Treatment algorithm
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observation and/or exclusion of the aneurysm from the intra-cranial circulation
Observation consists of periodic imaging studies of increasingly greater duration along with regular visits to the physician. Treatment consists either of open surgical clipping or endovascular obliteration.[18]
A 2021 systematic review concluded there is currently insufficient evidence to support either conservative treatment (e.g., treating risk factors, such as hypertension, or smoking cessation) or interventional treatments (microsurgical clipping or endovascular coiling) for individuals with unruptured intracranial aneurysms.[45]
The choice of observation or treatment needs to be made on a case-by-case basis by a specialist experienced in the management of cerebral aneurysms.
Treatment may be pursued when the lifetime risk of rupture is felt to exceed the risk of the proposed treatment approach.[44]
Small aneurysms (i.e., <7 mm) can generally be observed.[2]
Cavernous carotid artery aneurysms carry the lowest risk, anterior circulation aneurysms carry an intermediate risk, and posterior circulation aneurysms carry the highest risk of rupture.
Interval enlargement (>1 mm) is a strong risk factor for rupture and treatment is recommended even when overall size remains small.[18]
Symptomatic aneurysms should be considered for treatment regardless of size. Urgent consideration for treatment is needed for symptomatic intradural aneurysms.
Increased risk of treatment and shorter life expectancy tend to favour observation in older patients.
Comorbid medical illness also increases the risk of treatment.
Clinicians should be aware of the psychological burden of deferring interventional treatment of small unruptured intracranial aneurysms. Patient anxiety about a 'ticking time bomb' should be addressed where appropriate and incorporated into the shared decision-making process.[46]
Surgery for cerebral aneurysm involves placing a clip across the neck of an intracranial aneurysm and has a long track record of demonstrated efficacy. The attributable risk of the procedure is fairly low.[8]
Standard endovascular therapy for cerebral aneurysms involves insertion of soft metallic coils within the lumen of the aneurysm, which are detached once they are in place.[40][Figure caption and citation for the preceding image starts]: Example of a coil used to treat cerebral aneurysmsFrom: Sellar M. Practical Neurology. 2005;5:28-37. Used with permission [Citation ends].
For unruptured aneurysms, there is insufficient evidence to support a preference for either surgical clipping or endovascular coiling, and selection should be based on individual patient factors.[18][44][45] In addition, novel endovascular devices such as flow-diverter devices or intrasaccular flow disruptors may be considered for high-risk unruptured cerebral aneurysms (e.g., wide-necked bifurcation aneurysms) not suitable for standard interventional treatments; however, there is a low certainty of evidence for use of these devices.[44]
exclusion of the aneurysm from the intra-cranial circulation
Treatment recommended for ALL patients in selected patient group
Treatment with endovascular coiling or microsurgical clipping should be instituted as early as possible for the majority of patients with a ruptured aneurysm.[20][21]
Surgery involves placing a clip across the neck of an intra-cranial aneurysm. The attributable risk of the procedure is fairly low.[8] The size, location, and configuration of the aneurysm, along with brain oedema, vasospasm, and surrounding tenacious clot, all complicate microsurgical clipping and can increase procedural complications.
Standard endovascular therapy for cerebral aneurysms involves insertion of soft metallic coils within the lumen of the aneurysm, which are detached once they are in place.[40]
The coils promote thrombosis within the aneurysm dome.[41] Factors that complicate endovascular treatment are a wide neck, a giant aneurysm with intra-aneurysm thrombus, and the presence of eloquent arterial branches emanating from the aneurysm dome. Adjunctive devices including balloons and intra-cranial stents can be used in difficult cases, or alternative novel endovascular devices may be considered for selected patients.[43][44] Flow-diverter devices are not recommended for ruptured cerebral aneurysms due to a high rate of observed complications including aneurysm re-rupture, device thrombosis, and complications of associated dual antiplatelet therapy, and should only be considered when no other method of effective aneurysm treatment is feasible.[56][57] Current data suggest intrasaccular flow disruptors may be as safe in ruptured aneurysms as unruptured aneurysms, but limitations on their long-term occlusion rates preclude their routine recommendation over established methods.[58]
The preferred treatment depends on patient factors (age, clinical grade after the haemorrhage, comorbidities, and expected longevity) and aneurysm factors (location, size, shape, dome-to-neck ratio, and presence of calcification).
Data from a 2018 systematic review on randomised trials has shown that for patients in good clinical condition with ruptured aneurysms, coiling is associated with a better outcome than surgery. No consistent trial evidence exists for patients in a poor clinical condition.[54]
Extracranial-intracranial bypass can be considered if a clip application or coiling procedure cannot be performed.[55]
Treatment of unruptured co-existing aneurysms should also be considered. [Figure caption and citation for the preceding image starts]: Example of a coil used to treat cerebral aneurysmsFrom: Sellar M. Practical Neurology. 2005;5:28-37. Used with permission [Citation ends].[Figure caption and citation for the preceding image starts]: Progressive angiography images of a small dissecting aneurysm of the distal basilar artery after a subarachnoid and intraventricular haemorrhage on day 3 (A), day 23 (B), and day 30 (C), and 6 months after stent-assisted coiling (D). Arrows indicate proximal and distal stent markersFrom: Peluso JP, van Rooij WJ, Sluzewski M. BMJ Case Reports 2009; doi:10.1136/bcr.2007.121533. Used with permission [Citation ends].
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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer
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