Prevalence of heparin-dependent platelet antibodies in children after cardiopulmonary bypass.
OBJECTIVE
To determine the prevalence of heparin-dependent platelet antibodies (HDPA) in children requiring heparin for >5 days after cardiopulmonary bypass surgery.


METHODS
Prospective, observational study.


METHODS
Tertiary care pediatric intensive care unit.


METHODS
Thirty children were enrolled: 15 patients <30 days old and 15 patients between 30 days and 12 yrs of age.


METHODS
Detection of HDPA by heparin-platelet factor 4 enzyme-linked immunosorbent assay after 5-10 days of postoperative heparin exposure. Positive or equivocal results were confirmed with serotonin release assay.


RESULTS
There were no confirmed cases of HDPA in this study (95% confidence interval 0-11.6%). Despite the lack of HDPA, the study population was at high risk of thrombosis with symptomatic clot developing in six patients (20%). Clinical models developed in adults to determine the pretest risk of heparin-induced thrombocytopenia were not valid in this study population.


CONCLUSIONS
The prevalence of HDPA in children after cardiopulmonary bypass surgery is low. After bypass surgery, critically ill children are at risk of developing thrombosis from multiple etiologies, and suspicion of heparin-induced thrombocytopenia needs to be confirmed with laboratory testing including a functional assay.
Hanson
Sheila J
SJ
Department of Pediatrics, Critical Care Medicine, Children's Hospital of Wisconsin and Medical College of Wisconsin, Milwaukee, WI 53226, USA. shanson@mcw.edu
Punzalan
Rowena C
RC
Ghanayem
Nancy
N
Havens
Peter
P
D000906:Antibodies / Q000097:blood*; D000925:Anticoagulants / Q000009:adverse effects* / Q000276:immunology; D001792:Blood Platelets / Q000276:immunology*; D002315:Cardiopulmonary Bypass; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006493:Heparin / Q000009:adverse effects* / Q000276:immunology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D008297:Male; D010978:Platelet Factor 4 / Q000276:immunology; D011183:Postoperative Complications / Q000139:chemically induced / Q000276:immunology; D011446:Prospective Studies; D013921:Thrombocytopenia / Q000139:chemically induced / Q000276:immunology
D000906:Antibodies; D000925:Anticoagulants; D010978:Platelet Factor 4; D006493:Heparin