Long-term use of the low molecular weight heparin tinzaparin in haemodialysis

Fifty-two patients with chronic renal failure undergoing hospital haemodialysis were given a single bolus dose of tinzaparin (Innohep, Leo Laboratories, UK) into the arterial side of the dialyser, for up to 43 consecutive dialyses. The mean tinzaparin dose at the beginning was 2,139 IU anti-Xa and at the end 2,186 IU anti-Xa. Overall, tinzaparin proved a satisfactory anticoagulant for 1,370 (96.0%) out of 1,427 dialyses. Significant clot formation was prevented in 1,326 (92.8%) out of 1,429 dialyses. The clinically effective dose was associated with a mean plasma anti-Xa activity 1 h after dosing of 0.4 IU/ml and suppressed fibrinopeptide A formation for up to 4 h. Bleeding, from the skin or mucous membranes, was recorded at 27 (1.9%) of 1,408 dialyses. Prolonged fistula bleeding on completion of dialysis was recorded on only 20 occasions. Other haemorrhagic events included haematemesis, bruising and subconjunctival haemorrhage (each in 1 patient) and epistaxis (2 patients). Three patients died during the study of causes considered unrelated to tinzaparin therapy, myocardial infarction (2 patients) and multiple myeloma. Other adverse events reported included vomiting (3 patients) and hypotension (3 patients). Three patients ceased treatment due to haematemesis, prolonged bleeding from fistula puncture and thrombosis of the arteriovenous access, respectively. A small, but statistically significant, increase within the normal reference range was recorded in the mean values for aspartate aminotransferase and alanine aminotransferase.