Cardiopulmonary bypass with danaparoid sodium and ancrod in heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia (an overview)

Heparin induced thrombocytopenia is a serious side effect of a drug that is widely used in clinical practice. All patients exposed to heparin, administered by any route or at any dose, are at varying risk of developing HIT and its potentially devastating thrombotic complications. There are two clinical forms of HIT, type I and type II. Type I HIT, is a non-immunologic response, while type II HIT is an immunologic response to heparin therapy. Type I HIT is not associated with an increased risk of thrombosis and is characterized by reversible thrombocytopenia. Type II HIT occurs in approximately 1 to 3% of patients receiving unfractionated heparin. Type II HIT is more severe because of the increased risk of thrombotic events. Venous and arterial thromboembolic complications may lead to amputation, stroke, myocardial infarction, and death.

Argatroban for anticoagulation during cardiopulmonary bypass in an infant

Heparin induced thrombocytopenia (HIT) is a rare, but potentially life-threatening complication of heparin therapy. In patients with HIT, alternative means of anticoagulation are necessary. The authors present an infant with HIT who required anticoagulation during cardiopulmonary bypass for tricuspid valve excision in the treatment of bacterial endocarditis. The direct thrombin inhibitor, argatroban, was successfully used. Previous reports regarding the use of argatroban and other nonheparin anticoagulants for anticoagulation are reviewed and suggestions regarding argatroban dosing in infants are presented.

Heparin-induced thrombocytopenia in the pediatric intensive care unit population

OBJECTIVES

To report the occurrence of heparin-induced thrombocytopenia (HIT), discuss its pathophysiology, and outline an approach to management in the pediatric intensive care unit (ICU) patient.

DESIGN

Retrospective case reports.

SETTING

Pediatric ICU in a tertiary-care center.

PATIENTS AND RESULTS

Two pediatric ICU patients (2 and 6 mos of age) who developed HIT in the pediatric ICU. One was receiving heparin as a flush solution through a central line and the other had full heparinization during cardiopulmonary bypass. Both had received heparin during their neonatal course and developed thrombocytopenia; however, HIT was not considered as a possible diagnosis. HIT was diagnosed using a heparin-induced platelet aggregation study. The thrombocytopenia resolved with the cessation of heparin administration. One of the patients developed a deep vein thrombosis around a femoral venous catheter.

CONCLUSION

Although well described in the adult literature, there have been a limited number of reports of HIT in pediatric-aged patients. Given its potential for morbidity, HIT should be considered in the differential diagnosis of thrombocytopenia in the pediatric ICU patient.

[Extracorporeal circulation with danaparoid sodium for valve replacement in thrombocytopenia induced by type II heparin]

A type II heparin-induced thrombocytopenia (HIT) was diagnosed in a 64-year-old woman at day 20 of intravenous unfractionated heparin (UFH) therapy, given after myocardial infarction treated by angioplasty and intracoronary stent. The infarction was complicated by a mitral insufficiency that led to a mitral valve replacement. Cardiopulmonary bypass was successfully performed with sodium danaparoid (Orgaran), as an alternative to UFH, without thrombotic or haemorrhagic complications and the follow-up was uneventful.

Cardiopulmonary bypass in humans: bypassing unfractionated heparin

Seven anticoagulants besides unfractionated heparin have been used for human cardiopulmonary bypass (CPB), mainly in patients with heparin-induced thrombocytopenia. The collective experience with these alternative anticoagulants provides a perspective on current efforts aimed at improving CPB anticoagulation. Unfortunately, each alternative currently lacks a standard dosing schedule and a reliable method of monitoring the adequacy of its anticoagulant effect during CPB. Most also lack proven antidotes. Thus, unfractionated heparin remains the anticoagulant of choice for standard CPB.