Thrombin generation in mesalazine refractory ulcerative colitis and the influence of low molecular weight heparin

Background In ulcerative colitis (UC), a state of hypercoagulation has frequently been observed. Low molecular weight heparin (LMWH) has shown beneficial effects as an adjuvant treatment of steroid refractory UC in open trials. We assessed potential therapeutic effects of the LMWH reviparin in hospitalised patients with mesalazine refractory UC, as well as its influence on haemostasis factors. Methods Twenty-nine patients with mild-to-moderately active UC were included in a double-blind placebo controlled trial. All patients had a flare-up of disease under mesalazine treatment. Reviparin (Clivarin (R)) 3,436 IU anti-Xa/0.6 ml or placebo s.c. was added, and self-administered twice daily for 8 weeks. Patients were monitored for possible adverse events and changes in clinical symptoms. Endoscopical, histological, biochemical and haemostasis parameters were analysed. Results Tolerability and compliance were excellent and no serious adverse events occurred. No significant differences were observed on the clinical, endoscopical and histological outcome, as compared to placebo. A high intrinsic and extrinsic thrombin potential was found before LMWH therapy. However, the significant reduction in the thrombin generation by LMWH was not related to the reduction in disease activity. Conclusion The LMWH reviparine reduces thrombin generation in patients with mild-to-moderately active, mesalazine refractory UC, but is not associated with a reduction in disease activity