Innovation in the treatment of ascending aorta and arch pathology with novel catheter-based and hybrid procedures has driven the need for a strategy to guide their safe application. The ARCH-ARC (Aortic Arch Academic Research Consortium) was established to pragmatically develop consistent clinical end points and to standardize definitions for use in studies of these new technologies. The ARCH-ARC team, consisting of independent international specialists in cardiac surgery, vascular surgery, vascular medicine, cardiology, neurology, radiology, and clinical trials, along with US Food and Drug Administration, industry, and contract research organization representatives, held virtual meetings from 2021 to 2025. Consensus was used to identify appropriate clinical end points and to standardize definitions of end points for endovascular, hybrid, and open surgical procedures in clinical trials in the ascending aorta and arch. Drawing on previous ARC work in cardiac, neurological, renal, and bleeding end points, the ARCH-ARC focused on definitions and end points related to aortic arch-specific anatomy, pathology, and procedures and clinical, device, and imaging. The adoption of the ARCH-ARC consensus definitions and end points will provide a template for consistent adjudication and event reporting and facilitate comparisons of clinical research studies involving devices for ascending aorta and arch pathology.