Are men treated better than women? Outcome of male versus female patients after CABG using bilateral internal thoracic arteries

Background: Apart from smaller native coronary arteries a lower number of anastomoses and a lower ITA incidence have been suggested as being responsible for the increased mortality in female patients compared to males. The aim of this study was to clarify whether the outcome of females might be a consequence of a different regimen in anastomosis and ITA frequency. Methods: We evaluated operative data and early outcome of 6906 patients with isolated CABG operated between 1/96-7/03 3064 out of 5381 males received bilateral ITA (BITA) vs. 750 of 1525 females. Single ITA (SITA) was performed in 2126 males and 704 females. Results: Demographic and operative data: average age for male patients was 64.0 +/- 9.2 years, for females 68.5 +/- 8.6 years (p < 0.05). The prevalence of diabetes mellitus was significantly higher in females (34.6% vs. 27.4%, p < 0.01). Body mass index (BMI, 26.6 vs. 27.4 mean), incidence of main stem stenosis (23.0% vs. 23.5%), ejection fraction < 40% (7.8% vs. 10.1%), urgent or emergent operations (13.1% vs. 11.3%) and number of performed anastomoses (3.2 vs. 3.5 mean) showed no significant difference between males and females. Total ITA frequency did not differ (95.3% vs. 96.5%), but BITA frequency was significantly higher (56.9% vs. 49.2%, p < 0.01) in male patients. Overall 30-day mortality was 2.8% for males vs. 4.1% (p < 0.05) for females. Cardiac-related mortality was significantly higher in female patients (2.6% vs. 1.1%, p < 0.01). Non-cardiac-related mortality did not differ significantly. Graft-related mortality for males and females revealed 2.7% in the BITA, 3.3% in the SITA group and 6.9% for patients without ITAs and reached statistical significance (p < 0.01) for SITA or BITA vs. the no-ITA group, but not for BITA vs. SITA grafting. Nevertheless cardiac-related mortality in male and female patients without an ITA graft was more than two-fold higher compared to these with single ITAs and more than threefold higher compared to those with BITA grafting. Conclusions: Female gender, frequently associated with diabetes mellitus, presents a predictor for increased mortality in CABG. A discrimination of women with respect to a restriction of ITA grafting could be confirmed only for bilateral ITAs. The superior results of bilateral ITA grafts are independent of gender.