Coagulopathy of liver disease does not increase the filter life during continuous renal replacement therapy

Introduction

Clotting of haemofiltration circuits is a limiting factor in achieving efficient continuous renal replacement therapy (CRRT), yet systemic anticoagulation risks haemorrhage. Some patients, such as those with liver failure, are traditionally managed with no or minimal anticoagulation, because of abnormal clotting tests and therefore increased perceived risk of bleeding [1].

Methods

We retrospectively reviewed the CRRT circuit life in three groups of liver failure patients (acute liver failure (ALF), acute on chronic liver failure (ACLF) and postelective liver transplantation (LTx)), with two control groups (systemic sepsis (SS) and haematological malignancy (Haem)), admitted to the Royal Free Hospital ICU – a tertiary referral centre for liver disease and transplantation – between 2003 and 2007. Ten consecutive patients in each of the five groups were included in the study if they had renal failure and required continuous haemofiltration (CRRT) for more than 48 hours.

Results

The mean CRRT circuit life was significantly greater in the Haem group, compared with the others; 28.5 ± 25.7 hours, versus 11 ± 10.5 ALF, 11.6 ± 6.6 ACLF, 7.4 ± 5.1 LTx and 9.9 ± 5.9 SS, P < 0.05, with the Haem group requiring fewest new CCRT circuits within 48 hours; 2.7 ± 1.5 versus 4.3 ± 1.3 ALF, 4.2 ± 2.1 ACLF, 5.3 ± 1.5 LTx and 4.6 ± 1.5 SS, P < 0.05 and least blood transfusions; 1.4 ± 1.3 versus 4.8 ± 4.2 ALF, 4.2 ± 4.1 ACLF, 2.2 ± 2.1 LTx and 3.2 ± 1.2 SS. Transmembrane pressures were higher in those CRRT circuits that clotted due to the filter, compared with other causes, such as access dysfunction (123 ± 74 vs. 71.8 ± 29.3 mmHg, P = 0.009). In those patients where anticoagulation was started due to repeated filter clotting, the CRRT circuit life improved from 5.6 ± 3.4 to 19 ± 12.7 hours, P < 0.01.

Conclusion

Despite abnormal standard laboratory coagulation tests and thrombocytopenia, CRRT circuits clot frequently in liver failure patients. Anticoagulation did improve CRRT circuit survival without an obvious increase in bleeding or blood transfusion requirement. Anticoagulation should therefore be considered in these patients in cases of repeated circuit clotting.