Cardiac index predicts long-term outcomes in patients with heart failure

BACKGROUND: The role of cardiac index (CI) and right atrial pressure (RAP) for predicting long-term outcomes of heart failure has not been well established. The aim of this study was to investigate long-term cardiac outcomes in patients with heart failure having various combinations of CI and RAP. METHODS: A total of 787 heart failure patients who underwent right-heart catheterization were retrospectively categorized into the following four groups: Preserved CI (≥2.5 L/min/m(2)) and Low RAP (<8 mmHg) (PRE-CI/L-RAP; n = 285); Preserved CI (≥2.5 L/min/m(2)) and High RAP (≥8 mmHg) (PRE-CI/H-RAP; n = 242); Reduced CI (<2.5 L/min/m(2)) and Low RAP (<8 mmHg) (RED-CI/L-RAP; n = 123); and Reduced CI (<2.5 L/min/m(2)) and High RAP (≥8 mmHg) (RED-CI/H-RAP; n = 137). Survival analysis was applied to investigate which groups were associated with major adverse cardiovascular events (MACE). RESULTS: The RED-CI/L-RAP and RED-CI/H-RAP groups were significantly associated with MACE as compared with the PRE-CI/L-RAP and PRE-CI/H-RAP groups after adjustment for confounding factors (RED-CI/L-RAP vs. PRE-CI/L-RAP: HR 2.11 [95% CI 1.33–3.37], p = 0.002; RED-CI/H-RAP vs. PRE-CI/L-RAP: HR 2.18 [95% CI 1.37–3.49], p = 0.001; RED-CI/L-RAP vs. PRE-CI/H-RAP: HR 1.86 [95% CI 1.16–3.00], p = 0.01; RED-CI/H-RAP vs. PRE-CI/H-RAP: HR 1.92 [95% CI 1.26–2.92], p = 0.002), whereas the difference between the RED-CI/H-RAP and RED-CI/L-RAP groups was not significant (HR 1.03 [95% CI 0.64–1.66], p = 0.89). CONCLUSIONS: The hemodynamic severity categorized by CI and RAP levels provided clear risk stratification in patients with symptomatic heart failure. Low CI was an independent predictor of long-term cardiac outcomes.