Anatomical Variations of Brain Venous Sinuses in Patients with Arteriovenous Malformations: Incidental Finding or Causative Factor?

OBJECTIVE: Acquired anomalies of the dural venous sinuses (DVS) have been correlated extensively with the development of dural arteriovenous fistulas (DAVFs). Despite the known similarities of DAVFs' pathogenesis with that of arteriovenous malformations (AVMs), the relationship of venous sinuses anomalies with AVMs scarcely has been studied. We aimed to investigate whether patients with AVM show a greater prevalence of congenital DVS anomalies. We hypothesized that these congenital anomalies trigger AVM development during early childhood just as acquired DVS anomalies trigger DAVFs formation during adulthood.

METHODS: Angiographic anomalies of the brain venous sinuses were studied in a cohort of 45 consecutive patients with AVM and compared with the angiographic; venous sinus anomalies of a control group formed by a second consecutive; series of 45 patients with subarachnoid hemorrhage.

RESULTS: Congenital anomalies of any DVS were more frequent in patients with AVM than in the control group (49.8% vs. 22.2%; P = 0.015). Congenital abnormalities of the superior sagittal sinus not only were more frequent in patients with AVM (27% vs. 6.7%; P = 0.021) but seemed also related to the AVM location: in 5 of the 6 AVM cases with unilateral superior sagittal sinus aplasia, the AVM was ipsilateral to the venous anomaly.

CONCLUSIONS: Patients with AVM have a greater likelihood of congenital anomalies of any DVS. These anomalies seem to be related also to the AVM location. These findings suggest that congenital anomalies of DVS may be related to the development of AVMs.