Trial Information

Heparin-Induced Thrombocytopenia - Retrospective Analysis of Data on Incidence and Outcomes Study (HIT-RADIO Study)

HIT-RADIO is a retrospective chart-review study of patients who had a positive heparin PF-4
antibody test between 1/21/2008 and 9/25/2008 at selected hospitals associated with the
Transfusion Medicine/Hemostasis Clinical Trials Network .

Heparin-induced thrombocytopenia (HIT) is a major complication of the administration of
heparin and can result in life-threatening thrombosis with or without thrombocytopenia
(HIT-T) or can produce thrombocytopenia without clinically symptomatic thrombosis
("isolated" HIT). Isolated heparin-induced thrombocytopenia is defined as a fall in
platelet count associated with a positive heparin PF-4 antibody test, in the absence of
clinically overt thrombosis. While the treatment of HIT-T (HIT with thrombosis) with
anticoagulation is well established, the risks and treatment of isolated HIT are unclear.

It is anticipated that this data analysis will provide a current overview of the
implications of a positive heparin PF-4 antibody test in clinical practice. It should
determine the percentage of positive heparin PF-4 antibody tests that are associated with
thrombocytopenia and thrombosis (HIT-T) or "isolated" HIT at diagnosis and the subsequent
major clinical outcomes of death, limb amputation/gangrene, and new thrombosis. No
"snapshot" of such HIT patients has been conducted in the past decade and the results will
be important in assessing the impact of HIT in current medical care as well as documenting
current treatment strategies.