Heparin-like effect contributes to the coagulopathy in patients with acute liver failure undergoing liver transplantation

Abstract

Introduction: Liver transplantation (LT) in cirrhotics is characterized by severe coagulopathy, associated with a well documented heparin-like effect (HLE) seen by thromboelastography (TEG) after reperfusion. The amount of HLE present in patients with acute liver failure (ALF) and its role in their bleeding tendency before LT has not been investigated.

Aim: To investigate the presence and extent of HLE in patients with ALF undergoing LT and to compare the extent of HLE in this group with a group of cirrhotics undergoing LT.

Material and methods: Ten consecutive ALF and 10 cirrhotic patients undergoing LT were included. TEG (with and without heparinase I), surrogate total thrombin generation (TTG) derived by TEG and haemodynamic variables were recorded for every stage of the LT. HLE was defined as a correction of r+k times on TEG of more than 50% by the addition of heparinase I.

Results: Before incision, patients with ALF showed a significantly greater HLE compared with patients with cirrhosis (r+k time: 66 min corrected to 29 vs 45 min corrected to 32 min, P=0.001). After reperfusion, all the patients showed extensive HLE, without any difference between the two groups. Despite the greater HLE, patients with ALF showed similar TTG compared with the cirrhotic group. By the end of the operation, the extent of the HLE was greatly reduced in both the groups.

Conclusions: Before transplantation, patients with ALF have a greater HLE than patients with liver cirrhosis. However, this did not affect the thrombin generation calculated by TEG and resolved after transplantation.

Fig. 1

Native thromboelastography (TEG™) (a) and heparinase I TEG™ (b) in samples collected from a patient with acute liver failure at baseline before liver transplantation. Significant heparin-like effect is shown by the very slow rate of coagulation. Treatment of the sample with heparinase I significantly increased the rate of coagulation, indicating the presence of heparin-like substances.

Fig. 2

r+k times in native and heparinise I thromboelastography in patients with cirrhosis (a) and acute liver failure (b) at different stages during liver transplantation. Stage 1, baseline; stage 2, dissection; stage 3, anhepatic; stage 4, reperfusion; stage 5, end of operation.

Fig. 3

Comparative representation of heparin-like effect shown by the difference between native and heparinase I thromboelastography r+k times at different stages during orthotopic liver transplantation between cirrhotic and acute liver failure patients. Stage 1, baseline; stage 2, dissection; stage 3, anhepatic; stage 4, reperfusion; stage 5, end of operation.