title: Chimney Grafts in Aortic Stent Grafting: Hazardous or Useful Technique? Systematic Review of Current Data.
abstract: BACKGROUND
  The chimney graft (CG) technique was introduced to rescue accidentally covered aortic branches during aortic endovascular repair. It extends the sealing zone. There is concern about "gutter" type I endoleak (EL-I) and about the durability of CGs. The aim of the present report was to analyze the rapidly increasing existing data.
  
  
  METHODS
  A search was performed (PRISMA criteria) for all studies of visceral and thoracic/arch chimney grafts. Technical and clinical details and outcome were assessed.
  
  
  RESULTS
  The present review includes 831 patients who underwent EVAR/TEVAR (endovascular aneurysm repair/thoracic endovascular aneurysm repair) with one or more chimney, periscope, or sandwich grafts. For aortic visceral vessels 517 patients received 911 visceral CGs and 314 patients received 364 arch CGs. Most procedures (81% visceral and 69% arch CGs) were elective. Thirty day mortality was 4% for both groups. The rate of early EL-I was 13% (visceral CGs) and 11% (arch CGs). Most EL-I were handled conservatively (observation: 70% for visceral CG and 45% for arch CG). Early CG patency was high (97-99%) and remained high during follow up (median 17 months). Late (after 30 days) EL-I was reported in nine visceral (2%) and 12 arch (4%) CG cases. Few other late complications were reported, but those losing a kidney at the initial repair seemed to have a high risk of requiring permanent hemodialysis.
  
  
  CONCLUSIONS
  Increasing amounts of data support the benefit of visceral and arch chimney graft techniques. In particular, the low early mortality and complication rates and high long-term patency seem advantageous; however, the majority of cases have been treated electively, and there is a high risk of bias in all studies. Mid- to long-term data suggest few late complications, except in cases where one renal artery was sacrificed. The CG technique is valuable for complex urgent patients and needs further documentation for other patient groups.
authors.affiliation: Department of Vascular Diseases, Skåne University Hospital, Malmö, Sweden. Electronic address: bengt.lindblad@med.lu.se.
authors.forename: B
authors.initials: B
authors.lastname: Lindblad
authors.affiliation: Department of Vascular Diseases, Skåne University Hospital, Malmö, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Bin Jabr
authors.affiliation: Department of Vascular Diseases, Skåne University Hospital, Malmö, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Holst
authors.affiliation: Department of Vascular Diseases, Skåne University Hospital, Malmö, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Malina
mesh_terms: D001018:Aortic Diseases / 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; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology; D011474:Prosthesis Design; D018570:Risk Assessment; D012307:Risk Factors; D015607:Stents; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014654:Vascular Patency
keywords: Aortic branch revascularization; Chimney stent graft; Complex abdominal and arch pathologies; Endovascular treatment; Periscope grafts; Review; Sandwich grafts