Acute Coronary Syndrome (ACS) is characterized by a sudden decrease in blood flow to the heart due to  occlusion of  a coronary artery secondary to ruptured atherosclerotic plaque and thrombus formation. Among the coronary arteries, the left main coronary artery (LMCA) supplies a significant area of left ventricle. Therefore, occlusion of the LMCA often leads to more extensive myocardial infarctions, causing severe left ventricular dysfunction and typically carries a worse prognosis than ACS involving non-LMCA .The high mortality in LMCA-related ACS is primarily attributed to the rapid deterioration of cardiac function, leading to multisystem organ failure and fatal arrhythmias, if left untreated. Timely intervention is paramount in managing these cases. Historically, surgical revascularization through coronary artery bypass grafting (CABG) was the mainstay of treatment for LMCA disease. However, with the advancement of percutaneous coronary intervention (PCI), this less invasive approach has become a viable and increasingly preferred option for many patients, especially in the acute setting of ACS .Current clinical guidelines for the management of ACS recommend emergency revascularization through  PCI, particularly for patients presenting with cardiogenic shock . In fact, PCI has become the cornerstone of reperfusion therapy in ACS, offering rapid restoration of coronary blood flow and reducing myocardial damage. Patients undergoing PCI for LMCA disease often face more complex interventions due to the anatomical and clinical challenges associated with the artery. Therefore, concerns remain about long-term complications such as repeat revascularization, restenosis, and mortality.However, there is limited evidence regarding the long-term outcomes of PCI in patients with ACS involving LMCA in comparison to those with non-LMCA, particularly in the  resource-constrained settings like in Bangladesh. The objective of the present study was to investigate the long-term outcomes in patients undergoing PCI for ACS affecting the LMCA compared to those with ACS affecting non-LMCA.

This interventional study was conducted at the Department of Cardiology of M. H. Shamorita Medical College Hospital in Dhaka, Bangladesh, from January 2023 to June 2024. Applying inclusion and exclusion criteria , a total of 101 patients with ACS  ,who underwent PCI, were taken for the study by convenience sampling. 51 patients were selected in LMCA group and 50 were in non-LMCA group. All PCI were done by a single operator following standard guideline. Upfront or Bail out double stent strategy were implemented where applicable. All patients received guideline-directed medical therapy before, during and after PCI. Follow-up assessments were conducted at 3, 6, and 12 months, focusing on Major Adverse Cardiovascular Events (MACE) as the primary endpoint and persistent angina, repeat revascularization and stent thrombosis as secondary endpoints. Appropriate statistical tests were carried out to assess the differences in baseline characteristics and outcomes between the LMCA and non-LMCA groups. Continuous variables were expressed as mean with standard deviation (SD) and compared using either the Student’s t-test or the Wilcoxon rank test, depending on the distribution of the data. Categorical variables were expressed as percentages and compared using the Chi-squared test or Fisher’s exact test. For all statistical analyses, a two-sided p-value of <0.05 was considered to indicate statistical significance.

The mean age of LMCA and non-LMCA group was 56 and 54 years, respectively, with higher female proportion in LMCA group. Among the groups, STEMI was more prevalent in the non-LMCA group (24% vs. 16%), while unstable angina was more common in the LMCA group (55% vs. 42%).The patients in LMCA group  had more multiple-vessel coronary artery disease (39% vs. 22%) ; their lesions were more likely to be classified as type B (53% vs. 16%) and they  presented with more complex lesions: with a mean SYNTAX score of 23.6 vs. 7.78. However, left ventricular ejection fraction (LVEF) and serum creatinine levels did not significantly differ between the groups.  The MACE rate was notably higher in the LMCA group at 6%, compared to 2% in the non-LMCA group (p=0.013). Myocardial infarction (MI) occurred in 4% of the LMCA group, with no events in the non-LMCA group. Persistent symptoms and repeat revascularization were also more prevalent in the LMCA group (6% and 4%, respectively, p-value <0.05).

In conclusion, our study highlighted the comparative outcome of PCI in LMCA and non-LMCA related ACS. We observed higher rates of major adverse cardiovascular events, particularly myocardial infarction and repeat revascularization, after PCI in patients with ACS involving the LMCA. However, further research involving larger, multicenter clinical trials will be needed to validate our findings and investigate the effects of various procedural techniques on long-term outcomes.