Risk of hemorrhage in patients with untreated Spetzler-Martin grade IV and V arteriovenous malformations: a long-term follow-up study in 63 patients.
BACKGROUND
Treatment of Spetzler-Martin Grade IV and V brain arteriovenous malformations (ie, high-grade AVMs) carries a high risk of morbidity and even mortality. However, little is known about the behavior of these lesions if left untreated.


OBJECTIVE
To investigate the natural history of patients with high-grade AVMs.


METHODS
Patients with untreated high-grade AVMs admitted to our center between 1952 and 2005 were followed from admission until death, AVM rupture, or initiation of treatment. Rates of rupture and various risk factors were analyzed using Kaplan-Meier life table analyses and Cox proportional hazards models. Functional outcome was assessed 1 year after possible AVM rupture using the Glasgow Outcome Scale.


RESULTS
Sixty-three patients with a mean follow-up time of 11.0 years (range, 1 month to 39.6 years) were identified. Twenty-three patients (37%) experienced a subsequent rupture. The average annual rate of rupture was 3.3%. In patients with hemorrhagic presentation, the annual rate was 6.0%, compared to 1.1% in patients with unruptured AVMs (P = .001, log-rank test; hazard ratio, 5.09 [1.40-18.5, 95% CI]; P = .013, multivariate Cox regression model). One year after the first subsequent rupture, 6 patients (26%) had died, and 9 (39%) had moderate or severe disability.


CONCLUSIONS
Untreated high grade AVMs presenting with hemorrhage have a significant risk of subsequent rupture, and their rupture carries a higher risk of case fatality and permanent morbidity than AVMs in general. The risks associated with their treatment should be appraised in light of perilous natural history.
Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland. aki.laakso@hus.fi
Aki
A
Laakso
Reza
R
Dashti
Seppo
S
Juvela
Puchong
P
Isarakul
Mika
M
Niemelä
Juha
J
Hernesniemi
D000328:Adult; D001164:Arteriovenous Fistula / Q000150:complications*; D002543:Cerebral Hemorrhage / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D015600:Glasgow Coma Scale; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications*; D008297:Male; D016016:Proportional Hazards Models; D012307:Risk Factors; D012422:Rupture, Spontaneous