冠状动脉竞争血流对乳内动脉旁路血流及NO、ET含量影响的实验研究

Effects of competitive flow from differently stenotic coronary artery on the concentration of ET and NO in the blood in internal mammary artery graft

目的研究冠状动脉旁路移植（CABG）术后，未完全闭塞冠状动脉的竞争血流对左乳内动脉（加雌）旁路血流量、方向及旁路血流中一氧化氮（NO）、内皮素（ET）含量的影响。方法15只猪行㈣术建立不同程度狭窄的冠状动脉左前降支（LAD）与LIMA旁路血管竞争血流动物模型，并检测LIMA旁路血流中NO、ET含量。结果LAD近端狭窄程度越轻，LIMA旁路平均血流量越小，且收缩期逆向血流越大，IAD近端30％狭窄、50％狭窄时LIMA旁路的血流量均明显低于90％狭窄时（P〈0．01）。IAD近端30％和50％狭窄时旁路血流NO含量均明显低于IAD近端90％狭窄时（P〈0．05）；LIMA旁路血流中ET含量均较移植前高（P〈0．05）。结论CABG术后，来自未完全闭塞冠状动脉的竞争血流导致加雌旁路血流量下降并产生双向血流，进而引起旁路血流中NO含量显著下降，可能是早期LIMA血管旁路闭塞的主要机制。

Objective To determine the effects of competitive flow from differently stenotic coronary artery on the flow, the ooncentration of nitric oxide （NO）, and endothelin （ET） in the blood of left internal mammary artery （LIMA） graft and factors that may be involved in early graft failure. Methods Fifteen Chinese swines underwent coronary artery bypass grafting using IMA to left anterior descending （LAD） artery. The procedure was performed using an ＂off pump＂ technique. Different stonosis was mad on proximid LAD through a flow occlusion. The mean flow of LIMA and LAD proximal and distal to the anastomosis and the concentration of El＂ and NO in the blood of LIMA graft were measured respectively. Results When the stenosis of the proximal LAD was 30% or .50%, the mean flow of LIMA was significant lower than that of 90% （ P 〈 0.01 ）. An oscillating flow （retrograde/antegrade） was noted in the LIMA graft. When the stenosis of the proximal LAD was 30% and 50%, the content of NO in blood of LIMA graft were significant lower than that of 90%. The content of ET in the blood of LIMA graft was significant higher than that before grafting（ P 〈 0.05）. Conclusion During competitive flow from nature LAD,low levels of flow and oscillating flow may be poorly tolerated by the LIMA etMothelium, contribute to the decrease in NO content, may contribute LIMA earlier graft failure.