Volume 13 Supplement 1
Time-dependency, predictors and impact on outcome of infarct transmurality assessed by magnetic resonance imaging in patients with st-elevation myocardial infarction reperfused by primary percutaneous intervention
© de Waha et al; licensee BioMed Central Ltd. 2011
Published: 2 February 2011
Previous studies identifying predictors for transmural infarction in patients with ST-elevation myocardial infarction (STEMI) reperfused by primary percutaneous intervention (PCI), especially analyzing the time-dependency of transmural infarction, achieved inconsistent results and are limited due to small and highly-selected study samples. Furthermore it remains unclear whether transmural infarction assessed within the acute phase of STEMI is associated with adverse clinical outcome.
STEMI patients reperfused by primary PCI (n=322) within 720 min after symptom-onset underwent contrast-enhanced magnetic resonance imaging (MRI) at a median of 3 days after the index event (interquartile range [IQR 2;4]). Patients were subcategorized into tertiles according to time-to-reperfusion: lower tertile (< 175 min), middle tertile (175-320 min) and upper tertile (> 320 min). Infarct transmurality was assessed by a score with late-enhancement grading as <25%, 25-50%, 51-75% and >75% transmurality analyzing all 17 left ventricular segments. Transmural infarction was assumed if the hyperenhancement extended 75% of wall thickness in at least one segment. Clinical follow-up was performed after a median of 20 months (IQR 13;29). The primary endpoint was defined as a composite of death and congestive heart failure.
Overall, transmural infarction occurred in 50.6% (n=157) of all patients. The infarct transmurality score progressed significantly with increasing ischemic time (2.7 [IQR 2.1;3.1] for <175 min, 3.0 [IQR 2.4;3.4] for 175-320 min and 3.2 [IQR 2.8;3.5] for >320 min; p<0.001).
Using multivariable logistic regression analysis including parameters such as post-PCI TIMI-flow, ST-segment resolution and maximum creatine kinase levels, time-to-reperfusion was identified as the only independent predictor for transmural infarction (odds ratio 1.02, 95%CI 1.01-1.03, p=0.03).
Furthermore, in Cox regression analysis neither the presence of transmural infarction nor the transmurality score were associated with the occurrence of the primary composite endpoint (presence of transmural infarction: hazard ratio [HR] 1.22, 95%CI 0.53-2.79, p=0.64 / transmurality score HR 1.07, 95%CI 0.73-1.58, p=0.74).
In STEMI patients reperfused by primary PCI time-to-reperfusion is the only independent predictor for transmural infarction. However, infarct transmurality is not associated with the occurrence of death and congestive heart failure.
This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.