Background Blebs are rupture risk factors in intracranial aneurysms (IAs), but their prevalence, distribution, and associations with clinical factors as well as their causes and effects on aneurysm vulnerability remain unclear.
Methods A total of 122 blebs in 270 IAs selected for surgery were studied using patient-specific vascular reconstructions from 3D angiographic images. Bleb geometry, location on the aneurysm, and frequency of occurrence in aneurysms at different locations were analyzed. Associations between gender, age, smoking, hypertension, hormone therapy, dental infection, and presence of blebs were investigated.
Results Of all aneurysms with blebs, 77% had a single bleb and 23% had multiple blebs. Only 6% of blebs were at the neck, while 46% were in the body and 48% in the dome. Aneurysms with blebs were larger (p<0.0001), more elongated (p=0.0002), and with wider necks than aneurysms without blebs. Bleb presence was associated with dental infection (p=0.0426) and negatively associated with hormone therapy (p=0.0426) in women. Anterior and posterior communicating arteries had larger percentages of aneurysms with blebs than internal carotid arteries. Patients with a history of hypertension tended to have a larger percentage of aneurysms with blebs. However, these trends did not reach significance in this sample.
Conclusions Blebs are common in IAs, and most aneurysms harboring blebs have a single bleb. Blebs in the aneurysm neck are rare, but they are equally common in the body and dome. The presence of blebs in IAs was associated with dental infection, and negatively associated with hormone replacement therapy.
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Contributors SFSA, JF, SM, AMR, and JRC designed the study. AKY, CJS, APS, SAH, FTC, BRJ, MN, and JF contributed to data collection. FJD and FM contributed to development of methodology. FM and JRC designed the software tools. BJC simulated vascular reconstructions. SFSA, FJD, and JRC identified blebs in the dataset. SFSA curated the data. SFSA, JZ, and JRC performed the data analysis. SFSA, FM, SAH, FTC, JF, AMR, and JRC contributed to the interpretation of the results. AMR and JRC acquired funding, supervised students, and coordinated the project. SFSA and JRC drafted the manuscript. All authors contributed to the manuscript and approved the final version.
Funding This work was supported by NIH grant R01NS097457.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The protocols for patient consent, handling of patient data and analysis were approved by the institutional review board (IRB) at the University of Pittsburgh (Protocol # STUDY20020015), University of Illinois at Chicago (Protocol # 2015–0322), Allegheny General Hospital (Protocol # RC-5141), and Helsinki University Hospital. The whole study's IRB is overseen by the University of Pittsburgh IRB.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. The data that support the findings of this study are available from the corresponding author, upon request.
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