title: The PROTAGORAS study to evaluate the performance of the Endurant stent graft for patients with pararenal pathologic processes treated by the chimney/snorkel endovascular technique.
abstract: OBJECTIVE
  The chimney/snorkel endovascular aortic repair (ch-EVAR) is gaining ever-greater acceptance in the treatment of pararenal pathologic processes. However, the published experience includes mainly short-term clinical results with combinations of several abdominal devices and types of chimney grafts. The aim of this study was the midterm evaluation of the Endurant stent graft (Medtronic, Santa Rosa, Calif) as a standard abdominal device for ch-EVAR.
  
  
  METHODS
  Between January 2009 and January 2013, prospectively collected data of high-risk patients with pararenal pathologic processes who underwent ch-EVAR with placement of the Endurant abdominal device were analyzed. The chimney graft intended for use was a balloon-expandable covered stent. Main outcome measures were aneurysm sac regression and chimney graft patency.
  
  
  RESULTS
  A total of 187 snorkel/chimney grafts were successfully placed in 128 patients (mean age, 76.6 years). The technical success was 100%. The mean preoperative proximal neck length and aneurysm size were 4.7 mm and 64.8 mm (range, 48-135 mm), respectively. The postoperative new neck length after use of chimney grafts was 18.7 ± 6.3 mm. The mean aneurysm sac decreased significantly (60.8 mm; 95% confidence interval, 2.036-7.084; P = .001) after a mean radiologic follow up of 24.6 ± 17.4 months. Thirty-day mortality and midterm mortality were 0.8% and 17.2%, respectively. Two patients (1.6%) with single chimneys presented with late new onset of type Ia endoleak and underwent additional tube and multiple chimney placement. Primary chimney graft patency was 95.7%. Freedom from chimney graft-related reinterventions was 93.1%.
  
  
  CONCLUSIONS
  Standard use of the Endurant abdominal device for ch-EVAR in >120 patients is associated with high technical success, significant aneurysm sac regression, and low incidence of secondary procedures after 2-year radiologic follow-up. These results will give significant impetus to device selection, facilitating the standardization of technique.
authors.affiliation: Department of Vascular Surgery, St. Franziskus Hospital Münster, Münster, Germany; Clinic of Vascular and Endovascular Surgery, University of Münster, Münster, Germany. Electronic address: konstantinos.donas@googlemail.com.
authors.forename: Konstantinos P
authors.initials: KP
authors.lastname: Donas
authors.affiliation: Department of Vascular Surgery, St. Franziskus Hospital Münster, Münster, Germany; Clinic of Vascular and Endovascular Surgery, University of Münster, Münster, Germany.
authors.forename: Giovanni B
authors.initials: GB
authors.lastname: Torsello
authors.affiliation: Diagnostic Imaging Department, University Hospital of Udine, Udine, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Piccoli
authors.affiliation: Department of Vascular Surgery, St. Franziskus Hospital Münster, Münster, Germany; Clinic of Vascular and Endovascular Surgery, University of Münster, Münster, Germany; Division of Vascular Surgery, Thessaloniki University Hospital, Thessaloniki, Greece.
authors.forename: Georgios A
authors.initials: GA
authors.lastname: Pitoulias
authors.affiliation: Department of Radiology, St. Franziskus Hospital Münster, Münster, Germany.
authors.forename: Giovanni Federico
authors.initials: GF
authors.lastname: Torsello
authors.affiliation: Department of Vascular Surgery, St. Franziskus Hospital Münster, Münster, Germany; Clinic of Vascular and Endovascular Surgery, University of Münster, Münster, Germany.
authors.forename: Theodosios
authors.initials: T
authors.lastname: Bisdas
authors.affiliation: Department of Vascular Surgery, St. Franziskus Hospital Münster, Münster, Germany; Clinic of Vascular and Endovascular Surgery, University of Münster, Münster, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Austermann
authors.affiliation: Diagnostic Imaging Department, University Hospital of Udine, Udine, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Gasparini
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D001027:Aortography / Q000379:methods; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D057867:Endoleak / Q000209:etiology; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D005060:Europe; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D012074:Remission Induction; D015607:Stents; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014654:Vascular Patency