Incidence of hereditary thrombophilia in patients with cranial dural arteriovenous fistulae

Severe papilledema and multiple hypercoagulability abnormalities in patient with dural arterio-venous fistulas

A 54-year-old man noticed right-sided pulsatile tinnitus for the past six months and recently started experiencing transient visual obscurations when standing up. MRI demonstrated two separate brain dural arteriovenous fistulas (bdAVF) in sagittal and right sigmoid dural sinuses. Neuro-ophthalmological exam demonstrated severe bilateral optic disc edema with preserved visual acuity but early nerve fiber bundle defects on visual field testing. Hypercoagulable profile testing revealed very elevated D-dimer, significantly decreased protein S level and elevated homocysteine levels. This case highlights importance of referring all patients with bdAVFs for neuro-ophthalmological consultation as venous hypertension can cause increased intracranial pressure and resultant papilledema. Papilledema does not affect central vision until late stages when visual loss is irreversible thus screening for its presence and pre-treatment extent of peripheral visual loss is paramount. It also demonstrates that hypercoagulable workup should be initiated in all patients with bdAVF in order to prevent future thromboembolic events.

Association between Dural AVFs and Cerebral Venous Thrombosis

BACKGROUND AND PURPOSE

Recent reports suggest an association between dural AVFs and cerebral venous thrombosis. We aimed to investigate the specific temporal and anatomic association between the 2 conditions.

MATERIALS AND METHODS

A consecutive cohort of adult patients with dural AVFs was seen at Amsterdam University Medical Centers (2007-2020). An experienced neuroradiologist re-evaluated the presence and imaging characteristics of dural AVFs and cerebral venous thrombosis on all available imaging. The temporal (previous/concurrent/subsequent) and anatomic (same/adjacent/unrelated venous sinus or vein) association between dural AVFs and cerebral venous thrombosis was determined.

RESULTS

Among 178 patients with dural AVFs, the mean age was 58.3 (SD, 13.2) years and 85 (48%) were women. Of 55 patients (31%) with cerebral venous thrombosis, 34 (62%) were women. Four patients (7%) had cerebral venous thrombosis before the development of a dural AVF, 33 (60%) had cerebral venous thrombosis at the time of dural AVF diagnosis (concurrent), and 18 (33%) developed cerebral venous thrombosis during follow-up after conservative treatment. The incidence rate of cerebral venous thrombosis after a dural AVF was 79 per 1000 person-years (95% CI, 50-124). In 45 (82%) patients with dural AVFs and cerebral venous thrombosis, the thrombosis was located in the same venous sinus as the dural AVF, whereas in 8 (15%) patients, thrombosis occurred in a venous sinus adjacent to the dural AVF.

CONCLUSIONS

One-third of patients with a dural AVF in this study were diagnosed with cerebral venous thrombosis. In almost two-thirds of patients, cerebral venous thrombosis was diagnosed prior to or concurrent with the dural AVF. In 97% of patients, there was an anatomic association between the dural AVF and cerebral venous thrombosis. These data support the hypothesis of a bidirectional association between the 2 diseases.

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.

Transvenous Approaches to Embolization of Dural Arteriovenous Fistulae of the Cavernous Sinus

Dural arteriovenous fistulae of the cavernous sinus (CS) (previously often referred to indirect carotid cavernous fistulas) are rare vascular shunts involving meningeal branches and osseous branches of the external or internal carotid arteries and the CS. They typically present with ocular symptoms including pain, conjunctival injection, and proptosis. Left untreated there may be a risk of vision loss, and fistulas with cortical venous reflux through either the deep or superficial venous system may cause intracranial venous congestion or hemorrhage. Endovascular embolization is the standard treatment, and while transarterial routes may appear possible, transarterial embolization has considerable risks of ischemic complications. Conversely, transvenous routes achieve a high rate of fistula occlusion with a low risk of peri-procedural morbidity. Procedural success depends on identification of the venous outflows from the fistula and localization of the fistulous point, to select the best route of access to the CS, including the inferior petrosal sinus (IPS), intercavernous sinus, or superior ophthalmic vein, among others. Even if the IPS is not visualized, it may be possible to recanalize it to gain access to the CS. Embolization can be performed with a combination of coils, fibered coils, and liquid embolic agents, focusing on occlusion of the fistulous point or blocking high-risk venous outflow pathways. In this review we will highlight procedural pearls and potential pitfalls and our typical approach to these lesions based on illustrative examples.