Prognostic Value of Capnography During Rest and Exercise in Patients With Heart Failure

Abstract

©2012 Wiley Periodicals Inc.

New variables obtained from cardiopulmonary exercise testing (CPX) have received attention in recent years, in particular the partial pressure of end-tidal carbon dioxide (P_ETCO₂). The purpose of this study was to therefore comprehensively assess the ability of resting and exercise P_ETCO₂ to predict major cardiac events in a heart failure (HF) cohort referred for CPX. A total of 963 patients with systolic HF undergoing symptom-limited CPX were included in the analysis. Resting and exercise P_ETCO₂ along with other CPX variables were determined, and patients were followed for major adverse events. With regard to resting measures, multivariate analysis revealed that left ventricular ejection fraction was the most robust prognostic marker (P<.001) while resting P_ETCO₂ added significant predictive value and was retained in the regression (P<.001). When exercise data were considered, the multivariate analysis revealed that the P_ETCO₂ apex during exercise added predictive value and was retained (P<.05). In what is the largest evaluation of P_ETCO₂ in the assessment of systolic HF patients to date, the authors substantiate prior (smaller) studies showing prognostic utility of P_ETCO₂, both as a resting measure (an important potential screening tool) and during exercise. These data add to the rationale to incorporate P_ETCO₂ as a routine monitoring component in HF management.