[Beneficial effects of adenosine on myocardial no-reflow in a mini-swine model of acute myocardial infarction and reperfusion].
ABSTRACT To evaluate the beneficial effects of adenosine on myocardial no-reflow in a mini-swine model of acute myocardial infarction (AMI) and reperfusion.
Twenty-four animals were randomly assigned to 3 groups: 8 in controls, 8 in adenosine-treated and 8 in sham-operated. The groups were subjected to 3 hours of coronary occlusion followed by 60 minutes of reperfusion except the sham-operated group. Data on hemodynamics and coronary blood flow volume (CBV) were collected. The area of no-reflow was evaluated by both myocardial contrast echocardiography (MCE) in vivo and histopathological means and necrosis area was measured with triphenyltetrazolium chloride staining.
(1) In control group, systolic and diastolic blood pressure (SBP and DBP), left ventricular systolic pressure, maximal rate of increase and decline in left ventricular pressure (+/- dp/dtmax) and cardiac output significantly declined (P < 0.05-0.01), while left ventricular end-diastolic pressure (LVEDP) and pulmonary capillary wedge pressure (PCWP) significantly increased at the end of 3 hours of LAD occlusion (both P < 0.01), with +/- dp/dtmax further significantly declined (both P < 0.05) at 60 minutes of reperfusion. In adenosine treated group, the changes of SBP and DBP, left ventricular systolic pressure, +/- dp/dtmax, cardiac output, LVEDP and PCWP were the same as those in the control group after AMI and reperfusion, while left ventricular systolic pressure, +/- dp/dtmax, cardiac output, LVEDP and PCWP recovered significantly at 60 minutes of reperfusion compared with those at 6 hours AMI. (2) In control group, the coronary ligation areas (LA) were similar (P > 0.05) detected by MCE in vivo and histopathological evaluation, and the areas of no-reflow were both as high as 67.5% and 69.3%, respectively. The final necrosis area reached 99% of LA. Compared with those in the control group, there was no significant difference in LA on both MCE and histopathological evaluation in the adenosine-treated group, though the areas of no-reflow on both methods were significantly decreased to 21% and 22% (both P < 0.01) and final necrosis area was also significantly decreased to 75% of LA (P < 0.05). (3) In the control group, CBV were significantly declined to 45.8% and 50.6% of the baseline at immediately after release of 3 hours occlusion and at 60 minutes of reperfusion, respectively (both P < 0.01). In the adenosine-treated group, CBV were also significantly declined at immediately after release of 3 hours occlusion, and at 60 minutes of reperfusion (both P < 0.05), though significantly increased to 79.5% and 79.9% of the baseline which were both significantly higher than those in the control group.
Adenosine has an effective role in preventing myocardial no-reflow, improving left ventricular function and reducing infarct area during AMI and reperfusion in mini-swine.
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ABSTRACT: The objective of this study was to explore a new method for the identification of viable myocardium by means of two-dimensional (2D) strain imaging combined with adenosine stress echocardiography. A total of 15 anesthetized open-chest healthy mongrel dogs underwent left anterior descending coronary artery occlusion for 90 min followed by 120-min reperfusion. Adenosine was infused at 140 μg kg(-1) min(-1) over a period of 6 min. Images were acquired at baseline (when pericardial cradle was made), after reperfusion (when reperfusion finished) and after adenosine administration (while administration stopped). Measurements of the regional peak-systolic strain in radial, circumferential, and longitudinal motion on anterior wall and anterior septum were, respectively, performed under different conditions. The dogs were killed after the echocardiographic studies finished and then the area of infracted myocardium was defined by triphenyltetrazolium chloride histology. A segment with equal or less than 50% area of infracted myocardium was considered to be viable. As a result, 37 regions were viable whereas 53 were non-viable among 90 regions in 15 dogs. At baseline, there was no significant difference in peak-systolic radial strain (Rs), circumferential strain (Cs), and longitudinal strain (Ls) between the viable and non-viable groups. After reperfusion, Rs, Cs, and Ls in absolute value decreased compared to those at baseline in both groups, although there was no significant difference between these groups. Rs and Ls increased after adenosine administration compared to reperfusion (p < 0.01; p < 0.05) in viable group while there were no changes in non-viable group. Compared with non-viable group Rs, Cs and Ls in viable group increased significantly (p < 0.01; 0.05) after adenosine administration. There was a negative correlation between Rs and infarct size (r = -0.72). Cs and Ls correlated well with infarct size, respectively (r = 0.40; 0.67). A change of Rs more than 13.5% has a sensitivity of 83.8% and a specificity of 83.0% for viable whereas a change of Ls more than 11% allowed a sensitivity of 78.4% and a specificity of 88.7%. Combined with these two variables, the sensitivity and specificity could reach 91.9 and 79.2%. Two-dimensional strain imaging combined with adenosine stress echocardiography can provide a new way to distinguish viable myocardium from the non-viable.Heart and Vessels 01/2011; 26(2):206-13. · 2.13 Impact Factor