Predictors of Outcome in Critically Ill Cardiac Patients with a very long ICU stay–a retrospective bicentric study

Background Outcome predictors in critically ill cardiac patients with a very long ICU stay remain poorly defined. This study aimed to identify such predictors in this population. Methods This is a retrospective bi–centric study including critically ill surgical and medical cardiac patients with an ICU length of stay > 30 days. ICU–mortality was the primary endpoint; 1–year mortality was the secondary endpoint. A priori defined outcome predictors were analyzed by means of univariable and multivariable logistic regressions. Additionally, classification and regression tree (CART) analysis was employed to explore non–linear relationships and interactions. Results A total of 210 patients, among them 107 (51.0 %) surgical and 103 (49.0%) medical, were included. ICU mortality was 24.3 %. In the entire cohort, 1–year mortality was 46.7 %, whereas among patients who survived the ICU it was 29.6 %. Factors independently associated with ICU–mortality included baseline frailty (odds ratio (OR), 3.16 [95%–confidence interval (CI) 2.26–4.70] per point), prolonged continuous renal support (OR, 1.07 [1.03–1.13] per day), prolonged invasive ventilation (OR, 1.07 [1.01–1.14] per day) and prolonged vasopressor use (OR, 1.09 [1.02–1.17] per day), whereas prolonged inotrope use (OR, 0.93 [0.87–0.99] per day) was associated with lower ICU–mortality. CART analysis identified various patient groups with distinctly diverging ICU mortality. Conclusion In critically ill cardiac patients with a very long stay in ICU, irrespective of surgical or medical status, baseline frailty, prolonged renal support, invasive ventilation, and vasopressor use were independent predictors of ICU–mortality, whereas prolonged inotrope use was inversely associated with mortality. External validation is needed before these findings can be used for decision support. Trial registration The study was registered and approved by the Medical University of Vienna IRB on 31 ^st of August 2021 (EC number 1669/2021).