Abstract
BackgroundMyocardial contrast echocardiography has been used for determination of infarct size (IS) in experimental models. However, with intermittent harmonic imaging, IS seems to be underestimated immediately after reperfusion due to areas with preserved, yet dysfunctional, microvasculature. The use of exogenous vasodilators showed to be useful to unmask these infarcted areas with depressed coronary flow reserve. This study was undertaken to assess the value of adenosine for IS determination in an open-chest canine model of coronary occlusion and reperfusion, using real-time myocardial contrast echocardiography (RTMCE).MethodsNine dogs underwent 180 minutes of coronary occlusion followed by reperfusion. PESDA (Perfluorocarbon-Exposed Sonicated Dextrose Albumin) was used as contrast agent. IS was determined by RTMCE before and during adenosine infusion at a rate of 140 mcg·Kg-1·min-1. Post-mortem necrotic area was determined by triphenyl-tetrazolium chloride (TTC) staining.ResultsIS determined by RTMCE was 1.98 ± 1.30 cm2 and increased to 2.58 ± 1.53 cm2 during adenosine infusion (p = 0.004), with good correlation between measurements (r = 0.91; p < 0.01). The necrotic area determined by TTC was 2.29 ± 1.36 cm2 and showed no significant difference with IS determined by RTMCE before or during hyperemia. A slight better correlation between RTMCE and TTC measurements was observed during adenosine (r = 0.99; p < 0.001) then before it (r = 0.92; p = 0.0013).ConclusionRTMCE can accurately determine IS in immediate period after acute myocardial infarction. Adenosine infusion results in a slight better detection of actual size of myocardial damage.
Highlights
Myocardial contrast echocardiography has been used for determination of infarct size (IS) in experimental models
In the first minute of reperfusion, we observed a period of reactive hyperemia with an increase of 2.6 times (54.3 ± 25.6 ml·min-1) the baseline left anterior descending coronary artery (LAD) flow
At 30 minutes of reperfusion, LAD flow had already returned to baseline levels
Summary
Myocardial contrast echocardiography has been used for determination of infarct size (IS) in experimental models. This study was undertaken to assess the value of adenosine for IS determination in an open-chest canine model of coronary occlusion and reperfusion, using real-time myocardial contrast echocardiography (RTMCE). Previous studies using intermittent harmonic imaging demonstrated that IS can be underestimated by myocardial contrast echocardiography immediately after coronary reperfusion, because in some regions the microvascular damage occurs later than myocyte death, resulting in relatively preserved perfusion in infarcted areas [68]. In this setting, exogenous vasodilatation has proven to be useful to unmask necrotic area with abnormal microvascular coronary flow reserve, providing a more accurate assessment of IS. This study was undertaken to assess the additional value of exogenous vasodilation with adenosine for IS determination using RTMCE, in an open-chest canine model of coronary occlusion and reperfusion
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
