Occlusive hyperemia and normal pressure break through- physiopathology and management

Immediately following surgical excision of a cerebral AVM, even normal brain tissue surrounding the lesion is subject to hemorrhage, a phenomenon termed normal perfusion pressure breakthrough (NPPB) syndrome or occlusive hyperemia. According to this theory, arteries supplying cerebral AVMs become dilated and lose their capacity to dilate or constrict to autoregulate pressure. Acutely after removal of a cerebral AVM, excessive blood pressure in these arterial feeders can cause normal brain tissue to bleed. However, this theory still remains controversial.