ANTICOAGULANT WITH THE LOW-MOLECULAR-WEIG HT HEPARINOID ORG-10172 (ORGARAN(R)) DURING HEMODIALYSIS IN A PATIENT WITH HEPARIN-INDUCED THROMBOCYTOPENIA

A 48-yr-old patient was admitted to the ICU for cardiogenic shock and acute renal failure after coronay artery bypass graft surgery. A hepar in-induced thrombocytopenia (HIT) occurred during haemodialysis with u nfractioned heparin (UFH) as the anticoagulant. The dialysers, the cir cuits and the catheters were recurrently thrombosing and the platelet count decreased to 9 G . L(-1) on postoperative day 7. UFH was discont inued. Attemps to substitute UFH with a low molecular weight heparin ( LMWH) failed, due to the presence of a high cross-reactivity rate of L MWH with the heparin-dependent antibody. Intermittent haemodialysis wi thout anticoagulation using a predilution of the dialysers failed also and resulted in recurrent clotting. After informed consent of the pat ient, a new natural heparinoid Orgaran(R) (Org 10172, Organon, Oss Hol land) was administered. This agent is a mixture of several non heparin low molecular weight glycosaminoglycans, with proven anticoagulant ef ficacy, low cross-reactivity with the HIT antibody, and a half-time pr olonged over 18-25 hours. The treatment regimen consisted in a i.v. bo lus of 40-45 IU . kg(-1) prior to each dialysis procedure, performed e very two days. The platelet count increased to 200 G . L(-1), seven da ys after discontinuing heparin injection, and remained stable during t he administration of Orgaran(R). No other thrombosis occurred again. E ach procedure of four hours duration was monitored with the plasma ant i-Xa activity and APTT test. The mean anti-Xa plasma concentrations (0 .44 +/- 0.55 IU . mL(-1), 30 min after injection of Orgaran(R)) were w ell correlated with APTT test (r = 0.73, p < 0.01). As the drug tends to accumulate in plasma in case of renal failure, the dose should be t itrated according to the pre-dialysis plasma anti-Xa activity.