Initial Management of Suspected Heparin-Induced Thrombocytopenia: Opportunities for Education

Abstract 4686

According to the current recommendations for patients being evaluated for heparin-induced thrombocytopenia (HIT), a pretest assessment for the probability of HIT should be performed to evaluate the need for laboratory testing and the treatment modality that the patient should receive. The 4T score is an accepted clinical tool used for this purpose. For patients with a 4T score <4 discontinuation of heparin products is not indicated. However, in those patients who have a 4T ≥4, heparin should be discontinued and treatment with a direct thrombin inhibitor (DTI) should be initiated while performing the immunologic assay for HIT antibody.

In this study, a database of patients being tested for HIT at our institution was compiled and retrospective analysis was performed to determine whether our treatment population was being managed appropriately. The treatment of 159 patients in whom HIT antibody had been sent over a 2- year period, from 5/2008 to 5/2010, was assessed. Of the sample population, 32/159 (20%) had not been exposed to heparin prior to the HIT antibody being sent. Furthermore, the majority of the patients, 104/159 (65%) had a 4T score <4. Thus fully 85% of the patients tested in this cohort did not need to be tested. Of the latter group with heparin exposure but low clinical probability for HIT, 57/104 (54%) had heparin unnecessarily discontinued once HIT was suspected.

Most notably, 23/159 (14%) of the patients had a 4T greater than 4. The data for these patients indicates that the majority of them were not treated as per the current guidelines. As noted in the Table, 69% of these patients had either no treatment, meaning that heparin was not discontinued, or simply had heparin stopped with no DTI initiated. Only 5/23 (22%) of the patients in this cohort were placed on a DTI. Of these patients, 2 were also placed on warfarin, as they were noted to have active thromboses.

This data suggests that the management of patients suspected of having HIT at our institution is not consistent with the current recommendations with wasteful practices and inappropriate therapy. These results highlight opportunities for further education of clinicians regarding HIT.