Role of nitric oxide in echocardiographic evaluation of flow-dependent epicardial coronary vasodilation induced by reactive hyperemia in dogs <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

李天亮　邓又斌　王林　杨好意　毕小军　潘敏　张清阳　常青　黎春蕾

LI Tian-liang, DENG You-bin, WANG Lin, Yang Hao-yi, BI Xiao-jun, PAN Min, ZHANG Qing-yang, CHANG Qing, LI Chun-lei. Department of Ultrasound, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China

Abstract

Objective：To evaluate the role of nitric oxide (NO) in the echocardiographic detection of the flow-dependent epicardial coronary vasodilation induced by reactive hyperemia (RH).

Methods：In twelve instrumented dogs, the changes of internal diameter of the left anterior descending coronary artery (LADd) were investigated before and after RH under the condition with and without blockade of NO formation by intracoronary infusion of N^G-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase. LADd was measured using echocardiography. The percent change of LADd was calculated.

Results：Before intracoronary infusion of L-NAME, LADd increased significantly from (2.23 ± 0.19)mm to (2.52 ± 0.24)mm (P <0.01) after RH, and the percent change of LADd was (13.10 ± 3.59)%. After intracoronary infusion of L-NAME,  LADd did not chang significantly (P >0.05) when compared with that before intracoronary infusion of L-NAME. However, the percent change of LADd after RH with intracoronary infusion of L-NAME was dramatically lower than that without intracoronary infusion of L-NAME [(1.07 ± 2..97)% vs (13.10 ± 3.59)%, P <0.001].

Conclusions：The flow-dependent dilation of LAD detected by echocardiography is associated with endothelium-derived nitric oxide. Echocardiography can be used for assessment of coronary endothelial function.

Key words：Echocardiography; Nitric oxide; Coronary vessels; Endothelium,vascular