Sex Difference in Patients With Ischemic Heart Failure Undergoing Surgical Revascularization: Results From the STICH Trial (Surgical Treatment for Ischemic Heart Failure)

Abstract

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 dysfunction enrolled in the prospective STICH trial (Surgical Treatment for Ischemic Heart Failure Study).

Methods: The STICH trial randomized 1212 patients (148 [12%] women and 1064 [88%] men) with coronary artery disease and left ventricular ejection fraction ≤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 versus 59.3 years; P=0.016) with higher body mass index (27.9 versus 26.7 kg/m²; P=0.001). Women had more coronary artery disease risk factors (diabetes mellitus, 55.4% versus 37.2%; hypertension, 70.9% versus 58.6%; hyperlipidemia, 70.3% versus 58.9%) except for smoking (13.5% versus 21.8%) and had lower rates of prior CABG (0% versus 3.4%; all P<0.05) than men. Moreover, women had higher New York Heart Association class (class III/IV, 66.2% versus 57.0%), lower 6-minute walk capacity (300 versus 350 m), and lower Kansas City Cardiomyopathy Questionnaire overall summary scores (51 versus 63; all P<0.05). Over 10 years of follow-up, all-cause mortality (49.0% versus 65.8%; adjusted hazard ratio, 0.67; 95% confidence interval, 0.52-0.86; P=0.002) and cardiovascular mortality (34.3% versus 52.3%; adjusted hazard ratio, 0.65; 95% confidence interval, 0.48-0.89; P=0.006) were significantly lower in women compared with men. With randomization to CABG+MED versus MED treatment, there was no significant interaction between sex and treatment group in all-cause mortality, cardiovascular mortality, or the composite of all-cause mortality or cardiovascular hospitalization (all P>0.05). In addition, surgical deaths were not statistically different (1.5% versus 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 versus MED on all-cause mortality, cardiovascular mortality, the composite of death or cardiovascular hospitalization, or surgical deaths in patients with ischemic left ventricular dysfunction. Thus, sex should not influence treatment decisions about CABG in these patients.

Clinical trial registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00023595.

Keywords: coronary artery bypass; heart failure; women.