Exercise haemodynamic variables rather than ventilatory efficiency indexes contribute to risk assessment in chronic heart failure patients treated with carvedilol

Abstract

To evaluate the prognostic significance of traditional cardiopulmonary exercise testing (CPET) parameters in chronic heart failure (CHF) patients treated with beta-blockers. A total of 631 CHF patients were followed for cardiovascular death over 3.8 +/- 1.4 years; among them 79 (13%) died. All prognostic CPET parameters were related to outcome at univariate analysis, with haemodynamic-derived parameters [peak systolic blood pressure (SBP), peak circulatory power (CP) = peak oxygen consumption (pVO2) x peak SBP] and exertional oscillatory ventilation (EOV) reaching the highest chi2 (46.5, 40.9, and 22.6, respectively, all with P < 0.0001). Exertional oscillatory ventilation, although associated with high mortality rate (43 vs. 11%, P < 0.001), was detected in 42 (7%) patients. In non-EOV, again both peak SBP and peak CP reached the highest chi2 (30.6, and 21.6, respectively, all with P < 0.0001). Regarding CPET parameters, at multivariable analysis, peak SBP was the strongest risk index both in total and non-EOV populations, with 11% risk reduction every 5 mmHg increase. All traditional CPET risk parameters were informative in beta-blockers CHF patients, but peak SBP, peak CP, and EOV were the most predictive. In this low-risk population, EOV, although underrepresented, considerably enhanced risk stratification, although other ventilatory efficiency indexes provided less impressive predictive content. In large majority of non-EOV patients, peak SBP improved risk evaluation beyond other CPET parameters.