Pathophysiologic assessment of stagnating arteries after removal of arteriovenous malformations.

PURPOSE To assess the hemodynamics and pathophysiology of stagnating arteries after removal of arteriovenous malformations (AVMs). SUBJECTS 50 patients with supratentorial pial AVMs underwent pre- and postoperative angiographic studies. RESULTS The following characteristics were found to correlate with stagnating arteries: 1) advanced patient age, 2) large AVM size, 3) markedly dilated feeders, 4) early postoperative angiograms, and 5) delayed restoration of feeding artery diameter. CONCLUSIONS The rate of blood flow in the former feeding arteries, expressed as v x pi x r2 (v = mean velocity, r = vessel radius), suddenly decreases after removal of AVMs. When dilatation persists postoperatively in these arteries the flow velocity decreases and stagnation takes place. Delayed postoperative restoration of feeding artery diameter may be caused by a decrease of elasticity due to long-standing hemodynamic stresses, and by increased postoperative vascular resistance of these arteries.