Incidence of Heparin Induced Thrombocytopenia in the Transplant Population: A Large Retrospective Cohort, Single Transplant Centre Experience

Heparin induced thrombocytopenia (HIT), a prothrombotic complication of heparin therapy, can lead to serious thromboembolic events and cause significant morbidity and mortality. Its occurrence has never been studies in transplant patients, where use of heparin products is very common. We aim to study its prevalence in the transplant population at our institute.

This is a retrospective cohort, single center study which looked into the clinical and laboratory database of all the patients that has undergone any kind of transplant at our institution over a period of 25 years (January 1985 - December 2010). In patients with clinical suspicious of HIT, a pre-test probability was calculated using the 4T scoring system. Results of the laboratory test like the ELISA HIT antibody (HIT ab) test and the functional serotonin release assay test (SRA) along with clinical manifestation of skin necrosis or thromboembolic events were reviewed.

Medical records of 2800 patients that has undergone transplant from January 1985- December 2010 were reviewed. HIT antibody assay was performed in 262 patients in which HIT was suspected. Of these, only 48 (18%) patients (mean age 57 ± 11 years, 71% women) had HIT ab positive, 9 were pre transplant recipient and remaining 39 were post transplant recipients. Baseline characteristics of the transplant population are illustrated in Table.1. Confirmatory test, SRA was performed in 8 HIT antibody positive patients, of whom only 4 were positive. The mean 4T score in HIT suspected patients was 3.7 ±1.3, while the score in HIT ab positive patients was 4.2 ± 1.2. Thrombotic complications were seen in 11(0.4%) patients, with the highest incidence rate of 1% in heart transplant recipients. No transplant patient had skin manifestations. Direct Thrombin inhibitor (DTI) was used only in 5 patients who had thrombotic events. No other complication or mortality was reported in any of the HIT ab positive transplant patients.

To our knowledge, this is the first study of its kind that has shown very low incidence of HIT in transplant population. In conclusion, transplant patients can safely undergo any type of organ transplant, without having any peri or post operative complications or immediate mortality related to HIT.

No relevant conflicts of interest to declare.