Abstract Number: PB0260
Meeting: ISTH 2022 Congress
Background: Heparin-induced thrombocytopenia (HIT) is rare among pediatric patients. The diagnosis of HIT depends upon clinical decision tools to assess its pre-test probability, supported by laboratory evidence of anti-PF4/heparin antibodies detected by either immunoassays or functional platelet activation assays.
Aims: To compare the use of the 4T score clinical decision tool, clinical characteristics and laboratory findings between pediatric and adult patients with suspected HIT.
Methods: We compiled all pediatric patients in our center for whom HIT testing was performed during the years 2014-2020. These were compared 1:3 with a cohort of adult patients. Clinical and laboratory data were obtained from the computerized medical records.
Laboratory diagnosis of HIT was performed with either particle gel immunoassay (PaGIA), antibody detection by the automated ACL-TOP 750® or a functional heparin activation test (HAT). Statistical analysis was performed using GraphPad Prism (version 7.0), USA.
Results: The cohort included 34 children (under 18 years) and 105 adults. Adults mostly received heparins for thromboembolism prophylaxis and treatment (72.4%, n=76), and were more frequently treated with LMWH. Children were mostly exposed during cardiopulmonary bypass and ECMO (61.8%, n=21), and were more frequently treated with UFH.
Compared with adults, children had significantly higher 4T scores (Figure 1). Nevertheless, adults had a slightly higher rate of a positive diagnosis of HIT (Figure 2).
Six out of 16 adult patients with a positive HIT test presented with thrombosis (37.5%) whereas all 3 pediatric patients with positive HIT test presented with thrombosis (p value 0.087).
Conclusion(s): In children laboratory tests for HIT are performed in accordance with the 4T score more often than in adults. Despite this, a positive diagnosis of HIT in children remains rare.
A potentially higher incidence of thrombosis in children may be attributable to the severity of underlying illness.
To cite this abstract in AMA style:Cohen O, Lange K, Budnik I, Lubetsky A, Tamarin I, Rosenberg N, Kenet G, Levy-Mendelovich S. Comparison of heparin-induced thrombocytopenia workup and clinical characteristics between pediatric and adult patients [abstract]. https://abstracts.isth.org/abstract/comparison-of-heparin-induced-thrombocytopenia-workup-and-clinical-characteristics-between-pediatric-and-adult-patients/. Accessed September 26, 2022.
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