Prognostic Value of APACHE IV Score in Patients Bridged to Heart Transplantation on ECMO

Methods for risk stratification of candidates for heart transplantation (HTx) supported by extracorporeal membrane oxygenation (ECMO) are limited. We evaluated the reliability of the APACHE IV score to identify the risk of mortality in this patient subset in a multicenter study.

Between January 2010 and December 2022, 167 consecutive ECMO patients were bridged to HTx; they were divided into two groups, according to a cutoff value of APACHE IV score, obtained by receiver operating characteristic curve analysis for 90-day mortality. Kaplan-Meier survival curves were plotted, and compared through the log-Rank test. Cox regression model was used to estimate which factors were associated with survival.

The 90-day mortality prediction of the APACHE IV score showed an area under the curve of 0.87 (95% CI: 0.80-0.94), with a cutoff value of 49 (specificity 91.7%-sensibility 69.6%). 125 patients (74.8%) showed an APACHE IV score value < 49 (Group A), and 42 (25.2%) ≥ 49 (Group B). 90-day mortality was 11.2% in Group A and 76.2% in Group B (p < 0.01). Survival at 1 and 5 years was 85.5%, 77% versus 23.4%, 23.4% (p < 0.01) in Groups A and B. Mortality correlated at univariable analysis with recipient age, body mass index, mechanical ventilation, APACHE IV score, and platelets number. At multivariable analysis only APACHE IV score (HR: 1.07 [1.05-1.09, 95% CI]) independently affected survival.

The APACHE IV score represents a powerful predictor of survival in patients bridged to HTx on ECMO support, and could guide candidacy of patients on ECMO.