Objective: To investigate the features of plaques of saphenous venous graft (SVG) with virtual histology intravascular ultrasound (VH-IVUS) in patients underwent coronary artery bypass graft surgery. Methods: From March 2016 to March 2018, a total of 45 patients ((64.4±7.9) years old, 88.9% male (40 cases)) with ischemic symptoms after coronary artery bypass graft surgery and with coronary artery angiography evidenced SVG stenosis greater than or equal to 50%, who received percutaneous coronary intervention in Tianjin chest hospital were continuously included in this study, and the clinical data were retrospectively analyzed. VH-IVUS was performed before PCI to analyze plaque composition. The patients were divided into no smoking group (21 cases) and smoking group (24 cases), no diabetes group (30 cases) and diabetes group (15 cases), normal very low density lipoprotein cholesterin (VLDL-C) group (24 cases) and elevated VLDL-C group (21 cases), stable angina pectoris group (5 cases) and acute coronary syndrome group (40 cases), plaque burden (PB) < 70% group (11 cases) and PB ≥ 70% group (34 cases), without thin-cap fibroatheroma group (35 cases) and thin-cap fibroatheroma group (10 cases), and plaque features were compared between different groups. Results: The graft age was (8.9±3.7) years.The stenosis degree of SVG lesions was 90 (90, 98) %. The minimum lumen diameter was 1.6 (1.5, 1.8) mm. The vessel cross-sectional area was (12.1±4.0) mm(2). The plaque area was 8.6 (5.7,12.0) mm(2). The minimum lumen area was 2.5 (2.1,3.3) mm(2). The plaque burden was (75.3±8.3)%. The fibrotic tissue (FI) ratio was (65.1±10.1)%, fibrofatty plaque (FF) ratio was 13.8 (5.4,25.3) %, necrotic core tissue (NC) ratio was 12.0 (5.4,24.0)%, and dense calcium tissue (DC) ratio was1.0 (0.2,3.8)% in SVG lesions. There were no significant differences in SVG plaque area, FI area,FF area,NC area,and DC area between no smoking group and smoking group, no diabetes group and diabetes group, and normal VLDL-C group and elevated VLDL-C group. SVG plaque volume was significantly higher in acute coronary syndrome group than in stable angina pectoris group (262.2 (148.5,401.2) mm(3) vs. 93.1 (50.6,155.9) mm(3),P=0.006), and plaque area (10.1 (6.6,13.3) mm(2) vs. 5.0 (3.6,6.9) mm(2), P<0.001), FI area(4.8 (3.2,6.8) mm(2) vs. 2.8 (1.9,3.0) mm(2), P<0.001),and FF area (1.15 (0.60, 2.07) mm(2) vs. 0.30 (0.10,0.90) mm(2), P=0.009) were significantly larger in PB ≥ 70% group than in PB < 70% group.The NC area (1.75(0.40,2.78) mm(2) vs. 0.60 (0.20,1.30) mm(2), P=0.030) and DC area (0.35 (0.10,0.50) mm(2) vs. 0.00 (0.00,0.10) mm(2), P=0.006) were significantly larger in thin-cap fibroatheroma group than that in without thin-cap fibroatheroma group. Spearman correlation analysis showed that the plaque area of SVG lesion was positively correlated with FF area (r=0.64, P<0.001) and NC area (r=0.43, P=0.003). PB was positively correlated with FF area (r=0.50, P<0.001) and NC area (r=0.33, P=0.028). Graft age was positively correlated with FF area (r=0.30, P=0.047). Conclusions: The main components of SVG plaque are fibrotic tissue, conversely, calcified tissue is rare in patients with SVG stenosis after coronary artery bypass graft surgery. Fibrofatty tissue is increased in the plaque in patients with PB ≥ 70%. The necrotic component is also increased in patients with thin-cap fibroatheroma. The fibrofatty component increases and the plaque tends to be unstable in proportion with increaing age of the graft in this patient cohort.
目的： 应用虚拟组织学成像血管内超声（VH-IVUS）技术分析冠状动脉旁路移植术后隐静脉桥斑块特征。方法： 连续入选2016年3月至2018年3月在天津市胸科医院行冠状动脉造影示隐静脉桥狭窄≥50%并行介入治疗的冠状动脉旁路移植术后有心肌缺血症状患者45例，对其临床资料进行回顾性分析。入选患者年龄（64.4±7.9）岁，男性占88.9%（40例）。介入治疗前于隐静脉桥病变处行VH-IVUS检查，并进行斑块成分测定和分析。分别将入选患者分为不吸烟组（21例）和吸烟组（24例）、无糖尿病组（30例）和糖尿病组（15例）、极低密度脂蛋白胆固醇（VLDL-C）正常组（24例）和VLDL-C升高组（21例）、稳定性心绞痛组（5例）和急性冠状动脉综合征组（40例）、斑块负荷<70%组（11例）和斑块负荷≥70%组（34例）及非薄纤维帽斑块组（35例）和薄纤维帽斑块组（10例），比较不同组别之间的隐静脉桥斑块特征。结果： 入选患者隐静脉桥的桥龄为（8.9±3.7）年。隐静脉桥病变狭窄程度为90（90，98）%，最小管腔直径为1.6（1.5，1.8）mm，血管横截面积为（12.1±4.0）mm(2)，斑块面积为8.6（5.7，12.0）mm(2)，最小管腔面积为2.5（2.1，3.3）mm(2)，斑块负荷为（75.3±8.3）%。隐静脉桥病变的斑块成分中，纤维斑块的比率为（65.1±10.1）%，纤维脂质斑块的比率为13.8（5.4，25.3）%，坏死核心的比率为12.0（5.4，24.0）%，钙化斑块的比率为1.0（0.2，3.8）%。不吸烟组与吸烟组、无糖尿病组与糖尿病组和VLDL-C正常组与VLDL-C升高组患者的隐静脉桥斑块面积、纤维斑块、纤维脂质斑块、坏死核心和钙化斑块面积差异均无统计学意义（P均>0.05）。急性冠状动脉综合征组患者的SVG斑块容量大于稳定性心绞痛组[262.2（148.5，401.2）mm(3)比93.1（50.6，155.9）mm(3)，P=0.006]。斑块负荷≥70%组患者的隐静脉桥斑块面积[10.1（6.6，13.3）mm(2)比5.0（3.6，6.9）mm(2)，P<0.001]、纤维斑块面积[4.8（3.2，6.8）mm(2)比2.8（1.9，3.0）mm(2)，P<0.001]和纤维脂质斑块面积[1.15（0.60，2.07）mm(2)比0.30（0.10，0.90）mm(2)，P=0.009]均大于斑块负荷<70%组。薄纤维帽斑块组患者的隐静脉桥斑块坏死核心面积[1.75（0.40，2.78）mm(2)比0.60（0.20，1.30）mm(2)，P=0.030]和钙化斑块面积[0.35（0.10，0.50）mm(2)比0.00（0.00，0.10）mm(2)，P=0.006]均大于非薄纤维帽斑块组。Spearman相关分析显示，隐静脉桥病变斑块面积与纤维脂质斑块面积（r=0.64，P<0.001）和坏死核心面积（r=0.43，P=0.003）均呈正相关；隐静脉桥病变斑块负荷与纤维脂质斑块面积（r=0.50，P<0.001）和坏死核心面积均呈正相关（r=0.33，P=0.028）；隐静脉桥桥龄与纤维脂质斑块面积呈正相关（r=0.30，P=0.047）。结论： 冠状动脉旁路移植术后隐静脉桥病变斑块的主要成分为纤维组织，钙化组织成分很少；斑块负荷≥70%的斑块纤维脂质增多；薄纤维帽斑块坏死成分增多；随着桥龄增长，纤维脂质成分增多，斑块趋于不稳定。.
Keywords: Cardiac surgical procedures; Plaque; Saphenous vein; Ultrasonography, interventional.