Long-term survival benefit of coronary revascularization in patients undergoing stress myocardial perfusion imaging

Background: We assessed during a long-term follow-up the relationship between clinical outcome and coronary revascularization according to stress gated myocardial perfusion single-photon emission computed tomography (MPS) findings in an observational series of patients with suspected or known coronary artery disease (CAD). Methods and Results: The study group comprised 2059 patients. During a median follow-up of 61 months, 184 events occurred (126 cardiac death and 58 nonfatal myocardial infarction). The impact of revascularization during follow-up on event-free survival was evaluated with the extended Cox regression model, adjusting for potential clinical and MPS confounders. Revascularization was treated as a binary non-reversible time-dependent covariate. Predefined interactions tested were: 1) revascularization and summed difference score (SDS); 2) revascularization and post-stress left ventricular (LV) ejection fraction (EF); and 3) SDS and post-stress LVEF. Revascularization had a significant effect on event-free survival (adjusted hazard ratio 0.19; P<0.001). Significant interactions were found between revascularization and SDS (P=0.045) and LVEF and SDS (P=0.015). The protective effect of revascularization augmented as SDS increased. For SDS