What is the Transcarotid Artery Revascularization (TCAR) procedure?

Transcarotid Artery Revascularization (TCAR) Procedure

TCAR is a promising hybrid carotid revascularization technique that uses direct carotid access and flow reversal to reduce stroke risk during carotid stenting, particularly beneficial for high-risk surgical patients with specific anatomical considerations. 1

Procedure Overview

TCAR combines surgical and endovascular approaches with these key components:

1. Direct Carotid Access:

   • Surgical cut-down to expose the common carotid artery
   • Completely bypasses the aortic arch, eliminating embolism risk from arch cannulation 1
   • Requires a small incision at the base of the neck

2. Flow Reversal System:

   • Creates "dynamic" flow reversal through an ex vivo common carotid artery to femoral vein shunt
   • Reverses blood flow away from the brain during the procedure
   • Serves as primary mechanism for procedural stroke reduction 1, 2

3. Stent Deployment:

   • Placement of carotid stent via the direct carotid access
   • Currently uses conventional single-layer stents in most cases
   • Stent is deployed under flow reversal protection

Anatomical Requirements

TCAR has specific anatomical considerations that must be met:

• Disease-free common carotid artery at puncture site
• Common carotid artery diameter ≥6mm
• Internal carotid artery diameter between 4-9mm
• ≥5cm distance from clavicle to carotid bifurcation
• Minimal to no common carotid artery puncture-site atherosclerosis 1, 3

Clinical Outcomes

• Stroke Risk: Similar in-hospital stroke/death rates compared to carotid endarterectomy (CEA) 1
• Cranial Nerve Injury: Significantly lower rate (0.3%) compared to CEA (3.8%) 4
• Technical Success: High rates (98.7%) reported in clinical trials 5
• Flow Reversal Duration: No significant association between duration of flow reversal and neurologic complications 2

Ideal Candidates

TCAR has potential to become the preferred treatment modality for:

• Higher-risk patients with symptomatic or asymptomatic carotid stenosis
• Patients with high lesions extending to second cervical vertebra
• Cervical spine immobility
• Post-CEA restenosis
• Prior neck irradiation
• Hostile neck anatomy
• Patients with severe aortic or femoral artery pathology that makes transfemoral CAS challenging 1

Potential Complications

• Carotid Dissection: Most common procedural complication, often occurring during sheath placement 6
  • Management depends on ability to engage true lumen:
    • Endovascular repair preferred when true lumen is accessible
    • Open surgical repair more common when multiple access attempts fail 6
• Stroke: Overall low rate (1.3%) in high-volume centers 2

Current Limitations and Considerations

• Lack of prospective randomized evidence comparing TCAR with transfemoral CAS
• European guidelines view TCAR as promising but requiring further RCT evidence before recommending as alternative to CEA in symptomatic patients 1
• First-generation single-layer stents used in TCAR may not provide adequate protection against post-procedural cerebral events 1
• Combining flow reversal with anti-embolic stents may further improve outcomes 1

Eligibility Assessment

Studies show approximately 68-72% of carotid arteries in patients selected for revascularization meet TCAR eligibility criteria 3. Of arteries considered high-risk for transfemoral CAS, about 69% are eligible for TCAR, making it a viable alternative for many patients 3.

TCAR represents an important evolution in carotid intervention, particularly for high-risk surgical patients with specific anatomical considerations, though further comparative studies with CEA and newer-generation stents are needed to fully establish its role in carotid disease management.