title: Myocardium at risk is associated with adverse clinical events in women but not in men, after coronary artery bypass grafting.
abstract: BACKGROUND
  Women undergoing coronary artery bypass grafting (CABG) are at increased risk for morbidity and mortality. Factors responsible for this observation include smaller coronary size and delayed presentation. To date, no studies have examined the effect of the degree of myocardium at risk (MAR) on the relationship between female sex and adverse postoperative events.
  
  
  METHODS
  Consecutive patients undergoing first-time isolated CABG at a single institution from 2002-2007 were identified. MAR was calculated using the weighted Duke Index and was categorized as low, moderate, or high. Multivariable logistic regression models were created to compare the impact of MAR on adverse clinical events.
  
  
  RESULTS
  We identified 3741 patients, 3325 (89%) of whom had complete angiographic data. Women (n = 755) were older (P = 0.0001) and presented more often with hypertension (P = 0.0001), diabetes (P = 0.0001), heart failure (P = 0.0001), and an urgent/emergent situation (P = 0.002). After surgery, women experienced greater rates of adverse events (15.2% vs 9.3%; P = 0.0001). In a fully adjusted logistic regression model, the nested interaction of sex in MAR showed that women had a significantly greater risk of major adverse cardiovascular events (MACE) when MAR was high (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.3-2.6; P = 0.0004). Greater severity of MAR emerged as an independent predictor of adverse events among women (high: OR, 2.9; 95% CI, 1.2-7.3; moderate: OR, 2.2; 95% CI, 0.8-5.7; low: OR, 1.0), but not among men.
  
  
  CONCLUSIONS
  MAR was independently associated with higher rates of adverse events among women but not in men undergoing CABG. This finding may help explain differences in outcomes seen between women and men after revascularization.
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Maral
authors.initials: M
authors.lastname: Ouzounian
authors.affiliation: Division of Cardiac Surgery, London Health Sciences Centre, London, Ontario, Canada.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Currie
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Buth
authors.affiliation: New Brunswick Heart Centre, Saint John Regional Hospital, Saint John, New Brunswick, Canada.
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Yip
authors.affiliation: New Brunswick Heart Centre, Saint John Regional Hospital, Saint John, New Brunswick, Canada.
authors.forename: Ansar
authors.initials: A
authors.lastname: Hassan
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada. Electronic address: ghirsch@dal.ca.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Hirsch
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009674:Nova Scotia / Q000453:epidemiology; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors