Influence of sex and age on long-term survival in systematic off-pump coronary artery bypass surgery

Abstract

Off-pump coronary artery bypass surgery (OPCAB) is commonly used as an alternative to conventional on-pump coronary artery revascularization. Historically, sex and age have been shown to adversely affect operative mortality risk as well as long-term survival in conventional surgery. To evaluate the effect of gender and ageing on long-term mortality following OPCAB surgery. We have prospectively followed up 1000 consecutive and systematic OPCAB patients operated between September 1996 and April 2003. Average follow-up period was 64+/-28 months and was complete in 98% of the cohort. There were 223 women (21%) and 777 men (79%). Women were older, 68+/-10 versus 63+/-10 years (p<0.0001) and had higher prevalence of hypertension (p<0.0001), peripheral vascular disease (PVD) (p=0.03), recent myocardial infarction (p=0.04) and a smaller body surface (p<0.0001). History of congestive heart failure (CHF) (p=0.001) and unstable angina (p=0.003) was more frequent in men. Operative mortality was 2.8% in women and 1.4% in men (p=ns). Eight-year survival was 79+/-2.5% for men and 68+/-5% for women, (p=0.02). Cox regression analysis model revealed that age (HR: 2.81; 95% CI: 1.89-4.18), CHF (HR: 2.09; 95% CI: 1.33-3.31), PVD (HR: 1.72; 95% CI: 1.10-2.5), incomplete revascularization (HR: 2.35; 1.37-4.02), multiple internal thoracic artery (MITA) graft/patient (ITA/pt) (HR: 0.61; 95% CI: 0.44-0.84), left ventricular ejection fraction (LVEF) (HR: 0.19; 95% CI: 0.05-0.71) and cerebral vascular disease (HR: 1.50; 95% CI: 1.00-2.24) but not female sex (p=0.89) were significant predictors of long-term mortality. Above 65 years of age men and women had a comparable overall survival (p=0.7) whereas fewer than 65 women had a lower survival than men (p=0.001). Cox regression revealed that LVEF (HR: 0.06; 95% CI: 0.006-0.59), lesser use of MITA graft (HR: 0.45; 95% CI: 0.35-0.79), were significant causes of long-term mortality in the younger cohort. Female gender did not reach statistical significance (p=0.12). In this series of systematic OPCAB surgery, the lower survival rate observed in younger women was mostly related to a higher prevalence of preoperative comorbidity and a lesser use of MITA grafts than gender itself.