title: Impact of Renal Artery Angulation on Procedure Efficiency During Fenestrated and Snorkel/Chimney Endovascular Aneurysm Repair.
abstract: OBJECTIVE
  To determine the impact of renal artery angulation on time to successful renal artery cannulation and procedure efficiency during fenestrated and snorkel/chimney endovascular aneurysm repair (EVAR).
  
  
  METHODS
  The imaging and procedure logs of 77 patients (mean age 74.2 years; 63 men) who underwent complex EVAR (24 fenestrated, 53 snorkel/chimney) from 2009 to 2013 were reviewed. Renal artery angulation was measured on preoperative computed tomographic angiography scans. Time to renal artery cannulation was retrieved from the EVAR procedure logs and compared to preoperative renal artery angulation and other metrics of procedure efficiency (eg, procedure time, fluoroscopy time, blood loss, etc). In all, 111 renal arteries were available for renal artery angulation measurement (39 fenestrated, 72 snorkel/chimney); 22 renal cannulations were inappropriate for the comparative analyses due to concomitant visceral artery stenting (n=15), combined procedures (n=6), or unsuccessful cannulation (n=1).
  
  
  RESULTS
  For patients undergoing fenestrated EVAR, mean renal artery angulation was -28°±21° (range +37° to -60°), not significantly different (p=0.66) from patients receiving snorkel/chimney grafts (mean -30°±19°, range +22° to -65°). Comparative analysis using median renal artery angulation (-30° for both groups) demonstrated that renal artery cannulation during fenestrated EVAR was performed significantly faster in arteries with less downward (≥ -30°) angulation (16.0 vs 32.8 minutes, p=0.04), whereas cannulation in snorkel/chimneys was faster in arteries with greater downward (< -30°) angulation (10.9 vs 17.3 minutes, p=0.05). Fenestrated EVAR cases involving less downward (≥ -30°) renal artery angulation were also associated with shorter overall procedure time (187.7 vs 246.2 minutes, p=0.01) and decreased fluoroscopy time (70.3 vs 98.2 minutes, p=0.04). Immediate renal function decline, procedural complications, and postoperative issues were not associated with renal artery angulation.
  
  
  CONCLUSIONS
  Procedural efficiency may be optimized by considering renal artery angulation as one of several objective variables used in the selection of an appropriate endovascular strategy. The fenestrated approach is more efficient with less downward angulation to the renal arteries, while the snorkel/chimney strategy is facilitated by more downward renal artery angulation.
authors.affiliation: Division of Vascular Surgery, Stanford University Medical Center, Stanford, CA, USA ullery@gmail.com.
authors.forename: Brant W
authors.initials: BW
authors.lastname: Ullery
authors.affiliation: Division of Vascular Surgery, Stanford University Medical Center, Stanford, CA, USA.
authors.forename: Venita
authors.initials: V
authors.lastname: Chandra
authors.affiliation: Division of Vascular Surgery, Stanford University Medical Center, Stanford, CA, USA.
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Dalman
authors.affiliation: Division of Vascular Surgery, Stanford University Medical Center, Stanford, CA, USA.
authors.forename: Jason T
authors.initials: JT
authors.lastname: Lee
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D001027:Aortography; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000379:methods*; D057510:Endovascular Procedures / Q000379:methods*; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D008297:Male; D012077:Renal Artery / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: abdominal aortic aneurysm; chimney graft; endovascular aneurysm repair; fenestrated stent-graft; fluoroscopy use; parallel graft; procedure duration; renal artery cannulation; snorkel graft