Sex Difference in Patients with Ischemic Heart Failure Undergoing Surgical Revascularization: Results from the STICH Trial

BACKGROUND: Female sex is conventionally considered a risk factor for coronary artery bypass grafting (CABG) and has been included as a poor prognostic factor in multiple cardiac operative risk evaluation scores. We aimed to investigate the association of sex and the long-term benefit of CABG in patients with ischemic left ventricular (LV) dysfunction enrolled in the prospective Surgical Treatment for Ischemic Heart Failure Study (STICH) trial. METHODS: The STICH trial randomized 1212 patients [148 (12%) women and 1064 (88%) men] with CAD and LV ejection fraction (EF)≤ 35% to CABG + medical therapy (MED) versus MED alone. Long-term (10-year) outcomes with each treatment were compared according to sex. RESULTS: At baseline, women were older (63.4 vs 59.3, p=0.016) with higher BMI (27.9 vs 26.7, p=0.001). Women had more CAD risk factors (diabetes 55.4% vs 37.2%, hypertension 70.9% vs 58.6%, hyperlipidemia 70.3% vs 58.9%) except for smoking (13.5% vs 21.8%), and had lower rates of prior CABG (0% vs 3.4%, all p<0.05) than men. Moreover, women had higher New York Heart Association (NYHA) class (Class III/IV 66.2% vs 57.0%), lower 6-min walk capacity (300m vs 350m) and lower Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary scores (51 vs 63) (all p<0.05) than men. Moreover, women had higher New York Heart Association (NYHA) class (Class III/IV 66.2% vs 57.0%), lower 6-min walk capacity (300m vs 350m) and lower Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary scores (51 vs 63) (all p<0.05). Over 10-years of follow up, all- cause mortality (49.0% vs 65.8%, adjusted HR 0.67, CI 0.52­0.86, p=0.002) and CV mortality (34.3% vs 52.3%, adjusted HR 0.65, CI 0.48­0.89, p=0.006) were significantly lower in women compared to men. With randomization to CABG + MED vs. MED treatment, there was no significant interaction between sex and treatment group in all-cause mortality, CV mortality, or the composite of all-cause mortality or CV hospitalization (all p>0.05). In addition, surgical deaths were not statistically different (1.5% vs 5.1%, p=0.187) between sexes among patients randomized to CABG per protocol as initial treatment. CONCLUSIONS: Sex is not associated with the effect of CABG + MED vs. MED on all-cause mortality, CV mortality, the composite of death or CV hospitalization, or surgical deaths in patients with ischemic LV dysfunction. Thus, sex should not influence treatment decisions regarding CABG in these patients.