De Novo Pial Arteriovenous Fistula Associated With Cerebral Infarction and Venous Hypertension: Report of 2 Cases Suggesting a “Second Hit Theory”

Abstract

ABSTRACT BACKGROUND AND IMPORTANCE The etiology of de novo pial arteriovenous fistula (AVF) is unknown. We found 2 cases of de novo pial AVF, which appeared after cerebral infarction and which was associated with venous hypertension secondary to venous sinus thrombosis with a dural AVF (dAVF). Additional angiogenic stimuli (second hit) were considered as one of the mechanisms of de novo pial AVF. CLINICAL PRESENTATION A 63-yr-old male was admitted to our hospital due to an intraventricular hemorrhage. He had a history of cerebral infarction 2 yr before. Angiography demonstrated multiple dAVFs with bilateral occlusion of the distal transverse sinus associated with prominent retrograde cortical venous drainage. A pial AVF was found at the border of his previous cerebral infarction. Both lesions were successfully treated using endovascular technique. A second case involved a 47-yr-old female who was admitted to our hospital due to venous infarction also associated with sinus thrombosis. De novo pial AVF at the border of the venous infarction and dAVF at the transverse sigmoid junction were demonstrated on angiography 6 mo later. CONCLUSION We speculate that venous hypertension associated with additional angiogenic stimuli (second hit) due to brain ischemia and/or brain injury related to infarction caused de novo pial AVF in these 2 cases.