ACute Uncomplicated Type b Aortic Dissection: Endovascular Repair vs. Best Medical Therapy

Inclusion Criteria:

* Aged ≥18 years, regardless of race or ethnicity;
* Diagnosed with uncomplicated ABAD, i.e., a primary entry tear distal to left subclavian artery with no evidence of malperfusion, end-organ ischemia, rupture, or intractable pain, and onset of symptoms is ≤30 days prior to enrollment;
* Patient has been stabilized after the acute event with control of pain and blood pressure using ≤3 intravenous antihypertensive medications;
* Adequate imaging, e.g., CT with contrast (chest + abdomen+ pelvis) is available prior to enrollment; and
* Indicates willingness to comply with the study protocol and is able to provide a written informed consent;
* Meets criteria for inclusion in the National Death Index and Social Security Death Master File.

Exclusion Criteria:

* Diagnosed with Type A aortic dissection;
* Evidence of complicated ABAD;
* Chronic Type B aortic dissection (\>6 weeks from onset of symptoms);
* Unable to be randomized and undergo treatment according to protocol within 30 days of symptom onset;
* Diagnosed with traumatic dissection or penetrating ulcer;
* Anatomy is not suitable for TEVAR;
* Previous descending thoracic or abdominal aortic surgery (open or endovascular);
* Unsuitable access sites, including infection at access sites;
* Associated aortic aneurysm (descending aortic diameter ≥5.0 cm);
* Life expectancy \<2 years;
* Unable or unlikely to comply with BMT;
* Unable or refuse to comply with follow-up;
* Intend to participate in another trial within 3 months of enrollment;
* Pregnant or breast-feeding;
* Vasculitis or known genetic connective tissue disorder (Marfan's syndrome or Ehlers-Danlos syndrome)
* Active systemic infection;
* Chronic kidney disease stage 3-5 (estimated glomerular filtration rate \<60 mL/min/1.73m2);
* Cerebral vascular accident within past 3 months; or
* Clinically significant gastrointestinal bleeding, major surgery, myocardial infarction, or untreated coagulopathy within past 6 weeks.