The aim of the study was to determine the prognostic significance and determinants
of myocardial salvage assessed by cardiovascular magnetic resonance (CMR) in reperfused
ST-segment elevation myocardial infarction.
In acute myocardial infarction, CMR can retrospectively detect the myocardium at risk
and the irreversible injury. This allows for quantifying the extent of salvaged myocardium
after reperfusion as a potential strong end point for clinical trials and outcome.
We analyzed 208 consecutive ST-segment elevation myocardial infarction patients undergoing
primary angioplasty <12 h after symptom onset. T2-weighted and contrast-enhanced CMR
was used to calculate the myocardial salvage index (MSI). Patients were categorized
into 2 groups defined by the median MSI. The primary end point of the study was occurrence
of major adverse cardiovascular events defined as death, reinfarction, and occurrence
of new congestive heart failure within 6 months after the index event.
The median MSI was 48 (interquartile range 27 to 73). Major adverse cardiovascular
events were significantly lower in the MSI >or= median group (2.9% vs. 22.1%, p <
0.001). The stepwise Cox proportional hazards model revealed that the MSI was the
strongest predictor of major adverse cardiovascular events at 6-month follow-up (p
< 0.001). All prognostic clinical (symptom onset to reperfusion), angiographic (Thrombolysis
In Myocardial Infarction flow grade before angioplasty), and electrocardiographic
(ST-segment resolution) parameters showed significant correlations with the MSI (p
< 0.001 for all).
This study for the first time demonstrates that the MSI assessed by CMR predicts the
outcome in acute reperfused ST-segment elevation myocardial infarction. Therefore,
MSI assessment has important implications for patient prognosis as well as for the
design of future trials intended to test new reperfusion therapy efficacy. (Myocardial
Salvage Assessed by Cardiovascular Magnetic Resonance-Impact on Outcome; NCT00952224).