Exercise Duration and Peak Systolic Blood Pressure Are Predictive of Mortality in Ambulatory Patients with Mild-Moderate Chronic Heart Failure

Abstract

Background and Aims: It is a prevailing concept in chronic heart failure (CHF) that ventricular remodelling (evaluated via imaging) and neurohormonal activation (via biomarkers) exert major influences, such that the need to subject patients to haemodynamic evaluations and exercise testing has been questioned. We sought to investigate whether exercise and haemodynamic parameters lack independent prognostic value in a cohort of unselected ambulatory patients with mild-moderate CHF. Methods: Eighty-five consecutive patients with stable CHF in New York Heart Association functional classes I–IV, aged 55 ± 12 years, 84% males, left ventricular ejection fraction (LVEF) 37 ± 15%, participated in this study. Survivors were followed for a median of 5.08 years. All subjects underwent cardiopulmonary exercise testing to measure standard parameters including peak oxygen consumption, exercise duration and blood pressure. A sample of venous blood was taken to determine the N-terminal pro-brain natriuretic peptide (N-BNP) level. Echocardiography was performed at rest to measure LVEF. Predictors of mortality were sought using the Cox proportional hazards model. Results: All-cause mortality was 19% (16 deaths, 95% CI 11–29%). Age and LVEF did not independently predict mortality. Although various parameters including New York Heart Association class, peak oxygen consumption and N-BNP level were all predictive of outcome on univariate analysis, multivariate analysis identified reduced exercise duration and peak systolic blood pressure (SBP) to be the only independent predictors of all-cause mortality. Hazard ratios of 0.78 (95% CI 0.65–0.93, p = 0.007) and 0.79 (95% CI 0.66–0.95, p = 0.01) were associated with an increase in exercise duration of 1 min and 10 mm Hg peak SBP, respectively. Conclusions: Two simple parameters (exercise duration and peak SBP) that are easily measured by standard exercise testing are the strongest independent predictors of mortality which outperform LVEF and N-BNP in ambulatory patients with mild-moderate CHF.