Hypercoagulability in patients with indirect carotid cavernous fistulas

BACKGROUND To assess patients with indirect carotid-cavernous fistulas (CCF) for evidence of hypercoagulable state (HS) by combination of comprehensive medical questionnaire and laboratory testing. METHODS Patients with confirmed diagnosis of CCF treated between 2003 and 2019 were included and administered a questionnaire screening for HS risk factors and undergone laboratory investigations which included complete blood count (CBC), prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, antiphospholipid antibodies (lupus anticoagulant and anticardiolipin antibody titres), Factor V Leiden, prothrombin, protein C, protein S, antithrombin III, homocysteine, prothrombin G20210, CALR and JAK2 mutation screening. Participants with abnormal laboratory testing and/or past history of ischemic stroke, atrial fibrillation, cancer or hypercoagulability-associated hereditary disorders were deemed to have HS. RESULTS Twenty-two patients were enrolled. Seventeen were women and the mean age at diagnosis was 60. Fourteen (64%) had evidence of HS: six on medical history, three with laboratory evidence and five with both. Eight (36%) had current abnormal hypercoagulability markers. One had a diagnosis of Klippel-Trenaunay Syndrome, but no others had evidence of hereditary thrombophilia. Nine were on anti-coagulation initiated after diagnosis of stroke or atrial fibrillation discovered on average 5.5 years after the diagnosis of CCF. CONCLUSION A total of 64% percent of patients with previous indirect CCF had evidence of underlying HS indicating that hypercoagulability might play a role in the pathogenesis of CCF. The results support need for comprehensive testing for underlying HS in patients with indirect CCFs to better identify, manage, and prevent further thromboembolic events.