title: Reduced 30-day mortality in men after elective coronary artery bypass surgery with minimized extracorporeal circulation-a propensity score analysis.
abstract: BACKGROUND
  Impact of minimized extracorporeal circulation (MECC) for coronary surgery on mortality remains controversial and gender significantly influence outcome.
  
  
  METHODS
  We analyzed 3,139 male patients undergoing elective coronary surgery between 01/2004 and 05/2009. Using propensity score matching after binary logistic regression, 1,005 patients (from 1,119 patients) undergoing surgery with MECC could be matched with 1,005 patients (from 2,020 patients) undergoing surgery with conventional extracorporeal circulation (CECC). Primary outcome was 30-day mortality.
  
  
  RESULTS
  Unadjusted 30-day mortality was 2.7% in patients with CECC and 0.8% in those with MECC (mean difference -1.9%; p < 0.001). The adjusted mean difference (average treatment effect of the treated) after matching was -1.5% (95% confidence interval (CI) -2.6 to -0.4; p = 0.006). Postoperative hospital stay was shorter in patients operated with minimized systems (adjusted mean difference -0.8 days; 95% CI -1.46 to -0.09; p = 0.03) and incidence of postoperative neurocognitive dysfunction was also lower (adjusted mean difference -1.3%; 95% CI -2.2 to -0.4; p = 0.001). Chest tube drainage (adjusted mean difference +22 mL; 95% CI -47 to 91; p = 0.5) and risk for acute kidney injury, kidney injury and failure according to RIFLE criteria (adjusted mean difference -1.0%; 95% CI -2.5 to 0.6; p = 0.24) proved to be insignificant between both groups. Apart from reduced 30-day mortality, however, average treatment effects for intensive care unit stay, postoperative hospital stay, chest tube drainage and kidney injury did not significantly differ.
  
  
  CONCLUSIONS
  Using propensity score analysis, we observed an association between MECC and reduced 30-day mortality in men, but our results call for further analysis.
authors.affiliation: Department of Cardiothoracic Surgery, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, Regensburg 93053, Germany. micha.ried@t-online.de
authors.forename: Michael
authors.initials: M
authors.lastname: Ried
authors.forename: Reinhard
authors.initials: R
authors.lastname: Kobuch
authors.forename: Leopold
authors.initials: L
authors.lastname: Rupprecht
authors.forename: Andreas
authors.initials: A
authors.lastname: Keyser
authors.forename: Michael
authors.initials: M
authors.lastname: Hilker
authors.forename: Christof
authors.initials: C
authors.lastname: Schmid
authors.forename: Claudius
authors.initials: C
authors.lastname: Diez
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000401:mortality*; D005112:Extracorporeal Circulation / Q000009:adverse effects / Q000401:mortality*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D057216:Propensity Score; D016896:Treatment Outcome