VO2peak prior to transplant differentiates survival post kidney transplant.

ABSTRACT

The OPTN/UNOS utilizes the calculated estimated posttransplant survival (EPTS) score as the measure of post-kidney transplant survival to guide allocation of deceased donor kidney transplantation. This score does not include any metric of functional capacity. Peak oxygen uptake (VO2peak ), is an established predictor of survival among both the general and diseased populations. We assessed the association and discriminative capacity of VO2peak and that of EPTS score and all-cause mortality post-kidney transplant. Additionally, we assessed the "mortality risk" lower VO2peak conferred on those patients with low EPTS score. Among a cohort of 293 transplant recipients with at least 3-years post-transplant follow-up, the median VO2peak was 15.0 ml/Kg/min. Lower pre-transplant VO2peak and higher EPTS score conferred higher risk of post-transplant mortality. Among the cohort of "low-risk" patients (patients with EPTS score < 50) those with lower VO2peak had significantly higher risk of mortality (log rank p = 0.045). In fact, the mortality risk among those with low-EPTS (< 50) and low VO2peak  < 12 ml/Kg/min was equivalent to those with high EPTS (> 80) score. We concluded functional capacity as defined by VO2peak is an important reflection of post-transplant survival. VO2peak is able to identify those with low EPTS who have similar survival to that of high EPTS phenotype.