CTA may also be able to guide device selection. One complication after TEVAR is the development of a bird- beak endograft configuration in the proximal landing zone, which portends a higher risk of endoleak. This configuration results most commonly when the proximal landing zone sits within a highly curved or angulated Thoracic Aorta Interventional Planning and Follow-Up aortic arch [46]. Specially designed endografts that are less susceptible to these morphologic changes can therefore be selected when preoperative imaging identifies problematic anatomy. An important subset of TEVAR is its use in repair of pathologies involving the aortic arch. A detailed understanding of the spatial relationship of the arch vessels and the luminal changes throughout the diseased arch is required for proper patient and device selection [47]. Minimum proximal and distal landing-zone intervals are necessary, with reported values in the literature ranging from 20 to >50 mm [25,48]. When the proximal landing zone approaches or overlaps the origin of the left subclavian artery, there is an increased possibility of endoleak; in such cases, embolization of the artery or vascular bypass may be considered. Several commercially available devices require a normal-caliber proximal aorta with narrow acceptable landing-zone diameter ranges; for example, a recently approved multibranch endograft system requires a proximal aortic landing-zone diameter between 24 and 30 mm, thereby severely limiting the potential patient population [49,50]. Endograft sizing is of critical importance because an undersized graft may lead to fixation and sealing compromise, with resultant type I endoleaks and graft migration. It must be anticipated that most aortas increase in diameter over time as a result of age-related change and progression of aneurysmal disease in affected patients [51].
Thoracic Aortic Aneurysm or Dissection Treatment Planning and Follow Up. CTA may also be able to guide device selection. One complication after TEVAR is the development of a bird- beak endograft configuration in the proximal landing zone, which portends a higher risk of endoleak. This configuration results most commonly when the proximal landing zone sits within a highly curved or angulated Thoracic Aorta Interventional Planning and Follow-Up aortic arch [46]. Specially designed endografts that are less susceptible to these morphologic changes can therefore be selected when preoperative imaging identifies problematic anatomy. An important subset of TEVAR is its use in repair of pathologies involving the aortic arch. A detailed understanding of the spatial relationship of the arch vessels and the luminal changes throughout the diseased arch is required for proper patient and device selection [47]. Minimum proximal and distal landing-zone intervals are necessary, with reported values in the literature ranging from 20 to >50 mm [25,48]. When the proximal landing zone approaches or overlaps the origin of the left subclavian artery, there is an increased possibility of endoleak; in such cases, embolization of the artery or vascular bypass may be considered. Several commercially available devices require a normal-caliber proximal aorta with narrow acceptable landing-zone diameter ranges; for example, a recently approved multibranch endograft system requires a proximal aortic landing-zone diameter between 24 and 30 mm, thereby severely limiting the potential patient population [49,50]. Endograft sizing is of critical importance because an undersized graft may lead to fixation and sealing compromise, with resultant type I endoleaks and graft migration. It must be anticipated that most aortas increase in diameter over time as a result of age-related change and progression of aneurysmal disease in affected patients [51].