595Multilayer radial strain measurements can detect early reperfusion from ischemia. An experimental porcine study.


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Abstract

Background: Tissue Doppler Imaging (TDI) can measure strain in multiple myocardial layers and could become important for evaluating altered perfusion gradients across the myocardium. This study investigates if TDI analysis can detect alterations in deformation during reperfusion following sub-and midmyocardial ischemia.Methods: Eight pigs (46±5 kg) were anesthetized and sternotomized. An extracorporeal shunt was inserted from the brachiocaphalic to the LAD coronary artery. Registrations with open shunt were followed by 120 min of shunt stenosis before reperfusion. Measurements were performed after 90 min of stenosis and after 20 and 100 min of reperfusion. Microspheres for perfusion measurements in three layers of the anterior LV wall were injected and LV short-axis TDI views of the anterior wall was recorded. TDI images were analyzed for radial peak systolic strain using 3 regions of interest (2x6mm, SL=2mm) across the wall.Results: Strain and perfusion are shown in the Table. During stenosis, perfusion decreased in the mid- and subendocardium, while strain was reduced in all layers (P<0.05). At early reperfusion, hyperemia was present in all wall layers and strain increased in the mid- and subendocardial layer (P<0.05). At late reperfusion, blood flow in the same layers returned to baseline, while strain did not change.Conclusion: Multilayer radial TDI analysis can differentiate between ischemia and early reperfusion. This suggests that multilayer strain could become an important clinical method for evaluating the success of myocardial reperfusion following ischemia.

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