The introduction of thoracic endovascular aortic repair (TEVAR) in 1994 has radically changed the treatment of thoracic aortic pathology, and TEVAR is now the recommended therapy for complicated TBADs and other thoracic aorta diseases. To date, the use of TEVAR in the treatment of uncomplicated dissections (uTBAD) is uncertain, although it is presumed that a prophylactic procedure can prevent later complex surgery and early death. Several analyses have found that TEVAR confers improved aortic remodeling and possibly survival, although these were underpowered for this specific outcome. In addition, there are several reports regarding the uncertain benefit or harm of this intervention in the vascular surgery community. Put another way, there is equipoise, and the need for robust evidence in the form of a randomized clinical trial has been clearly iterated by the European Society of Vascular Surgery. This randomized, open-label, two-armed controlled study directly addresses this question of whether TEVAR alters 5-year survival among patients with an uTBAD. Patients will be randomized to either standard medical therapy (SMT) alone or TEVAR in addition to SMT. The primary outcome is 5-year survival, while secondary outcomes include aortic-related mortality, neurological events, quality of life, costs, re interventions and readmissions. in addition, subgroup analyses based on the extent of treatment. Sample size calculations based on previous reports indicate the need to include approximately 554 patients. Patients will be recruited from multiple centres in Scandinavia. Based on the population (24 million) and incidence of uTBAD (approximately 480 per year), and depending on the total number of participating centres, a conservative estimate of two to three years is required for enrolment.