title: Shuttering of the superior mesenteric artery during fenestrated endovascular aneurysm repair.
abstract: OBJECTIVE
  Shuttering occurs when a scallop or fenestration does not align perfectly with the target vessel ostium and is potentially minimized by stenting. The current United States Food and Drug Administration-approved fenestrated endovascular aneurysm repair (f-EVAR) device is most commonly configured with an unstented superior mesenteric artery (SMA) scallop, thereby subjecting the SMA to risk of partial coverage. We aimed to describe the incidence, severity, and clinical effect of SMA shuttering during f-EVAR.
  
  
  METHODS
  Patients undergoing f-EVAR using the commercially available Zenith (Cook Medical, Bloomington, Ind) fenestrated stent graft system containing an SMA scallop at our institution between September 2012 and January 2014 were included for analysis. Corrected multiplanar reformatted images on postoperative computed tomographic angiography were reviewed to measure SMA shuttering, defined as the percentage of scallop misalignment relative to the SMA ostial diameter.
  
  
  RESULTS
  Of the 28 f-EVAR cases performed at our institution during the study period, 18 patients (78% male) had an SMA scallop and were included in this analysis. The median age was 78 years (interquartile range [IQR], 72-81 years), and the median abdominal aortic aneurysm size was 61 mm (IQR, 56-64 mm). Fifty-one vessels were targeted (18 SMA scallops, 32 renal fenestrations, 1 renal snorkel), with covered stents placed in all fenestrations. Target vessel catheterization and successful branch stent deployment was achieved in 100% of patients. SMA shuttering measured on postoperative computed tomographic angiography of any amount occurred in 50% of patients (range of SMA shuttering, 12%-40%). The severity of SMA shuttering varied: one patient had 11% to 20%, four had 21% to 30%, and four had 31 to 40%. When compared with patients without shuttering, patients with any SMA shuttering were noted to have a shorter infra-SMA neck length (17 vs. 25 mm; P = .007), higher volume of intraprocedural contrast administration (100 vs. 66 mL; P = .001), and had a trend toward longer procedural durations (240 vs. 188 minutes; P = .09). No association was found between SMA shuttering and the preoperative measured clock position of the visceral vessels, percentage of device oversizing, number of target vessels per patient, aortic diameter at the SMA or seal zone, aneurysm neck morphology, infrarenal neck length, scallop width, or SMA ostial diameter. No acute or chronic events of mesenteric ischemia were noted during a median clinical follow-up period of 11 months (IQR, 5-14 months).
  
  
  CONCLUSIONS
  Even with the custom design of currently available fenestrated technology, shuttering of the SMA occurred in one-half of the patients in our cohort, although no clinical events were noted. Further details of the incidence, magnitude, and tolerance of SMA shuttering during f-EVAR are warranted to fully understand the clinical implication of this radiographic finding. Future design considerations for advanced EVAR should take into account SMA shuttering to further refine operative planning.
authors.affiliation: Division of Vascular Surgery, Stanford University Medical Center, Stanford, Calif.
authors.forename: Brant W
authors.initials: BW
authors.lastname: Ullery
authors.affiliation: Division of Vascular Surgery, Stanford University Medical Center, Stanford, Calif.
authors.forename: George K
authors.initials: GK
authors.lastname: Lee
authors.affiliation: Division of Vascular Surgery, Stanford University Medical Center, Stanford, Calif. Electronic address: jtlee@stanford.edu.
authors.forename: Jason T
authors.initials: JT
authors.lastname: Lee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D001027:Aortography / Q000379:methods; D001807:Blood Vessel Prosthesis; D002140:California / Q000453:epidemiology; D057510:Endovascular Procedures / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D017538:Mesenteric Artery, Superior / Q000000981:diagnostic imaging / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control*; D011474:Prosthesis Design; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome