PB0644 - Clinical characteristics and monitoring of oral anticoagulation with vitamin K antagonists in pediatric patients

Background: Vitamin K antagonists (VKA) are the most prescribed oral anticoagulants in pediatrics. However, VKA monitoring in children is complicated in "real world" .

Aims: To describe clinical features of pediatric patients receiving VKA. We analyze variables related to treatment, time in therapeutic range (TRT), and hemorrhagic and thrombotic complications.

Methods: A longitudinal, descriptive and prospective study was done. We reviewed clinical records of patients under 18 years old treated with AVK managed with anticoagulation monitoring between 2013 and 2023 . Sociodemographic variables, clinical characteristics and monitoring of anticoagulation were analyzed.

Results: Forty-four patients (98%) received acenocoumarol. Median age 13 years (IQR=10; 0-18). Valvular pathology (n=22; 48%) was the most frequent indication for anticoagulation (Table 1). Median duration of treatment was 10 months (IQR= 34; range 0-140). Anticoagulation monitoring was performed in 34 patients (79%), median of anticoagulation controls was 14 (IQR= 6.5; extremes 10-27). TRT at 6 months was >60% in 7 patients (43.7%). Currently, 9 patients (20%) are on VKA treatment. Last 12 months, 5 (55.5%) presented optimal TRT. Median of controls in the last 6 and 12 months were 16 (RIQ= 10; extremes 7-22) and 27 (RIQ= 9.5; extremes 19-42) respectively. In 13 patients (28.9%) treatment was temporarily discontinued. 31 hospitalizations occurred in 19 patients (42.2%). 13.3% (n=6) had 11 bleeding events. One (2.2%) developed prosthetic valve thrombosis treated with fibrinolysis and had intracranial hemorrhage (Table 2). 3 patients (7.9%) were exitus: 1 fungal infection after a cardiac transplantation, 1 severe heart failure, and 1 of unknown cause.

Conclusion(s): Most frequent indications for anticoagulation were cardiac valvular heart disease and congenital heart disease. Although the TRT achieved is slightly less than optimal, a low prevalence of thrombotic complications was observed. Individual variability and significant differences between children and adults reinforce to implement anticoagulation monitoring to achieve a better efficacy.