Abstract
Normal perfusion pressure breakthrough phenomenon is a serious complication in surgery for AVMs. In this report, we studied capillary vessels of the brain adjacent to the nidus of arteriovenous malformations. We analyzed surgical specimens of 8 patients with large AVMs with a nidus of more than 4 cm and 10 patients with medium sized AVMs (4>nidus>2cm) histopathologically. The results indicate that the capillary vessels of almost all cases were stained well by the factor VIII related antigen immunohistochemically, no matter how large they were. The capillary vessels in patients with large AVMs could be stained positively with factor VIII related antigen at sites much farther from the nidus than could the vessels in patients with smaller AVMs. One patient developed postoperative intracerebral hemorrhage because of perfusion breakthrough syndrome. In this case, the capillary vessels were stained poorly with factor VIII related antigen, and astrocytes were stained by GFAP around the capillary vessels. Therefore, we must be careful with cases where capillary vessels stain poorly because the capillaries adjacent to the nidus are severely injured by ischemia, which is most probably the cause of breakthrough hemorrhage.
