ImportanceEndovascular treatment is not recommended for aortic pathologies in patients with connective tissue diseases (CTDs) other than in redo operations and as bridging procedures in emergencies. However, recent developments in endovascular technology may challenge this dogma.ObjectiveTo assess the midterm outcomes of endovascular aortic repair in patients with CTD.Design, Setting, and ParticipantsFor this descriptive retrospective study, data on demographics, interventions, and short-term and midterm outcomes were collected from 18 aortic centers in Europe, Asia, North America, and New Zealand. Patients with CTD who had undergone endovascular aortic repair from 2005 to 2020 were included. Data were analyzed from December 2021 to November 2022.ExposureAll principal endovascular aortic repairs, including redo surgery and complex repairs of the aortic arch and visceral aorta.Main Outcomes and MeasuresShort-term and midterm survival, rates of secondary procedures, and conversion to open repair.ResultsIn total, 171 patients were included: 142 with Marfan syndrome, 17 with Loeys-Dietz syndrome, and 12 with vascular Ehlers-Danlos syndrome (vEDS). Median (IQR) age was 49.9 years (37.9-59.0), and 107 patients (62.6%) were male. One hundred fifty-two (88.9%) were treated for aortic dissections and 19 (11.1%) for degenerative aneurysms. One hundred thirty-six patients (79.5%) had undergone open aortic surgery before the index endovascular repair. In 74 patients (43.3%), arch and/or visceral branches were included in the repair. Primary technical success was achieved in 168 patients (98.2%), and 30-day mortality was 2.9% (5 patients). Survival at 1 and 5 years was 96.2% and 80.6% for Marfan syndrome, 93.8% and 85.2% for Loeys-Dietz syndrome, and 75.0% and 43.8% for vEDS, respectively. After a median (IQR) follow-up of 4.7 years (1.9-9.2), 91 patients (53.2%) had undergone secondary procedures, of which 14 (8.2%) were open conversions.Conclusions and RelevanceThis study found that endovascular aortic interventions, including redo procedures and complex repairs of the aortic arch and visceral aorta, in patients with CTD had a high rate of early technical success, low perioperative mortality, and a midterm survival rate comparable with reports of open aortic surgery in patients with CTD. The rate of secondary procedures was high, but few patients required conversion to open repair. Improvements in devices and techniques, as well as ongoing follow-up, may result in endovascular treatment for patients with CTD being included in guideline recommendations.