A prospective study of the prevalence of heparin‐induced antibodies and other associated thromboembolic risk factors in pediatric patients undergoing hemodialysis

Abstract

Heparin, which is used at high doses in hemodialysis patients, may induce antibodies favoring thromboembolic complications. We prospectively investigated the prevalence of heparininduced platelet-reactive antibodies in a cohort of 38 pediatric hemodialysis patients, by means of heparin/platelet factor 4 (H/PF4) ELISA and heparin-induced platelet activation assay (HIPA). We also assessed other acquired and congenital hypercoagulable states. Heparin-induced antibodies were detected in 13 and 21% of patients with HIPA and ELISA, respectively. Anti-H/PF4 antibodies were negatively correlated with the number of hemodialysis sessions. These antibodies disappeared after a median time of 6 months despite continuing heparin treatment. The prevalence of antiphospholipid antibodies was 21% (anticardiolipin 10.5%, anti-b2GPI 13%, and lupus anticoagulant 5%). Blood levels of homocysteine, factor VIII, and fibrinogen were significantly higher and factor II levels were significantly lower in hemodialysis patients than in controls, whereas factor VII, factor IX, and natural coagulation inhibitor levels were similar in patients and controls. Overall, 26 of 38 patients had at least one biomarker of hypercoagulability, but only 1 patient, without anti-H/PF4 antibodies, presented with thrombosis. In conclusion, heparin induces the transient production of anti-H/PF4 antibodies in children undergoing hemodialysis, but other abnormalities probably contribute to hypercoagulability. These findings may help to improve the diagnosis and management of thrombotic events in hemodialysis patients. Am. J. Hematol. 81:328-334, 2006. V V C 2006 Wiley-Liss, Inc.

Thrombophilic Factors Do Not Predict Outcomes in Renal Transplant Recipients Under Prophylactic Acetylsalicylic Acid

“…In our cohort, the seemingly high global prevalence of thrombophilic factors (80.6%) is related to the fact that we tested for the majority of acquired or inherited thrombophilic factors (9) simultaneously, which has not been done previously. The prevalence of each individual thrombophilic factor we report here is within the range reported by others (6,11,14,19–21,26–30). These prevalences are higher than those observed in the general population (except for FV, prothrombin and GPIIIa genetic variants).…”

“…One limitation of our study is that we did not perform a second assay to control for positive lupus anticoagulant and antiphospholipid antibodies. While this would have been desirable, the prevalence we found with this single assay was similar to the figures usually reported in dialysis patients (21,26–30). This suggests that our population was not biased toward an overrepresentation or underrepresentation of patients with these two thrombophilic factors.…”

Systematic review on heparin-induced thrombocytopenia in children: a call to action

“…Nine studies were included for investigation of the primary objective. A total of 335 neonates comprising patients undergoing cardiac surgery, with or without cardio‐pulmonary bypass (CPB), or admitted to a neonatal intensive care unit (NICU), and 558 older children undergoing cardiac surgery (the vast majority under CPB), undergoing hemodialysis or admitted to a pediatric intensive care unit (PICU) were included (Table A,B).…”

A Practical Guide to the Management of the Fetus and Newborn With Hemophilia

“…In some circumstances—for example a 250 IU vial of FVIII concentrate given to a 3 kg newborn—this could result in factor levels substantially above 100% of normal. Elevated FVIII has been associated with thrombotic events in some populations of pediatric patients, 48,49 while elevated FIX has not. 48 However, neither association has been examined specifically in newborns, so it is worth considering the potential risks of elevated factor levels as the result of replacement therapy in these patients.…”