title: A systematic review and meta-analysis of in situ versus composite bilateral internal thoracic artery grafting.
abstract: This meta-analysis examines whether there is any advantage of coronary artery bypass graft with bilateral internal thoracic artery (BITA) as an in situ versus composite graft.
  
  
  
  We searched MEDLINE and EMBASE Databases from 1996 to 2016 for studies that compared coronary artery bypass graft with BITA as in situ versus composite graft. Data were extracted by 2 independent investigators and meta-analyzed with the use of random effects.
  
  
  
  Two randomized controlled trials (RCTs; n = 705), 2 matched (n = 1688), and 4 unadjusted observational studies (n = 3517) met inclusion criteria. Composite grafting trended towards greater distal anastomoses (+0.22, 95% confidence interval, -0.01 to +0.45 anastomoses/patient; P = .06 [4 unadjusted observational studies]) and greater distal anastomoses using an internal thoracic artery (+0.80, 95% confidence interval, 0.41-1.18 anastomoses/patient; P < .001 [1 RCT]). There were no differences in perioperative or longer-term composite cardiovascular outcomes comparing in situ versus composite BITA or individual outcomes of mortality, repeat revascularization, myocardial infarction, and cardiovascular mortality. Pooled results differed by study type with pooled results from lower-risk-of-bias RCTs typically showing increases in events rates, and pooled results from higher-risk-of-bias unadjusted observational studies typically showing decreases in event rates of in situ versus composite BITA. Post hoc subgroup analysis suggested possible improvements in all-cause mortality and revascularization for in situ BITA in studies with short-term (<5 years) versus longer-term follow-up, regardless of study type.
  
  
  
  Our meta-analysis found that use of BITA as a composite graft configuration facilitated greater internal thoracic artery revascularization but both grafting strategies offer similar clinical outcomes. Our study supports the use of in situ and composite BITA for select patients but high-quality, long-term prospective trials are needed.
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, Toronto, Ontario, Canada. Electronic address: yanagawab@smh.ca.
authors.forename: Bobby
authors.initials: B
authors.lastname: Yanagawa
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, Toronto, Ontario, Canada.
authors.forename: Subodh
authors.initials: S
authors.lastname: Verma
authors.affiliation: Applied Health Research Centre, Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada.
authors.forename: Peter
authors.initials: P
authors.lastname: Jüni
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, Toronto, Ontario, Canada.
authors.forename: Derrick Y
authors.initials: DY
authors.lastname: Tam
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, Toronto, Ontario, Canada.
authors.forename: Amine
authors.initials: A
authors.lastname: Mazine
authors.affiliation: Department of Cardiothoracic Surgery, Mount Sinai Beth Israel, New York, NY.
authors.forename: John D
authors.initials: JD
authors.lastname: Puskas
authors.affiliation: Critical Care and Medicine Departments, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Jan O
authors.initials: JO
authors.lastname: Friedrich
mesh_terms: D000368:Aged; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007387:Internal Mammary-Coronary Artery Anastomosis / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome; D014654:Vascular Patency
keywords: bilateral internal thoracic artery; coronary artery bypass graft; graft patency