Response to exercise in patients with liver cirrhosis: implications for liver transplantation.

End-stage liver cirrhosis is a systemic disease carrying a short-term desperate prognosis without liver transplantation. Given the discrepancy between the growing number of candidates and the limited available liver grafts, the pre-transplantation screening process has become a challenging task. Cardiopulmonary exercise testing, by measuring maximal oxygen consumption at peak exercise, provides a global integrative approach of the health status of an individual. In the setting of liver cirrhosis, decreased oxygen consumption at peak exercise may result from a combination of multiple extra-hepatic complications, including deconditioning, malnutrition-associated muscle weakness, anaemia, cirrhotic cardiomyopathy, and hepato-pulmonary syndrome for instance. In addition, oxygen consumption at peak exercise not only correlated with the severity of the liver disease, but it is also independently associated with survival following liver transplantation. The present article aims to review the numerous determinants of impaired aerobic capacity in patients with severe liver disease, and to discuss how useful is cardiopulmonary exercise testing as a critical tool in the pre-transplantation assessment of these patients.