Neurovascular
Procedure Guide
Indications
Symptomatic stenosis >50%
Asymptomatic stenosis >70%
Nml PSV in large arteries = 60-100 cm/sec; >125 a/w >50% stenosis; >230 a/w >70% stenosis
ICA:CCA <2 (nml); 2-4 (>50% stenosis); >4 (>70% stenosis)
EDV > 100cm/s a/w >70% stenosis
Some payers (e.g. CMS in the US) require confirmation of degree of stenosis with CTA or MRA vs DSA during the procedure if CTA/MRA are contraindicated.
Etiologies: atherosclerosis >> Moyamoya, Ehlers-Danlos syndrome, Marfan’s syndrome, α1-antitrypsin deficiency, FMD, catheter manipulation, ADPKD, osteogenesis imperfecta
Contraindications
Allergy to antiplatelet medication, nickel, titanium, cobalt, chromium
Uncontrolled bleeding diathesis
(Relative) recent stroke, fresh clot, sepsis, circumferential calcification, severe tortuosity
Efficacy and alternatives
Optimal medical therapy (OMT), e.g, ASA, statins, should be pursued regardless and may be the best choice for high risk lesions in older patients.
Carotid Endarterectomy (CEA) vs Carotid Artery Stenting (CAS): Multiple trials with mixed data. Choice will likely depend more on local skill/preference than strict guidelines.
Historically, CEA was preferred generally unless high surgical risk (>3%) or patient cosmetic concerns with neck scar, e.g, meta-analyses have shown higher [OR 1.86 (1.05-3.31)] peri-procedural stroke with stenting; yet, death, stroke, and MI were similar [OR 0.92 (0.68-1.26)] with longer follow up.
However, this data is mixed with some studies showing less peri-operative stroke with CAS for patients <60 years old. For patients 60-70 years old with. low surgical risk, some studies suggest a trade off with higher peri-operative stroke with CAS but less MI and nerve damage.
Newer trials such as CREST with routine use of embolic protection devices or SPACE and SPACE II are showing similar outcomes with no difference between CAS and CEA outcomes at 10 years for patients enrolled in CREST. Overall trend for both have trended towards lower, comparable risk profiles (see charts below). Per US Centers for Medicare & Medicaid Services (CMS), decision should be based on shared decision making with patient for specific risk profile and anatomy.
Pre-procedure care
Carotid US often used for initial evaluation and screening. CTA/MRA to confirm degree of stenosis and for procedurally planning.
NASCET criteria are often used for calculating the degree of stenosis, which is a ratio of smallest luminal diameter in the area of stenosis over the diameter of the lumen of the closest normal appearing cervical portion of the ICA.
ECST is an alternative, which is [(1 - smallest luminal diameter in the area of stenosis) / (estimated normal lumen diameter)] x 100
Optimize medical therapy (statin, BP control, smoking cessation, healthy diet, weight control, and antiplatelet therapy).
Neurological assessment by neurologist or NIHSS scale certified professional before and after CAS for CMS coverage in the US.
CBC, INR/Coags, Cr, ECG, Type & screen
Start clopidogrel, ASA, and statin 2-4d prior
procedure
Arterial access, often CFA or radial but can also directly access the carotid called transcarotid artery revascularization (TCAR)
Place long flexible 6/7F sheath for support
Use 4-5F pigtail for aortic arch angiography
Select the common carotid with hydrophilic guidewire and catheter, e.g., vert catheter.
Exchange wire for stiff exchange length wire and advance 6-7F guide catheter ~20mm proximal to the target lesion
Deploy embolic protection device and confirm position with angiogram.
One option is a distal embolic protection device in the ICA but this requires crossing the lesion to deploy.
Another option is inflating balloon catheters in the CCA and ECA to reverse ICA flow (“proximal protection”). Avoids crossing the lesion with a protect device but requires an intact circle of Willis.
Some perform pre-stent balloon angioplasty is necessary to advance stent.
Position stent to cover ENTIRE lesion and deploy followed by further angioplasty if needed.
Self-expanding stents, often on a 0.014 or 0.018 system, are preferred to balloon expanding given the mobility and risk of crushing the stent.
Often requires covering the origin of the ECA, which is well tolerated.
Confirm placement and remove protection device
Access closure
Complications
Intra-procedure bradycardia (can give atropine 0.6-1mg IV or glycopyrrolate 0.2mg IV), hyperperfusion syndrome (1.1%), ICH, stroke (symptomatic 6-9%, asymptomatic 2-4%, less in newer trials), arterial dissection, MI (1%)
Post-procedure care & Follow Up
Bed rest until next morning with DVT prophylaxis
Neurological assessment by neurologist or NIHSS scale certified professional before and after CAS for CMS coverage in the US.
Continue clopidogrel and ASA for 6wks and then ASA alone for life
Follow up dopplers at 6mo and 1yr