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.

There is also a body of evidence for TCAR from the SVS VQI, which demonstrates a comparable benefit/risk profile to CEA in patients in both high and standard surgical risk patients. Furthermore, TCAR has shown significantly reduced odds of certain procedural complications such as cranial nerve injury when compared to CEA as well as significantly shorter procedural times and significantly reduced odds of hospital length of stay greater than 1 day. In a recent analysis from the SVS VQI, TCAR was shown to be non-inferior to CEA in patients at standard risk for adverse events from CEA leading to FDA approval of expanded indications to include both standard and high surgical risk patients.

Objective:

The TCAR Surveillance Project is a prospective, continuous duration, case controlled, national observational registry of consecutive patients treated with TCAR using FDA-cleared proximal embolic protection devices with flow reversal and FDA-approved carotid artery stents intended for transcarotid delivery in hospitals participating in the CAS Registry of the SVS PSO VQI. This registry will provide a platform for data collection and analysis to provide ongoing surveillance of all existing and future TCAR devices.

TCAR outcomes will be compared to those of CEA in the standard and high surgical risk population as recorded in the SVS PSO VQI CEA Registry. Acute, periprocedural and long-term outcomes will be analyzed in propensity matched, risk adjusted cohorts. Standardized data elements available in both the CAS and CEA registries will be employed to make the comparisons. Participating hospitals are responsible for data entry using a secure, web-based data entry interface. Completeness and accuracy of data entry will be monitored by the SVS PSO.

The primary endpoint for both TCAR and CEA is death and/or ipsilateral carotid territory stroke at one year. The secondary endpoint will be any stroke during the initial hospitalization and death at 30 days post procedure.

Methods:

All patients, both high surgical risk and standard 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.