Thrombophilia screening in asymptomatic children

High prevalence of thrombophilic traits in children with family history of thromboembolism

OBJECTIVES

To determine a proximate family history of venous thromboembolism (VTE) in (1) the prevalence of thrombophilia; (2) the frequency of recommended changes in management resulting from thrombophilia evaluation; and (3) outcomes in longitudinal follow-up.

STUDY DESIGN

Laboratory thrombophilia investigation was performed in 56 children with first- or second-degree family history of thromboembolism before age 55 years, but without personal history of thromboembolism, who were enrolled in a prospective inception cohort. VTE risk factors, family history, thrombophilia findings, and management recommendations were systematically collected, along with thromboembolism risk episodes/exposures, prophylactic anticoagulation, major bleeds, and thromboembolism events during follow-up.

RESULTS

The frequencies of all thrombophilia traits were higher than the general population. Among 32 children who underwent complete laboratory evaluation, 34% had >or=2 traits. Thrombophilia testing led to recommendations for risk-based transient antithrombotic prophylaxis in 71% of subjects. No thromboembolism episodes developed during more than 900 patient-months of follow-up, although at-risk exposures were infrequent.

CONCLUSION

Risk-stratified approaches to primary prevention of pediatric VTE should be further evaluated in cooperative prospective studies.

Thrombophilia in Children: Who to Test, How, When, and Why?

Thrombosis and thrombotic risk factors in children are receiving increased attention, and pediatric hematologists frequently are asked to evaluate children with symptomatic thrombosis, or asymptomatic children who have relatives affected with either thrombosis or thrombophilia. The clinical utility of thrombophilia testing has become increasingly debated, both in adults and children. Children with thrombosis are a heterogeneous group, and it is unlikely that a single approach to testing or treatment is optimal or desirable. A causative role of inherited prothrombotic defects in many pediatric thrombotic events, particularly catheter-related thrombosis, has not been established. Pediatric patients most likely to benefit from thrombophilia testing include adolescents with spontaneous thrombosis and teenage females with a known positive family history who are making choices about contraception. Recent data suggest that some inherited thrombophilic defects are associated with a higher risk of recurrent venous thromboembolism in children, though optimal management of these patients has yet to be determined. The decision to perform thrombophilia testing in asymptomatic patients with a family history should be made on an individual basis after discussion with the family. Given that the field of pediatric thrombosis continues to evolve, and the settings in which many of these events occur are unique to childhood, prospective longitudinal analyses of such patients to determine outcome and response to treatment as well as the impact of known thrombophilic states on these outcomes are clearly needed.