Database Supporting the Study: Detailed Description The study relies on a synthesis of data from multiple large-scale, multicenter registries, with the International Registry of Acute Aortic Dissection (IRAD)

The International Registry of Acute Aortic Dissection (IRAD) serves as a primary database supporting studies on acute aortic dissection (and related conditions like intramural hematoma). It is one of the largest and most influential multicenter, international registries dedicated to this life-threatening cardiovascular emergency. Establishment and Purpose IRAD was founded in 1996 as a grassroots initiative by cardiovascular specialists to address the limited data available on acute aortic dissection at the time. The registry’s core mission is to collect standardized, high-quality data from a large number of patients to better understand the epidemiology, etiological factors, modes of presentation, clinical features, diagnostic approaches, management strategies (medical, surgical, and endovascular), and short- and long-term outcomes of acute aortic dissection worldwide. It aims to raise awareness, provide evidence-based insights to improve diagnosis and treatment, inform clinical guidelines, and drive collaborative research on this rare but devastating condition. Structure and Organization • Coordinating Center: Located at the Michigan Cardiovascular Outcomes Research and Reporting Program (MCORRP) within Michigan Medicine (University of Michigan Medical Center). • Participating Centers: IRAD is a consortium of 58–62 large referral/tertiary centers (exact count varies slightly by source and updates) across 13 countries, spanning North America (primarily the US and Canada), Europe, the Middle East, Asia, and Australasia. Examples include major institutions such as Mayo Clinic, Cleveland Clinic, Massachusetts General Hospital, University of Tokyo, and others in Germany, Italy, Spain, France, Japan, China, India, and more. Sites are aortic centers of excellence that enroll patients prospectively or retrospectively using standardized forms. • Data Collection: Patient data are gathered via detailed, standardized forms covering demographics, medical history, risk factors (e.g., hypertension in ~77%, atherosclerosis, Marfan syndrome, prior cardiac surgery), presenting symptoms (e.g., sudden severe chest/back pain, atypical presentations), physical findings, imaging modalities (CT increasingly dominant at ~69%), management decisions, complications (e.g., malperfusion, shock, tamponade), and outcomes (in-hospital mortality, post-discharge follow-up). The registry has evolved to include interventional cohorts (e.g., IRAD Interventional Cohort since 2010) to track advances like endovascular therapies. Scale and Key Statistics IRAD has enrolled over 7,300 patients (with ongoing enrollment), making it one of the most comprehensive sources for acute aortic dissection data. Patients are typically ~63 years old on average, ~2/3 male, with ~67% type A dissections and ~33% type B. It captures real-world data from diverse populations, revealing variations (e.g., higher type B prevalence in Black patients, genetic links in younger cases). Impact and Contributions • Publications and Influence: Over 105 peer-reviewed publications (with more ongoing), including foundational papers in journals like JAMA and Circulation. Insights have shaped guidelines, highlighted chronobiological patterns (e.g., peak incidence mornings and winter), reduced diagnostic delays via risk markers, tracked mortality improvements (e.g., type A in-hospital mortality drop from ~31% to ~22%), and emphasized complications like malperfusion or false lumen thrombosis as predictors. • Ongoing Role: IRAD supports multicenter analyses, working groups on genetics, surgical/endovascular techniques, follow-up, and patient education. It remains voluntary and self-sustaining (with funding from industry, foundations, and sites), adapts to field advances, and continues expanding centers and projects. In studies synthesizing data from large registries, IRAD often forms the backbone due to its rigorous, multinational scope and long-term tracking, providing robust evidence where single-center or smaller datasets fall short. For the most current details or access (restricted to participating healthcare providers), refer to the official site at iradonline.org.