Myocardium at risk in ST-elevation myocardial infarction: comparison of T2 edema imaging using magnetic resonance versus angiographic scoring
© Fuernau et al; licensee BioMed Central Ltd. 2010
Published: 21 January 2010
The assessment of the area at risk (AAR) in acute myocardial infarction (AMI) with T2-weighted imaging using magnetic resonance imaging (MRI) is a relatively new method with only limited clinical data; yet, sufficient validating studies are lacking.
Purpose of this trial was to assess the AAR and myocardial salvage by MRI and to compare it to the validated angiographic APPROACH-score in a large consecutive patient cohort.
From November 2006 to February 2008 202 patients undergoing primary angioplasty in AMI with ST-elevation were enrolled. Myocardial salvage was assessed by MRI 2-4 days after primary PCI with measurement of the extension of myocardial edema in T2-weighted images and of infarct size with delayed enhancement imaging. Angiographic scoring was done by use of the APPROACH-score.
All images were assessable for measurements of the AAR, infarct size and consecutively myocardial salvage. All infarcts consistently revealed a pattern with both reversibly and irreversibly injured tissue. In contrast to the infarcted area, reversible damage was always transmural. The AAR in the MRI-studies showed a good correlation with the angiographic AAR (r = 0.870; p < 0.001). However, as shown by Bland-Altman-analyses there was a certain bias towards an overestimation of the AAR by MRI in comparison to angiographic scoring (35.7 ± 10.9%LV vs. 28.0 ± 10.5%LV, difference 7.7 ± 5.5 p < 0.001). The infarct size measured by MRI was 18.0 ± 11.6%LV. The calculated myocardial salvage was 17.7 ± 11.7%LV. The time from symptom-onset to reperfusion had a significant impact on the myocardial salvage.
AAR measurement by MRI shows excellent correlation to the angiographic APPROACH-score with slight overestimation. This might be explained by the former validation of the angiographic score by pathological studies mostly in human hearts without recent myocardial infarction.
This article is published under license to BioMed Central Ltd.