B54-09 The Systemic Congestion Index: Correlation With the Pulmonary Artery Pulsatility Index and Mortality in Critically Ill Patients

Abstract Rationale The pulmonary artery (PA) pulsatility index (PAPi), defined as the ratio of PA pulse pressure to right atrial pressure, is an invasive hemodynamic measure of right ventricular (RV) function associated with mortality in pulmonary hypertension and heart failure. The systemic congestion index (SCI), defined as the ratio between systemic pulse pressure and central venous pressure (CVP), has emerged as a less invasive method to measure right and left ventricular function and shown to predict adverse outcomes in valvular heart surgery. The SCI has been proposed as a less invasive measurement of biventricular failure but its correlation with PAPi and association with hospital mortality remain unclear. Methods We used the MIMIC-IV database (electronic health records from Beth Israel Deaconess Medical Center). We included patients admitted to the intensive care unit who underwent right heart catheterization with documented values for systolic and diastolic blood pressures, PA systolic and diastolic pressures and CVP. A random measurement in time was chosen for patients with multiple times during which all measurements were recorded. We calculated the PAPi and SCI for each patient. We used linear regression and Pearson’s correlation to quantify the association between PAPi and SCI and used separate logistic regression models to quantify associations between PAPi and hospital mortality and between SCI and hospital mortality. Associations between PAPI and SCI and mortality were modeled with natural cubic splines to account for non-linear associations. From the mortality models, we reported the area under the receiver operating characteristic curve (AUC), a measure of model discrimination. Results We identified 6,394 patients; 4134 (65%) had sepsis and 2748 (43%) had heart failure. A total of 479 (7.5%) died. Median PAPi was 1.6 (IQR 1.1-2.4) and median SCI was 5.1 (IQR 3.5-7.7). SCI and PAPi were positively correlated (r 0.80; 95% CI 0.79-0.81); each 1-point increase in SCI was associated with a 0.21-point increase in PAPi (95% CI, 0.21-0.22). There was a non-linear relationship between SCI and mortality (Figure). SCI had higher discrimination for mortality (AUC 0.70) compared to PAPi (AUC 0.54; difference in AUCs 0.16; 95% CI 0.12-0.19). Discussion In this retrospective study of critically ill patients with pulmonary artery measurements, SCI and PAPi were strongly positively correlated but SCI had better predictive performance for hospital mortality relative to PAPi. These results suggest that SCI may have use as a less invasive alternative to PAPi to monitor biventricular function and risk stratify critically ill patients. This abstract is funded by: None