A Simple Scoring System to Predict Survival after Venoarterial Extracorporeal Membrane Oxygenation

Patients undergoing consideration for venoarterial extracorporeal membrane oxygenation (VA ECMO) require an immediate risk profile assessment in the setting of incomplete or no information. A retrospective cohort study of 100 patients undergoing VA ECMO placement at three institutions was carried out. Variables strongly associated with survival to discharge were used to calculate a risk stratification score. Indications for VA ECMO support included postcardiotomy shock (24%), ischemic etiologies (33%), nonischemic cardiomyopathy (32%), and other etiologies (11%). Pre-VA ECMO arrest occurred in 69%, and 30% of patients underwent cannulation during arrest. Survival to discharge was 38%. Three variables demonstrated a strong trend toward predicting survival to discharge: lactate >10 mmol/L (p = .054), albumin <3 g/dL (p = .062), and platelet count <180 K/uL (p = .064), and these variables were included in a scoring system. The extremes of age and duration of pre-VA ECMO ventilation were associated with a dismal prognosis and were also included. These five variables were used to construct a mortality prediction score. A score of 0 was associated with 10% expected mortality, whereas a score of 4+ was associated with 100% expected mortality. Mortality increased in a stepwise fashion with increasing scores. The expected mortality closely paralleled the observed mortality. A simple scoring system composed of easily collected variables may help predict mortality. However, it is not intended to replace an experienced clinician's judgment, but to enhance it.