Introduction: Left main coronary artery (LMCA) is a large vessel which supplies the majority of left ventricle and critical lesion at the bifurcation of LMCA can lead to life threatening condition. Therefore, percutaneous coronary intervention (PCI) on LMCA bifurcational stenosis is considered as a complex high risk indicated patient and procedure (CHIP). Goal: In this study, we investigated the impact of urgent and elective PCI on outcomes of patients with LMCA bifurcational stenosis. Materials and Methods: Patients who underwent for urgent PCI due to acute myocardial infarction (AMI) or elective PCI due to stable coronary artery disease (CAD) for their LMCA bifurcational stenosis. Any lesion with >50% stenosis on coronary angiography was considered as a critical stenosis. LMCA bifurcational stenosis was evaluated by Medina classification. Difference between urgent and elective PCI group were compared by independent sample t-test and chi-square test. Association between treatment strategy (urgent or elective PCI) and prognosis were evaluated by Cox proportional hazard regression, and survival rate was evaluated by Kaplan-Meier methods. Ethical approval was taken from the ethical committee of the Health Science University of Medical Sciences (№30/1А) in June 12, 2012. Results: A total of 82 patients with LMCA bifurcational stenosis were included (mean age 62±11, male 76.8%) and 14 of them underwent urgent PCI due to AMI and 68 of had elective PCI due to stable CAD. Patients who underwent urgent PCI had significantly higher 30-day mortality (1.5% vs. 21.4%, p<0.05) and all-cause mortality (7.4% vs. 35.7%, p<0.003) compared to the elective PCI group. Urgent PCI for LMCA bifurcational stenosis due to AMI was associated with increased risk of death (HR=3.63, 95% CI 1.02-12.9, p<0.05). Kaplan-Meier estimation showed that patients in the urgent PCI group had significantly lower survival compared to the elective PCI group. Conclusion Unanticipated urgent PCI for patients with LMCA bifurcational stenosis due to AMI is associated with higher risk of short and long-term mortality. Patients who underwent urgent PCI for LMCA bifurcational stenosis had significantly lower survival compared to elective PCI group.

Introduction : Intravascular ultrasound (IVUS) is an advanced technology used to guide percutaneous coronary intervention (PCI) in patients with stable coronary artery disease (CAD). Goal: This study aims to describe the first successful implementation of IVUS in patients with stable CAD in Mongolia. Materials and Methods : Patients with CAD who underwent either CAG or IVUS-guided PCI were prospectively selected. All patients provided informed consent, which was approved by the Ethical Committee of the Ministry of Health of Mongolia (March 17, 2023, №23/014). For patients who underwent CAG-guided PCI, stent deployment was performed under conventional CAG guidance, while stent implantation was performed under IVUS guidance in patients who underwent IVUS-guided PCI. Stent restenosis at 1-year follow-up was selected as the primary endpoint. The differences between the CAG-guided PCI and IVUS-guided PCI groups were compared using independent sample t-tests and chi-square tests. The association between treatment strategy (CAG-guided PCI vs. IVUS-guided PCI) and all cause restenosis (the study endpoint) was analyzed. Results: A total of 51 patients with stable coronary artery disease (CAD) who underwent coronary angiography CAG guided PCI and intravascular ultrasound (IVUS)-guided PCI were included in the present study. The mean age was 63±9.44 years, with 88.2% male (n=45). In the IVUS-guided PCI group, the minimal lumen area (mm²) was 4.46±1.1, and after stenting, the minimal stent area was 8.59±0.5, showing a statistically significant difference (p<0.001). The stent restenosis rate at 1-year follow-up in the CAG-guided PCI group and the IVUS-guided PCI group were 16% and 3.84%, respectively. The restenosis rate in the IVUS-guided PCI group was lower than in the CAG-guided PCI group. Conclusion Complete expansion of the stent on the coronary artery wall is effective in improving long term outcomes of PCI, and IVUS guided coronary artery intervention has better long-term results compared to angiography-guided PCI group (96.1% vs 84%).