Risk factors for serious adverse events related to vitamin K antagonists in children with congenital or acquired heart disease: a prospective cohort study.

OBJECTIVES: To assess the occurrence of thrombosis and major bleeding in children with congenital or acquired heart disease (CAHD) treated with VKA and to identify risk factors for these serious adverse events (SAE). STUDY DESIGN: All children enrolled in our VKA dedicated educational program between 2008 and 2022 were prospectively included. The time in therapeutic range (TTR) was calculated to evaluate the stability of anticoagulation. Statistical analysis included Cox proportional hazard models. RESULTS: We included 405 patients. Median follow-up was 18.7 (9.3-49.4) months. The median TTR was 83.1 % (74.4 %-95.3 %). No deaths occurred because of bleeding or thrombotic events. The incidences of thrombotic and major bleeding events were 0.9 % (CI95 % [0.1-1.8]) and 2.3 % (CI95 % [0.9-3.8]) per patient year, respectively. At 1 and 5 years, 98.3 % (CI95 % [96.2 %-99.2 %]) and 88.7 % (CI95 % [81.9 % 93.1 %]) of patients were free of any SAE, respectively. Although the mechanical mitral valve (MMV) was associated to major bleeding events (HR = 3.1 CI95 % [1.2-8.2], p = 0.02) in univariate analysis, only recurrent minor bleeding events (HR = 4.3 CI95 % [1.6-11.7], p < 0.01) and global TTR under 70 % (HR = 4.7 CI95 % [1.5-15.1], p < 0.01) were independent risk factors in multivariable analysis. In multivariable analysis, giant coronary aneurysms after Kawasaki disease (HR = 7.8 [1.9-32.0], p = 0.005) was the only risk factor for thrombotic events. CONCLUSION: Overall, VKA therapy appears to be safe in children with CAHD. Suboptimal TTR, regardless of the indication for VKA initiation, was associated with bleeding events.

Home point-of-care international normalised ratio monitoring sustained by a non-selective educational program in children.

Adverse events related to vitamin K antagonist (VKA) therapy might be reduced by point-of-care international normalised ratio (POC INR) monitoring supported by an education program (EP). Our aim was to evaluate the efficacy of a non-selective VKA paediatric EP (regardless of the social, economic, educational or linguistic levels) by analysing the time spent in the therapeutic range (TTR), VKA adverse events and compliance to treatment, and INR control prescriptions. The EP was modified from the pediatric EP previously described but improved by a specifically devised child-focused game. One hundred four consecutive children (median age 8 years) receiving VKA were included in a standardised EP. Patients were in self-testing, and dose adjustments were made by a single physician for three tolerance ranges according to the underlying disease: [2.5-4], [1.8-3.2], and [1.5-2.5]. The median follow-up was 481 days [70-1,001]. The overall TTR was 81.4% [36-100]. The TTR were 74%, 85.6% and 89% for the ranges [2.5-4], [1.8-3.2], and [1.5-2.5], respectively. These results were sustainable during the study period. Only one serious VKA adverse event was recorded. The median number of POC INR tests was 2.5 [1.6-5.7] INR per patient and month. Patients/families performed POC INR when requested in 86.9% of the cases. More than 90% of the families found the EP supportive and wished to follow a long-term reinforcement program. In conclusion, this non-selective child-focused EP for VKA therapy, strongly supported by our dedicated game, is useful in maintaining efficacy, safety and compliance to anticoagulation and its monitoring.