Long-term follow-up studies in patients with brain arteriovenous malformations (AVM) have yielded contradictory results regarding both risk factors for rupture and annual rupture rate. We performed a ...long-term follow-up study in an unselected, consecutive patient population with AVMs admitted to the Department of Neurosurgery at Helsinki University Central Hospital between 1942 and 2005.
Patients with untreated AVMs were followed from admission until death, occurrence of AVM rupture, initiation of treatment, or until the end of 2005. Patients with at least 1 month of follow-up were included in further analysis. Annual and cumulative incidence rates of AVM rupture as well as several potential risk factors for rupture were analyzed using Kaplan-Meier life table analyses and Cox proportional hazards regression models.
We identified 238 patients with a mean follow-up period of 13.5 years (range, 1 month-53.1 years). The average annual risk of hemorrhage from AVMs was 2.4%. The risk was highest during the first 5 years after diagnosis, decreasing thereafter. Risk factors predicting subsequent AVM hemorrhage in univariate analysis were young age, previous rupture, deep and infratentorial locations, and exclusively deep venous drainage. Previous rupture, large AVM size, and infratentorial and deep locations were independent risk factors according to multivariate models.
According to this long-term follow-up study, AVMs with previous rupture and large size, as well as with infratentorial and deep locations have the highest risk of subsequent hemorrhage. This risk is highest during the first few years after diagnosis but remains significant for decades.
Long-term follow-up studies in patients with brain arteriovenous malformations (AVM) have been scarce and without proper statistical estimates of mortality. We performed a retrospective survival ...study in 623 consecutive patients with AVMs admitted to the Department of Neurosurgery in Helsinki University Hospital between 1951 and 2005.
Patients were followed from admission until death or the end of 2005. Patient survival was estimated using the relative survival ratio, which provides a measure of the excess mortality experienced by the patients compared with the general Finnish population matched by age, sex, and calendar time.
Median follow-up was 11.9 years, and total follow-up was 10,165 person-years. Treatment was conservative in 155 patients. Total AVM occlusion was attained in 356 patients, and partial occlusion was obtained in 94 patients. Overall, 206 deaths were observed. Of these, 100 were related to AVMs. Diagnosis of AVM was associated with significant long-term excess mortality, with cumulative relative survival ratios of 0.85 (95% confidence interval, 0.81-0.88) and 0.69 (95% confidence interval, 0.62-0.75) at 10 and 30 years after admission, respectively. Men had higher excess mortality than women. The excess in mortality was highest in conservatively treated patients, intermediate in patients with partially occluded AVMs, and lowest in those with totally occluded AVMs. The subgroup with the best outcome consisted of those with totally occluded unruptured AVMs, which did not demonstrate excess mortality after the first year.
AVMs are associated with long-term excess mortality that may be reduced by active, even partial, treatment. Male patients have a higher excess mortality rate than female patients.
Abstract
OBJECTIVE
Long-term follow-up studies in patients with brain arteriovenous malformations (AVM) have yielded contradictory results regarding both risk factors for rupture and annual rupture ...rate. We performed a long-term follow-up study in an unselected, consecutive patient population with AVMs admitted to the Department of Neurosurgery at Helsinki University Central Hospital between 1942 and 2005.
METHODS
Patients with untreated AVMs were followed from admission until death, occurrence of AVM rupture, initiation of treatment, or until the end of 2005. Patients with at least 1 month of follow-up were included in further analysis. Annual and cumulative incidence rates of AVM rupture as well as several potential risk factors for rupture were analyzed using Kaplan-Meier life table analyses and Cox proportional hazards regression models.
RESULTS
We identified 238 patients with a mean follow-up period of 13.5 years (range, 1 month–53.1 years). The average annual risk of hemorrhage from AVMs was 2.4%. The risk was highest during the first 5 years after diagnosis, decreasing thereafter. Risk factors predicting subsequent AVM hemorrhage in univariate analysis were young age, previous rupture, deep and infratentorial locations, and exclusively deep venous drainage. Previous rupture, large AVM size, and infratentorial and deep locations were independent risk factors according to multivariate models.
CONCLUSION
According to this long-term follow-up study, AVMs with previous rupture and large size, as well as with infratentorial and deep locations have the highest risk of subsequent hemorrhage. This risk is highest during the first few years after diagnosis but remains significant for decades.
