Heparin-induced Thrombocytopenia in a Uremic Patient Requiring Hemodialysis

Abstract

Heparin-induced thrombocytopenia (HIT) is an uncommon but potentially serious complication of hemodialysis, and subsequent reexposure to heparin after the disappearance of antiheparin-PF4 complex antibodies (HIT antibody) has been controversial. We report a 60-year-old woman who was sensitized to unfractionated heparin (heparin) as anticoagulant during hemodialysis (HD) and heparin flush on a nonsession day. The patient suddenly developed acute systemic reactions with acute pulmonary embolism a few minutes after manipulation with heparin flush on day 9, a nonsession day. Although there was no evidence of pulmonary embolism on a pulmonary scintigram on the next day, the fifth HD session was discontinued owing to recurrence of acute systemic reactions and massive clots in the dialyzer 30 min into the session. After confirmation of the presence of HIT antibody and maturation of vascular access fistula, a sixth HD session was carried out with argatroban, a synthetic direct thrombin inhibitor, with a bolus of 10 mg and continuous infusion of 0.5 mg/kg/hr as an alternative to heparin. Optimal dose adjustment of argatroban through activated partial thromboplastin time (APTT) monitoring led to a bolus of 5 mg and continuous infusion of 0.15 mg/kg/hr. The patient's HD treatment at the same doses 3 times a week followed an uneventful course over 6 months. HIT antibody was seronegative about 40 days after the cessation of heparin treatment. Reexposure to heparin was attempted with the monitoring of HIT antibody and platelet counts before and after the sessions on day 210. The titers of HIT antibody compared with before the level of reexposure showed a transient insignificantly small peak, and dialysis with heparin has been maintained to date with no recurrence of HIT. The measurement of HIT antibody titer could be useful in assessing not only the effect of argatroban to replace heparin but also in predicting the recurrence of HIT due to reexposure.