Unprotected Left Main Disease: Clinical Outcomes Following Deferral, Coronary Artery Bypass Grafting, or Percutaneous Coronary Intervention

BACKGROUND: The prognostic benefit of revascularization for unprotected left main (LM) disease remains uncertain, as guideline endorsement of percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) precludes comparison with deferral, which is unlikely to be assessed in a randomized trial. OBJECTIVES: This study aimed to evaluate the prognostic impact of revascularization (PCI/CABG) versus deferred treatment of isolated, unprotected LM disease using real-world data. METHODS: Patients with isolated, unprotected LM disease identified by invasive coronary angiography on the indication chronic coronary syndrome between January 2002 and January 2021, registered in the Western Denmark Heart Registry, were identified and split into four groups: Defer ≤ 50% stenosis, defer > 50% stenosis, PCI, or CABG. Acute coronary syndrome (ACS), revascularization, stroke, and all-cause mortality risks within 5 years were assessed. Adjusted analyses were conducted. RESULTS: Of 4848 patients identified, 2819 patients underwent PCI, 467 CABG, 992 were in the defer ≤ 50% group, and 570 in defer > 50%. The 5-year survival probability was 89.5% for PCI, 94.1% for CABG, 91.7% for defer ≤ 50%, and 84.0% for defer > 50% (p < 0.0005%). Cumulative incidence of ACS was 7.9% for PCI, 3.0% for CABG, 5.3% for defer ≤ 50%, and 8.2% for defer > 50% (p < 0.0005). For revascularization, numbers were 10.2%, 7.0%, 7.6%, and 15.4% (p < 0.0005) and stroke 3.6%, 2.1%, 2.5%, and 3.8% (p < 0.005). In adjusted analyses, the results were unchanged. CONCLUSIONS: Using real-world data, this study demonstrated that either PCI or CABG was associated with improved survival in patients with LM disease, when diameter stenosis exceeded 50%. PCI was associated with higher rates of non-fatal ACS and repeat revascularization compared to CABG but similar rates as deferred treatment. CLINICAL PERSPECTIVES: The prognostic benefit of revascularization for isolated and unprotected left main disease remains uncertain, as guideline endorsement of PCI or CABG precludes comparison with deferral. Deferred revascularization of unprotected LM disease with >50% diameter stenosis in patients with chronic coronary syndrome was associated with increased all-cause mortality and non-fatal acute coronary syndrome. Revascularization remains the treatment of choice in patients with significant unprotected LM disease for prognostic benefit.