Objective: To investigate the effect of coronary microemboliation (CME) on coronary microvascular injury and myocardial endothelin-1 (ET-1) level.
Methods: CME was induced in 10 miniswines by selective infusion of microspheres (45 microm) into left anterior descending artery (LAD). The ET-1 level in coronary sinus was measured with radioimmunoassay. The microvascular integrity indicator CFR was measured by Doppler flow wire in LAD at baseline and after infusion of microspheres.
Result: Compared to the baseline, CFR decreased significantly with different doses of microspheres. ET-1 level increased significantly with doses of 5 x 10(4) and peaked with 10 x 10(4), and progressively decreased from doses of 12 x 10(4) to 15 x 10(4) microspheres. There was negative correlation between ET-1 and CFR (r=-0.31, P=0.02).
Conclusion: The extent of microvascular injury is not linearly related to the extent of microembolization, but it is closely associated with myocardial ET-1 level.