What is the role of transcarotid artery revascularization (TCAR) in the treatment of atherosclerotic disease of the carotid artery?

Updated: Sep 29, 2021
  • Author: Jake F Hemingway, MD; Chief Editor: Vincent Lopez Rowe, MD  more...
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Answer

Transcarotid artery revascularization (TCAR) represents an alternative to transfemoral CAS in patients deemed to be at high risk for CEA because of the presence of medical comorbidities or certain high-risk anatomic factors (eg, high carotid bifurcation, previous neck surgery, or previous irradiation).

Multiple studies have compared safety outcomes between TCAR and CEA, [17]  with TCAR having lower rates of stroke in comparison with transfemoral CAS. [18, 19]  The primary benefit of TCAR over transfemoral CAS is the ability to avoid navigating an often diseased aortic arch, by virtue of the direct common carotid access that is obtained surgically in TCAR. Additionally, the use of dynamic flow reversal allows the institution of embolic protection before crossing of the carotid lesion is attempted.

Much as with CAS, CMS has approved reimbursement for TCAR in the following patients [27] :

  • Symptomatic patients with high-grade stenosis (≥70%) who are considered to be at high risk for CEA

However, the creation of the Society for Vascular Surgery (SVS) TCAR Surveillance Project extended coverage to the following patients:

  • Asymptomatic high-risk patients with ≥80% stenosis
  • Symptomatic high-risk patients with ≥50% stenosis

Anatomic considerations

In addition to the above, to be eligible for TCAR, the following anatomic requirements must be met:

  • Distance greater than 5 cm exists between the access site and the carotid lesion
  • Common carotid artery diameter  exceeds 6 mm
  • Common carotid artery access site and the site of proximal clamp placement on the common carotid artery are free of disease.

The following anatomic features and lesion characteristics are not favorable for carotid stenting and thus represent contraindications for TCAR:

  • Severe, circumfirentially calcified lesion
  • Severe carotid tortuosity

Preparation for procedure

Dual antiplatelet therapy (DAT) with aspirin (75-325 mg/day) and clopidogrel (75 mg/day), initiated prior to the proedure, is strongly recommended. Statin therapy should also be initiated at the initial preoperative appointment, if it has not already been started.

Procedure

The procedure is performed either in an operating room with C-arm capabilities or in an angiographic suite. With the patient under either local or general anesthesia, the proximal ipsilateral common carotid artery is exposed through a short (3-cm) incision at the base of the neck, with dissection carried down between the two heads of the sternocleidomastoid.

After proximal circumferential control of the common carotid artery is gained, the patient is anticoagulated with heparin to achieve an activated clotting time (ACT) greater than 250 s. A 5-0 polypropylene "U" stitch is placed at the planned puncture site to aid in later closure. The common carotid artery is directly punctured with the use of a micropuncture access kit, and initial angiography is performed to confirm the carotid anatomy.

The carotid artery sheath is carefully advanced over a stiff, floppy-tipped wire, with care taken to ensure that the lesion is not engaged in the process; after successful placement, this sheath is flushed. A femoral venous sheath is then placed in the right or left common femoral vein percutaneously under US guidance, and the dynamic flow reversal system is connected. The patient is pretreated with glycopyrrolate (0.2 mg) prior to common carotid clamp placement to prevent hypotension and bradycardia during carotid bulb angioplasty and stenting.

The common carotid artery proximal to the arterial sheath is clamped, and flow reversal is started. The internal carotid artery stenosis can then be crossed with a 0.014-in. wire, and the lesion is predilated before stent placement. Postdilation of the stent is optional and depends on the amount of residual stenosis present.

Completion angiography is performed in two views to confirm adequate stent expansion. The wire is then removed, the proximal common carotid artery clamp is removed, and antegrade perfusion to the carotid artery is restored. The flow reversal system is disconnected, allowing the return of all blood to the patient, and the arterial sheath is removed. The already placed polypropylene suture is used to close the carotid artery access site, and protamine is given to reverse anticoagulation. The femoral venous sheath can be removed, with hemostasis obtained by means of direct manual pressure.

After the procedure, the patient is usually monitored within an intensive care unit (ICU) and discharged the next day.


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