The Role of Hemodynamic Assessment in Patients with Cerebral AVMs

Abstract

In order to investigate cerebral hemodynamics in arteriovenous malformations (AVM), 27 patients — after a complete angiographic study — undertook cerebral blood flow (CBF) measurements and 17 of them also transcranial Doppler (TCD) sonography. On admission, 12 patients presented neurological impairment unrelated to previous hemorrhage. The mean AVM volume was 27 cm3. In 17 patients the lesion was surgically removed; in 12 of them embolization was performed pre-operatively. Five patients underwent moderate to severe hyperemic complications. Clinical aspects (neurological presentation and post-operative deterioration due to hyperemic complications) were related to the following radiological and instrumental factors:AVM volume, AVM location, angiographic steal (adjacent and/or remote), hemispheric hypoperfusion, regional hypoperfusion (adjacent and/or remote), and mean flow velocity on AVM feeders. As compared to patients without deficits, patients with neurological deficits unrelated to previous hemorrhage presented higher AVM volume (31 cm3 vs. 26 cm3), lower hemispheric CBF (45 vs. 50 m1/100g/min) and higher flow velocity on TCD (133 vs. 122 cm/s); no relation was found with respect to angiographic steal (type and incidence), AVM location and regional hypoperfusion. As compared to patients without hyperemic complications, patients with post-operative hyperemic complications presented a higher incidence of angiographic steal, adjacent and remote (3/5 vs. 1/12), a higher AVM volume (29 vs. 21 cm3 as mean), a higher hemispheric CBF (61 vs. 46 m1/100g/min; p < 0.05) and a higher flow velocity on TCD (137 vs. 111 cm/s). Hyperemic complications were less frequent in patients with frontal AVMs, who also presented the lowest CBF values. Regional steal detected on angiography and regional hypoperfusion were not associated, neither flow velocity was significantly increased in patients presenting any of these two features; nevertheless all of these aspects were influenced by volume and location of the AVM. In conclusion, angiographic steal, regional hypoperfusion and increased TCD velocity presented a correlation with AVM volume and location; moreover clinical deficits (on admission) and hyperemic complications were both related with higher AVM volume and TCD velocity, but were associated with different CBF patterns.