Prevalence, predictors and prognosis of incidental intracranial aneurysms in patients with suspected TIA and minor stroke: a population-based study and systematic review

Abstract

IntroductionUnruptured intracranial aneurysms (UIAs) are common incidental imaging findings, but there are few data in patients with transient ischaemic attack (TIA)/stroke. The frequency of UIA might be higher due to shared risk factors, but rupture risk might be reduced by intensive secondary prevention. We determined the prevalence and prognosis of UIA in patients with suspected TIA/minor stroke.MethodsAll patients referred to the population-based Oxford Vascular Study (2011–2020) with suspected TIA/minor stroke and non-invasive angiography were included. We determined the prevalence of incidental asymptomatic UIA and the risk of subsequent subarachnoid haemorrhage (SAH) by follow-up on intensive medical treatment, with guideline-based monitoring/management. We also did a systematic review of UIA prevalence/prognosis in cohorts with TIA/stroke.FindingsAmong 2013 eligible patients, 95 (4.7%) had 103 previously unknown asymptomatic UIA. Female sex (OR 2.3, 95% CI 1.5 to 3.7), smoking (2.1, 1.2 to 3.6) and hypertension (1.6, 1.0 to 2.5) were independently predictive of UIA, with a prevalence of 11.1% in those with all three risk factors. During mean follow-up of 4.5 years, only one SAH occurred: 2.3 (95% CI 0.3 to 16.6) per 1000 person-years. We identified 19 studies of UIA in TIA/stroke cohorts (n=12 781), all with either symptomatic carotid stenosis or major acute stroke. The pooled mean UIA prevalence in patients with TIA/stroke was 5.1% (95% CI 4.8 to 5.5) and the incidence of SAH was 4.6 (95% CI 1.9 to 11.0) per 1000 person-years.InterpretationThe 5% prevalence of UIA in patients with confirmed TIA/minor stroke is likely higher than that in the general population. However, the risk of SAH on intensive medical treatment and guideline-based management/monitoring is low.

Effect of Renin-Angiotensin-Aldosterone System Inhibitors on the Rupture Risk Among Hypertensive Patients With Intracranial Aneurysms

“…Furthermore, ischemic stroke was also found to be associated with a reduced rupture risk in this study. Similar to this finding, a large population-based cohort study 39 reported that the rupture risk of intracranial aneurysms is 2.3 per 1000 person-year among patients with confirmed transient ischemic attack/stroke, which is far lower than that in general population (7.8 per 1000 person-year) reported by Greving et al 3 On the one hand, patients with ischemic stroke have a higher opportunity to undergo angiography imaging screening, resulting in an early detection of incidental unruptured intracranial aneurysms. Subsequently, the guideline-based monitoring on the aneurysms would be certainly initiated in the early phase, which has a positive impact on the outcomes.…”

Prevalence and Risk Factors for Unruptured Intracranial Aneurysms in the Population at High Risk for Aneurysm in the Rural Areas of Tianjin

“…The prevalence of intracranial aneurysms was 1.8–3.0% in the general population ( 1 , 5 , 17 ). A previous study reported that the prevalence of UIA was higher among those with transient ischemic attack or minor stroke than in the general population ( 13 ), and the prevalence was as high as 5%. However, among the local population in Hong Kong, the prevalence of UIA among residents with immediate family members suffering from aneurysmal SAH was 2.3% ( 18 ).…”

“…Therefore, stroke patients will have a higher burden of unruptured intracranial aneurysms (UIA). At present, studies on UIA have shown that the risk of intracranial aneurysms is 70% higher in stroke patients than in the normal population ( 12 , 13 ), and a family history of stroke has been identified as an independent risk factor for UIA ( 12 ). However, there is no study on the prevalence and risk factors for UIA in those with a family history of stroke in China.…”

The emergency department incidence of incidental intracranial aneurysm on computed tomography angiography (EPIC-ACT) study

“…Based on available evidence, the baseline prevalence of incidental intracranial aneurysm was estimated at 2% [6]. A sample size calculation determined that for a desired precision of 1% and a corresponding 95% confidence interval, we required a sample size of 1064 patients.…”

“…This may be driven by awareness of the risks associated with interventions resulting from the discovery of a new and possibly inconsequential aneurysm. However, notwithstanding the fact that any aneurysm detected incidentally is at risk of subsequent rupture [6], the background rate of aneurysms in an ED population is likely overestimated. Unfortunately, the published data on the background rate of aneurysms is based largely on cadaveric studies, invasive angiography, and magnetic resonance angiography (MRA) and therefore may not reflect the true incidence of incidental aneurysms that would be identified through CTA [7].…”