Transcarotid Artery Endovascular Revascularization

Transcarotid Artery Endovascular Revascularization

Anesthesia type	GA or MAC
Airway	ETT vs Natural Airway
Lines and access	PIV x 2 (one large bore), A-line
Monitors	Standard, 5 Lead
Primary anesthetic considerations
Preoperative	DAPT morning of surgery, beta-blockers, volume status, baseline neuro exam
Intraoperative	- Bradycardia/asystole during carotid balloon inflation (prevent with glyco) - Maintaining elevated SBP goal during flow reversal & monitoring rSO2 - Cerebral Hyperperfusion after stenting deployment (Maintain lowered SBP goal discussed with surgeon)
Postoperative	- Post-Stent hypotension & bradycardia (incr risk for MI, ischemic stroke, stent thrombosis - Early neurological assessment after extubation and during the immediate postop period
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Goal: Restoring laminar blood flow through a stenotic carotid artery narrowed by atherosclerotic or neointimal hyperplastic disease.

Also referred to as a TCAR, a transcarotid artery endovascular revascularization is an alternative to carotid endarterectomy for the management of carotid stenosis in patients who are determined to be poor open repair candidates based on high surgical risk or lesion location (such as a high/distal carotid artery bifurcation or a carotid lesion close to the skull base, that would make carotid endarterectomy (CEA) technically difficult).¹ Transcarotid artery revascularization (TCAR) is an alternative to transfemoral carotid artery stenting (TF-CAS) and is meant to decrease the risk for micro-embolic strokes through flow reversal through the carotid during stent placement (see below).^1,2,3,4

Overview

Surgical procedure:

The common carotid artery (CCA) is exposed via a small incision superior to the clavicle.

A flexible sheath is inserted into the CCA proximal to the lesion being stented and the distal end (outside the vessel) is connected to a flow reversal system (FRS).

At the same time the femoral vein is also being accessed either percutaneously or via surgical exposure, and a 2nd flexible sheath is inserted. The extraluminal end of the femoral sheath is attached to the other end of the flow reversal system (FRS).

Once connected blood flow from the high pressure CCA to the low pressure femoral vein through the FRS. After flow reversal wires are threaded past the lesion, if indicated pre-dilation of the vessel with balloon angioplasty occurs at this time, followed by deployment of the intralumenal stent. The FRS acts as a filter removing any plaques or disrupted intralumenal, decreasing the risk of micro-embolic strokes.

After successful placement, flow reversal is turned off and blood flow resumes in its normal direction. Sheaths removed and arteriotomy closed. ^2,3,4

Video with overview of steps: TCAR | TransCarotid Artery Revascularization Procedure Narrated Animation | Silk Road Medical | https://www.youtube.com/watch?v=MI2s4rv0dJA ⁴

Indications: ^2,5

General indications for carotid revascularization for stenotic atherosclerotic lesions are the same, regardless of revascularization approach (CEA, TF-CAS, TCAR).

- Asymptomatic Carotid Stenosis: Atherosclerotic narrowing of the extracranial ICA of 80-99% without recent stroke or TIA & with life expectancy of >5years. Of note, asymptomatic chronic complete (100%) occlusion not managed with revascularization procedures.

- Symptomatic Carotid Stenosis: Stroke or TIA referable to the appropriate carotid artery vascular distribution within the previous six months AND carotid stenosis > 50%.. Ideally revascularization within 2 weeks of symptom onset.

Stent placement is preferred to carotid endarterectomy if the patient have ANY of a number of comorbid medical disease or anatomical factors (see below) that would complicate the hemodynamic management intraoperatively putting the patient at elevated risk for CV complications (hemodynamic instability / vasoplegia, MI, stroke, arrhythmia, etc) or surgical/airway access.

Medical:

• Age > 75
• Congestive Heart Failure
• LVEF < 35%
• >2 diseased coronaries w/ 70% stenosis
• Unstable angina or abnormal stress test
• MI within 6 weeks
• Need for additional open heart surgery
• Need for major surgery (including vascular)
• Uncontrolled diabetes
• Severe pulmonary disease

Anatomic:

• Prior head/neck surgery or irradiation
• Spinal immobility  
• Restenosis post carotid endarterectomy (CEA)
• Surgically inaccessible lesion
• Laryngeal palsy; Laryngectomy
• Permanent contralateral cranial nerve injury
• Contralateral occlusion
• Severe tandem lesions
• Bilateral stenosis requiring treatment

Preoperative management

Patient evaluation:

Assess for the listed conditions/diseases above.

System	Considerations
Airway	Neck mobility, ability to tolerated surgical positioning. Prior neck radiation
Neurologic	Baseline neurologic exam, post operatively at risk for micro-embolic strokes. Assess if carotid stenosis is symptomatic (see below)
Cardiovascular	Exercise tolerance, assess for listed cardiovascular comorbid diseases above
Pulmonary	Exercise tolerance
Gastrointestinal
Hematologic	Ensure taking dual anti-platelet therapy per surgical team's directions
Renal	Current volume status, relative hypovolemia may adversely affect ability to induce HTN during flow reversal
Endocrine	Check BG
Other

Labs and studies

All carotid surgeries are considered high-risk & pre-surgical testing should follow AHA/ACA guidelines for high-risk noncardiac surgery.⁶

• CBC, electrolytes, creatinine, PT/INR/aPTT
• T&C; consider requesting to have 2 units of pRBC on hold
• 12 lead EKG
• Consider Stress Test (exercise or pharmacology) if:
  • Poor or unknown functional status
  • Calculated risk for major adverse cardiovascular events (MACE) is >1% on the VQI or NSQIP calculator
• TTE if concerned for CHF, pulmonary HTN, or valvular disease (may impair ability to safely induce needed hypertension intraoperatively)
• Per surgical team's preference either CT angiogram v Carotid ultrasound to define anatomy

Operating Room Setup³

TCAR can be preformed under GA or MAC with regional anesthesia. If planning to use MAC, have supplies for full conversion to GA emergently.

Have appropriate vasoactive medication available to quickly titrate blood pressure intraoperatively

- Push Medications: consider Epi, NE, Phenylephrine, Nitroglycerin, Esmolol, Nicardipine

- Prepared Drips: Norepinephrine (or preferred short acting vasopressor) spiked & in line, consider having for vasodilatory drip of choice in room

Additional Medications: Heparin & Protamine

Patient Preparation & Premedication³

- Verify that patient is taking Dual Antiplatelet Therapy (DAPT; Aspirin / Plavix) & a statin for the last 7 days including the morning of surgery. If dose not taken, discuss giving preOP with surgical team

- Continue home beta-blockers

- Verify medication that impact BP control or cause refractory hypotension compromising cerebral blood flow on induction or during flow reversal (ARB/ACEi) have not been taken

Regional & Neuraxial Techniques1^{1, 3}

Superficial Cervical Plexus Block

- With block procedure can be preformed with MAC

- Benefit in GA cases by decreasing opioid requirement, allows for more rapid neurologic assessment postoperatively

Intraoperative management³

Monitoring & Access

- Standard ASA monitors, 5 lead EKG

- Pre-induction arterial line

- PIV x 2 (note vasoactive medications will be in PIVs, make sure lines are well secured & running smoothly)

- Cerebral oximetry to monitor adequacy of collateral circulation via the Circle of Willis during flow reversal; ideally placed and calibrate while patient is awake.

- Intraoperative ACT monitoring during heparinization (target 250-350; verify goal with surgical team)

Induction & Airway Management³

- If planning on MAC with natural airway & superficial cervical plexus block, consider sedation with dexmedetomidine or remifentanil infusion.

GA: Slow controlled induction, goal to maintain BP at baseline to prevent decreased cerebral perfusion

Positioning^2,3

- Supine, neck extended, shoulder roll, head turned away from surgical site

- Run lines & monitors outside of fluoroscopy path to optimize surgical field

Maintenance & Surgical Considerations³

TIVA/Balanced anesthetic/inhalational anesthetic are reasonable

Have clear communication with the surgical team about what stage of the surgery they are in, critical for BP management/patient safety during a TCAR.

- Surgical Exposure: maintain BP at baseline or slightly higher

- Carotid Balloon Inflation: Can cause Bradycardia/asystole due to proximity near carotid baroreceptors. Give preventative glycopyrrolate (unless patient has contraindications to having a further elevated HR; baseline HR > 90 or severe CAD)

- Flow Reversal: Maintain SBP >160 or 20% above baseline SBP to aid perfusion via Circle of Willis. Closely monitor cerebral oximeter (rSO2) during this time.

• If cerebral oximeter (rSO2) decreases by >10%, treat by either increasing FiO2 or augmenting BP up to 20% above baseline (or both). Note that drops in rSO2 of >12% from baseline shown as a reliable, sensitive, and specific threshold for the detection of brain ischemia.

- Stent Deployment: Risk for acute cerebral hyperperfusion. Stop vasopressors, have closed loop communication about BP goal with surgical team and give push vasoactive medications as needed to meet goals (commonly SBP 110-140). Not uncommon to require boluses of nitroglycerin/esmolol/nicardipine to achieve this rapidly

- During Closing, post-stent hypotension & bradycardia is common due to persistent carotid baroreceptor stimulation & may require vasopressor support to insure adequate cerebral perfusion until hemodynamics stabilize.

Emergence³

- Avoid bucking due to neck incision & carotid artery puncture.

- Consider remifentanil, dexmedetomidine, or appropriate opioid titration prior to emergence

- If hypertensive (BP above goal) after extubation have short acting vasodilatory medications available (nitroglycerin/esmolol), if persistent consider longer acting anti-hypertensive medications (Labetalol/Hydralazine) ; be mindful to monitor closely postoperatively, remains at risk for post-stent hypotension (see above)

Postoperative management

Disposition

Requires close neurologic and hemodynamic monitoring postoperatively

Consider ICU vs PACU/IMC.

Pain management

- Opioids

- Regional anesthesia

Potential complications³

• Bleeding due to catheter dislodgement: higher risk during MAC as opposed to GA
• Hematoma: Neck and groin access sites
• Embolic stroke: More likely during surgical exposure or during device placement secondary to to insufficient flow reversal
• Reperfusion Injury: Acute cerebral hyperperfusion due to ipsilateral ACA/MCA distribution now seeing higher pressure and flow since no longer obstructed by stenotic segment of carotid artery. Stroke like syndrome which can manifest as encephalopathy or unilateral sensory / motor deficits, seizure, or rarely, intracranial hemorrhage
• Stroke due to hypoperfusion (watershed infarction): Possibly due to insufficient collateral flow via Circle of Willis or post-stent hypotension (see Maintenance & surgical considerations)
• Stent Thrombosis: More likely if persistently hypotensive
• Myocardial ischemia/ infarction: Monitor for post-stent hypotension 

References

1.) Malas  MB, Leal  J, Kashyap  V, Cambria  RP, Kwolek  CJ, Criado  E.  Technical aspects of transcarotid artery revascularization using the ENROUTE transcarotid neuroprotection and stent system.   J Vasc Surg. 2017;65(3):916-920. doi:10.1016/j.jvs.2016.11.042

2.) Columbo JA, Martinez-Camblor P, O’Malley AJ, et al. Association of Adoption of Transcarotid Artery Revascularization With Center-Level Perioperative Outcomes. JAMA Netw Open. 2021;4(2):e2037885. doi:10.1001/jamanetworkopen.2020.37885

3.) Ankam A, Kinthala S, Madabhushi P. Anesthetic Considerations for Transcarotid Artery Revascularization: Experience and Review of Forty Cases From a Single Medical Center. Cureus. 2020 Dec 24;12(12):e12250. doi: 10.7759/cureus.12250. PMID: 33505816; PMCID: PMC7822093.

4.) Silk Road Medical. TCAR surveillance project. Accessed January 1, 2020. https://silkroadmed.com/tcar-surveillance-project/

5.) Brott TG, Halperin JL, Abbara S, et al. 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS guideline on the management of patients with extracranial carotid and vertebral artery disease. Stroke 2011; 42:e464.

6.) ACC/AHA Guideline Update for Perioperative Cardiovascular Evaluation for Noncardiac Surgery—Executive Summary A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines