PB0284 - Resolution rates of provoked venous thrombus embolism in pediatric patients managed at a tertiary care center

Background: The incidence of venous thromboembolism (VTE) is increasing in children, provoked by multiple risk factors such as central vascular catheters (CVCs), cancer, infection, and estrogen therapy. Until recently, pediatric patients with provoked VTE were routinely treated with anticoagulation for 3 months as long as risk factors were resolved. There is limited evidence regarding resolution rates in pediatric patients at the end of treatment period.

Aims: To determine rates of complete resolution (CR), partial resolution (PR), and stable thrombosis (ST) in pediatric patients with provoked VTE.

Methods: Retrospective chart review of non-neonate pediatric patients (>1 month to 18 years of age) with VTE diagnosed in or admitted to McMaster Children’s Hospital between 2008 and 2020 (inclusive). Data extraction included demographics, thrombosis diagnosis, management, and follow-up imaging.

Results: 377 patients were diagnosed with 444 clots (Upper extremity deep vein thrombosis (DVT): 132, lower extremity DVT: 96, Pulmonary embolism: 54, Cerebral sinovenous thrombosis: 47 Inferior/superior vena cava: 22, Portal vein thrombosis: 28, Renal vein thrombosis: 3, Cardiac: 25, Other VTE: 37). Median age was 10 years and male to female ratio was 0.90:1. Of the 228 DVT episodes, 141 were occlusive DVT, 76 were non-occlusive DVT, and 11 were unknown. Common provoking factors were CVCs (50.7%), infection (34.7%), surgery (21.8%), and oral contraceptives (10.3%). The most frequently used anticoagulants were low-molecular-weight heparin (81.7%), direct oral anticoagulants (5.0%), and warfarin (2.7%). Seven patients (1.9%) had surgical thrombectomy. Out of 248 patients that had a 3-month follow up, there were 287 clots. The rates of CR, PR, and ST were 56.4%, 30.9%, and 12.7%, respectively. Seven patients (2.8%) had recurrent thrombosis.

Conclusion(s): The rate of CR in pediatric patients with provoked VTE is comparable to adults. Larger prospective multicenter studies are required to further validate these research findings.