Coronary artery bypass grafting – is gender really an issue?

Introduction: This retrospective analysis examines the influence of gender on perioperative outcome of coronary bypass surgery.

Patients and methods: 10714 patients with coronary artery bypass grafting between 1994 and 2007 were analysed. The patients were divided into two groups: male (8191) and female (2523). Within the groups, the influence of diabetes mellitus was analysed using subgroup-analysis. Variables were compared using student's t-test or Chi-square test, if appropriate.

Results: Female patients were older at the time of surgery (69±8 vs. 65±9 years, p<0.05). The incidence of diabetes was higher in the female group (42% vs. 29%, p<0.05) as well as the rate of insulin dependent patients (50% vs. 33%, p<0.05). All other risk factors differed not significantly. Preoperative cardiac medication did not differ between the groups. Male patients had more bilateral mammary arteries used (10.6% vs. 6.8%) but the total number of anastomoses was similar in. In-hospital mortality was higher in female patients (3.5% vs. 1.8%, p<0.05). In-hospital mortality was highest in insulin-dependend woman (4.9% vs. 1.8%, p<0.05). The rate of strokes (3.6%) was also highest in female diabetic patients. The length of stay on ICU (5.4 vs. 4.3 days), and the incidence of postoperative psychosnydroms (12% vs. 9.4%) were also higher in diabetic women.

Conclusions: The influence of gender on perioperative outcome is overlapped by the higher age at time of surgery also influencing the individual risk profile. The presence of diabetes, especially when insulin-dependend, is a very strong risk factor when combined with female sex.