Approach Considerations
Access for carotid artery stenting (CAS) can be obtained through a variety of approaches, as follows:
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Femoral - This is the approach preferred by most interventionalists; it avoids technique-related angulation and offers improved guide-wire and catheter maneuverability
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Brachial/radial - A brachial approach is associated with a risk of damaging the median nerve; moreover, owing to the extreme angulation, manipulation of the catheter is difficult with this approach
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Carotid - Both percutaneous and direct open exposures have been reported, and both have been associated with the risk of causing inadvertent dissection and inadvertent crossing of the stenotic lesion; however, newer techniques of transcervical CAS with flow reversal [19] have been associated with high technical success, almost zero mortality, and very low rates of major or minor stroke, myocardial infarction (MI), and complications
Carotid Stent Insertion
Before and for a minimum of 30 days after CAS, dual-antiplatelet therapy (DAPT) with aspirin (81-325 mg/day) plus clopidogrel (75 mg/day) has been recommended. [20] For patients intolerant of clopidogrel, ticlopidine (250 mg q12hr) may be substituted.
The 2018 guidelines on carotid and vertebral artery disease from the European Society for Vascular Surgery (ESVS) suggested that preintervention statin therapy may reduce procedural complications. [21] The guidelines recommended starting DAPT with aspirin (300 mg initially for up to 14 days followed by 75 mg/day if the patient is not already taking aspirin) and clopidogrel (75 mg/day) 3 days prior to CAS. Aspirin and clopidogrel should be continued for at least 1 month, followed by clopidogrel thereafter, unless the treating physician opts for an alternative long-term antiplatelet regimen.
The standard technique for CAS is described below. Certain steps may vary, depending on the patient’s anatomy and the surgeon's preferences (see the image below).
Key steps in carotid stenting. Image courtesy of Kurt Mansor, Jobst Vascular Institute.
The patient is placed in a supine position. Both femoral regions are prepared and draped in a standard fashion. Anatomic landmarks are marked on the patient (ie, the anterior superior iliac spine and pubic tubercle).
The femoral pulsation is palpated, and a micropuncture needle is inserted one fingerbreadth below the inguinal ligament. Upon entry into the artery, a hydrophilic wire is inserted through the needle by means of the Seldinger technique. The needle is removed and is replaced by a 4-French sheath. The sheath is upsized to 6 French.
A guide wire is advanced into the aorta under direct fluoroscopy. An H1 catheter is placed over the guide wire and positioned in the aortic arch. Heparin 80 IU/kg is administered. An aortogram is obtained in the left anterior oblique position at 45° of angulation. The aortic arch, innominate artery, left common carotid artery (CCA), and left subclavian artery are identified. Selective catheterization of the left or right common artery is performed.
The guide wire is placed in the external carotid artery (ECA), and the H1 catheter is then placed in the ECA. The guide wire is replaced with a stiffer wire (Amplatz/Lunderquist wire). A shuttle sheath is advanced to the CCA. A carotid arteriogram is obtained (in anteroposterior, lateral, and intracerebral views).
The lesion is crossed with 0.014-in. wire. A cerebral protection device (CPD) is positioned with a monorail system. Predilatation is performed with a 2- to 3-mm balloon. The stent is placed across the lesion and deployed.
A repeat arteriogram is performed (see the image below). Any residual stenosis exceeding 30% is treated with balloon angioplasty. Sheaths and wires are removed, and an access site closure device is deployed.
Images show vessel before and after carotid artery stenting. Image courtesy of Cheong Lee, MD.
Complications
Potential complications of CAS include the following:
Long-term outcomes of CAS remain to be fully defined. One study reviewed records for 219 patients who underwent CAS to assess the risk of carotid stent fractures or deformations following the procedure. Results showed a 15% rate of fracture or deformation at 2 years and a 50% rate at 4 years. Open-cell stents led to deformation more frequently than closed-cell stents did, and stent fractures were significantly associated with heavy calcification. These are potentially important early observations that should be recorded for all CAS patients to determine future clinical implications. [22]
In a 2018 meta-analysis of randomized controlled trials aimed at assessing the safety of CAS vs CEA for asymptomatic carotid stenosis with average risk, Cui et al found that as compared with CEA, CAS had a higher rate of periprocedural stroke and periprocedural minor stroke and a similar rate of periprocedural major stroke, periprocedural ipsilateral stroke, or MI. [23] They were not able to reach any robust conclusions about midterm to long-term complications.
A meta-analysis by Yuan et al that assessed CAS against CEA in the setting of asymptomatic carotid stenosis found that CEA was associated with a lower risk of perioperative stroke and a higher risk of MI but that CEA and CAS appeared to be essentially equivalent with regard to the risk of death. [24]
Hemodynamic instability—as defined by hypertension (systolic blood pressure >160 mm Hg), hypotension (systolic blood pressure < 90 mm Hg), bradycardia (heart rate < 60 beats/min), or a combination thereof—has been reported to occur after CAS. [26] Patients with prolonged hemodynamic instability after the procedure are at increased risk for TIA and stroke.
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Key steps in carotid stenting. Image courtesy of Kurt Mansor, Jobst Vascular Institute.
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Images show vessel before and after carotid artery stenting. Image courtesy of Cheong Lee, MD.
