CPX testing predicts mortality in heart failure with reduced EF

(HealthDay)—Variables measured during a cardiopulmonary exercise (CPX) test can predict and discriminate mortality in patients with heart failure with reduced ejection fraction (HFrEF), according to a study published in the Feb. 23 issue of the Journal of the American College of Cardiology.

Steven J. Keteyian, Ph.D., from the Henry Ford Hospital in Detroit, and colleagues report on the strength of the association among variables measured during a CPX test and all-cause mortality in patients with HFrEF. Ten CPX test variables were measured at baseline among 2,100 patients enrolled in the Heart Failure-A Controlled Trial Investigating Outcomes of Exercise Training.

The researchers identified 357 deaths over a median follow-up of 32 months. With the exception of respiratory exchange ratio, all CPX variables correlated with all-cause mortality (P < 0.0001). Percent predicted peak oxygen uptake (ppVo₂) and exercise duration were able to predict and discriminate mortality equally (c-index, 0.69). Among men and women, respectively, the strongest predictor of mortality was peak Vo₂ and exercise duration. Percent ppVo₂, exercise duration, and peak Vo₂ were similarly able to predict and discriminate mortality, in multivariable analyses. A 10 percent one-year mortality rate corresponded to peak Vo₂ of 10.9 ml/kg⁻¹/min⁻¹ in men versus 5.3 ml/kg⁻¹/min⁻¹ in women.

"Peak Vo₂, exercise duration, and percent ppVo₂ carried the strongest ability to predict and discriminate the likelihood of death in patients with HFrEF," the authors write. "The prognosis associated with a given peak Vo₂ differed by sex."

One author disclosed financial ties to Merck Research Laboratories.

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