The IMPACT Score: A New Score to Predict the Risk of Early Mortality in Cardiogenic Shock Patients Treated With Venoarterial Extracorporeal Membrane Oxygenation

Abstract

Objectives: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) requires considerable human and financial resources. Few studies have focused on early mortality (ie, occurring within 72 hours after VA-ECMO implantation). The objective of this study was to establish a prognosis score-the IMPACT score (prediction of early mortality associated with VA-ECMO using preimplantation characteristics)-by determining the risk factors associated with early mortality.

Design: This was a retrospective and observational study.

Setting: The study was conducted at a University hospital.

Participants: This single-center retrospective study included 147 patients treated with VA-ECMO for cardiogenic shock between 2014 and 2021.

Methods: The primary outcome was early mortality (ie, occurring within 72 hours after VA-ECMO implantation). Multivariate logistic regression was performed using a bootstrapping methodology to identify factors independently associated with early mortality. To construct the score, identified variables had points (pts) assigned corresponding to their odds ratio.

Results: A total of 147 patients were included in the study. Early mortality (<72 hours) was 26% (38 patients). Four variables were established: cardiac arrest (2 pts), lactate levels (3 pts), platelet count <100 g/L (4 pts), and renal-replacement therapy (5 pts). The IMPACT score had an area under the receiver operating characteristic curve of 0.78 (95% CI 0.86-0.70) to predict early mortality.

Conclusions: In the authors' experience, 26% of patients treated with VA-ECMO presented early mortality. The IMPACT score is a reliable predictor of early mortality and may assist with VA-ECMO initiation decision-making.

Keywords: VA-ECMO; cardiogenic shock; early mortality; score.