ISCHEMIC STROKE / PREVENTION
Management of intracranial stenosis
Created 10/12/2021, last revision 07/11/2023
- intracranial stenosis is a significant stroke risk factor [Bos, 2014]
- it is a cause of ~10% of strokes
- the annual risk of recurrent stroke in symptomatic IC stenosis is 4-18%
- EC/IC Bypass Trial, WASID
- the highest risk is present in the first 14 days after the first event
- modern imaging modalities (TCD/TCCD, CTA, and MRA) allow non-invasive and easy diagnosis of intracranial stenoses [Degnan, 2011]
Etiopathogenesis
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Diagnostic evaluation
TCD/TCCD
-
detection of the stenosis itself (→ see here)
- optimal for screening and follow-up
-
evaluation of the distal flow, including cerebral vasomotor reactivity (CVR)
-
detection of MES (microembolic signals)
CT/MR angiography
-
the optimal imaging method is CTA
-
non-contrast intracranial MRA may overestimate the stenosis grade
Digital subtractive angiography
- currently replaced by CTA in most cases
Xe133-CT
- enables to determine the cerebral blood flow (CBF)
Intravascular sonography (IVUS) [Zacharatos, 2010]
- used in cardiology, now it is tested in carotid and intracranial territories
- clarifies the morphology of the stenosis (which can help in etiological diagnosis – atherosclerotic plaque vs. inflammation, etc.)
Optic coherent tomography (OCT)
- OCT uses near-infrared light to image arterial anatomy with much higher resolution than IVUS (10 vs. 100 um)
- used in cardiology, also tested in vascular neurology
- assessment of plaque structure (Yang, 2021)
- assessment of stent position after the procedure and in the follow-up period
- the potential for use during the stenting procedure is investigated
- assessment of plaque structure (Yang, 2021)
- outperforms IVUS in the determination of plaque morphology (presence of thrombus, bleeding, fibrous cap rupture, etc.) and in differentiating other causes of stenosis
Management
Asymptomatic stenosis |
- antiplatelet therapy + aggressive treatment of vascular risk factors (see below)
- endovascular intervention is not indicated
Symptomatic stenosis |
- the risk of recurrent stroke/TIA or vascular death in patients with IC stenosis is 10-12%/year [Chimowitz,2005]
- older studies reported a risk of up to 22%/year with conservative treatment; despite that, the risk is ~2 times higher than in patients with extracranial stenosis
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Intracranial angioplasty procedure
- after the procedure, maintain dual antiplatelet therapy (aspirin 100 mg + clopidogrel 75 mg)
- duration of DAPT
- coated stents: 6-12 months (Taxus, Pharos)
- standard stent (Wingspan): at least 4 weeks
- then switch to long-term monotherapy
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