PubMed1999
Dural arteriovenous fistulas (dAVFs) can cause cerebral venous hypertension (VHT). The most common mechanism is due to the fact that some dAVFs can drain retrogradelly in cortical (better defined as leptomeningeal) veins (directly or after drainage in a dural sinus) causing venous engorgement and consequently an impairment of the cerebral venous drainage. However, more rarely, dAVFs without a cortical venous drainage can also be responsible for VHT probably due to dAVF shunts causing insufficient antegrade cerebral venous drainage. In addition, dAVFs are often associated with stenosis and/or thrombosis of dural sinus(es) which can worsen the VHT. Raised pressure within the superior sagittal sinus causes impeded cerebrospinal reabsorption in the arachnoid villi allowing increased intracranial pressure. The venous engorgement in the cortical veins can cause a venous congestive encephalopathy analogous to the venous congestive myelopathy of the spinal dural AVFs. Clinically VHT can cause not only symptoms related to increased intracranial pressure but also seizures, neurological deficits, impairment of the cognitive functions and dementia. An important aspect is the risk of hemorrhage in dAVFs with a leptomeningeal venous drainage leading to VHT. Although the term VHT sensu strictu should be used if venous pressure measurements are performed, angiographic criteria for VHT such as delayed circulation time, venous engorgement and abnormal visualization of the cerebral veins are well established. The purpose of our study was to evaluate the angiographic signs of VHT in patients with dAVF and to study the course of the VHT and of the clinical signs of increased intracranial pressure before and after dAVF endovascular treatment. A retrospective chart analysis of 22 patients (13 males, 9 females) ranging in age from 20 to 87 years (mean: 53 ys.) with a dAVF associated with angiographic signs of VHT was performed. Ten dAVFs were located on the transverse/sigmoid sinus(es), 6 on the superior sagittal sinus, 3 on the petro-tentorial incisura, 1 on the inferior petrosal sinus, 1 on the anterior ethmoidal region and 1 on the Galen vein region. All dAVFs had a retrograde leptomeningeal venous drainage. Stenosis or thrombosis of the dural AVF sinus was observed in 17 cases and stenosis or thrombosis of another sinus(es) and/or of the jugular vein in 8 cases. In 11 patients, the angiographic signs of VHT were global affecting the entire cerebral venous drainage and, in the other 11 patients, the VHT was focal. The VHT caused clinical symptoms of increased intracranial pressure in 18 patients. Other clinical findings included: bruit (11 cases), seizures (3 cases), vertigo (3 cases), visual deficits (2 cases) and impairment of cognitive functions (4 cases). Three patients presented hemorrhage (one parenchymal hematoma, one hemorrhagic infarction and one subarachnoid hemorrhage). The 4 patients without clinical symptoms of increased intracranial pressure presented only bruit in 2 cases, bruit and vertigo in 1 case, bruit and hemorrhagic infarction in another one. The dAVFs were treated by endovascular therapy (arterial approach: 3 cases, venous approach: 6 cases and both arterial and venous approach: 13 cases). Endovascular sessions ranged from 1 to 7 (mean: 2.8) for each patient. After the endovascular treatment, in 12 patients with complete occlusion of the dAVF, the disappearance of angiographic signs of VHT and clinical cure were observed. In 8 patients with partial occlusion of the dAVF, the disappearance of angiographic signs of VHT and clinical cure were observed in 4 cases (almost complete dAVF occlusion in 2 cases); in the other 4 cases, only reduction the angiographic signs of VHT and clinical improvement were obtained. In all 16 patients who were clinically cured angiographic signs of VHT disappeared despite the persistence of dAVF shunts as observed in 4 cases. (ABSTRACT TRUNCATED)