Heparin-induced thrombocytopenia from venous thromboembolism treatment.

OBJECTIVES

We aimed to characterize the clinical experiences of patients in whom heparin-induced thrombocytopenia (HIT) complicated heparin therapy for venous thromboembolism (VTE) and who switched to argatroban.

DESIGN

A retrospective analysis of previously reported prospective, multicentre, historical-controlled Argatroban-911 and Argatroban-915 studies of argatroban therapy in HIT.

SETTING

Inpatient.

SUBJECTS: Patients (n = 145) administered heparin for VTE and who developed HIT were identified.

INTERVENTIONS: Patients were treated with argatroban 2 mcg kg(-1) min(-1) for up to 14 days, adjusted to maintain activated partial thromboplastin times 1.5 to three times baseline. Patient characteristics, anticoagulation and outcomes were summarized. The primary end-point was a composite of death, amputation, or new thrombosis within 37 days of argatroban initiation.

RESULTS

During heparin therapy, platelet counts decreased (mean +/- SD nadir: 78 +/- 67 x 10(9) L(-1)), and 75 (52%) patients developed thrombosis. After heparin was discontinued, patients received argatroban (mean dose 2.1 +/- 1.2 mcg kg(-1) min(-1)) for 6.8 +/- 4.3 days. By day 6 of argatroban therapy, the mean platelet count rose to >150 x 10(9) L(-1). The primary end-point occurred in 41 (28.3%) patients (values of 26-44% are reported for argatroban therapy of HIT from any heparin indication). Seventeen (11.7%) patients, including 12 who had also experienced thrombosis whilst on heparin, developed new thrombosis after argatroban initiation, typically on the day argatroban was discontinued or later (n = 10). Seven (4.8%) patients experienced major bleeding.

CONCLUSIONS

For VTE patients with HIT, argatroban provides effective anticoagulation, with outcomes comparable with those reported for other argatroban-treated HIT patients. New thrombosis in this setting occurred most often in patients with existing HIT-associated thrombosis, before HIT recognition or either at/after argatroban discontinuation.