Outcome of ST-segment elevation myocardial infarction (STEMI) patients with significant non-infarct related artery (IRA) lesions
Authors: Grech N , Mizzi JMM , Formosa RF , Wang CYW , Gatt PMG , Buttigieg MLB , Spiteri JS , Agius MA , Gatt RG , Axisa ABA , Camilleri WC , Mercieca Balbi MMB , Xuereb SX , Xuereb RGX , Cassar Maempel ACM 
Published: May 2022

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
Multivessel disease is common (50%) in patients presenting with ST-segment elevation myocardial infarction (STEMI), and this is associated with a higher mortality compared to single-vessel disease. The optimal timing for revascularisation of significant non-infarct related artery (IRA) (non-culprit) lesions in STEMI patients remains controversial. The two main approaches include immediate revascularisation during the primary percutaneous coronary intervention (PPCI) or deferred (48 hours after the index procedure) percutaneous coronary intervention (PCI). The European Society of Cardiology guidelines recommend consideration of immediate non-IRA PCI in STEMI patients with cardiogenic shock, while revascularisation of other patients with non-IRA significant lesions should be considered prior to hospital discharge.

Purpose
To determine the optimal timing of intervention of significant non-IRA lesions in patients presenting with STEMI.

Methods
Coronary angiograms of nationwide STEMI patients who underwent a PPCI between 2013 and 2017 were reviewed to determine whether a significant non-IRA lesion was present (defined as &gt;70% stenosis, or &gt;50% of left main stem). The patients were divided into Group 1: immediate PCI of the non-IRA lesion during the PPCI, and Group 2: deferred PCI of non-IRA lesion prior to hospital discharge.
Patients were followed up till end 2020 to determine whether a major adverse cardiovascular event occurred (death, myocardial infarction [MI], hospitalization due to pulmonary oedema and revascularization with repeat PCI and coronary artery bypass [CABG]). Chi-square and Fisher’s exact test were used for statistical analysis.

Results
1080 patients underwent a PPCI between 2013 and 2017. 578 patients were excluded as they had no bystander disease, and a further 340 were excluded as they underwent CABG or medical treatment for the non-IRA lesions. From the remaining cohort, 55 patients were stratified to group 1 and 107 patients in group 2. There were no significant differences in baseline characteristics (Picture 1). Picture 2 demonstrates the distribution of non-IRAs which required PCI.
Patients who had immediate non-IRA lesion PCI had a significantly higher mortality (Group 1, 21.8% vs Group 2, 8.4%, p=0.016) and more admissions with pulmonary oedema (Group 1, 10.9% vs Group 2, 0.9%, p=0.006). Group 1 patients were found to have a higher occurrence of cardiac arrest during the PPCI (10.9% vs 0.9%, p=0.006) and cardiogenic shock (12.7% vs 3.7%, p=0.046). There were no differences with regards to angina (p=0.386), MI (p=0.426) or re-vascularisation with repeat PCI (p= 0.090) or CABG (p=0.114).

Conclusion
STEMI patients who underwent immediate PCI to non-IRA lesions had a poorer outcome with higher rates of mortality and pulmonary oedema admissions compared to the deferred PCI cohort. Large randomised controlled trials are required to determine the optimal timing for intervention of significant non-IRA lesions.