Patient characteristics, management, and outcomes of acute myocardial infarction due to unprotected left main stem occlusion: insights from a real-world multicentre registry over a 12-year period
Authors: Alexandre A , Braga M , Campinas A , Dias-Frias A , Sa-Couto D , Calvao J , Brandao M , Passos Silva M , Pires De Morais G , Carlos Silva J , Santos R , Brochado B , Luz A , Silveira J , Torres S 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Introduction
Acute myocardial infarction (AMI) due to unprotected left main coronary artery (LMCA) occlusion is a potentially life-threatening disease. AMI management has evolved over the past two decades, and mortality has decreased considerably. Though, little information on patient characteristics, management, and mortality trends in the most recent years is available regarding acute unprotected LMCA occlusion.

Purpose
We aimed to assess trends in patient characteristics, management, and outcomes for acute myocardial infarction due to LMCA occlusion between 2008 and 2020.

Methods
We conducted a retrospective multicentre registry of patients with AMI with unprotected LMCA occlusion admitted in three tertiary hospitals between 2008 and 2020. Patients were divided according to timeline of presentation, and we sought to compare clinical characteristics, management, and outcomes between a past group (from January 2008 to December 2012) and a contemporary group (from January 2017 to December 2020).

Results
Of 128 patients with AMI from unprotected LMCA occlusion, 28 were included in the past group [from January 2008 to December 2012 (group 1)] and 48 were included in the contemporary group [from January 2017 to December 2020 (group 2)]. No statistically significant differences in baseline risk factors were found between the two groups, except for hypertension (50.0% in group 1 vs 75.0% in group 2, p=0.027). There was no difference regarding presentation with cardiogenic shock (57.1% vs 64.6%, p=0.520). Median symptom-to-balloon time was high but similar in both groups [180 min (120-300) vs 210 min (120-420), p=0.640]. Radial access was more frequent used in the contemporary group (33.0% vs 10.7%, p=0.028), as well as the administration of glycoprotein IIb/IIIa inhibitors (14.6% vs 12.0%, p=0.004) and the implantation of drug-eluting stents (100% vs 63.2%, p=0.010). The use of mechanical circulatory support device was surprisingly higher in group 1 (82% vs 46%, p=0.002), but the intra-aortic pump balloon (IABP) was the only device available in that group. In the contemporary group, the use of IABP, Impella device, and extracorporeal membrane oxygenation was 37.5%, 20.8%, and 2.1%, respectively. The second antiplatelet agent was also different between groups, with a higher percentage of ticagrelor loading in the contemporary group. In-hospital mortality (46.4% in group 1 vs. 54.2% in group 2, p=0.520) and 1-year cumulative mortality (60.7% vs 60.4%, p=0.741) were high in both groups, but no statistically significant difference was found in survival analysis (p=0.794; log-rank test).

Conclusion
In our real-world population, despite the use of newer drugs and more advanced devices being more common in the contemporary group, patients with AMI due to LMCA occlusion are still a subpopulation with poor prognosis. Innovative strategies are needed to make a difference.