Abstract
Objective The use of apixaban in the pediatric cardiac population
is expanding. We describe our apixaban dosing and monitoring strategy in
children and young adults awaiting heart transplantation, along with
outcomes related to bleeding and thrombosis during wait-list and early
post-transplant periods. Methods This study is a retrospective,
single center analysis of all patients receiving apixaban while awaiting
cardiac transplantation. Weight-based dosing was monitored with peak
drug-specific anti-Xa chromogenic analysis. Significant post-operative
bleeding defined by chest tube output or need for surgical intervention.
Results From September 2020 through December 2022, 19 patients,
median age 13.5 years (6.1, 15.8 years), weighing 48.9 kg (15.4, 67.6)
received apixaban while awaiting transplant. Indication for apixaban was
prophylaxis (n=18, 3 with ventricular assist devices) and treatment of
thrombus (n=1). There were no clinically relevant non-major or major
bleeding, nor thrombotic events while awaiting transplant. The median
time from last apixaban dose to arrival in the operating room was 23.2
hours (15.6-33.8), with median random apixaban level of 37 ng/ml (28.3,
59), 6.3 hours (4.8, 8.4) prior to arrival in the operating room. 32%
of patients had significant post-operative bleeding based on chest tube
output post-transplant or need for intervention. No patients meeting
criteria for significant postoperative bleeding were thought to be
attributable to apixaban. Conclusion Careful use of apixaban can
be safe and effective while awaiting heart transplant. There was no
appreciable increase in perioperative bleeding. The use of apixaban is
promising in providing safe, predictable and efficacious anticoagulation
while avoiding additional patient stressors.