Liver transplantation is a complex and life-saving procedure that offers hope to patients with end stage liver disease. Despite significant advancements in surgical techniques and perioperative care, the occurrence of post-transplant complications remains a significant concern. Among these complications, acute kidney injury (AKI) and early allograft dysfunction (EAD) are particularly challenging, as they can have profound implications on both short-term and long-term outcomes. Consequently, the pursuit of robust prognostic markers to anticipate these complications and facilitate early intervention has garnered substantial scientific interest.
Serum neutrophil gelatinase-associated lipocalin (NGAL) is a promising and well-studied biomarker that has been shown to predict AKI in multiple other disease settings including after cardiac surgery (1). In addition, one study found arterial lactate concentration at the end of liver transplantation to be predictive of EAD (2).
In a recently published article in Scientific Reports, Cho et al. (3) aimed to build on previous work and determine whether serum NGAL, lactate, or lactate-adjusted NGAL at the end of surgery could predict AKI and EAD. In a retrospective cohort of 353 patients undergoing living donor liver transplantation at Seoul National University Hospital, the investigators found that lactate-adjusted NGAL at the end of surgery significantly increased prognostic accuracy for AKI (area under the curve [AUC], 0.89; 95% confidence interval [CI], 0.85–0.92) and EAD (AUC, 0.88; 95% CI, 0.84–0.91) compared with the individual biomarkers when added to the clinical model. Furthermore, the authors determined that the optimal cutoffs for lactate-adjusted NGAL were 191 and 125 for AKI and EAD, respectively.
Although the findings from the study by Cho et al. (3) are promising, the road to full integration into clinical practice requires additional validation and comprehensive assessment across diverse patient populations and transplantation centers. The study was a single-center, retrospective cohort study with a relatively small sample size. Notably, the study was based on patients with a low model for end stage liver disease and with mostly hepatocellular carcinoma. Therefore, it remains to be seen whether lactate-adjusted NGAL remains a good prognostic tool at the same cutoffs in the broader transplant population, of whom many are more severely ill and may have elevations in serum NGAL and lactate for a multitude of reasons.
The findings in the study by Cho et al. (3) should prompt validation studies in prospective cohorts, together with further studies to assess whether targeted interventions provided to patients with elevated, lactate-adjusted NGAL are effective in preventing and mitigating the severity of AKI and EAD.