Myocardial Perfusion after Transmyocardial Mechanical Revascularization in Rat Heart Transplant Model, Acute Model

Jeon, Yang Bin; Shinn, Sung Ho; Chung, Won Sang; Kang, Jung Ho

Abstract

BACKGROUND: Transmyocardial revascularization (TMR) in end stage ischemic heart disease results in variable clinical responses. We investigated the acute effect of early reperfusion and the angiogenesis after formation of the transmyocardial channel in a transplanted rat heart model with acute myocardial infarction. MATERIAL AND METHOD: In the 30 transplanted hearts we induced acute myocardial infarction by ligating the proximal left coronary artery and inserted a porous 22G intravenous cannula into the left ventricle. After ten minutes of reperfusion, we removed the cannula. At every stage, we recorded the heart rate, QRS size, and left coronary arterial blood flow using the electrocardiogram and Doppler. One week later the rats were sacrificed and evaluated for the patency of intramyocardial channels and the angiogenesis. RESULT: The heart rates after ligation and after cannula insertion were 239.1+/-61.7, 235.8+/-58.0 bpm respectively, and they were statistically significantly slower than that of before ligation, 277.6+/-40.3 bpm (p=0.017, p=0.007 respectively). QRS sizes before ligation, after ligation, and after cannula insertion were 3.6+/-3.3 mm, 2.8+/-3.3 mm, and 2.4+/-2.2 mm, respectively, and there was no significant difference in the three groups. Doppler findings after ligation showed that average peak and mean values of coronary perfusion were significantly decreased from 2.11+/-0.17 kHz, 1.25+/-0.22 kHz to 0.83+/-0.15 kHz, 0.38+/-0.11 kHz (p<0.05 respectively). After insertion of the porous cannula, the average peak and mean values of coronary perfusion were 0.61+/-0.05 kHz and 0.33+/-0.05 kHz respectively, but there was no statistically significant change compared to values after ligation. In all cases except one, pathologic findings showed no patent channels in the acute stage, however, one case showed the angiogenesis.
CONCLUSION
We confirmed that TMR in a rat heart transplant model did not show blood flow through the channel in the acute stage. However, reperfusion effect in some cases had a potential for angiogenesis.