Noninvasive markers of liver steatosis and fibrosis after liver transplantation – Where do we stand?

Protocol liver biopsy predicts graft survival after liver transplantation

BACKGROUND

The use of protocol liver biopsy to monitor liver allograft status remains controversial. There is limited data from modern transplantation populations that includes protocol biopsies to evaluate its value in predicting clinical outcomes.

METHODS

All protocol liver biopsies were identified from 875 patients who underwent liver transplantation at Helsinki University Hospital between 2000 and 2019. Each histologic component was analyzed for its ability to predict long-term outcomes, especially graft survival. We determined the frequency of significant biopsy findings based on the Banff working group definition. Liver function tests (LFTs) and clinical markers were evaluated for their ability to predict significant biopsy findings.

RESULTS

In total, 867 protocol liver biopsies were analyzed. Significant findings were identified in 20.1% of the biopsies. In the first protocol biopsy, steatohepatitis (hazard ratio [HR] 3.504, p = .03) and moderate or severe congestion (HR 3.338, p = .04) predicted graft loss. The presence of cholangitis (HR 2.563, p = .04), necrosis (HR 7.635, p < .001), mild congestion (HR 4.291, p = .009), and significant biopsy finding (HR 2.540, p = .02) predicted inferior death-censored graft survival. While the degree of elevation of LFTs was positively associated with significant biopsy findings, the discrimination was poor (AUC .572-.622). Combined LFTs and clinical risk factors remained suboptimal for discriminating significant biopsy findings (AUC .696).

CONCLUSIONS

Our findings support the use of protocol liver biopsies after liver transplantation since they frequently revealed changes associated with long-term outcomes, even when LFTs were normal.

A Comprehensive Review of Liver Allograft Fibrosis and Steatosis: From Cause to Diagnosis

Despite advances in posttransplant care, long-term outcomes for liver transplant recipients remain unchanged. Approximately 25% of recipients will advance to graft cirrhosis and require retransplantation. Graft fibrosis progresses in the context of de novo or recurrent disease. Recurrent hepatitis C virus infection was previously the most important cause of graft failure but is now curable in the majority of patients. However, with an increasing prevalence of obesity and diabetes and nonalcoholic fatty liver disease as the most rapidly increasing indication for liver transplantation, metabolic dysfunction-associated liver injury is anticipated to become an important cause of graft fibrosis alongside alloimmune hepatitis and alcoholic liver disease. To better understand the landscape of the graft fibrosis literature, we summarize the associated epidemiology, cause, potential mechanisms, diagnosis, and complications. We additionally highlight the need for better noninvasive methods to ameliorate the management of graft fibrosis. Some examples include leveraging the microbiome, genetic, and machine learning methods to address these limitations. Overall, graft fibrosis is routinely seen by transplant clinicians, but it requires a better understanding of its underlying biology and contributors that can help inform diagnostic and therapeutic practices.

Fibrosis and steatosis of the liver graft: Are non-invasive tests useful? A short review

As life expectancy of liver transplanted patients improves, new questions are arising to avoid progressive graft loss. The spectrum of chronic inflammation and fibrosis are known to be important triggers in the alteration of graft function. Liver biopsy remains the gold standard to better understand progressive, normal, and abnormal histological modifications of the graft. In parallel, the interest for metabolic steatosis development in post-transplantation is also growing. Long-term survival of these patients involves the management of comorbidities including metabolic syndrome and cardiovascular diseases. Early detection of altered graft parenchyma, and monitoring of its evolution are undoubtedly essential. Non-invasive methods including transient elastography and fibrosis biomarkers are attractive tools to avoid drawbacks and complications of liver biopsy. Accuracy of these methods are well-known in a pre-transplantation setting, but evidence is lacking in post-transplantation setting. We review current knowledge of progressive liver fibrosis and steatosis development after transplantation and non-invasive methods of their assessment.