Hereditary antithrombin deficiency pilot project registry from the American Thrombosis and Hemostasis Network.

ABSTRACT

BACKGROUND: Patients with hereditary antithrombin deficiency (HAD) have an increased risk of venous thromboembolism (VTE). The American Thrombosis and Hemostasis Network (ATHN) 12 HAD Pilot Project established a registry to collect data on patients with HAD. OBJECTIVES: To inform current practice and serve as a platform to design a multicenter global registry for patients with HAD. METHODS: The HAD registry was designed in 2020 to identify 100 patients with HAD receiving care at ATHN-affiliated centers. Demographics, type of HAD, thrombotic events, risk factors, anticoagulants, and antithrombin (AT) concentrate administration were recorded. RESULTS: Ninety-four patients were included; 65% were females; 51% had type 1 HAD. Mean age at diagnosis was 26 years (SD, 18 years); 61% had VTE 55% deep vein thrombosis and 27% pulmonary embolisms. Eight patients had arterial thrombosis. Recurrent thrombosis occurred in 58.6% of patients (44.8%) despite anticoagulation. The main risk factor for thrombosis in females was estrogen. Direct oral anticoagulants were prescribed in 30%, heparin in 34%, and warfarin in 32%. There were 139 pregnancies. Low-molecular-weight heparin was administered in 33% and AT concentrate in 19% and 11% prior to and after delivery, respectively. Twelve patients developed thrombosis in pregnancy. Seventy-nine patients underwent 239 surgeries or procedures, mainly gastrointestinal and vascular. Overall, 35% of participants received AT concentrate without adverse events. CONCLUSION: In ATHN 12, VTE was the predominant manifestation, frequently recurrent. There was a trend toward using direct oral anticoagulants. Low-molecular-weight heparin was administered in one-third of pregnancies and AT concentrate in one-fifth without adverse events. These data should encourage prospective studies to optimize the management of these patients.