POST-REPERFUSION LIVER BIOPSY AND ITS VALUE IN PREDICTING MORTALITY AND GRAFT DYSFUNCTION AFTER LIVER TRANSPLANTATION

Comprehensive Approach to Assessment of Liver Viability During Normothermic Machine Perfusion

Liver transplantation is the most effective treatment of advanced liver disease, and the use of extended criteria donor organs has broadened the source of available livers. Although normothermic machine perfusion (NMP) has become a useful tool in liver transplantation, there are no consistent criteria that can be used to evaluate the viability of livers during NMP. This review summarizes the criteria, indicators, and methods used to evaluate liver viability during NMP. The shape, appearance, and hemodynamics of the liver can be analyzed at a macroscopic level, while markers of liver injury, indicators of liver and bile duct function, and other relevant indicators can be evaluated by biochemical analysis. The liver can also be assessed by tissue biopsy at the microscopic level. Novel methods for assessment of liver viability are introduced. The limitations of evaluating liver viability during NMP are discussed and suggestions for future clinical practice are provided.

Postreperfusion Liver Biopsy as Predictor of Early Graft Dysfunction and Survival After Orthotopic Liver Transplantation

BACKGROUND

Postreperfusion liver biopsy (PRB) can assess the degree of ischemia/reperfusion injury (IRI) after orthotopic liver transplantation (OLT). The influence of IRI on graft outcomes and overall survival is controversial.

AIM

To determine the correlation between the severity of IRI in PRB and overall graft and patient survival and, secondarily, to identify factors on PRB that predict poor graft outcomes.

METHODS

This is a retrospective analysis of all patients who underwent OLT using donation after brain death (DBD) with PRB. The severity of IRI in PRB was graded. Predictors of IRI were assessed using univariate and multivariate analysis and the Kaplan-Meier with log rank test for the graft and overall survival, respectively.

RESULTS

We included 280 OLTs (64.7%). The histopathological assessment of IRI severity was as follows: no IRI (N = 96, 34.3%), mild IRI (N = 65; 23.2%), moderate IRI (N = 101; 36.1%), and severe IRI (N = 18; 6.4%). The incidence rates of initial good graft function (IGGF), primary nonfunction and early allograft dysfunction (EAD) were 32.5%, 3.9%, and 18.6%, respectively. Severe IRI was associated with a lower incidence of IGGF (OR: 0.34, 95% CI 0.12-0.92; P = 0.03). Patients with severe IRI tended to have a higher incidence of EAD (33.2% vs. 18.6, P = 0.23). The cold ischemia time was an independent predictor of severe IRI on the multivariate analysis. Severe IRI was associated with poor 1- and 5-year overall survival rates (67% and 44%, respectively, compared with 84 and 68% in nonsevere IRI). Patients with severe IRI exhibited worse graft and overall survival.

CONCLUSIONS

Cold ischemia time predicts the development of severe IRI. Patients with severe IRI show worse graft and overall survival and a lower incidence of IGGF, suggesting that histopathological findings could be useful for identifying patients at high risk of worse outcomes after OLT.

ATORVASTATIN CAN PREVENT HEPATIC REMOTE REPERFUSION INJURY

Background:

Some studies have shown that statins have a promising effect on protection against reperfusion injury.

Aim:

To evaluate the ability of ischemic postconditioning, statins and both associated to prevent or minimize reperfusion injury in the liver of rats subjected to ischemia and reperfusion by abdominal aorta clamping.

Method:

Were used 41 Wistar rats, which were distributed into five groups: ischemia and reperfusion (I/R), ischemic postcondictioning (IPC), postconditioning + statin (IPC+S), statin (S) and Sham. It was performed a medium laparotomy, dissection and isolation of the infra-renal abdominal aorta; excepting Sham group, all the others were submitted to the aorta clamping for 70 min (ischemia) and posterior clamping removing (reperfusion, 70 min). In the IPC and IPC+S groups, postconditioning was performed between the ischemia and reperfusion phases by four cycles of reperfusion and ischemia lasting 30 s each. In IPC+S and S groups, preceding the surgical procedure, administration of 3.4 mg/day of atorvastatin was performed for seven days by gavage. The left hepatic lobe was removed for histological study and euthanasia was performed.

Results:

The mean hepatic injury was 3 in the I/R group, 1.5 in the IPC group, 1.2 in the IPC+S group, 1.2 in the S group, and 0 in the SHAM group. The I/R group had a higher degree of tissue injury compared to the others in the statistical analysis and there was no difference between the others (p<0.01).

Conclusion:

Ischemic postconditioning and atorvastatin were able to minimize hepatic reperfusion injury, either alone or in combination.

THE USE OF MELD SCORE (MODEL FOR END-STAGE LIVER DISEASE) AND DERIVATIVES IN CARDIAC TRANSPLANTATION

Introduction:

Heart transplantation is still the best therapeutic alternative for the treatment of end-stage heart failure. The use of criteria that consider the complications associated with this procedure can guarantee a better evaluation of the recipient and prepare the team for possible unsatisfactory post-transplant results. The use of the MELD score has been expanded to evaluate cirrhotic patients undergoing various procedures, including cardiac transplantation.

Objective:

To analyze the knowledge on MELD score and its derivatives to the prognosis of patients with end-stage heart failure considered for heart transplantation.

Method:

Was carried out an integrative review of the publications of the last ten years in Pubmed and Lilacs databases, using the descriptors “heart transplantation”, “liver disease” and “prognosis”. From the total of 111 articles found, six were selected and composed the sample.

Results:

The MELD-XI score (eXcluding INR) was the most analyzed in the studies due to the exclusion of INR, since many patients with heart failure use anticoagulants, which may alter their value. MELD and derivatives were associated with unsatisfactory results in cardiac transplantation.

Conclusion:

The MELD score can be considered as a good predictor for heart transplantation; however, there are still few studies that make this correlation.

HIGHER VALUES IN LIVER ELASTOGRAPHY AND MELD SCORE ARE MORTALITY PREDICTORS ON LIVER TRANSPLANT WAITING LIST

BACKGROUND

Liver elastography have been reported in hepatocellular carcinoma (HCC) with higher values; however, it is unclear to identify morbimortality risk on liver transplantation waiting list.

AIM

To assess liver stiffness, ultrasound and clinical findings in cirrhotic patients with and without HCC on screening for liver transplant and compare the morbimortality risk with elastography and MELD score.

METHOD

Patients with cirrhosis and HCC on screening for liver transplant were enrolled with clinical, radiological and laboratory assessments, and transient elastography.

RESULTS

103 patients were included (without HCC n=58 (66%); HCC n=45 (44%). The mean MELD score was 14.7±6.4, the portal hypertension present on 83.9% and the mean transient elastography value was 32.73±22.5 kPa. The median acoustic radiation force impulse value of liver parenchyma was 1.98 (0.65-3.2) m/s and 2.16 (0.59-2.8) m/s in HCC group. The HCC group was significantly associated with HCV infection (OR 26.84; p<0.0001), higher levels of serum alpha-fetoprotein (OR 5.51; p=0.015), clinical portal hypertension (OR 0.25; p=0.032) and similar MELD score (p=0.693). The area under the receiver operating characteristics (AUROC) showed sensitivity and specificity for serum alpha-fetoprotein (cutoff 9.1 ng/ml), transient elastography value (cutoff value 9 kPa), and acoustic radiation force impulse value (cutoff value 2.56 m/s) of 50% and 86%, 92% and 17% and 21% and 92%, respectively. The survival group had a mean transient elastography value of 31.65±22.2 kPa vs. 50.87±20.9 kPa (p=0.098) and higher MELD scores (p=0.035).

CONCLUSION

Elastography, ultrasound and clinical findings are important non-invasive tools for cirrhosis and HCC on screening for liver transplant. Higher values in liver elastography and MELD scores predict mortality.

BILIARY COMPLICATIONS AFTER LIVER TRANSPLANTATION

BACKGROUND

Biliary reconstitution has been considered the Achilles's heel of liver transplantations due to its high rate of postoperative complications.

AIM

To evaluate the risk factors for occurrence of biliary strictures and leakages, and the most efficient methods for their treatment.

METHOD

Of 310 patients who underwent liver transplantation between 2001 and 2015, 182 medical records were retrospectively analyzed. Evaluated factors included demographic profile, type of transplantation and biliary reconstitution, presence of vascular and biliary complications, their treatment and results.

RESULTS

153 (84.07%) deceased donor and 29 (15.93%) living donor transplantations were performed. Biliary complications occurred in 49 patients (26.92%): 28 strictures (15.38%), 14 leakages (7.7%) and seven leakages followed by strictures (3.85%). Hepatic artery thrombosis was present in 10 patients with biliary complications (20.4%; p=0,003). Percutaneous and endoscopic interventional procedures (including balloon dilation and stent insertion) were the treatment of choice for biliary complications. In case of radiological or endoscopic treatment failure, surgical intervention was performed (biliodigestive derivation or retransplantation (32.65%). Complications occurred in 25% of patients treated with endoscopic or percutaneous procedures and in 42.86% of patients reoperated. Success was achieved in 45% of patients who underwent endoscopic or percutaneous procedures and in 61.9% of those who underwent surgery.

CONCLUSION

Biliary complications are frequent events after liver transplantation. They often require new interventions: endoscopic and percutaneous procedures at first and surgical treatment when needed. Hepatic artery thrombosis increases the number of biliary complications.

DIFFERENT PROTOCOLS OF POSTCONDITIONING DOES NOT ATTENUATE MESENTERIC ISCHEMIA-REPERFUSION INJURY AFTER SHORT-TERM REPERFUSION

Background

Mesenteric ischemia is a challenging diagnosis. Delay in diagnosis can lead to extent bowel necrosis and poor outcomes. Ischemia and reperfusion syndrome plays an important role in this scenario.

Aim

To access effects of different post-conditioning cycles on mesenteric ischemia-reperfusion syndrome.

Method

Twenty-five rats were assigned into five groups: Sham, used to establish normal parameters; control group, submitted to mesenteric ischemia for 30 min; in groups GP3, GP1 and GP30, ischemia was followed by post-conditioning protocol, which consisted of 1 cycle of 3 min (GP3), 3 cycles of 1 min (GP1) or 6 cycles of 30 s (GP30), respectively. Ileum samples were harvested after one hour of reperfusion. Intestinal mucosal injury was evaluated through histopathological analysis.

Results

The average of mesenteric injury degree was 0 in the sham group, 3.6 in the control group, 3.4 in GP3, 3.2 in GP1, and 3.0 in GP30; villous length average was 161.59 in sham group, 136.27 in control group, 135.89 in GP3, 129.46 in GP1, and 135.18 in GP30. Was found significant difference between sham and other groups (p<0.05); however, there was no difference among post-conditioning groups.

Conclusion

Post-conditioning adopted protocols were not able to protect intestinal mucosa integrity after mesenteric ischemia and short term reperfusion.