REDEFINED ROLE OF ANGIOGENESIS IN THE PATHOGENESIS OF DURAL ARTERIOVENOUS-MALFORMATIONS

To investigate the role of angiogenesis in the pathogenesis of dural a rteriovenous malformations (AVMs), 40 rats underwent common carotid ar tery-external jugular vein (CCA-EJV) anastomosis, bipolar coagulation of the vein draining the transverse sinus, and sagittal sinus thrombos is to induce venous hypertension. Fifteen rats underwent a similar sur gical procedure, but venous hypertension was not induced. The 55 rats were divided into seven groups. Four groups, each containing 10 rats, underwent induced venous hypertension. The other three groups, each co ntaining five rats, did not undergo induced venous hypertension. After 1, 2, or 3 weeks, dura mater was obtained from one group of hypertens ive rats and from one group of nonhypertensive rats and was assayed fo r angiogenic activity (rabbit cornea bioassay). The remaining group of 10 hypertensive rats was not assayed to determine if sampling affecte d dural AVM formation. Unlike rats without CCA-EJV anastomosis, rats w ith CCA-EJV anastomosis had significantly increased postoperative sagi ttal sinus pressures (p < 0.0001). Mean angiogenesis indices were sign ificantly greater in rats with venous hypertension than in rats withou t venous hypertension (p = 0.004). Dural AVMs formed in 42% of the 55 rats and facial AVMs formed in 51%. Angiogenic activity correlated pos itively with Venous hypertension (p = 0.74). Development of dural AVMs correlated positively with both Venous hypertension (p = 0.0009) and angiogenic activity (p = 0.04). These data indicate that venous hypert ension may induce angiogenic activity either directly or indirectly by decreasing cerebral perfusion and increasing ischemia, and that dural AVM formation may be the result of aberrant angiogenesis.