Predictors of mortality following extracorporeal membrane oxygenation support in an unselected, critically ill patient population

Introduction
Mechanical circulatory support (MCS) has been established as a means of augmenting circulation in patients with critically decreased systolic function due to a variety of underlying clinical reasons. Different methods of MCS may be used, with the venous-arterial extracorporeal membrane oxygenation system (VA-ECMO) being one of the most utilized devices in everyday care. Aim: To determine independent predictors influencing mortality outcomes following VA-ECMO therapy in a large, unselected, adult, critically ill patient population in cardiogenic shock (CS).

Material and methods
Data on 235 consecutive, real-world VA-ECMO treatments were assessed. Analysis was conducted for all subjects requiring MCS with the VA-ECMO as the first instalment, regardless of underlying cause or eventual upgrade. All potential clinical factors influencing mortality were examined and evaluated.

Results
Overall mortality was ~66% at median 28 days follow-up and significantly depended upon pH < 7.3 (HR = 3.56; p < 0.001), and age ≥ 65 years (HR = 1.96; p = 0.001). Acute coronary syndrome (ACS) as an indication for VA-ECMO displayed a nearly significant value (HR = 1.44; p = 0.07). Heart transplant (hTX) primary graft failure as an indication for the VA-ECMO displayed a clearly favorable outcome (HR = 0.51, p = 0.025); all data based on multivariate Cox regression analysis.

Conclusions
Mortality in patients requiring VA-ECMO remains high. We conclude that only decreased pH values and advanced age clearly influence mortality in this MCS scenario. ACS also bodes unfavorably, whereas hTX as an indication clearly shows better survival.