Prevalence and Clinical Significance of Heparin Induced Antibodies in Chronic Hemodialysis Patients and Cardiac Surgery Patients

Abstract

The prevalence of heparin-induced antibodies (HIA) varies widely among reported series, but is generally higher in cardiac surgery than hemodialysis patients. This study was designed to explore the reasons behind the different prevalence of HIA in these two populations. Blood samples from all hemodialysis and cardiac surgery patients in our hospital were examined for HIA. Heparin-induced thrombocytopenia (HIT) was suspected when platelet count was <150,000 in the hemodialysis group, and >50% decline in platelet count in the cardiac surgery group. 79 hemodialysis and 40 cardiac surgery patients were studied. HIA prevalence was significantly higher in cardiac surgery than in hemodialysis patients (65% v 10.1%, respectively, P<0.00001). Conversely, the prevalence of suspected clinical HIT was 37.5% in the hemodialysis and 11.5% in the cardiac surgery group. Prevalence of HIA was higher in patients who were tested during the first 90 days of hemodialysis than in those tested at later times. One-year mortality was 37% in HIA positive and 19% in HIA negative hemodialysis patients. Prevalence of HIA was significantly lower in hemodialysis as compared with cardiac surgery patients. Our data suggest that the observed difference in HIA prevalence was either population dependent, or due to different timing of heparin administration in the two groups.