Outcomes of ST-Elevation Myocardial Infarction due to spontaneous coronary artery dissection: a nationwide cohort sample
Authors: Elkaryoni A , Klappa A , Doukas D , Luke D , John A , Allen S , Bakir M , Leya F , Lewis B , Darki A , Lopez J , Steen L 
Published: October 2021

Abstract

Background
Spontaneous coronary artery dissection (SCAD) is a common, non-atherosclerotic cause of myocardial infarction (MI). While conservative therapy is preferred in most cases, its role among those presenting as ST-elevation myocardial infarction (STEMI) remains undefined.

Purpose
We aimed to explore outcomes of SCAD causing STEMI, stratifying cases by involved coronary artery and revascularization status.

Methods
We used the Nationwide Readmission Database (2015–2018) to identify patients hospitalized with STEMI by using ICD-10-Clinical modification codes, and then stratified them into SCAD or no-SCAD groups. Each group was further subdivided by involved coronary artery (i.e., left main, left anterior descending, left circumflex, or right coronary artery), and if revascularization (i.e., percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG)) was performed. We excluded patients &gt;55 years old or with iatrogenic dissection. The age restriction allows us to compare a similarly aged group of patients. The primary outcome was in-hospital mortality. Cardiogenic shock, acute kidney injury, mechanical complications, length of stay, and 30-day readmission for all-cause, heart failure or MI were secondary outcomes.

Results
Of the 17,556 patients with STEMI identified, 338 (1.9%) had SCAD. Patients with SCAD were younger (median age (IQR) 46.0 (33–90) vs 49.0 (41–57); p&lt;0.001) and more likely to be female (67% vs 21.6%, p&lt;0.001). They were less likely to have PCI (55.3% vs. 80.7%; p&lt;0.001), more likely to undergo CABG (4.7% vs 1.3%; p&lt;0.001), with left main and left anterior descending coronary arteries more often affected (2.4% vs 1.1%, and 53.3% vs 48.6%; p for both =0.05, respectively). In-hospital mortality did not differ between groups (3.6% vs 3.3, p=0.81). Revascularization was associated with lower in-hospital mortality among no-SCAD patients (2.6% vs 7.0%, p&lt;0.001), but not among SCAD patients (4.0% vs 3.1%, p=0.76) even when stratified by involved coronary artery. Revascularization among SCAD patients was associated with lower 30-day readmission rates for MI (0.0% vs 2.8%, p=0.05). SCAD patients were less likely to have acute kidney injury (6.5% vs 11.2%, p=0.01), but had a longer length of stay (median (IQR) 3.0 (1.0–6.0) vs 2.0 (1.0–4.0), p&lt;0.001). Both groups had similar rates of cardiogenic shock (11.8% vs 10.6%, p=0.56), mechanical complications (0.6% vs 0.3%, p=0.22), and 30-day readmission rates for all-cause, and heart failure.

Conclusion
In-hospital mortality did not differ between patients with STEMI due to SCAD or no-SCAD. Although revascularization was not associated with lower in-hospital mortality among SCAD patients (regardless of involved coronary artery), their 30-day readmission rate for MI was lower suggesting further studies are warranted to explore patient subsets of SCAD that may benefit from revascularization.

Funding Acknowledgement
Type of funding sources: None.