Orgaran in heparin-induced thrombocytopenia

Abstract

Patients who develop heparin-induced thrombocytopenia (HIT) frequently need further anticoagulation to treat an ongoing thromboembolic problem or to prevent one. Orgaran (Org 10172), a low-molecular-weight (LMW) glycosaminoglycuronan, has shown a low frequency (10%) of cross-reactivity in vitro with sera containing the HIT antibody, in contrast to the much higher frequency of cross-reactivity (approximately 80%) shown by the LMW heparins. This paper summarises the results of intravenous or subcutaneous Orgaran treatment in 57 of 67 Australian patients, in whom the diagnosis of HIT was reasonably confirmed by exclusion of other causes of thrombocytopenia and by objective tests. The presenting indications for Orgaran were: continuous venovenous haemofiltration and haemodialysis (n = 21), thrombo-embolism treatment (n = 23), thrombo-embolism prophylaxis (n = 10), and anticoagulation for coronary artery by-pass graft (n = 4), peripheral by-pass graft surgery and plasmapheresis (n = 1 each). The results showed Orgaran to be a safe, well-tolerated, effective (successful treatment in over 90% of patients) anticoagulant in patients with a high thrombotic and/or bleeding risk even if critically ill and requiring haemofiltration. The complete results of the world-wide study in 161 patients confirmed not only these clinical findings in the subgroup of 57 Australian patients, but also the low cross-reactivity (12%) of Orgaran with the HIT serum factor.