Coagulation parameters in patients with cirrhosis and portal vein thrombosis treated sequentially with low molecular weight heparin and vitamin K antagonists

Abstract

Background/aims: Information on coagulation for cirrhotics on anticoagulants is scanty. We investigated plasma from 23 cirrhotics treated with low-molecular-weight-heparin (LMWH) followed by vitamin K antagonists (VKA).

Methods: On days 1-4 patients received full-dose LMWH. On day-5 VKA was started and LMWH was terminated when INR therapeutic-interval was reached. Blood was collected at peak and trough during LMWH, LMWH+VKA and VKA. Non-cirrhotics on VKA were included as controls.

Results: Anti-factor Xa increased from baseline-to-peak during LMWH. During LMWH+VKA was high and reverted to zero during VKA. INR was slightly high at baseline, trough or peak during LMWH and increased to 2.2 during LMWH+VKA or VKA. Mean VKA weekly-doses for cirrhotics and controls were 28.5mg and 28.6mg. Protein C decreased upon VKA, but not to the expected extent. Endogenous-thrombin-potential (ETP) decreased from baseline (1436nMmin) to trough (1258nMmin) and peak (700nMmin) during LMWH and was further reduced during LMWH+VKA (395nMmin).

Conclusions: Target-INR for cirrhotics can be reached by VKA dosages similar to those for non-cirrhotics. ETP reduction parallels the effect of LMWH and/or VKA. Whether these parameters represent the antithrombotic action elicited by these drugs remains to be determined by clinical-trials and laboratory-measurements. ETP, being a global-test reflecting both pro- and anti-coagulants targeted by antithrombotic drugs, seems the candidate for these trials.

Keywords: Anti-FXa activity; Anticoagulation; Antithrombin; Factor II; Factor VIII; INR; Protein C; Thrombin generation.