Treatment for Type B Aortic Dissection using Allay Aortic Stent

Inclusion Criteria:

* Have a type B aortic dissection extending to the celiac trunk or beyond
* Are eligible for thoracic endovascular treatment with stent grafts as per local guidelines, and physician's decision
* Have been elected for treatment with commercially available stent graft as per their IFU within 90 days of dissection symptoms onset

Exclusion Criteria:

* General Exclusion Criteria:

  * Age \< 18 years
  * Pregnant, breast-feeding or planning on becoming pregnant during the entire duration of the study
  * Unable to provide written informed consent
  * Unable or unwilling to comply with the requirements of the study protocol
  * Taking part already in an investigational device or drug study that could interfere with the outcomes being studied
  * Active drug addiction or known history of drug abuse within one year of treatment
* Medical Exclusion Criteria:

  * Aortic rupture (free or contained including haemothorax, increasing periaortic hematoma, or mediastinal hematoma)
  * Aortic fistula
  * Suspicion of bowel necrosis or irreversible visceral ischemia
  * Stage 5 chronic kidney disease
  * Life expectancy of less than 2 years due to any other medical condition than the dissection to be treated
  * Active malignancy
  * Known sensitivities or allergies to the device materials (including cobalt, chromium, nickel)
  * Known sensitivities or allergies to contrast materials that cannot be pre-medicated
  * Mycotic aortic aneurysm or active systemic infection that may place the patient at increased risk of endovascular infection
  * American Society of Anaesthesiologists (ASA) class V (moribund patient not expected to live 24 hours with or without operation)
  * Diagnosed or suspected congenital degenerative connective tissue disease (e.g., Marfan's, Loeys-Dietz or Ehlers-Danlos syndrome)
  * Uncorrectable coagulopathy, bleeding diathesis or refusal of blood transfusion
  * Any major cardiovascular or cerebrovascular ischemic event, including myocardial infarction or stroke, or treatment of such event, within 90 days prior to enrolment
  * Any aortic-related interventional or surgical procedure within 30 days prior to enrolment
  * Any planned aortic-related interventional or surgical procedure within 30 days after the study procedure
* Anatomical Exclusion Criteria:

  * Aneurysmal dilatation of the false lumen defined as maximum transaortic diameter \>55 mm in women or \>60 mm in men in the thoraco-abdominal segment or \>50 mm in women or \>55 mm in men in the abdominal segment, measured inner-wall to inner-wall;
  * Inadequate proximal landing zone for the stent graft, such zone being \<20 mm long
  * Inadequate proximal landing zone geometry for the Allay® Aortic Stent (e.g. aortic kink)
  * Planned implantation of a stent graft with a distal diameter \>38 mm or \<20 mm
  * Aorta or iliac anatomy not allowing the advancement of the delivery system
  * Subject in whom the thoracic stent graft is either 1) not implanted in its intended position and/or 2) leads to any serious device complication, and/or who has 3) persistent static obstruction of the visceral or both renal arteries, prior to Allay® Aortic Stent implantation, will not be implanted with the Allay® Aortic Stent and will be withdrawn from the study