Abstract
Background
Individuals with inherited antithrombin deficiency (IATD) have a high risk of venous
thromboembolism (VTE). Most VTEs are managed with direct oral anticoagulants (DOACs),
but the utility of DOACs in antithrombin deficiency (ATD) is unreported.
Materials and Methods
Patients with IATD treated with DOAC were identified from our institutions' IATD registry.
We assessed patients' characteristics, ATD type, and initial VTE characteristics,
thrombosis recurrence and bleeding rates.
Results
Thirty-three patients received DOACs for 73 (38.5–111.5) months (median (interquartile
range)). Prior to taking DOACs, 12 (36%) patients had VTE recurrence: these occurred
after anticoagulation was ceased (4), nonadherence to VKA prior to DOAC use (3), or
during heparin use in pregnancy (5). There were no VTE recurrences on standard-dose
DOAC, except in a noncompliant patient receiving dabigatran. There was one recurrence
with compliant DOAC use—a patient receiving rivaroxaban 10 mg. Six (18%) patients
experienced clinically relevant bleeding, which was predominantly menorrhagia (5/6).
One major bleeding event, intracranial hemorrhage, occurred in a patient receiving
full-dose rivaroxaban who had refractory hypertension (0.5 events/100 patient-years).
In this cohort, compliant DOAC users had an overall VTE recurrence rate of 0.5/100
patient-years, whereas with low-dose DOACs the event rate was 3.5/100 patient-years.
Conclusion
Standard-dose DOACs appear efficacious and relatively safe in IATD.
Keywords
venous thromboembolism - antithrombin deficiency - anticoagulation - direct oral anticoagulants
