The majority of ruptured aneurysms are small with low rupture risk scores. (September 2022)

• Record Type: Journal Article
• Authors: Webb, Matthew; Fischer, Victoria; Farrell, Ryan; Towne, Jonathan; Birnbaum, Lee; Rodriguez, Pavel; Mascitelli, Justin
• Is Part Of: Journal of clinical neuroscience. Volume 103(2022)
• Page Start: 148
• Page End: 152
• Publication Date: 2022-09
• Subjects: Intracranial aneurysm -- ISUIA -- PHASES score -- Rupture risk -- Subarachnoid hemorrhage -- UCAS; Brain -- Surgery -- Periodicals; Neurosciences -- Periodicals; Nervous system -- Surgery -- Periodicals; Brain -- surgery -- Periodicals; Neurosurgical Procedures -- Periodicals; Neurosciences -- Periodicals; Electronic journals; 616.8
• DOI: 10.1016/j.jocn.2022.06.015
• Languages: English
• ISSNs: 0967-5868

Abstract

Highlights: The ISUIA, UCAS, and PHASES studies provide calculators to estimate the risk of rupture of intracranial aneurysms. The calculators were applied to a series of 246 ruptured intracranial aneurysms to assess the theoretical rupture risk of each aneurysm (had it been discovered in the unruptured state). The majority of aneurysms were small (<7mm), and the average annual rupture risk was low (<1%). Abstract: Background: Understanding the rupture risk of unruptured intracranial aneurysms has important clinical implications given the morbidity and mortality associated with subarachnoid hemorrhage (SAH). The ISUIA, UCAS, and PHASES studies provide rupture risk calculations. Objective: We apply the risk calculations to a series ruptured intracranial aneurysms to assess the rupture risk for each aneurysm (had they been discovered in the unruptured state). Methods: This is a retrospective study of 246 patients with SAH from a ruptured saccular aneurysm. The ISUIA, UCAS, and PHASES calculators were applied to each patient/aneurysm to demonstrate a theoretical annual risk of rupture dichotomized by aneurysm location. Results: The average diameter of the aneurysms was 5.5 ± 3.1 mm. Three quarters (75%) of the aneurysms measured <7 mm and 48.8% were <5 mm. The anterior communicating artery (Acomm) was the most common location of rupture (24.7%). Posterior communicating artery aneurysms (Pcomm) were the third most common at 16.2%. The average ISUIA 1-year rupture risk was 0.46 ± 0.008%. The average UCAS 1-year rupture risk was 0.93% ± 0.01. The annual PHASES rupture risk was 0.32 ± 0.004%. The highest risk locations were the vertebral artery (up to 10.3% per year) and superior cerebellar artery (up to 2.7% per year). On average, Acomm aneurysms had 1 year risk no higher than 1.1% and Pcomm aneurysms no higher than 1.2% per year. Conclusion: We observed that in a small retrospective series of ruptured aneurysms, the majority were <7 mm and that the theoretical rupture risk of these aneurysms, had they been discovered in the unruptured state, is low (<1% per year). Our study has a number of limitations and these results should be validated in a larger multicenter study.