SummaryHeparin-induced thrombocytopenia (HIT) with thrombosis occurs in about 1 in 2,000 heparin-treated patients. The arterial or venous thromboses may threaten life and limb hence alternative anticoagulation is needed. Some alternative treatments are possible i.e. LMWH, Ancrod, prostacyclin analogues, Dextran, aspirin and oral anticoagulants, but each has its drawbacks. This report reviews treatment of HIT patients with Orgaran (Org 10172), a low molecular weight heparinoid.Because of its proven antithrombotic activity Orgaran was used to treat 230 HIT patients. One hundred and fifty, nine patients presented with at least one thrombotic problem, which in 88 was due to the heparin use. 92.8% of the patients were considered to have adequately responded to Orgaran during the treatment period. Fifty-nine deaths (25.7%) occurred of which 7 (3.0%) were attributed to Orgaran use. The remaining 52 deaths, 27 of which occurred after Orgaran treatment was successfully terminated, were due to the severe underlying disorders in these patients. These results and the lower cross-reactivity rate (≈10%) with the heparin-induced antibody compared with that of the LMWH (>90%) suggest that although problems remain, Orgaran can be a valuable alternative treatment for patients who suffer from HIT and who require anticoagulation.

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Summary Aim: To compare clinical outcomes in a randomised comparison of treatment with danaparoid sodium (a heparinoid), or dextran 70, for heparin-induced thrombocytopaenia (HIT) plus thrombosis. Methods: Forty-two patients with recent thrombosis and a clinical diagnosis of probable HIT who presented at ten Australian hospitals during a study period of six and one half years were randomly assigned to open-label treatment with intravenous danaparoid or dextran 70, each combined with oral warfarin. Thirty-four patients (83%) had a positive platelet aggregation or 14C-serotonin release test for HIT antibody. Twenty-five received danaparoid as a bolus injection of 2400 anti-Xa units followed by 400 units per hour for 2 h, 300 units per hour for 2 h, and then 200 units per hour for five days. Seventeen received 1000 mL dextran 70 on day one and then 500 mL on days 2-5. Patients were reviewed daily for clinical evidence of thrombus progression or resolution, fresh thrombosis or embolism, bleeding or other complications. The primary trial endpoint was the proportion of thromboembolic events with complete clinical resolution by the time of discharge from hospital. Results: With danaparoid, there was complete clinical recovery from 56% of thromboembolic events compared to 14% after dextran 70 (Odds Ratio 10.53, 95% Confidence Interval 1.6–71.4; p = 0.02). Clinical recovery with danaparoid was complete or partial in 86% of thromboembolic events compared with 53% after dextran 70 (Odds Ratio 4.55, 95% Confidence Interval 1.2–16.7; p = 0.03). Overall clinical effectiveness of danaparoid was rated as high or moderate in 88% of patients compared with 47% for dextran 70 (p = 0.01). One patient given danaparoid died of thrombosis compared with three patients given dextran 70. The platelet count returned to normal after a mean of 6.7 days with danaparoid and 7.3 days with dextran 70. There was no major bleeding with either treatment. Conclusion: danaparoid plus warfarin treatment for HIT with thrombosis is effective, safe, and superior to dextran 70 plus warfarin.

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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 (≈ 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.