The overall incidence of AKI following LT using grafts from DCD in this study was 42.2%, which is similar to those used living donor liver grafts or partly used DCD donors [1,3,16]. CIT reduction may be the reason as CIT is an important risk factor for the development of AKI . The most DCD donors come from our organ procurement organization for transplantation at our center, allowing us to keep the CIT short. As expected, MELD score pre-operative of recipient and CIT of graft were the most important factors following LT. The predictive risk of post-LT AKI when recipient with a MELD score ≥ 15 alone was 43.9%. The risk increases in the presence of prolonged CIT and excess RBC transfusions, especially the donor CIT ≥ 7 hours, the incidence of AKI will rise to 85.3%.
Surprisingly, Cox multivariate stepwise regression revealed that a mild increase in AST pre- LT was negatively associated with AKI. However, AST was not an independent predictor of AKI in univariate analysis, implying that AST indirectly affects AKI through ischemia preconditioning (IP), a method that may alleviate IRI injury . This is consistent with the findings of another study, which found that mild injury of renal function prior to OLT may protect against AKI post-OLT via the IP . IP is another method with extensive preclinical evidence that has a protective effect on the graft and other organs, but clinical evidence has been more ambiguous . But from the pathophysiological mechanism, there is hope for reducing IRI through IP.
The fifth predictor was mechanical ventilation duration that more than 40 hours post-operation potentially increasing the risk of AKI. This may be controversial for patients who require prolonged ventilatory support after transplantation are usually severely ill or have a more complicated procedure than those who extubated early. However, theoretically MV may lead to the development of AKI through haemodynamic factors or ventilator-induced lung injury by triggering a pulmonary inflammatory reaction and subsequent systemic release of inflammatory mediators . Clinically, prolonged mechanical ventilation time is a risk factor for AKI 48 hours after surgery . Third, early extubation can improve splanchnic and liver blood flow, which may result in better liver graft recovery, which is the foundation of stabilizing other organs function in liver transplantation [22,23]. Early extubation is feasible and safe in LT patients, with potential physiologically benefits optimal patient outcomes . This does not simply imply extubating at a specific time, but suggests that personalized care for patients on a liver transplant and early extubation successful is dependent on the recipient's pretransplant condition, intraoperative events, and clinicians' ability to predict posttransplant complications .
This is the first model to predict the risk of AKI in liver transplant recipients using DCD grafts, and evaluated the impact of MELD and CIT on AKI after LT simultaneously, which is more suitable for the current MELD based liver transplantation policy and donor selection criteria expansion situation.This prediction model has some limitations: it is a single-center study with a small sample size, false-positive outcomes are possible. Furthermore, other parameters impacting donor quality, such as age, BMI, and so on, were not considered. Third, more modifiable risk factors such as low blood pressure and intraoperative vasopressor use were not included in the model.
In conclusion, significant modifications in recipient and donor criteria have a significant impact on the outcome of liver transplantation. Despite the MELD score and CIT are the most important risk factors for renal dysfunction in DCD liver transplants, the prognosis may improve due to novel organ preservation techniques and other methods that can reduce IRI.