Risk of Rupture of Unruptured Intracranial Aneurysms in Relation to Patient and Aneurysm Characteristics: An Updated Meta-Analysis

Utrecht University, Utrecht, Utrecht, Netherlands
Stroke (Impact Factor: 5.72). 04/2007; 38(4):1404-10. DOI: 10.1161/
Source: PubMed


We updated our previous review from 1996 on the risk of rupture of unruptured intracranial aneurysms, aiming to include the newly published articles.
We reviewed all studies from our former meta-analysis and performed a Medline search for new studies published after 1996. We calculated overall risks of rupture for studies with a mean follow-up time of <5, 5 to 10, and >10 years. Relative risks (RR) were calculated by comparing the risk of rupture in patients with and without potential risk factors. We aimed to perform multivariable analyses of the different risk factors with meta-regression analysis.
We included 19 studies (10 new) with 4705 patients and 6556 unruptured aneurysms (follow-up 26 122 patient-years). The overall rupture risks were 1.2% (follow-up <5 years), 0.6% (follow-up 5 to 10 years), and 1.3% (follow-up >10 years). In the univariable analysis, statistically significant risk factors for rupture were age >60 years (RR 2.0; 95% confidence interval [CI], 1.1 to 3.7), female gender (RR 1.6; 95% CI, 1.1 to 2.4), Japanese or Finnish descent (RR 3.4; 95% CI, 2.6 to 4.4), size >5 mm (RR 2.3; 95% CI, 1.0 to 5.2), posterior circulation aneurysm (RR 2.5; 95% CI, 1.6 to 4.1), and symptomatic aneurysm (RR 4.4; 95% CI, 2.8 to 6.8). Meta-regression analysis yielded implausible results.
Age, gender, population, size, site, and type of aneurysm should be considered in the decision whether to treat an unruptured aneurysm. Pooled multivariable analyses of individual data are needed to identify independent risk factors and to provide more reliable risk estimates for individual patients.

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    • "This seems to be a case where aneurysm growth in the absence of hemorrhage was associated with subarachnoid inflammation. This is a rare situation since most reports of growing aneurysms do not mention headache as a symptom and most patients are being reimaged as part of scheduled follow-up [14]. Even when they develop symptoms, headache is not universal [8]. "
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    ABSTRACT: This case highlights the potential importance of new-onset headache, even in the absence of other worrisome features, in a patient with a cerebral aneurysm. A 61-year-old Caucasian woman presented with nonspecific insidious onset of headache, a superior cerebellar artery aneurysm and cerebrospinal fluid lymphocytosis. She had a subarachnoid hemorrhage 21 days later, at which time the aneurysm had enlarged. The aneurysm was repaired endovascularly and the patient recovered with a modified Rankin score of 1. This case suggests that new onset of chronic headache in a patient with an unruptured aneurysm may be due to aneurysm growth and can be associated with cerebrospinal fluid lymphocytosis. Headaches are common and may occur incidentally in patients with cerebral aneurysms, but new-onset headache, even if mild, should prompt consideration for timely aneurysm repair.
    Journal of Medical Case Reports 10/2013; 7(1):244. DOI:10.1186/1752-1947-7-244
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    • "Of all cerebral aneurysms, the anterior communicating artery (ACoA) aneurysm is the most frequent and represents an increased risk of rupture as compared to aneurysms in other locations [1] [2] [3] [4] [5] [6] [7] [8]. Transcranial clip ligation (via the pterional transsylvian, supraorbital or interhemispheric corridors) presents significant technical challenges because of the deep and midline location of these lesions. "
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    ABSTRACT: The endoscopic transnasal approach to the anterior communicating artery (ACoA) complex is not widely performed. This cadaveric study investigated the surgical relevance of the anterior endoscopic approach to the treatment of ACoA aneurysms. Bi-nasal endoscopic transtubercular surgery was carried out on fresh adult cadavers. Primary outcomes measures incorporated dimensions of the endonasal corridor (operative field depth, lateral limits, size of the transplanum craniotomy and dural opening); vascular exposure (proximal and distal anterior cerebral arteries [ACA], ACoA, clinoidal internal carotid artery [ICA] segment); and operative manoeuvrability defined by clip placements (ipsilateral and contralateral). Eight cadaver heads were used (mean age 84±7years, range 76-94years, 75% female). Mean operative depth was 97±4mm. The lateral corridors were limited proximally by the alar rim openings (31±2mm), and distally by the optic nerves (22±6mm). The endonasal craniotomy dimensions were 21±5mm anteroposteriorly, and 22±4mm laterally. Vascular exposure was achieved in 100% of subjects for the ACoA segment and the ACA segments proximal to the ACoA (A1). The ACA segments distal to the ACoA (A2) were accessible only in 40% of subjects. Endonasal clip placement across the ACoA segment, clinoidal ICA, A1 and A2 were 100%, 90%, 90%, and 30%, respectively. The ventral endoscopic endonasal approach to the ACoA complex provides excellent vascular visualisation without brain retraction or gyrus rectus resection. However, the limitation in access to the A2 for temporary clip placement may prove to be a significant limitation of this approach.
    Journal of Clinical Neuroscience 10/2013; 21(5). DOI:10.1016/j.jocn.2013.07.034 · 1.38 Impact Factor
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    • "On the other hand, current treatments of IAs also carry a risk. Thus, accurate assessment of IA rupture is essential for clinicians to balance the risk of surgery against the risk of natural IAs rupture [6, 7]. "
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    ABSTRACT: Although wall shear stress (WSS) has long been considered a critical indicator of intracranial aneurysm rupture, there is still no definite conclusion as to whether a high or a low WSS results in aneurysm rupture. The reason may be that the effect of WSS direction has not been fully considered. The objectives of this study are to investigate the magnitude of WSS ( WSS ) and its divergence on the aneurysm surface and to test the significance of both in relation to the aneurysm rupture. Patient-specific computational fluid dynamics (CFD) was used to compute WSS and wall shear stress divergence (WSSD) on the aneurysm surface for nineteen patients. Our results revealed that if high WSS is stretching aneurysm luminal surface, and the stretching region is concentrated, the aneurysm is under a high risk of rupture. It seems that, by considering both direction and magnitude of WSS, WSSD may be a better indicator for the risk estimation of aneurysm rupture (154).
    The Scientific World Journal 09/2013; 2013(3):508131. DOI:10.1155/2013/508131 · 1.73 Impact Factor
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