Background: Acute kidney injury (AKI) is one of the postoperative complications following orthotopic liver transplantation (OLT), and is related to the high morbidity and mortality. Although there were numerous propensity factors for AKI, their cumulative influence remains unclear. Our aims were to develop a score model to predict postoperative AKI and to evaluate the impact of AKI on the recipients' long-term survival.
Methods: We retrospectively analyzed 99 adult patients underwent OLT in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology between October 2014 and July 2020. The patients were dichotomized into the non-AKI and the AKI groups according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria. We defined stage-1 AKI as mild AKI, stage-2 AKI and stage-3 AKI as severe AKI.
Results: Overall, 29 (29.29%) patients developed AKI after OLT, of these, stage-1, stage-2, stage-3 account for 20.20% (20 of 99 patients), 2.02% (2 of 99 patients), 7.07% (7 of 99 patients), respectively; and 13.79% of postoperative AKI patients (4 of 29 patients) accepted renal replacement therapy (RRT). Operative time and MELD-Na score predicted the postoperative AKI, with odds ratio of 1.006, 1.061, respectively. The generated AKI prediction model is as follows: -5.594+0.007×operative time+0.060×MELD-Na. The area under the receiver operating characteristic curve (AUC) for the AKI prediction model was 0.762, and the sensitivity and specificity were 79.3%, 61.4%, respectively. There was no difference in long-term survival among the mild AKI group and the non-AKI group (P=0.751). However, the impact of severe AKI on long-term survival of patients was statistically significant when comparing the non-AKI group and the mild AKI group (P=0.001, P=0.011).
Conclusions: AKI occurs frequently in adult patients after OLT, and it poses a threat to patients' long-term survival. The severe AKI has negative impact on long-term survival, while the mild AKI has limited impact on long-term survival, compared with non-AKI group. The novel AKI prediction model has prognostic value in identifying patients at high risk for postoperative AKI.
Keywords: Acute kidney injury; orthotopic liver transplantation; prediction score model; risk factors.