The Influence of Gender in Patients Undergoing Coronary Artery Bypass Graft Surgery: an Eight-Year Prospective Hospitalized Cohort Study

BACKGROUND: We prospectively assess if there are any outcome differences between men and women undergoing coronary artery bypass graft surgery. STUDY DESIGN: This is an eight-year, prospective, hospitalization cohort study. Data were collected on 225 variables concurrently with admission. The main outcome was mortality. In addition, we evaluated 12 morbidity outcomes. To minimize confounding, we controlled for 18 other variables. RESULTS: We analyzed 5,324 patients (1,742 women; 3,582 men). Women were significantly older, with more African Americans and more Medicaid-insured (p < 0.05). Men had significantly higher body surface area, creatinine, tobacco history, prior myocardial infarctions, left ventricular hypertrophy, and cardiac pump time (p < 0.05). Women had significantly more diabetes, hypercholesterolemia, hypertension, previous cerebrovascular disease, urgency of the surgical procedure, fewer arterial grafts, and reduced functional capacity by the New York Heart Association classification (p < 0.05). Using multiple regression analysis there was no difference for mortality, positive bacterial cultures, ICU length of stay, arrhythmias, reoperation for bleeding, pulmonary complications, gastrointestinal complications, and return to the ICU. Women had significantly more intraoperative complications (RR = 2.09, 95% CI 1.35-3.23), length of stay (RR = 1.01, 95% CI 1.002-1.027), and low cardiac output conditions (RR = 1.10, 95% CI 1.01-1.20). Males developed more neurologic complications (RR = 0.85, 95% CI 0.75-0.95). CONCLUSIONS: Women undergoing coronary artery bypass graft surgery have more comorbidities at surgical presentation compared with men. Women have more unadjusted mortality, which is confounded by the difference in age and body surface area. But, even after multiple adjustments, female gender is a predictor of higher morbidity in patients undergoing coronary artery bypass graft.