Background The STICH trial showed superiority of coronary artery bypass plus medical treatment (CABG) over medical treatment alone (MED) in patients with left ventricular ejection fraction (LVEF) 35%. In previous publications, percutaneous coronary intervention (PCI) prior to CABG was associated with worse prognosis. Objectives The main purpose of this study was to analyse if prior PCI influenced outcomes in STICH. Methods and Results: Patients in the STICH trial (n=1212), followed for a median time of 9.8 years, were included in the present analyses. In the total population, 156 had a prior PCI (74 and 82, respectively, in the MED and CABG groups). In those with vs. without prior PCI, the adjusted hazard-ratios (aHRs) were 0.92 (95% CI=0.74-1.15) for all-cause mortality, 0.85 (95% CI=0.64-1.11) for CV mortality, and 1.43 (95% CI=1.15-1.77) for CV hospitalization. In the group randomized to CABG without prior PCI, the aHRs were 0.82 (95% CI=0.70-0.95) for allcause mortality, 0.75 (95% CI=0.62-0.90) for CV mortality and 0.67 (95% CI=0.56-0.80) for CV hospitalization. In the group randomized to CABG with prior PCI, the aHRs were 0.76 (95% CI=0.50-1.15) for all-cause mortality, 0.81 (95% CI=0.49-1.36) for CV mortality and 0.61 (95% CI=0.41-0.90) for CV hospitalization. There was no evidence of interaction between randomized treatment and prior PCI for any endpoint (all adjusted p>0.05). Conclusion In the STICH trial, prior PCI did not affect the outcomes of patients whether they were treated medically or surgically, and the superiority of CABG over MED remained unchanged regardless of prior PCI.