Revascularization in patients with severe left main(LM) stenosis significantly improves their prognosis. Outcomes of percutaneous coronary interventions(PCI) with drug-eluting stents(DES) are comparable with coronary aortic bypass grafting(CABG), especially in selected patients with low and intermediate complexity. All patients undergoing PCI for significant LM disease between March 2013 – November 2019 were included in a prospective registry. We analyzed preprocedural characteristics, mortality rate and time-to-first death during follow up.

The cohort included 295 patients, mean age 67.20 ± 10.97 years, 209 (70.8%) were males, and the majority - 242 (82%) were with unprotected LM stenosis. The decision for LM revascularization was based on patients’ clinical and angiographic characteristics assessed by risk score calculators – Logistic Euroscore II and Syntax score-I. Every patient was discussed with Heart Team. Patients with acute coronary syndrome(ACS), including ST-elevation myocardial infarction(STEMI) were not excluded from the study. During follow up, all patients were assessed for major adverse cardiovascular events(MACE) defined as death, ischemia driven target lesion revascularization(TLR) and stroke at hospital discharge, 1st, 6th,12th month and yearly after, with mean follow up for 31.44 ± 21.92 (0.20 – 85.17) months. For the aim of this study in addition to pre- and periprocedural characteristics, we assessed overall mortality (in-hospital and out-hospital) and time-to-first death between three groups of patients: ACS with ST-elevation, non-ST-elevation ACS, and stable angina patients.

The distribution between different groups was as follows STEMI patients - 25(8.5%), ACS without ST elevation - 155 (52.5%) and 115 (39%) had stable chronic angina. The majority of patients (242 (82%)) had unprotectedLMstenosis (UPLMS). The overall mortality rate was 15.6% and as it was expected in STEMI PCI was higher than for other indications – 44.0% vs 14.8% for ACS w/o ST elevation and 10.4% for stable patients (p < 0.001). Тhеse results were mainly due to in-hospital mortality – 3.7% (respectively 28.0% vs 1.9% vs 0.9%, p < 0.001). During follow up despite the trend of higher mortality in STEMI patients (22.2%), it does not reach significance between groups (respectively 13.2% for ACS w/o ST elevation and 9.6% for the stable patients (p= 0.289). Event free survival analysis presented that after acute phase mean time-to-first death in STEMI group was 1586.13 days (95% CI:1987.66- 2262,99) and no significant difference was found between different clinical presentations (Log Rank Test, p=0.121). There was no difference in the clinical presentations between protected and UPLMS (p=0.278) and also in the in-hospital and overall mortality rate (p=0.120 and p=0.813).

Clinical presentation has important prognostic significance in patients with LM coronary artery disease with worse outcome in those presenting with STEMI as compared to different clinical scenario. Our study showed that in-hospital mortality for LM STEMI treated with PCI is high, but survivors had similar mortality risk during follow up, regardless of their index clinical presentation.