title: The influence of prototype testing in three-dimensional aortic models on fenestrated endograft design.
abstract: The fenestrated Anaconda endograft (Vascutek/Terumo, Inchinnan, UK) is intended for the treatment of abdominal aortic aneurysms with an insufficient infrarenal landing zone. The endografts are custom-made with use of high-resolution, 1-mm-slice computed tomography angiography images. For every case, a nonsterile prototype and a three-dimensional (3D) model of the patient's aorta are constructed to allow the engineers as well as the physician to test-implant the device and to review the fit of the graft. The aim of this investigation was to assess the impact of 3D model construction and prototype testing on the design of the final sterile endograft.
  
  
  
  A prospectively held database on fenestrated endovascular aortic repair patients treated at a single institution was completed with data from the Vascutek engineers' prototype test results as well as the product request forms. Changes to endograft design based on prototype testing were assessed and are reported for all procedures.
  
  
  
  Between April 1, 2013, and August 18, 2015, 60 fenestrated Anaconda devices were implanted. Through prototype testing, engineers were able to identify and report potential risks to technical success related to use of the custom device for the respective patient. Theoretical concerns about endograft fit in the rigid model were expressed in 51 cases (85.0%), and the engineers suggested potential changes to the design of 21 grafts (35.0%). Thirteen cases (21.7%) were eventually modified after the surgeon's testing of the prototype. A second prototype was ordered in three cases (5.0%) because of extensive changes to endograft design, such as inclusion of an additional fenestration. Technical success rates were comparable for grafts that showed a perfect fit from the beginning and cases in which prototype testing resulted in a modification of graft design.
  
  
  
  Planning and construction of fenestrated endografts for complex aortic anatomies where exact fit and positioning of the graft are paramount to allow cannulation of the aortic branches are challenging. In the current series, approximately one in five endografts was modified after prototype testing in an aortic model. Eventually, success rates were comparable between the groups of patients with a good primary prototype fit and those in which the endograft design was altered. Prototype testing in 3D aortic models is a valuable tool to test the fit of a custom-made endograft before implantation. This may help avoid potentially debilitating adverse events associated with misaligned fenestrations and unconnected aortic branches.
authors.affiliation: Department of Vascular and Endovascular Surgery, Wilhelminenspital, Vienna, Austria.
authors.forename: Fadi
authors.initials: F
authors.lastname: Taher
authors.affiliation: Department of Vascular and Endovascular Surgery, Wilhelminenspital, Vienna, Austria; Sigmund Freud University, Vienna, Austria. Electronic address: juergen.falkensammer@alumni.mayo.edu.
authors.forename: Juergen
authors.initials: J
authors.lastname: Falkensammer
authors.affiliation: Vascutek/Terumo, Inchinnan, United Kingdom.
authors.forename: Jamie
authors.initials: J
authors.lastname: McCarte
authors.affiliation: Department of Vascular and Endovascular Surgery, Wilhelminenspital, Vienna, Austria.
authors.forename: Johann
authors.initials: J
authors.lastname: Strassegger
authors.affiliation: Department of Vascular and Endovascular Surgery, Wilhelminenspital, Vienna, Austria.
authors.forename: Miriam
authors.initials: M
authors.lastname: Uhlmann
authors.affiliation: Department of Vascular and Endovascular Surgery, Wilhelminenspital, Vienna, Austria.
authors.forename: Philipp
authors.initials: P
authors.lastname: Schuch
authors.affiliation: Department of Vascular and Endovascular Surgery, Wilhelminenspital, Vienna, Austria.
authors.forename: Afshin
authors.initials: A
authors.lastname: Assadian
mesh_terms: D000368:Aged; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D001027:Aortography / Q000379:methods; D001317:Austria; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D000072226:Computed Tomography Angiography; D017076:Computer-Aided Design; D016208:Databases, Factual; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D066230:Patient-Specific Modeling; D011183:Postoperative Complications / Q000209:etiology / Q000517:prevention & control; D011237:Predictive Value of Tests; D066330:Printing, Three-Dimensional; D011474:Prosthesis Design; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents; D016896:Treatment Outcome