Higher mortality in women undergoing coronary artery bypass grafting

While men have higher rates of cardiovascular disease, several studies report women having higher mortality after cardiac surgery, reasons for which are unclear. We compared characteristics and outcomes of coronary artery bypass grafting (CABG) by sex.

All patients undergoing isolated CABG during July 2010-June 2012 were grouped by sex for retrospective analyses.

A total of 168 (20.5%) women and 650 (79.4%) men were included, followed-up for 1.4 plus or minus 0.6 years. Women were older (66.4 vs 64.0 years; p=0.007), with higher body mass index (30.1 vs 28.8 kg/m²; p=0.004), increased prevalence of hypertension (78.9% vs 67.8%; p=0.008), current smoking (20.2% vs 13.1%; p=0.027), chronic respiratory disease (22.6% vs 15.4%; p=0.028) and estimated glomerular filtration rate (74 vs 81 ml/min/1.73 m²; p=0.007). Women had less grafts performed (3.1 vs 3.3; p=0.014) and less use of radial grafts (14.9% vs 25.2%; p=0.004). Female sex was independently associated with higher 30-day mortality (4.8% vs 0.8%) odds ratio 5.63, 95% confidence interval 1.67-19.0; p=0.005 and medium-term mortality hazards ratio 2.49, 1.06-5.84; p=0.037 (1-year survival 93.9% vs 98.1%); but not surgical morbidity (21.4% vs 16.9%; p=0.661).

Women had higher 30-day and medium-term mortality after CABG even after adjusting for higher prevalence of risk factors and comorbidities.