Impact of impaired aerobic capacity on liver transplant candidates.

Background: Oxygen consumption at peak exercise (peak VO2) is the most accurate index of aerobic capacity (AC), which reflects the physical condition of an individual and is currently considered the gold standard for cardiorespiratory fitness. Evaluation of peak VO2 to identify high-risk candidates for liver transplantation (LT) may represent an interesting approach. The aims of this study were (a) to describe AC and identify factors independently associated with peak VO2; (b) to analyze the prognostic value of peak VO2 in patients referred for preliminary evaluation of LT; and (c) to provide preliminary data on the influence of peak VO2 on length of hospitalization and the need for oxygen support after LT.

Results: Peak VO2 was determined in patients referred for preliminary evaluation for LT. One hundred thirty-five candidates were included. More than half had severe alterations in peak VO2. Age, gender, model-for-end-stage liver disease (MELD) score, tobacco use, and hemoglobin were independently associated with peak VO2. Candidates with severe alterations in peak VO2 had a lower 1-year survival than others. Model-for-end-stage liver disease score and peak VO2 were independently associated with survival. In patients with a MELD above 17, those with severe alterations of peak VO2 AC had lower 1-year survival than the others. Among patients who underwent LT, those with severe impairment of peak VO2 showed a trend toward a higher mean length of hospitalization after LT and had significantly longer need for oxygen support.

Conclusions: Peak VO2 is severely impaired in candidates for LT and affects survival and post-LT course. Perioperative respiratory rehabilitation programs validated in lung and heart transplantation must be tested.