title: Bilateral Internal Thoracic Artery Grafting Increases Mediastinitis: Myth or Fact?
abstract: BACKGROUND
  There is controversy about the risk of mediastinitis associated with the use of both internal thoracic arteries (ITA).
  
  
  METHODS
  We performed a case-control study of patients operated on at a single institution from January 2003 to December 2014. A total of 3,118 consecutive patients undergoing isolated coronary artery bypass graft surgery were included; 81.3% (n = 2,533) underwent bilateral ITA (BITA) grafts exclusively and constitute the BITA group, and 18.7% (n = 585) constitute the single ITA (SITA) group. Mediastinitis was defined as deep tissue mediastinal infection, with clinical or microbiologic evidence. Continuous variables were expressed as mean ± SD, and categoric variables as percentage (range). Student's t test and Fisher's exact test were used, as appropriate. Propensity score matching analysis was performed according to the nearest neighbor estimation method (n = 1,040).
  
  
  RESULTS
  The incidence of diabetes mellitus was similar in both groups (29%, p = 0.9). The BITA patients were more like to be younger (p < 0.001), men (p < 0.001), had a higher prevalence of hypertension (p < 0.01), higher body mass index (p < 0.001), lower prevalence of left ventricular dysfunction (p < 0.001) and of previous myocardial infarction (p < 0.01), and greater use of off-pump coronary artery bypass graft surgery (p < 0.01). The BITA patients had lower unadjusted hospital mortality (1.6%, versus 5.3% for SITA, p < 0.0001). The total incidence of mediastinitis was 1.8% (BITA 1.9% versus SITA 1.5%, p = 0.6). Diabetes (p < 0.01) and nonelective surgery (p = 0.004) were the only predictors of mediastinitis in the entire population. Propensity score matching showed no differences in mediastinitis: BITA 2.5% versus SITA 1.3% (p = 0.17).
  
  
  CONCLUSIONS
  In this series of patients, BITA did not increase the risk of mediastinitis in the total population or in the propensity score matched subgroups.
authors.affiliation: Department of Cardiac Surgery, Instituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina. Electronic address: jmvrancic@icba.com.ar.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Vrancic
authors.affiliation: Department of Cardiac Surgery, Instituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Fernando
authors.initials: F
authors.lastname: Piccinini
authors.affiliation: Department of Cardiac Surgery, Instituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Mariano
authors.initials: M
authors.lastname: Camporrotondo
authors.affiliation: Department of Cardiac Surgery, Instituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Espinoza
authors.affiliation: Department of Cardiac Surgery, Instituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Juan I
authors.initials: JI
authors.lastname: Camou
authors.affiliation: Department of Infectious diseases, Instituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Francisco
authors.initials: F
authors.lastname: Nacinovich
authors.affiliation: Department of Infectious diseases, Instituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Pablo Fernandez
authors.initials: PF
authors.lastname: Oses
authors.affiliation: Department of Cardiac Surgery, Instituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Daniel
authors.initials: D
authors.lastname: Navia
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007387:Internal Mammary-Coronary Artery Anastomosis / Q000009:adverse effects*; D008297:Male; D008480:Mediastinitis / Q000209:etiology*; D008875:Middle Aged