Early and Long-Term Outcomes of Patients With Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention to the Left Main Coronary Artery.

Patients who undergo percutaneous coronary intervention (PCI) to the left main (LM) coronary artery in the setting of acute coronary syndrome (ACS) were not adequately studied in the era of modern PCI. We investigated early and long-term outcomes of these patients, especially those with a true LM bifurcation stenosis. The Left Main Intervention in Acute Coronary Syndrome (LIMACS) is a multicenter registry that enrolled patients who underwent PCI to unprotected LM disease in the setting of ACS using a drug-eluting stent. The study included 360 patients (age 65 ± 12 years, men 74%, ST-elevation myocardial infarction 65%). During index hospitalization, 25% of patients developed cardiogenic shock and 15% died. Cardiogenic shock (adjusted odds ratio [adjOR] 26, 95% confidence interval [CI] 7 to 93) and final Thrombolysis in Myocardial Infarction (TIMI) grade <3 flow (adjOR 7, 95% CI 1.6 to 31) were associated with in-hospital mortality. The 3-year mortality (37%) correlated with left ventricular ejection fraction ≤40% (adjHR 2.4 [1.4 to 4.2]), Killip class II to IV at presentation (adjHR 1.7 [1.02 to 2.8]), LM culprit (adjHR 1.7 [1.04 to 2.8]), true LM bifurcation stenosis (adjHR 1.8[1.1 to 2.9]), final TIMI grade <3 flow (adjHR 3.2 [1.7 to 5.8]), and radial access (adjHR 0.58 [0.38 to 0.99]). In patients with true LM bifurcation stenosis (n = 127), 2-stent strategy was adopted in 60% and was associated with lower 3-year mortality or repeat revascularization than 1-stent strategy (48% vs 69%, p = 0.012). In conclusion, patients who undergo PCI to the LM in the setting of an ACS sustain high adverse event rates. Hemodynamic status, LM culprit lesion, femoral access, and failure to restore normal flow are major determinants of adverse outcomes. In patients with LM true bifurcation lesions, outcomes are impaired, especially with 1-stent strategy.