An occlusion and stenosis of the venous drainage system in cerebral AVMs--angiographical investigation

We investigated angiographically occlusion or stenosis of draining veins in cases of arteriovenous malformations (AVMs). The subjects were 51 cases who were diagnosed as cerebral AVMs by angiography in our hospital between April 1973 and January 1991. Those consisted of 8 dural AVMs, 3 mixed pial-dural AVMs, and 40 pial AVMs. Angiography was stereoscopically done in all cases. Angiograms obtained prior to treatment were retrospectively analyzed. Cases of dural AVMs or arteriovenous fistulae in the cavernous sinus were excluded from the subjects. Eight of 51 cases (16%) had occlusion or stenosis of draining veins; i.e., 2 dural AVMs, 1 mixed pial-dural AVM, 5 pial AVMs. One of 2 dural AVMs was located in the sigmoid sinus, and another involved the superior sagittal sinus. One mixed pial-dural AVM was a vein of Galen aneurysm. Occlusion or stenosis was recognized at the junction of the vein of Galen to the straight sinus (3 cases), in the straight sinus (2 cases), at the junction of the vein of Labbe to the transverse sinus (1 case), in the superior sagittal sinus (1 case), and in the sigmoid sinus (1 case). Two of 8 cases with occlusion or stenosis of draining vein presented with hemorrhage at the site of AVMs. In cases of pial AVMs, occlusion or stenosis of draining vein seemed be related to endothelial changes due to turbulent and irregular flow. On the other hand, in cases of dural AVM with dural sinus occlusion, sinus abnormalities may precede the formation of fistulous communications.(ABSTRACT TRUNCATED AT 250 WORDS)