An Analysis of the Characteristics of Lung Transplant Patients That Develop Heparin Induced Thrombocytopenia Type II (HIT) after Transplant

Abstract

Purpose Post-op lung transplant patients (LT) develop thrombocytopenia; to date the incidence or implications of HIT in LT has not been characterized. We describe the characteristics of patients undergoing lung transplantation who developed HIT. Methods and Materials This is a single center, retrospective chart review of LT who developed HIT after transplantation from 2006-2012. Charts were reviewed for demographic data, heparin exposure, hospital length of stay (LOS) and BOS. Results Seven patients out of 612 LT (n=7, age of 58±10 years, range 43-70 years, diagnosis: UIP=6, COPD=1) were identified with HIT after transplant. Time to diagnosis of HIT was 12±6 (range 2-20 days). Two patients underwent cardiopulmonary bypass with transplant and one patient was bridged on veno-venous ECMO. Baseline platelet count prior to OR was 180±95 k/ul (range 65-324 k/ul), average time to 50% drop in platelets was 7±5 days (range 1-12 days). Thromboembolic events (upper extremities=6, lower extremities=2, line related=6) were identified at mean day 12±7 (range 5-22 days). Six patents developed positive platelet factor 4 test and 5 of them had a positive serotonin release assay test. LT with a negative serology were still treated for HIT due to the high clinical suspicion. All patients were treated with bivalirudin and the platelet count returned to normal values in 6 patients (mean 16±11 days, range 7-37 days) and remained on warfarin. On follow up none of the patients demonstrated BOS and surveillance bronchoscopies were not done for acute cellular rejection. The hospital LOS was on average 27 days compared to 17 days in the control group (p = 0.012). Conclusions HIT, although rare, should be considered during the post-op period in LT presenting with thrombocytopenia and exposure to heparin. Platelet counts went back to baseline with discontinuation of heparin and initiation of bivalirudin. None of our patients had progressed to BOS. Hospital LOS was significantly higher in the HIT group compared to similar controls.