title: Bilateral Internal Mammary Artery Use for Coronary Artery Bypass Grafting Remains Underutilized: A Propensity-Matched Multi-Institution Analysis.
abstract: BACKGROUND
  Bilateral internal mammary arterial (BIMA) grafts have repeatedly demonstrated superior outcomes compared with single IMA (SIMA) after coronary artery bypass grafting (CABG). Despite known survival benefits with BIMA use, perceived perioperative challenges often preclude BIMA use. We hypothesized that the use of BIMA remains underutilized, even in low-risk patients.
  
  
  METHODS
  A total of 43,823 primary, isolated CABG patients in a regional Society of Thoracic Surgeons Database were evaluated. Patients were stratified by BIMA versus SIMA use. Surgical candidates considered "low risk" for BIMA use included the following: age less than 70 years; no or mild chronic lung disease; body mass index less than 30; and absence of diabetes. The BIMA patients (n = 1,333) were 1:1 propensity matched to SIMA patients (n = 1,333) and outcomes were compared.
  
  
  RESULTS
  Overall, BIMA use was 3%; 24% (n = 10,327) of patients met "low-risk" criteria for BIMA use. Among "low-risk" patients, BIMA utilization was 6%. Propensity-matched comparisons revealed similar preoperative risk profiles between BIMA and SIMA patients (Predicted Risk of Mortality [PROM] 1.1% vs 1.1%, p > 0.05). The BIMA use was associated with longer cross-clamp time (71 vs 62 minutes, p < 0.05). Importantly, BIMA use was not associated with increased postoperative mortality, morbidity, or hospital length of stay (all p > 0.05). However, hospital readmission within 30 days was 41% greater for BIMA patients compared with SIMA patients (p = 0.01).
  
  
  CONCLUSIONS
  Bilateral IMA graft use appears to remain underutilized in the modern surgical era, even in low surgical risk patients. The BIMA use does not appear to increase the risk of postoperative morbidity, although requires longer operative times and a higher risk for readmission. Efforts to more clearly understand surgeon motivators for the use of BIMA grafting are needed.
authors.affiliation: University of Virginia, Charlottesville, Virginia.
authors.forename: Damien J
authors.initials: DJ
authors.lastname: LaPar
authors.affiliation: University of Virginia, Charlottesville, Virginia.
authors.forename: Ivan K
authors.initials: IK
authors.lastname: Crosby
authors.affiliation: Mid Atlantic Cardiothoracic Surgeons, Norfolk, Virginia.
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Rich
authors.affiliation: Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Quader
authors.affiliation: Inova Heart and Vascular Institute, Falls Church, Virginia.
authors.forename: Alan M
authors.initials: AM
authors.lastname: Speir
authors.affiliation: University of Virginia, Charlottesville, Virginia.
authors.forename: John A
authors.initials: JA
authors.lastname: Kern
authors.affiliation: University of Virginia, Charlottesville, Virginia.
authors.forename: Curt
authors.initials: C
authors.lastname: Tribble
authors.affiliation: University of Virginia, Charlottesville, Virginia.
authors.forename: Irving L
authors.initials: IL
authors.lastname: Kron
authors.affiliation: University of Virginia, Charlottesville, Virginia. Electronic address: gorav@virginia.edu.
authors.forename: Gorav
authors.initials: G
authors.lastname: Ailawadi
mesh_terms: D001026:Coronary Artery Bypass / Q000379:methods* / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008323:Mammary Arteries / Q000637:transplantation; D008875:Middle Aged; D057216:Propensity Score; D012189:Retrospective Studies