SVS VQI TransCarotid Revascularization Surveillance Project

Background:

Contemporary randomized trials of transfemoral carotid artery stenting (TF CAS) and carotid
endarterectomy (CEA) have shown comparable long-term ipsilateral stroke prevention (>30 days)
but have consistently demonstrated higher periprocedural (< 30 day) stroke rates, including
contralateral stroke, compared with CEA, with the highest risk centered around "day zero".
Potential etiologies for this excess risk likely relate to embolization during unprotected
catheterization of the aortic arch and supraaortic vessels from a TF approach and/or
suboptimal distal embolic protection during CAS. TransCarotid Artery Revascularization (TCAR)
combines the surgical principles of neuroprotection with minimally invasive endovascular
techniques to treat stenosis in the carotid artery. It involves surgical exposure and
clamping of the proximal common carotid artery with continuous carotid blood flow reversal
via an extracorporeal arteriovenous shunt from the target carotid artery to a femoral vein,
during which carotid bifurcation/internal carotid artery stenting is performed. Thus, TCAR
avoids catheter manipulation in the aortic arch and emulates the "clamp and backbleed" method
of neuroprotection during CEA, but differs from CEA in that the carotid artery is accessed
through a smaller, supra-clavicular incision below the main plexus of cranial nerves.
Further, the direct transcarotid approach allows the use of larger bore sheaths and tubing to
achieve higher reverse carotid artery flow rates than is possible with smaller transfemoral
catheters.

Published TCAR Data:

The initial study of TCAR in patients deemed to be at high risk for complications from CEA
have shown that TCAR appears to provide superior stroke and death outcomes when compared to
prior registry results from both CEA and TF CAS. Schermerhorn, et al reported outcomes from
the Society for Vascular Surgery (SVS) Vascular Registry in high surgical risk patients and
found that in this real world registry, the 30-day stroke and death rates in symptomatic
patients for CEA and TF CAS were 6.4% and 7.9% respectively. (Citation: Schermerhorn) In
asymptomatic, high risk patients, the 30-day stroke and death rates for CEA and TF CAS were
3.7% and 4.8% respectively. In contrast, a recent study of TCAR (ROADSTER pivotal trial) ,
the 30-day stroke and death rates for both symptomatic and asymptomatic patients were 2.8%
and 2.9%, respectively. (Citation: Kwolek) While these initial results of TCAR are
encouraging, they involved only 114 patients in the pivotal trial, such that further
evaluation is clearly important.

Objective:

The objective of the VQI TransCarotid Artery Revascularization Surveillance Project is to
evaluate the safety and effectiveness of TCAR in real world practice, using a contemporaneous
comparison with CEA. Stroke and death outcomes data in TCAR and CEA patients deemed to be at
high risk for complications from CEA will be collected and analyzed using the SVS PSO CAS and
CEA Registries. High surgical risk is defined according to the CMS criteria published in the
National Coverage Determination for Percutaneous Transluminal Angioplasty (20.7) and listed
in the inclusion criteria. The evaluation of these alternate strategies for surgical
treatment of carotid artery disease is central to the mission of the SVS PSO.

Methods:

All high surgical risk patients treated with TCAR and CEA in the SVS PSO CAS and CEA
Registries will be included and separately analyzed as symptomatic and asymptomatic, with
symptomatic defined as a history of ipsilateral stroke, TIA and/or amaurosis fugax within 180
days of the procedure. 30-day and one-year outcomes will be analyzed in propensity matched,
risk adjusted cohorts. Any FDA-cleared proximal embolic protection device and FDA-approved
carotid artery stent system indicated for the transcarotid approach will be included in the
registry. Sites participating in VQI are audited for consecutive case submission by
comparison with claims data. A Steering Committee within the SVS PSO will monitor the quality
and completeness of submitted data, and adjudicate any questionable outcomes by querying
sites for clarifying information. This committee will be responsible for scientific analysis
and periodic publication of the results.

Inclusion Criteria:

Patients undergoing TCAR or CEA who are considered high surgical risk as defined by the CMS
criteria published in the National Coverage Determination for Percutaneous Transluminal
Angioplasty (20.7). Any of the following criteria qualify a patient for inclusion in the
high surgical risk TCAR or CEA cohort:

Anatomic High Risk Inclusion Criteria:

- Contralateral carotid artery occlusion

- Tandem stenoses >70%

- High cervical carotid artery stenosis

- Restenosis after carotid endarterectomy

- Bilateral carotid artery stenosis requiring treatment

- Hostile neck which the Investigator deems safe for transcarotid access including but
not limited to prior neck irradiation, prior radical neck dissection or cervical spine
immobility

Clinical High Risk Inclusion Criteria:

- Patient is >= 75 years of age

- Patient has >= 2-vessel coronary artery disease and history of angina of any severity

- Patient has a history of unstable angina or Canadian Cardiovascular Society (CCS)
angina class 3 or 4

- Patient has congestive heart failure (CHF) - New York Heart Association (NYHA)
Functional Class III or IV

- Patient has known severe left ventricular dysfunction with LVEF <30%.

- Patient has had a myocardial infarction > 72 hours and < 6 weeks prior to procedure.

- Patient has severe pulmonary disease (COPD) with either FEV1 <50% predicted or chronic
oxygen therapy or resting PO2 of <= 60 mmHg (on room air)

- Patient has permanent contralateral cranial nerve injury

- Patient has chronic renal insufficiency (serum creatinine > 2.5 mg/dL).

Exclusion Criteria:

- Patients undergoing TCAR or CEA who do not meet at least one of the above inclusion
criteria, plus patients who have received a previous stent in the target artery.