- Oral presentation
- Open Access
Quantifying the area at risk using the infarct lateral border: importance of infarct transmurality
© Jensen et al; licensee BioMed Central Ltd. 2012
- Published: 1 February 2012
- Myocardial Infarction
- Left Atrium
- Ischemia Time
- Lateral Border
- Precise Quantification
The wavefront phenomenon describes the transmural progression of myocardial infarction (MI) from endocardium to epicardium with increasing ischemia duration. A corollary is once subendocardial MI has developed, the infarct lateral border (InfarctLatBor) delineates the Area-at-risk (AAR) lateral border, and thus, can be used to measure overall AAR size. However, with short ischemia time a confluent subendocardial layer of infarction may not develop, and InfarctLatBor may underestimate AAR size. The transmural extent of infarction necessary for InfarctLatBor to accurately reflect AAR size is unknown.
In-vivo assessment of InfarctLatBor with delayed-enhancement-CMR (DE-CMR) has been compared with surrogates of the AAR (ECG, angiographic scores, T2-weighted-CMR). However, no comparison exists with a pathology-based truth standard of the AAR (i.e microspheres). We sought to examine: (1) on pathology studies, the threshold of infarct transmurality necessary for the InfarctLatBor to accurately delineate the AAR, and (2) the ability of in-vivo DE-CMR (via InfarctlatBor assessment) to quantify the AAR in comparison with pathology.
In 15 canines, MI with various infarct transmuralities was produced by temporary occlusion (50-120mins) of the LAD or LCx. A complete LV short-axis stack (7mm thickness, no gap) of DE-CMR images were obtained following gadoversetamide administration (0.2mmol/kg). Prior to sacrifice, the infarct-related-artery was reoccluded at the same site (same suture) and microspheres (1-10μ, 2 million, Duke scientific corp.) were injected into the left atrium to determine AAR size (AARPATH). After TTC-staining the infarct lateral border was used to estimate AAR size (InfarctLabBorPATH).
The lateral border of infarction allows for precise quantification of true AAR size unless a subendocardial layer of infarction less than 10% transmural is present. In-vivo DE-CMR assessment of the infarct lateral border can be used to accurately estimate AAR size, however, underestimation may occur if mean infarct transmurality is near 10%.
This study was funded in part by following NIH-grant: 5R01HL064726-07.
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.