Who are these subpopulations who should undergo screening?
A 1996 paper by Butler et al12 concluded that patients with adult polycystic kidney disease would benefit from routine screening. Other high risk populations would include patients with a family history of aneurysms in the absence of other genetic syndromes, patients with Marfans, Ehlers-Danlos, vasculopathies, and possibly hypertensive patients who smoke, heavy alcohol abusers as well as drug abusers. As alluded to by Wardlaw et al, more studies need to be done.
In 2000, The American Heart Association Stroke Council published Recommendations for the Management of Patients With Unruptured Intracranial Aneurysms: A Statement for Healthcare Professionals From the Stroke Council of the American Heart Association. The paper, which involved a comprehensive study of the literature, contains the following recommendations19:
“To date, there have been no randomized controlled clinical trials that addressed the cost effectiveness of screening for intracranial aneurysms, and only grade C recommendations can be made.
Screening for asymptomatic intracranial aneurysms in the general population is not indicated. Patients with environmental risk factors such as cigarette smoking and alcohol use have an increased risk of SAH, but this has not been associated with an increased frequency of intracranial aneurysms,54,55,56,57,58 and screening for aneurysms is not warranted in this population. Theoretical modeling suggests that screening is not efficacious in populations with the genetic syndromes mentioned here or in family members with a single first-degree relative with aneurysmal SAH or an intracranial aneurysm; the latter was recently substantiated in a study that used Markov analysis methodology.49 These suggestions require confirmation in further studies.
In populations with the FIA syndrome (2 first-degree relatives), screening programs have demonstrated the increased incidence of intracranial aneurysms. However, cost-effectiveness has not been evaluated in clinical studies, and recommendations regarding screening in this group are controversial.52,59 Further information about the natural history of UIAs will help to guide future recommendations about screening programs. Until the efficacy of screening groups with the FIA syndrome has been evaluated in a population-based clinical study, screening should be considered on an individual basis.
Because the annual rate of new aneurysm formation in patients treated for aneurysmal SAH is reported to be as high as 1% to 2%, late radiological evaluation of this population should be considered.50,19”
As you can see, there is still some controversy regarding the use of non-invasive screening techniques in high risk populations. The take home message is that while certain high risk populations may benefit, randomized controlled trials are needed before definitive recommendations can be made. In the meantime, screening in high risk patients may be undertaken at the discretion of the PCP, Neurologist or Neurosurgeon.