In recent years, the treatment options for patients with severe cardiorespiratory failure have been extended by the implementation of mechanical circulatory support (MCS). Identification of patients that benefit most from this cost-intensive treatment modality is of central importance, but is also challenging. Previous studies unravelled certain patient characteristics that should be taken into account, such as age, weight, and underlying pathology, and also the delay until MCS implementation as well as tissue hypoxia as prognostic factors. Relevant comorbidities included neurologic, renal, and hepatic disorders. Of note, baseline liver function tests predicted outcome in patients on extracorporeal life support (ECLS), including short-term and long-term mortality. Most strikingly, increased levels of alkaline phosphatase and total bilirubin indicated unfavourable short-term and long-term survival even after adjustment for age, gender, left ventricular function, and relevant known comorbidities such as impaired renal function and diabetes. Therefore, the assessment of liver function tests may be regarded as another piece in the complex puzzle of our efforts perceiving the ideal ECLS candidate with positive long-term outcome.