乳内动脉行心中静脉动脉化改善心肌缺血的作用与机制

目的采用猪右乳内动脉在非体外循环下行选择性心中静脉动脉化(CVBG),评价其疗效并对其机制进行初步探讨。方法将12只右冠状动脉重度弥漫性狭窄的中华实验小型猪雌雄不限,月龄7～10个月,体重(40±5)kg]按随机数字表法分为两组,每组6只。实验组:采用右乳内动脉行CVBG;对照组:单纯开胸。右冠状动脉内膜剥脱术后8周对两组猪行超声心动图检查,术后6 h、3个月行冠状动脉造影、移植血管血流量测定及超声心动图检查,术后3个月处死动物前行非放射性彩色微球检测,观察两组猪心功能、移植血管血流量、移植血管通畅性和缺血心肌微循环再灌注情况。结果右冠状动脉内膜剥脱术后8周,两组左心室功能无差异。实验组行CVBG术后6 h和3个月心脏收缩和舒张功能均较对照组有所改善(术后3个月射血分数:52%±6%vs.44%±5%,t=-2.500,P=0.031)。实验组术后6 h、3个月移植血管血流量分别为(44.50±5.86)ml/min、(43.33±5.01)ml/min(P=0.718),搏动指数(PI)分别为0.73±0.14、0.80±0.14(P=0.858)。实验组术后6 h和3个月行冠状动脉造影显示:乳内动脉桥及吻合口均能顺利通过造影剂,无狭窄;施行CVBG后,经非放射性彩色微球法检测可见心肌各层的血流量均较对照组有所增加穿壁心肌:(0.33±0.05)ml(/g min)vs.(0.19±0.03)ml(/g min),P<0.05],尤其是心内膜下心肌。结论采用乳内动脉行CVBG,可改善心肌缺血的近、中期疗效,其机制可能是通过改善心肌微循环而实现的。

Efficacy and Mechanism of Coronary Vein Bypass Grafting to Improve Myocardial Ischemia Using Internal Mammary Artery

Objective To evaluate the outcome and explore the mechanism of coronary vein bypass grafting(CVBG) performed by anastomosing the right internal mammary artery with the middle cardiac vein via off-pump surgery.Methods Twelve Chinese experimental miniswines(either male or female,age from 7 to 10 months,body weight 40±5 kg) with severely diffuse stenosis in the right coronary artery were randomly divided into control group and experiment group with 6 miniswines in each group,using a random number table method.CVBG was performed in the experiment group and sham surgery was performed in the control group.To assess cardiac function,graft flow,graft patency and micro-circulation reperfusion of ischemia myocardium,following measurements were conducted.Eight weeks after right coronary endarterectomy,transthoracic echocardiography was performed for both groups.Coronary angiography,graft flow and echocardiography were performed or measured 6 hours and 3 months after CVBG or sham surgery.Measurement of myocardial blood flow with non-radioactive colored microspheres was also conducted 3 months after surgery for two groups.Results There was no statistical difference in cardiac function 8 weeks after right coronary endarterectomy between the two groups.There were significant improvements in cardiac systolic and diastolic function(ejection fraction 3 months after operation: 52%±6% vs.44%±5%,t=-2.500,P=0.031) in the experiment group after CVBG compared with the control group.Graft flow of the experiment group 6 hours and 3 months after CVBG were 44.50±5.86 ml/min and 43.33±5.01ml/min respectively(P=0.718),and pulsatility index(PI) was 0.73±0.14 and 0.80±0.14 respectively(P=0.858).Internal mammary artery grafts and the anastomoses were all patent without stenosis,documented by coronary artery angiography for the experiment group 6 hours and 3 months after CVBG.Myocardial flow in all aspects especially in the subendocardial layer,estimated by non-radioactive colored microsphere injection,was significantly higher in the experiment group after CVBG than that of the control group,transmural flow was 0.33±0.05ml/(g min) vs.0.19±0.03 ml/(g min)(P<0.05).Conclusion Ischemic conditions of the myocardium can be relieved by CVBG using internal mammary artery in a short-term to medium-term period.The mechanism may be due to improvement of the myocardial micro-circulation.