This report presents the 30-day results of the Safety and Efficacy Study for Reverse Flow Used During Carotid Artery Stenting Procedure (ROADSTER) multicenter trial and evaluates the safety and efficacy of ENROUTE Transcarotid NPS (Silk Road Medical Inc, Sunnyvale, Calif), a novel transcarotid neuroprotection system that provides direct surgical common carotid access and cerebral embolic protection via high-rate flow reversal during carotid artery stenting (CAS). A prospective, single-arm, multicenter clinical trial was performed to evaluate the use of the ENROUTE Transcarotid NPS during CAS procedures performed in patients considered to be at high risk for complications from carotid endarterectomy. Symptomatic patients with ≥50% stenosis and asymptomatic patients with ≥70% stenosis were eligible to be treated with any U.S. Food and Drug Administration-approved carotid artery stent. The primary end point was the composite of all stroke, myocardial infarction (MI), and death at 30days postprocedure as defined in the Food and Drug Administration-approved study protocol. Secondary end points included cranialnerve injury; 30-day stroke, death, stroke/death, and MI; acute device, technical, and procedural success; and access site complications. All major adverse events were adjudicated by an independent clinical events committee. Between November 2012 and July 2014, 208 patients were enrolled at 18 sites. Sixty-seven patients were enrolled as lead-in cases, and 141 were enrolled in the pivotal phase. In the pivotal cohort, 26% were symptomatic and 75% were asymptomatic. Acute device and technical success were 99% (140 of 141). By hierarchical analysis, the all-stroke rate in the pivotal group was 1.4% (2 of 141), stroke and death was 2.8% (4 of 141), and stroke, death and MI was 3.5% (5 of 141). One patient (0.7%) experienced postoperative hoarseness from potential Xth cranial nerve injury, which completely resolved at the 6-month follow-up visit. The results of the ROADSTER trial demonstrate that the use of the ENROUTE Transcarotid NPS is safe and effective at preventing stroke during CAS. The overall stroke rate of 1.4% is the lowest reported to date for any prospective, multicenter clinical trial of CAS.