Dysplastic Vessels after Surgery for Brain Arteriovenous Malformations
Background and Purpose: To determine frequency and predictors of residual dysplastic vessels on cerebral angiography after surgery for brain arteriovenous malformation (AVM). Methods: The 240 prospectively enrolled surgical patients from the New York AVM Databank underwent 269 AVM-related surgical procedures between July-01, 1989 and June-30, 2000. Reported postoperative brain angiographic findings were classified post hoc as (1) normal, (2) persistent dysplastic vessels, (3) residual AVM, (4) focal hyperemia in the surgical bed, or (5) other changes. Univariate and multivariate models were applied to determine associations with dysplastic vessels on postoperative angiography. The factors evaluated were patient age, gender, preoperative AVM size, anatomic AVM location, number of embolization procedures prior to surgery, and the time interval between AVM surgery and the postoperative angiogram. Results: Of the 224 documented angiograms, 73 (34%) were performed immediately and 147 (65%) one or more days after surgery. In 100 (45%) of them, no abnormal changes were seen, while 78 (35%) showed dysplastic vessels, 24 (11%) had evidence for a residual AVM, 16 (7%) showed focal hyperemia, and 6 (2%) yielded other findings. The frequency of dysplastic vessels was significantly correlated with increasing initial size of the removed AVM (p=0.0001); the mean diameter of AVMs in patients showing dysplastic vessels after surgery was significantly larger (41mm, SD ±14) than in those without residual dysplastic vessels (27mm, SD±13; p<0.0001). No statistically significant association was found between residual dysplastic vessels and the occurrence of symptomatic perioperative intracerebral hemorrhage. Conclusions: The findings suggest that angiographic abnormalities may be found in as many as half of cases studied after AVM surgery, the most common abnormality being persistent dysplastic vessels. Preoperative AVM size was found to be an independent correlate with the occurrence of dysplastic vessels after surgery.