General information
- 10–15% of patients presenting with carotid territory stroke or transient ischemic attacks (TIA) are found to have carotid occlusion.
- Prevention of subsequent stroke in symptomatic patients with carotid artery occlusion remains a difficult challenge.
- The overall rate of subsequent stroke is 7% per year for all stroke and 5.9% per year for ischemic stroke ipsilateral to the occluded carotid artery.
- These risks persist even despite treatment with antiaggregants and anticoagulants.
- The prevalence of asymptomatic carotid occlusion is not known, and the incidence of ipsilateral stroke in never symptomatic carotid occlusion is negligible.
Presentation
- 3 patterns of stroke with acute carotid artery occlusion:
- Stump emboli:
- Produces cortical infarcts.
- Emboli usually go up the external carotid (higher flow, and reverse flow that may occur through ICA initially prevents emboli from ICA). Later, ICA emboli may occur.
- Whole hemisphere stroke
- Watershed infarct
- In symptomatic patients:
- Hemiparetic TIA 53%,
- Dysphasic TIA 34%,
- Fixed neuro deficit 21%,
- Crescendo TIAs 21%,
- Amaurosis fugax 17%,
- Acute hemiplegia 6%.
- One series had 27% asymptomatic.
- Patients may have the so-called “slow carotid stroke” of carotid occlusion, which is a stuttering progressive stroke.
- TIA aggravated by arm exercises
- Proximal subclavian artery occlusion --> retrograde flow down vertebral arteries into subclavian arteries (subclavian steal syndrome)
Pathology
- The plaques formed in the carotid vessels can be divided into four types:
- Type l: predominantly hemorrhage, lipid, cholesterol, and proteinaceous material
- Type Il: dense fibrous connective tissue with >50% volume of hemorrhage, lipid, cholesterol, and proteinaceous material
- Type Ill: dense fibrous connective tissue with volume of hemorrhage, lipid, cholesterol,
- and proteinaceous material
- Type IV: dense fibrous connective tissue
Natural history
- Stroke rates for patients with mild deficit + angiographically proven ICA occlusion = 3 or 5% per year
- 2- 3.3% related to occluded side.
- In patients with acute ICA occlusion and profound neurological deficit:
- 2–12% make good recovery,
- 40–69% will have profound deficit,
- 16–55% will have died by the time of follow-up.
Treatment
- Endovascular thrombolysis and stenting for acute carotid occlusion
- Intra-arterial thrombolysis within 6 hours of stroke onset may increase recanalization rates to 37–100% and clinical improvement to 53–94% without significant increase in haemorrhagic transformation when compared with intravenous thrombolytic therapy alone.
- Although results appear promising, RCTs on cervical carotid thrombolysis and/or stenting are lacking.
- Surgery
- Endarterectomy
- Fogarty balloon catheter embolectomy (utilizing a No. 2 French catheter with 0.2ml balloon gently passed 10–12cm up ICA from small arteriotomy made distal to atheromatous plaque13),
- Surgical results
- 32% (15/47 cases) immediate surgical failures (no or minimal back bleeding),
- At least 3 deaths.
- Patency rate and duration of occlusion
- < 2 days 70– 100%,
- 3–7 days 50–100%,
- 8–14 days 27–58%,
- 15–30 days 4–61%,
- > 1 month 20– 50%.
- Extracranial-intracranial bypass
- Restored patency rate is inversely related to suspected duration of occlusion.
- Chronically occluded ICA has poor patency rate and little gain from re-opening.
- Determining the exact time of occlusion is frequently impossible. One must often rely on clinical grounds; therefore an occasional chronic occlusion will be included.
- Retrograde filling of ICA to petrous or cavernous segment from ECA (e.g. via ophthalmic) or from contralateral ICA is a good sign of operability.
- Cai et al 2021 Meta analysis
- EC-IC bypass was no better than conservative treatment
Guidelines
- Emergency operations for acute neuro deficit associated with total occlusion should not be performed after about 2 hrs.
- Extremely poor neuro status (lethargy/coma) is a contraindication to surgery.
- Patients without persistent neuro deficit: operate ASAP.
- If the patient has recurrent TIAs (despite maximal medical therapy) following recent carotid occlusion, and no definite infarct on MRI, consider by-pass surgery.
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