Medical Device News Magazine’s interviewed two leading Vascular Surgeons who presented compelling presentations on Trans Carotid Artery Revascularization (TCAR) at the Annual Meeting of the Society for Vascular Surgery Meeting held June 20 – 23, 2018 in Boston, MA.
Our first question was asked of Marc Schermerhorn, MD, Chief, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center Professor of Surgery, Harvard Medical School regarding his presentation, “In-hospital Outcomes of Trans Carotid Artery Revascularization (TCAR) and Carotid Endarterectomy (CEA) in the SVS Vascular Quality Initiative.”
MDNM: Dr. Schermerhorn, your presentation on “In-hospital Outcomes of Trans Carotid Artery Revascularization (TCAR) and Carotid Endarterectomy (CEA) in the SVS Vascular Quality Initiative” presented at the SVS was viewed by many as impressive. Please elaborate about the data collected, and patient outcomes. How will this data favorably or unfavorably impact the SVS Vascular Quality Initiative?
DR. SCHERMERHORN: Our study evaluated a fairly large number of patients over a two-year period, with 1,182 receiving Trans Carotid Artery Revascularization (TCAR) compared 10,797 receiving Carotid Endarterectomy (CEA) from January 2016 to March 2018. Our overall finding showed that although the patients receiving TCAR were older, sicker and more likely to be symptomatic with a higher degree of stenosis, the stroke and death rate compared to CEA was the same. When we evaluated individual outcomes of stroke, death, and MI separately or combined both unadjusted and through a multi variable analysis, we did not see any difference in the outcomes of TCAR or CEA. However, we did find different benefits in patients receiving TCAR. With TCAR, there was a significantly lower amount of cranial nerve injuries, less time spent in the operating room and fewer patients with a prolonged length of stay. Given the number of patients in each arm of the study, we feel comfortable that these results are real. The main outcome we evaluated was stroke and death, and we showed that outside of a very controlled clinical trial setting like the ROADSTER trial, the results of TCAR were excellent and outcomes were equivalent to CEA in stroke and death. The study was a wonderful demonstration of the value of the SVS Vascular Quality Initiative, and provided access to new technology much more rapidly. I believe that more clinicians should adopt the TCAR technology as it has been demonstrated to be safe and effective and seems to be an excellent alternative to CEA.
Right now TCAR is primarily being used for high risk patients based on CMS reimbursement criteria. The outcomes of our study have now shown TCAR in high risk patients to be comparable to CEA in stroke and death, and better in terms of cranial nerve injury occurrence, with the CEA comparison group being primarily non-high risk. I hope that as we continue to enroll patients in the study and evaluate results, that CMS would consider broadening the reimbursement criteria to also include non-high-risk patients for TCAR.
Medical Device News Magazine spoke with Mahmoud Malas, MD, MHS, Professor of Surgery, Johns Hopkins School of Medicine, Director of the Center of Research Excellence and Surgical Trials, Johns Hopkins Medical Institutes, Chief of Endovascular Surgery, JHBMC regarding his presentation on “TransCarotid Artery Revascularization (TCAR) vs. Transfemoral Carotid Artery Stenting (TFCAS) in the SVS Vascular Quality Initiative” (SS24).
MDNM: Dr. Malas. What does the future bring as it relates to TCAR?
DR. MALAS: Overall, this project is a great example of how the SVS Vascular Quality Initiative allows us to evaluate new technology efficiently and more timely than the lengthy and expensive process of clinical trials. The results of this study demonstrate real world outcomes because of enrollment of high risk patients from different sites across the country. Many of these patients were actually excluded from ROADSTER II Trial due to the strict exclusion criteria like any other clinical trial. Because there is no super selection of patients, this study allows us to see how the TCAR with Enroute flow reversal system performs in real world setting. We have known for a while that Transfemoral Carotid Artery Stenting (TFCAS) has higher risk of stroke compared to Carotid Endarterectomy (CEA). However, our study is the first study to actually compare Transfemoral Carotid Artery Stenting (TFCAS) to TransCarotid Artery Revascularization (TCAR). We showed that TCAR is superior to TFCAS, as it carries less incidence of adverse neurological events. Direct carotid access with dynamic flow reversal provides CEA like protection avoiding the arch and eliminate any lesion manipulation without protection.
In this study we present the preliminary results of the TCAR Surveillance Project. Follow up studies comparing TCAR to TFCAS and to CEA after complete enrollment are needed to provide conclusive evidence. However, based on the initial results of this study, I believe that TCAR as a hybrid procedure is a great option for sicker patients with difficult anatomy, who are at a high risk for surgery. We have shown that the TCAR procedure is safe and effective, and the outcomes are superior when compared to Transfemoral Carotid Artery Stenting and comparable to Carotid Endarterectomy.
MDNM: We asked Dr. Sumaira Macdonald MBChB (Commendation), MD, MRCP (UK) FRCP (London) FRCP (Edinburgh), FRCR (UK), EBIR (EU), PhD, Vascular Interventional Radiologist, Chief Medical Officer, Silk Road Medical, Inc Triallist: CAVATAS, STAG, BIAS 1, ICSS, ACST2 to provide additional insight for our readership:
MDNM: Let’s look at carotid stenting in general. What are some of the issues related to other carotid stenting or carotid endarterectomy approaches, in particular preventing stroke and how is the design and interventional approach resolving this major issue?
DR. MACDONALD: All interventional strategies focusing on the control of the embolic burden of the carotid bifurcation have prophylactic intent i.e. they are justified only when meaningful stroke prevention can be achieved. All carotid stents, be they placed via a Trans Femoral (TF) or Transcarotid (TC) route are equally good at preventing ipsilateral stroke for up to ten years beyond 30 days of deployment (CREST, ICSS and numerous other randomized trials). The art is in the management of the peri-procedural (30-day) stroke hazard so that a stent can be delivered safely i.e. that one does not cause a stroke in attempting to prevent a subsequent stroke. A glaringly consistent message across all trials of TF-CAS versus CEA is that the former is associated with twice the (minor) stroke excess as the latter at thirty days. These minor strokes cannot simply be dismissed as irrelevant as they impact significantly on a patient’s quality of life per the CREST trial. The reasons for excess stroke hazard in TF-CAS are myriad but include arch navigation (an endo-hostile arena) and the crossing of an untreated lesion with a distal Embolic Protection Device (EPD) when the flow is antegrade. Filters are well named – they filter – so that microemboli which may impact subclinically and/or on cognitive function are allowed to pass through to the cerebral circulation. CEA although well scrutinized in prior randomized trials has a good stroke/death safety record but is vulnerable to excess 30-day stroke/death in medically co-morbid patients (Schermerhorn) and excess local complications (hematoma, return to OR, cranial nerve injury) regardless of prior risk stratification but compounded in patients with anatomic risk factors (high lesion, restenosis post CEA, radiotherapy, for example). TCAR is a hybrid that avoids the endo-hostile arch and the surgically hostile carotid bifurcation to achieve compelling 30-day safety data across all relevant parameters.
MDNM: Tell us more about the TCAR Surveillance Project launched in 2016?
DR. MACDONALD: The TCAR Surveillance Project (or Transcarotid Surveillance Project) resides under the auspices of the Patient Safety Organization (PSO) of the Society of Vascular Surgery (SVS) Vascular Quality Initiatives (VQI), a program that seeks to address quality control and benchmarking across many index vascular/endovascular procedures to include carotid, aortic and peripheral vascular. This initiative is the result of perhaps previously unanticipated collaboration between the SVS, CMS and the FDA. The TSP provides an open-ended vehicle for data collection with no completion date. Patients who are considered to be at increased risk from anatomic and/or medical co-morbidities per CMS criteria may be offered TCAR within the TSP and reimbursement is garnered for symptomatic patients with 50-99% carotid stenosis and asymptomatic patients with ≥80% stenosis. The premise here is that the primary endpoint of this unrestricted registry is one-year survival free of ipsilateral stroke with the secondary endpoint being 30-day stroke/death hazard. The intention is to compare TCAR with propensity matched CEA populations within this registry and to share these data with both CMS and the FDA.
MDNM: What does the future bring as it relates to TCAR and do you expect guidelines to change?
DR. MACDONALD: Regarding the future of TCAR, Silk Road Medical Inc. and our investors believe wholeheartedly in its ability to become the Standard of Care for carotid revascularization across patient populations. All the accruing evidence base points to predictable, consistent results with excellence in outcomes despite the fact that these results reflect early evaluations in relatively inexperienced hands US-wide in desperately co-morbid patients. Changes in Guidelines and Societal recommendations rely on the consolidation of reliable evidence – such as the output from the TSP VQI initiative and exacting scrutiny of this caliber is wholly welcomed.