Comparative-Effectiveness of Procedures for Carotid Revascularization - PROJECT SUMMARY 1 Carotid artery stenosis is a major risk factor for ischemic stroke, a leading cause of morbidity and mortality in the 2 United States. Patients with carotid stenosis are typically managed with a combination of antiplatelet and 3 cholesterol-lowering medications and are considered for procedural revascularization to decrease their risk of 4 stroke. There are three different procedures for carotid revascularization: surgical carotid endarterectomy (CEA), 5 percutaneous transfemoral carotid artery stenting (TF-CAS), and a procedure that was recently approved in 6 2015, transcarotid artery revascularization (TCAR). The efficacy and safety of CEA and TF-CAS have been 7 rigorously studied in more than a dozen randomized clinical trials. However, TCAR has not, and evidence 8 supporting its use is currently limited to small single-arm prospective studies and propensity-matched analyses 9 with limited follow up. Furthermore, the major National Institutes of Health-sponsored randomized trial of carotid 10 revascularization, the Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis 11 Trial (CREST-2), which began in December 2014 and is still in progress, does not include TCAR and therefore 12 cannot resolve the question of TCARs effectiveness. Despite this, TCAR has risen to rapid popularity and is now 13 in use at 570 centers in the United States with 30,951 implants as of April 2022. The objective of this project is 14 two-fold. First, with no ongoing comparative trial of TCAR, determining how this new procedure should be used 15 in contemporary practice relies on observational research. In this proposal, we will define the 5-year risk of stroke 16 after TCAR versus CEA versus TF-CAS. We will resolve important limitations of prior published studies of TCAR, 17 including lack of long-term results, accounting for the competing risk of death, and in establishing which patients 18 are most likely to benefit from this new procedure. In doing so, we will inform both patients and clinicians what 19 role TCAR should play in their treatment plans. Second, TCAR represents an opportunity to both advance our 20 knowledge of this new procedure, and simultaneously fill key conceptual knowledge gaps in Dr. Columbo’s 21 training as a comparative-effectiveness researcher. In vascular care, it is not uncommon for procedures to be 22 implemented in patients without a randomized trial. This makes comparative-effectiveness research using 23 observational data vital to ensure that patients are receiving safe and effective care. TCAR is an excellent 24 example of why this type of research is important. This mentored award will allow Dr. Columbo to work under 25 the guidance of the mentorship team to further his development in comparative-effectiveness research using 26 observational data, training in the responsible conduct of research, interpretation and clinical applicability of the 27 findings, and grant writing. The educational objectives outlined in this proposal will complement Dr. Columbo’s 28 existing skills and provide him with a well-rounded skillset for comparative-effectiveness work. While these skills 29 will be used to evaluate TCAR in this proposal, they are broadly applicable to evaluating new procedures that 30 are introduced in the future, launching Dr. Columbo’s career as an independent investigator.
