ABSTRACT
Objective To compare the effects of different doses of adenosine(AD)on the left coronary blood flow(CBF)and left coronary flow reserve(CFR)in mini-swine.Methods By using Doppler flow wire and intracoronary ultrasound imaging catheter at the middle segment of LAD,coronary average peak flow velocity(APV)and lumen area were measured in 10 healthy mini-swines.CBF was calculated from the equation of 0.6 APV times 0.5 lumen area.Intracoronary bolus injection of different dose AD(12μg,18μg,24 μg and 36μg,separately)was used to induce maximal coronary hyperemic reaction.CFR was defined as the ratio of hyperemic CBF to resting CBF.Results Intracoronary bolus injection of 18μg AD level induced a maximal coronary vasodilation.Significant difference in the hyperemic CBF existed between 12 μg AD dose and 24μg or 36μg AD dose(P＜0.05).No significant difference in heart rate,blood pressure,rCBF and CFR was found among three different AD dose groups(18μg,24μg,and 36μg).Conclusion CBF and CFR in mini-swine can be effectively assessed by bolus injection of AD with the dose of(18～24)μg.
ABSTRACT
Objective By using percutaneous endovascular microcatheter technique to establish an animal model of coronary microembolization in mini-swine which is suitable for long-term observation.Methods Coronary microembolization was established in 10 mini-swine by infusing 15 × 10~4 microspheres (φ45μm) selectively into the left anterior descending artery (n = 10). Coronary flow reserve (CFR) was measured by Doppler wire and left ventricular eject fraction (EF) was assessed by echocardiography.Hematoxylin and eosin (HE) staining and nitroblue tetrazolium (NBT) dye were used to demonstrate the presence of microembolization after the procedure of coronary microembolization. The ultra-structures of cardiomyocyte were observed by transmission electron microscopy (TEM). Before sacrifice, the CFR measurement and coronary angiography were performed again in survival animals. Results The coronary microvascular integrity (CFR < 2.0) and left ventricular function (EF < 50% ) were damaged by coronary microembolization. One month after the procedure, all the 10 animals survived and were able to receive the angiography and CFR measurement again. HE staining and NBT dye could demonstrate the presence of microembolization. The edema and fibrosis of cardiomyocytes could be revealed with TEM. Conclusion The animal model of coronary microembolization can be established in mini-swine by using percutaneous endovascular microcatheter technique. The model is suitable for long-term observation, the preparation is technically-simple and minimally-invasive with very low mortality. Therefore, this kind of animal model is an ideal experimental form for studying the mechanism of coronary microembolization.