Right Atrial Pressure Predicts Mortality Among LVAD Recipients: Analysis of the INTERMACS Database

Abstract

Risk stratifying candidates for left ventricular assist device (LVAD) is challenging. While INTERMACS profiles provide some prognostic insights, there is an ongoing search for better tools. We studied pre-LVAD haemodynamic parameters in predicting post-LVAD mortality. We analysed the INTERMACS dataset for the ability of right atrial pressure (RAP), pulmonary capillary wedge pressure (PCWP), pulmonary arterial systolic (PASP) and diastolic pressures (PADP), mean pulmonary artery pressure, transpulmonary gradient, cardiac output, cardiac power output and INTERMACS profiles, all recorded before LVAD implantation, to predict mortality. Among 18,733 patients in the INTERMACS dataset, we found that, RAP was the main significant haemodynamic predictor of mortality (13.1 vs. 14.4 mmHg in survivors and non-survivors, respectively, p<0.001), and a higher RAP also predicted the need for extra-corporeal membrane oxygenation (ECMO) support (p<0.001) and intra-aortic balloon pump (p<0.001). Right atrial pressure had a significantly higher area under the curve (AUC) in predicting mortality compared with PASP (difference between areas 0.0338, p<0.0001), PADP (difference between areas 0.0414, p<0.0001), PCWP (difference between areas 0.0290, p=0.0001) and pulmonary artery pulsatility index (difference between areas 0.0105, p=0.0052). Kaplan Meier survival curves showed that RAP≥13 mmHg was the optimal cut-off value to predict mortality (log-rank p<0.001). On Cox regression analysis, RAP remained an independent predictor of mortality (hazard ratio 1.008, 95% confidence interval 1.003-1.013, p=0.003) after covariate adjustment. According to time of death, a higher RAP remained a significant predictor of mortality at 1 month, 3 months, 6 months, 1 year, and beyond 1 year (all p<0.001). RAP remained a predictor for mortality within INTERMACS profiles. After excluding early deaths (first 3 months), the RAP remained a significant predictor of mortality, while INTERMACS profiles were no longer significant. In general, haemodynamic variables, as well as other criteria including INTERMACS profiles, are weak predictors of mortality. Right atrial pressure is the main consistent haemodynamic predictor of mortality in LVAD recipients. It outperforms other haemodynamic parameters, and keeps its value within each INTERMACS profile.