Acute myocardial infarction (MI) typically occurs from a plaque rupture or erosion within a coronary artery,known as the infarct-related artery (IRA) In patients with NSTEMI compared with those with ST-segment–elevation MI, identification of the IRA can be challenging because patients are more likely to present with either multivessel coronary artery disease (CAD) or insignificant CAD

2. Introduction
 Acute myocardial infarction (MI) typically
occurs from a plaque rupture or erosion within a
coronary artery,known as the infarct-related
artery (IRA)
 In patients with NSTEMI compared with those with
ST-segment–elevation MI, identification of the
IRA can be challenging because patients are more
likely to present with either multivessel
coronary artery disease (CAD) or insignificant
CAD

3. Introduction
 The correct identification of the IRA in
acute MI has obvious importance for
coronary revascularization strategies

4. Background
 Determining the infarct-related artery
(IRA) in NSTEMI can be challenging
 Delayed-enhancement cardiac magnetic
resonance (DE-CMR) can accurately
identify small MIs

5. Objective
 To determine whether DE-CMR improves the
ability to identify the IRA in patients
with NSTEMI

6. Methods
 In this 3-center, prospective study,
authors enrolled 114 patients presenting
with their first MI
 Patients underwent DE-CMR followed by
coronary angiography
 The interventional cardiologist was
blinded to the DE-CMR results

7. Methods
 Later, coronary angiography and DE-CMR
images were reviewed independently and
blindly for identification of the IRA
 The pattern of DE-CMR hyperenhancement
was also used to determine whether there
was a nonischemic pathogenesis for
myocardial necrosis

8. Determining an IRA match or mismatch
between DE-CMR and CA
IRA: Infarct-related artery; DE-CMR: delayed-enhancement cardiac magnetic resonance; CA: coronary angiography

9. Baseline Characteristics of the Patients

10. Baseline Characteristics of the Patients

11. Results
 IRA was not identifiable by coronary
angiography in 37% of patients (n=42)
 In these,IRA or a new noncoronary artery
disease diagnosis was identified by DE-
CMR in 60% and 19% of patients,
respectively
 A different IRA or a noncoronary artery
disease diagnosis was identified by DE-
CMR in 14% and 13%, respectively

12. Results
 Overall, DE-CMR led to a new IRA
diagnosis in 31%, a diagnosis of
nonischemic pathogenesis in 15%, or
either in 46% (95% CI, 37%–55%) of
patients
 Of 55 patients undergoing
revascularization, 27% had
revascularization solely to nonculprit
coronary artery territories as determined
by DE-CMR

13. Summary of Results

14. Some Patient Examples

15. Frequency of IRA by DE-CMR and CA
based on severity of CAD
IRA: Infarct-related artery; DE-CMR: delayed-enhancement cardiac magnetic resonance; CA: coronary angiography; CAD: Coronary artery disease

16. Conclusions
 Identification of the IRA by coronary
angiography can be challenging in
patients with NSTEMI
 In nearly half, DE-CMR may lead to a new
IRA diagnosis or elucidate a non-ischemic
pathogenesis
 Revascularization solely of coronary
arteries that are believed to be non-
culprit arteries by DE-CMR is not
uncommon