SURGICALLY INDUCED ANGIOGENESIS TO COMPENSATE FOR HEMODYNAMIC CEREBRAL-ISCHEMIA

Background and Purpose The ischemic brain may stimulate angiogenesis t o compensate for impaired circulation. We examined the conditions prom oting such angiogenesis to provide the basis for surgical treatment. M ethods The degree of cerebral hemodynamic stress was studied in patien ts with moyamoya disease using the stable xenon-enhanced computed tomo graphic acetazolamide tolerance test and positron emission tomography. Patients were subjected to surgery in which scalp arteries were place d on the cerebral cortex without vessel-to-vessel anastomosis. Formati on of the newly vascularized collateral network connecting the implant ed artery to cortical arteries was assessed angiographically 12 to 17 months after surgery. Results Preoperative average resting cerebral bl ood flow for cortex that developed revascularization of cortical arter ies was not significantly different from that for cortex that did not. However, cortex that developed revascularization had an average preop erative increase of blood flow by acetazolamide treatment of -3.29+/-4 .6 mL/min per 100 cm(3) (n=20), which was significantly less (P=.0034) than that of cortex that did not show revascularization (20.7+/-4.3 m L/min per 100 cm(3); n=9). Good revascularization developed when the c ortex showed increase of blood flow by acetazolamide treatment of less than 0 (steal phenomenon). Preoperative positron emission tomography data indicated that revascularization developed when the cortex was un der ''misery perfusion.'' Postoperative hemodynamics were ameliorated by revascularization. Conclusions Angiogenesis to connect the implante d scalp arteries to the cerebral cortical arteries was selectively ini tiated when ischemia of hemodynamic origin existed.