Clopidogrel Dosing Scheme in Pediatric Cardiac Patients 0-24 Months Old Using P2Y12 Reaction Unit Monitoring.

OBJECTIVE: The use of clopidogrel for postprocedural primary thromboprophylaxis in pediatric cardiac patients is becoming more common. This study aimed to explore, using P2Y12 reaction unit (PRU) values, whether the currently recommended static low clopidogrel dose of 0.2 mg/kg/day for patients under 24 months is optimal, or if a gradual dosage escalation would be more appropriate; and to propose a hypothetical dosing scheme for clopidogrel thromboprophylaxis in these patients. METHODS: Exploratory, retrospective cohort study in cardiac patients 0-24 months old receiving clopidogrel for thromboprophylaxis between 2018 and 2021. Data collected from medical records included patient demographics and diagnoses, clopidogrel dosing and duration, PRU values, concomitant anticoagulant and antiplatelet therapies, adverse events, and outcomes. Exponential and linear regression analyses were employed to model dosage as a function of time using therapeutic PRU values and to identify the best-fit dosing scheme for clopidogrel. RESULTS: Forty-four cardiac patients on clopidogrel for thromboprophylaxis were included. No statistically significant difference was observed between the predicted dosing from the fitted and the referent regressions, indicating that the observed clopidogrel doses that achieved a therapeutic PRU followed a dosing gradient inconsistent with the static low dose (0.2 mg/kg/day) recommended by the Platelet Inhibition in Children On cLOpidogrel (PICOLO) trial during the first 24 months of age. CONCLUSIONS: Pediatric cardiac patients may require a gradual escalation of clopidogrel dosing with age, in contrast to the static low dose recommended by the PICOLO trial during the first 24 months of life. An age-based dosing scheme may prove beneficial for this age group. Prospective studies evaluating age-based clopidogrel dosing in this patient population could offer further insight into this relationship.