冠状动脉不同狭窄程度的竞争血流对旁路移植乳房内动脉血管桥血流的影响

目的：研究冠状动脉不同狭窄程度的竞争血流对旁路移植乳房内动脉（IMA）血管桥血流的影响。方法：选用中华小型猪，建立猪冠状动脉分流术（CABG）后IMA桥血管竞争血流动物模型，在冠状动脉左前降支（LAD）近端不同狭窄情况下，用即时血流检测仪（TTFM）分别测量LAD吻合口近端、远端、左侧乳房内动脉（LIMA）桥血流量及方向、波形、搏动指数（PI）值，并进行对比分析。结果：LAD近端完全开放、30％、50％、75％、90％狭窄、全部闭塞时LIMA桥平均血流量分别为(9.75±1.45)、(11.63±1.69)、(15.63±2.26、(19.75±2.37)、(23.50±2.34)和（26.75±2.11）ml/min；PI值分别为4.4±1.7、4.1±1.6、4.2±1.9、3.7±1.8、3.3±1.6、2.5±1.4。LAD近端90％狭窄及全部闭塞时LIMA桥的血流量均明显高于LAD近端完全开放、30％狭窄、50％狭窄时的血流量(P<0.01)，各组PI值相比，差异无统计学意义（P>0.05）。LAD近端未完全闭塞时LIMA血管桥均可出现双向血流，LAD近端各种狭窄程度LAD远端血流量差异无统计学意义（P>0.05）。结论：冠状动脉竞争血流确实存在。来自未完全闭塞冠状动脉的竞争血流造成的桥血流量减少和血流方向改变可能是造成CABG术后早、中期IMA血管桥衰坏的重要因素。

Effects of competitive blood flow from differently stenotic coronary artery on internal mammary artery graft flow

Objective:To study the effects of competitive blood flow from differently stenotic coronary artery on internal mammary artery graft flow. Methods: Coronary artery bypass grafting (CABG) was conducted in 15 Chinese miniswines using left internal mammary artery(LIMA) anastomosed to left anterior descending artery (LAD). The proximal LAD was mad differently stenotic (0%,30%,50%,75%,90% and 100%) through a flow occlusion and the mean flow of LIMA and LAD proximal and distal to the anastomosis were respectively measured through the transit time flow measurement (TTFM). Results:The mean flow of LIMA was (9.75±1.45), (11.63±1.69), (15.63±2.26), (19.75±2.37), (23.50±2.34) and (26.75±2.11)ml/min, respectively. The mean pulsatility index (PI) value was respectively 4.4±1.7, 4.1±1.6, 4.2±1.9, 3.7±1.8, 3.3±1.6 and 2.5±1.4. Themean flow of LIMA when the stenosis of the proximal LAD was 90% or 100% was significant higher than that of LIMA when the stenosis of the proximal LAD was 0%, 30% or 50%（P<0.01）. When the proximal LAD was not fully occluded, there were dual flow in LIMA. There were no difference in LAD flow distal to the anastomosis. Conclusion: The competitive flow from patent LAD does exist and has important effects on IMA graft flow and may be an important cause of IMA graft failure.