title: Comparative geometric analysis of renal artery anatomy before and after fenestrated or snorkel/chimney endovascular aneurysm repair.
abstract: OBJECTIVE
  The durability of stent grafts may be related to how procedures and devices alter native anatomy. We aimed to quantify and compare renal artery geometry before and after fenestrated (F-) or snorkel/chimney (Sn-) endovascular aneurysm repair (EVAR).
  
  
  METHODS
  Forty patients (75 ± 6 years) underwent computed tomographic angiography before and after F-EVAR (n = 21) or Sn-EVAR (n = 19), with a total of 72 renal artery stents. Renal artery geometry was quantified using three-dimensional model-based centerline extraction. The stented length was computed from the vessel origin to the stent end. The branch angle was computed relative to the orthogonal configuration with respect to the aorta. The end-stent angle was computed relative to the distal native renal artery. Peak curvature was defined as the inverse of the radius of the circumscribed circle at the highest curvature within the proximal portion from the origin to the stent end and the distal portion from the stent end to the first renal artery bifurcation.
  
  
  RESULTS
  Sn-renals had greater stented length compared to F-renals (P < .05). From the pre- to the postoperative period, the origins of the Sn-left renal artery and right renal artery (RRA) angled increasingly downward by 21 ± 19° and 13 ± 17°, respectively (P < .005). The F-left renal artery and RRA angled upward by 25 ± 15° and 14 ± 15°, respectively (P < .005). From the pre- to the postoperative period, the end-stent angle of the Sn-RRA increased by 17 ± 12° (P < .00001), with greater magnitude change compared to the F-RRA (P < .0005). Peak curvature increased in distal Sn-RRAs by .02 ± .03 mm(-1) (P < .05). Acute renal failure occurred in 12.5% of patients, although none required dialysis following either F- and Sn-EVAR. Renal stent patency was 97.2% at mean follow-up of 13.7 months. Three type IA endoleaks were identified, prompting one secondary procedure, with the remainder resolving at 6-month follow-up. One renal artery reintervention was performed due to a compressed left renal stent in an asymptomatic patient.
  
  
  CONCLUSIONS
  Stented renal arteries were angled more inferiorly after Sn-EVAR and more superiorly after F-EVAR due to stent configuration. Sn-EVAR induced significantly greater angle change at the stent end and curvature change distal to the stent compared to F-EVAR, although no difference in patency was noted in this small series with relatively short follow-up. Sn-RRAs exhibited greater end-stent angle change from the pre- to the postoperative period as compared to the F-RRA. These differences may exert differential effects on long-term renal artery patency, integrity, and renal function following complex EVAR for juxta- or pararenal abdominal aortic aneurysms.
authors.affiliation: Division of Vascular Surgery, Stanford University, Stanford, Calif.
authors.forename: Brant W
authors.initials: BW
authors.lastname: Ullery
authors.affiliation: Division of Vascular Surgery, Stanford University, Stanford, Calif.
authors.forename: Ga-Young
authors.initials: GY
authors.lastname: Suh
authors.affiliation: Division of Vascular Surgery, Stanford University, Stanford, Calif.
authors.forename: Jason T
authors.initials: JT
authors.lastname: Lee
authors.affiliation: Division of Vascular Surgery, Stanford University, Stanford, Calif.
authors.forename: Brian
authors.initials: B
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Stanford University, Stanford, Calif.
authors.forename: Robert
authors.initials: R
authors.lastname: Stineman
authors.affiliation: Division of Vascular Surgery, Stanford University, Stanford, Calif.
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Dalman
authors.affiliation: Division of Vascular Surgery, Stanford University, Stanford, Calif. Electronic address: cpc@stanford.edu.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Cheng
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D001027:Aortography / Q000379:methods; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011474:Prosthesis Design; D011857:Radiographic Image Interpretation, Computer-Assisted; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D012079:Renal Circulation; D015607:Stents; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014654:Vascular Patency