Abstract: To explore the effect of coronary artery stenosis degree on internal mammary artery blood flow. Methods: Coronary artery bypass grafting was performed in 15 minipigs on beating heart under offpumping and the left internal mammary artery was anastomosed to left anterior descending artery. Different stenosis degrees of LAD were made by an occluder encircling around LAD, and the internal mammary artery flow was measured by transient transonic flowmeter. Results: The internal mammary artery flow was significantly different according to LAD stenosis degree and higher than nonstenosis when the stenosis was more than 50%. Conclusion: There are significant competitive flow between the left anterior descending artery and the internal mammary artery after coronary artery bypass grafting when the stenosis degree of LAD is lower than 50%. This is an ideal animal model to study the competitive flow between the left anterior descending artery and the internal mammary artery after coronary artery bypass grafting.

Key words: Coronary artery bypass grafting, Internal mammary artery, Competitive flow, Mode