title: Clinical and angiographic outcomes associated with surgical revascularization of angiographically borderline 50-69% coronary artery stenoses.
abstract: OBJECTIVE
  Coronary artery bypass grafting (CABG) improves outcomes in patients with multivessel coronary artery disease. Bypass of angiographically significant lesions ≥70% is recommended, yet little is known about the incidence/outcomes with bypasses of 50-69% angiographically borderline lesions (ABLs) without fractional flow reserve testing. The objective of this study was to investigate the incidence and outcomes of bypass of 50-69% ABLs.
  
  
  METHODS
  Between 2007 and 2013, 3195 patients underwent isolated first multivessel CABG. Patients with an isolated ABL of a major epicardial vessel were included. Outcomes of interest included time to all-cause mortality, and 30-day and 1-year mortality.
  
  
  RESULTS
  Among 350 patients with an ABL, 268 (76.6%) had the vessel containing the ABL bypassed, while 82 (23.4%) did not. The mean follow-up was 4.2 years. Patients with a bypassed ABL were older (66.1 vs 62.5 mean years, P = 0.006) but otherwise similar in sex, comorbidities, diabetes, ejection fraction and number of coronary stenoses. Cardiopulmonary bypass time was longer in patients with bypassed ABLs (104.2 vs 90.4 min, mean, P < 0.001). Unadjusted overall mortality until the end of follow-up was higher among patients with bypassed ABLs (11.6 vs 3.7%, P = 0.034). After multivariable adjustment, the association between ABL bypass and mortality was attenuated (hazard ratio 2.84, 95% confidence interval: 0.87-9.23, P = 0.080). No differences were observed in unadjusted 30-day (1.1 vs 0.0%, P = 0.336) or 1-year mortality (4.1 vs 0.0%, P = 0.062). Repeat revascularization rate of patients with bypassed ABLs was numerically higher (4.1 vs 0.0%, P = 0.107).
  
  
  CONCLUSIONS
  In an unselected cohort of patients with ABLs, bypass of borderline 50-69% lesions is frequently performed and not associated with improved long-term survival. Our findings suggest that the routine surgical revascularization of 50-69% ABLs may not be warranted.
authors.affiliation: Division of Cardiology, University of Alberta Hospital, Edmonton, AB, Canada.
authors.forename: Janek M
authors.initials: JM
authors.lastname: Senaratne
authors.affiliation: Division of Cardiology, University of Alberta Hospital, Edmonton, AB, Canada Division of Cardiac Surgery, Mazankowski Alberta Heart Institute, Edmonton, AB, Canada Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease, Calgary, AB, Canada Cardiovascular Health and Stroke, Strategic Clinical Network, AB, Canada Faculty of Nursing, University of Alberta, Edmonton, AB, Canada.
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Norris
authors.affiliation: Division of Cardiology, University of Alberta Hospital, Edmonton, AB, Canada.
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Graham
authors.affiliation: Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease, Calgary, AB, Canada.
authors.forename: Diane
authors.initials: D
authors.lastname: Galbraith
authors.affiliation: Division of Cardiac Surgery, Mazankowski Alberta Heart Institute, Edmonton, AB, Canada.
authors.forename: Jayan
authors.initials: J
authors.lastname: Nagendran
authors.affiliation: Division of Cardiac Surgery, Mazankowski Alberta Heart Institute, Edmonton, AB, Canada.
authors.forename: Darren H
authors.initials: DH
authors.lastname: Freed
authors.affiliation: Division of Cardiology, Jewish General Hospital, McGill University, Montreal, QC, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Afilalo
authors.affiliation: Division of Cardiology, University of Alberta Hospital, Edmonton, AB, Canada Division of Critical Care, University of Alberta Hospital, Edmonton, AB, Canada sv9@ualberta.ca.
authors.forename: Sean
authors.initials: S
authors.lastname: Van Diepen
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000401:mortality* / Q000706:statistics & numerical data; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization / Q000401:mortality* / Q000706:statistics & numerical data; D011446:Prospective Studies
keywords: Angiography; Coronary artery bypass grafting; Coronary artery disease