From the Guidelines
Family members with a history of cerebral aneurysms should undergo radiological screening for aneurysms every 5 to 7 years.
Recommended Surveillance Protocol
The recommended surveillance protocol is based on the presence of ≥2 first-degree relatives with known cerebral aneurysms, which increases the risk of harboring a cerebral aneurysm to 12% 1.
- Screening interval: Every 5 to 7 years for individuals 20 to 80 years of age with a family history of ≥2 first-degree relatives with known cerebral aneurysms 1.
- Screening modality: Noninvasive imaging such as MRA or CTA is recommended for screening 1.
- Risk factors: Hypertension, tobacco use, and family history are important risk factors for cerebral aneurysms, and screening may be beneficial in individuals with these risk factors 1.
- Cost-effectiveness: Radiological screening for aneurysms is cost-effective when performed every 5 to 7 years for individuals with a family history of ≥2 first-degree relatives with known cerebral aneurysms 1. It is essential to note that the American Heart Association guidelines recommend offering screening to patients with 2 family members with intracranial aneurysms or SAH 1, and noninvasive screening for unruptured intracranial aneurysms in patients with no more than 1 relative with SAH or intracranial aneurysms is not recommended 1.
From the Research
Surveillance Protocol for Cerebral Aneurysms in Family Members
The recommended surveillance protocol for cerebral aneurysms in family members with a history of cerebral aneurysms is as follows:
- Screening is currently recommended in families with ≥2 affected first-degree relatives 2, 3
- Individuals with ≥1 affected first-degree relative may also benefit from screening, as they have a higher prevalence of intracranial aneurysms (average 4.8%) and an increased risk of subarachnoid hemorrhage 2
- Repeated screening should be considered in relatives who have been treated for familial intracranial aneurysms 3
- The yield of screening is high in first-degree members of families with familial subarachnoid hemorrhage, making it a recommended practice 3
Factors Associated with Increased Risk of Intracranial Aneurysms
Several factors are associated with an increased risk of intracranial aneurysms, including:
- A history of treatment for ruptured or unruptured intracranial aneurysms (relative risk 5.5) 3
- Having three or more affected relatives (relative risk 3.3) 3
- Initial aneurysm size, with larger aneurysms having a higher risk of growth and rupture 4, 5
- Aneurysm growth, which is associated with an increased risk of subarachnoid hemorrhage 4, 5
Imaging Follow-up for Untreated Unruptured Intracranial Aneurysms
Imaging follow-up is recommended for patients with untreated unruptured intracranial aneurysms, including those with aneurysms smaller than the current treatment threshold of 7 mm 4, 5
- The risk of aneurysm rupture per patient-year is 5% with growth, and 0.2% without growth 4
- Aneurysm size is the only predictor of future growth, with larger aneurysms having a higher risk of growth and rupture 5
- More frequent (semiannual) surveillance imaging may be warranted for newly diagnosed aneurysms and aneurysms ≥ 5 mm 5