Improved Prognostic Performance of Cardiac Power Output With Right Atrial Pressure: A Subanalysis of the ESCAPE Trial

Abstract

BackgroundThe initial derivation of cardiac power output (CPO) included the difference between mean arterial pressure (MAP) and right atrial pressure (RAP) in the numerator, before multiplying by cardiac output (CO). We hypothesized that the inclusion of RAP (CPO–RAP) would enhance the prognostic performance of this parameter in those with an elevated RAP. Methods and ResultsWe obtained patient-level data from the ESCAPE trial via the Biolincc database. Participants with full final hemodynamics were included in the analysis. The CPO–RAP was calculated as [(MAP – RAP) × CO)]/451 Watts (W), and the CPO was calculated as (MAP × CO)/451. The primary outcome was freedom from left ventricular assist device, heart transplant, or death at 6 months. Included participants (n = 157) were a median of 58 years of age (interquartile range [IQR] 49–67 years), 27% were women, and 59% had ischemic cardiomyopathy. The median CPO was 0.70 W (IQR 0.50–0.90 W), and the median CPO–RAP was 0.62 W (IQR 0.47-0.79 W). In univariable logistic regressions, the CPO was not associated with the primary outcome (odds ratio 0.32, 95% confidence interval 0.08–1.29, P = .11), but the CPO-RAP was (odds ratio 0.10, 95% confidence interval 0.02–0.54, P < .01). In Kaplan-Meier analyses, there were no significant difference in outcomes with CPO (76% vs 64%, P = .08), but for CPO–RAP, there were significant differences in outcomes (81% vs 63%, P = .01). When further delineating CPO–RAP by RAP above or below the median, there was no significant difference in the outcome for participants with a RAP 8 or less (94% vs 79%, P = .07), but a significant difference in participants with a RAP of more than 8 mm Hg (66% vs 45%, P < .05). ConclusionsThe inclusion of RAP resulted in a significant association with the primary outcome; CPO alone was not.