Article
Determinants for the size threshold of intracranial aneurysms at the time of rupture
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Authors
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Amr Abdulazim
- Klinik für Neurochirurgie, Universitätsmedizin Mannheim, Universität Heidelberg, Germany
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Sapna Rawal
- Division of Neuroradiology, Department of Medical Imaging, University of Toronto, Canada
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Kerim Beseoglu
- Klinik für Neurochirurgie, Heinrich Heine Universität, Düsseldorf, Germany
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Daniel Hänggi
- Klinik für Neurochirurgie, Universitätsmedizin Mannheim, Universität Heidelberg, Germany
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Nima Etminan
- Klinik für Neurochirurgie, Universitätsmedizin Mannheim, Universität Heidelberg, Germany
| Published: | June 8, 2016 |
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Outline
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Objective: To further elucidate the most relevant determinants for the size of intracranial aneurysms (IA) at the time of rupture, we investigated the relevance of the aneurysm and parent artery morphology versus modifiable cardiovascular risk factors for the rupture size threshold of IAs.
Method: We performed a retrospective analysis of our subarachnoid hemorrhage (SAH) database. Epidemiological data on cardiovascular risk factors (hypertension, smoking) were collected. Maximum aneurysm diameter, neck size, and the parent vessel diameter proximal and distal to the aneurysm neck were measured. Aneurysm morphology (smooth or irregular) was assessed based on reconstruction images. Univariate analysis was performed to identify associations between potential determinants for the size of ruptured IA. A multivariable negative binomial regression analysis was performed and adjusted risk ratios (aRR) calculated to evaluate the impact of parent vessel diameter on ruptured aneurysm size while accounting for the effect of important cofactors.
Results: Data from 467 SAH patients admitted to our department between January 2005 and October 2014 were included. Mean aneurysm diameter in SAH patients with no history of risk factors was 7.13 ± 4.41 mm (95% CI 6.35 to 7.92), compared to 6.36 ± 3.00 mm (95% CI 5.84 to 6.87; p=0.2822) for current or ever smoking SAH patients and 6.01 ± 2.93 mm (95% CI 5.73 to 6.47; p=0.0305) for SAH patients with hypertension. Mean diameter of lobulated IAs was 6.44 ± 3.32 mm (95% CI 6.00 to 6.87) compared to 6.58 ± 3.79mm (95% CI 6.10 to 7.07) for non-lobulated IAs. In the univariate analysis there was a significant association between the ruptured aneurysm diameter and aneurysm location site or aneurysm and parent artery morphology (aspect ratio, size ratio, mean parent vessel diameter) as well as presence of hypertension. In the multivariable analysis, mean parent artery diameter (aRR: 1.44 (CI 1.39 to 1.49; p<0.0001), size ratio (aRR: 1.27 (CI 1.25 to 1.30; p<0.0001) and lobulation (aRR: 1.06 (1.01 to 1.10; p=0.0123) were the most significant and independent determinants for ruptured IA size.
Conclusions: Our data highlight that the rupture size threshold of aneurysms is significantly determined by actual parent artery diameters, rather than the exact aneurysm location, morphology or the presence of cardiovascular risk factors. These findings warrant further exploration in longitudinal cohorts, using additional radiological surrogates which acknowledge the parent artery diameter.
