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<div><p>Background</p><p>Prior research has shown that patients with stable ischemic heart disease who undergo delayed coronary artery bypass graft (CABG) surgery face higher mortality rates than those who receive CABG within the time recommended by physicians. However, this research did not account for percutaneous coronary intervention (PCI), a widely available alternative to delayed CABG in many settings. We sought to establish whether there was a difference in mortality between timely PCI and delayed CABG.</p><p>Methods</p><p>We identified 25,520 patients 60 years or older who underwent first-time non-emergency revascularization for angiographically-proven, stable left main or multi-vessel ischemic heart disease in British Columbia between January 1, 2001, and December 31, 2016. We estimated unadjusted and adjusted mortality after index revascularization or last staged PCI for patients undergoing delayed CABG compared to timely PCI.</p><p>Findings</p><p>After adjustment with inverse probability of treatment weights, at three years, patients who underwent delayed CABG had a statistically significant lower mortality compared with patients who received timely PCI (4.3% delayed CABG, 13.5% timely PCI; risk ratio 0.32, 95% CI 0.24–0.40).</p><p>Interpretation</p><p>Patients who undergo CABG with delay have a lower risk of death than patients who undergo PCI within appropriate time. Our results suggest that patients who wish to receive CABG as their revascularization treatment will receive a mortality benefit over PCI as an alternative strategy.</p></div>