Estimating the Annual Rate of De Novo Multiple Aneurysms
Object: Individuals with unruptured intracranial aneurysms experience a higher rate of rupture if their history includes another aneurysm that has previously bled. The authors used systematic review and metaregression to estimate the annual rate of development of second de novo aneurysms after subarachnoid hemorrhage.
Methods: This investigation included studies in which more than 300 patients with intracranial aneurysms were de scribed, and in which the age of the patients and the proportion with multiple aneurysms were documented. Studies describing delayed follow-up angiography that was performed after treatment of aneurysms were also reviewed.
Twenty studies were included in a between-study analysis. The univariate odds ratio (OR) for multiple intracranial aneurysms per year of age was 1.085 (95% confidence interval [CI] 1.015–1.165); this value was calculated using a hierarchical model for between-study heterogeneity. Five studies were included that provided age stratification. The estimated OR for multiple intracranial aneurysms per year was 1.011 (95% CI 1.005–1.018). Four follow-up studies were available.
Conclusions: According to the three different approaches (study-level, patient-level, and follow-up analyses), the estimated annual rates of development of de novo aneurysms were 1.62% (95% CI 0.28–3.59%), 0.28% (95% CI 0.12–0.49%), and 0.92% (95% CI 0.64–1.25%), respectively. The estimated annual rate of development of second de novo aneurysms ranged from 0.28 to 1.62%.
The rate of rupture is higher in individuals with unruptured intracranial aneurysms if their history includes an other lesion that has previously bled. The incidence of SAH and the prevalence of unruptured intracranial aneurysms increase with age. The most common cause of delayed recurrent SAH after aneurysm clipping is de novo lesions. There is not enough information about the prevalence of de novo lesions in the years after an aneurysm ruptures or about the value, if any, of screening investigations. We estimated the association between patient age and multiple intracranial aneurysms by using systematic review and metaregression. This association was used to estimate the rate at which new intracranial aneurysms develop in patients who have experienced a previous rupture.
We propose the following simple model for aneurysm development. In a given population of patients an intracranial aneurysm will occur in some individuals, and a second lesion will subsequently develop in a proportion of these. The prevalence of multiple intracranial aneurysms among patients who initially had single lesions increases with age. The overall rate of de novo aneurysm formation can be estimated based on this association. Both individuals with a single and those with multiple lesions may experience an aneurysm rupture. The incidence of such ruptures will be moderately higher in individuals with multiple lesions. The rate of de novo aneurysm formation will be slightly overestimated if it is derived from patients who mostly present with aneurysm rupture.
Object: Individuals with unruptured intracranial aneurysms experience a higher rate of rupture if their history includes another aneurysm that has previously bled. The authors used systematic review and metaregression to estimate the annual rate of development of second de novo aneurysms after subarachnoid hemorrhage.
Methods: This investigation included studies in which more than 300 patients with intracranial aneurysms were de scribed, and in which the age of the patients and the proportion with multiple aneurysms were documented. Studies describing delayed follow-up angiography that was performed after treatment of aneurysms were also reviewed.
Twenty studies were included in a between-study analysis. The univariate odds ratio (OR) for multiple intracranial aneurysms per year of age was 1.085 (95% confidence interval [CI] 1.015–1.165); this value was calculated using a hierarchical model for between-study heterogeneity. Five studies were included that provided age stratification. The estimated OR for multiple intracranial aneurysms per year was 1.011 (95% CI 1.005–1.018). Four follow-up studies were available.
Conclusions: According to the three different approaches (study-level, patient-level, and follow-up analyses), the estimated annual rates of development of de novo aneurysms were 1.62% (95% CI 0.28–3.59%), 0.28% (95% CI 0.12–0.49%), and 0.92% (95% CI 0.64–1.25%), respectively. The estimated annual rate of development of second de novo aneurysms ranged from 0.28 to 1.62%.
The rate of rupture is higher in individuals with unruptured intracranial aneurysms if their history includes an other lesion that has previously bled. The incidence of SAH and the prevalence of unruptured intracranial aneurysms increase with age. The most common cause of delayed recurrent SAH after aneurysm clipping is de novo lesions. There is not enough information about the prevalence of de novo lesions in the years after an aneurysm ruptures or about the value, if any, of screening investigations. We estimated the association between patient age and multiple intracranial aneurysms by using systematic review and metaregression. This association was used to estimate the rate at which new intracranial aneurysms develop in patients who have experienced a previous rupture.
We propose the following simple model for aneurysm development. In a given population of patients an intracranial aneurysm will occur in some individuals, and a second lesion will subsequently develop in a proportion of these. The prevalence of multiple intracranial aneurysms among patients who initially had single lesions increases with age. The overall rate of de novo aneurysm formation can be estimated based on this association. Both individuals with a single and those with multiple lesions may experience an aneurysm rupture. The incidence of such ruptures will be moderately higher in individuals with multiple lesions. The rate of de novo aneurysm formation will be slightly overestimated if it is derived from patients who mostly present with aneurysm rupture.