocol. Results: 212 CHF patients completed the CPET with a peak RER ≥1.0. Of these, 48 patients died and one was transplanted during follow‐up. In surviving patients, the median follow‐up period was 42 months (IQR 34–49 months). The ratio V E /V CO 2 slope/pV O 2 was calculated for each individual and its ability to predict outcome compared with other variables. The Cox multivariable survival analysis showed that pV O 2 was the strongest independent predictor of mortality in CHF patients. Conclusion: Our study shows that the composite variable V E /V CO 2 slope/pV O 2 is a less effective prognosticator than pV O 2 alone in patients with CHF.