title: Use of covered chimney stents for pararenal aortic pathologies is safe and feasible with excellent patency and low incidence of endoleaks.
abstract: BACKGROUND
  To present the clinical experience of consecutive series with use of balloon-expandable and self-expanding chimney endografts (balloon-expandable covered stent group [BECS] vs self-expanding covered stent group [SECS]) in the endovascular treatment of challenging aortic pathologies requiring renal and/or visceral revascularization.
  
  
  METHODS
  Between January 2009 and May 2011, data for 37 high-risk patients from one center and 35 patients from another institution, with pararenal aortic pathologies treated by the chimney endovascular technique, were prospectively collected. The chimney-graft technique is based on the deployment of a covered or bare-metal stent parallel to the aortic endograft, thereby creating a conduit that runs outside the aortic main endograft, and has been proposed to ensure secure proximal fixation extending the sealing zones.
  
  
  RESULTS
  Forty-six consecutive target vessels (43 renal arteries and 3 superior mesenteric arteries) were revascularized by the Advanta (Atrium, Hudson, NH) BECS (1.2 chimneys/patient); in contrast, 81 consecutive target vessels (64 renal arteries, 11 superior mesenteric arteries, and 6 celiac trunks) were revascularized by the Viabahn (Gore, Flagstaff, Ariz) SECS (2.3 chimneys/patient). The success rate for target vessel preservation was 97.8% for the BECS group and 100% for the SECS group in the entire follow up. There was one symptomatic left renal artery occlusion of the BECS group treated by open thrombectomy of the left renal artery and placement of 8-mm Dacron (BBraun, Aesculap AG, Tuttlingen, Germany) iliorenal bypass. Additionally, one patient underwent repeat balloon angioplasty with a 5-mm balloon due to high-grade in-stent stenosis of a 6 × 59 Advanta stent graft 12 months postoperatively. Overall, one perioperative (and not present in the computed tomography angiography at discharge) type Ia endoleak was detected in the BECS group. In contrast, five perioperative type Ia endoleaks were present in the SECS group; however, only one of them was persistent in the radiological imaging and was treated by proximal extension of a 5-mm cuff, 1 year postoperatively, due to continuous aneurismal sac increase. No patient of any subgroup developed postoperative persistent renal insufficiency with need of hemodialysis. Thirty-day and during the follow-up procedure-related mortality was 0% for both BECS and SECS groups.
  
  
  CONCLUSIONS
  In summary, midterm results of use of covered chimney stents for pararenal aortic pathologies show safety and feasibility with excellent patency and low incidence of endoleaks.
authors.affiliation: Department of Vascular Surgery, St. Franziskus Hospital Münster and the Clinic for Vascular and Endovascular Surgery, Münster University Hospital, Münster, Germany. k.donas@gmx.at
authors.forename: Konstantinos P
authors.initials: KP
authors.lastname: Donas
authors.forename: Felice
authors.initials: F
authors.lastname: Pecoraro
authors.forename: Giovanni
authors.initials: G
authors.lastname: Torsello
authors.forename: Mario
authors.initials: M
authors.lastname: Lachat
authors.forename: Martin
authors.initials: M
authors.lastname: Austermann
authors.forename: Dieter
authors.initials: D
authors.lastname: Mayer
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Panuccio
authors.forename: Zoran
authors.initials: Z
authors.lastname: Rancic
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000800:Angioplasty, Balloon / Q000009:adverse effects / Q000295:instrumentation*; D001018:Aortic Diseases / 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*; D057867:Endoleak / Q000000981:diagnostic imaging / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D005858:Germany; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D015607:Stents; D013557:Switzerland; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014654:Vascular Patency