Lee R T, Loree H M, Fishbein M C
Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
J Am Coll Cardiol. 1994 Dec;24(7):1639-44. doi: 10.1016/0735-1097(94)90168-6.
Our aim was to test the hypothesis that maximal stresses in saphenous vein atherosclerotic stenoses are greater than those in native coronary artery stenoses.
The patency of coronary artery saphenous vein bypass grafts decreases with time, usually because of thrombosis. Plaque rupture has been described as one mechanism of vein graft thrombosis.
Twenty-six nonruptured human lesions were studied. Fourteen lesions were from native coronary arteries, and 12 were from saphenous vein bypass grafts placed a mean +/- SD of 9.8 +/- 3.3 years before pathologic study. The finite element method was used to determine the distribution of stress in the lesion, using estimates of material properties from previous measurements of human tissues.
Maximal circumferential stresses were significantly higher in the saphenous vein lesions (median 352 kPa [interquartile range 161 to 475]) than in the coronary artery lesions (median 104 kPa [interquartile range 75 to 185]) (p = 0.05). Thin-walled cylinder formulations predict that stresses are proportional to the radius of the vessel and inversely proportional to the minimal wall thickness. In this study, there was a good correlation between the maximal stress in the 26 lesions and the ratio of the square root of lumen area to minimal fibrous cap thickness (r = 0.83, p < 0.001).
Maximal circumferential tensile stresses in saphenous vein bypass graft stenoses are higher than in native coronary artery atherosclerotic stenoses. These data suggest that strategies that decrease stresses in bypass graft atherosclerotic lesions, such as prevention of lipid accumulation, could reduce the probability of plaque rupture in bypass grafts.
我们的目的是检验以下假设，即大隐静脉粥样硬化狭窄处的最大应力大于冠状动脉狭窄处的最大应力。
冠状动脉大隐静脉旁路移植血管的通畅性会随时间下降，通常是由于血栓形成。斑块破裂被认为是静脉移植血管血栓形成的一种机制。
研究了26个未破裂的人体病变。14个病变来自冠状动脉，12个来自大隐静脉旁路移植血管，这些移植血管在病理研究前平均放置了9.8±3.3年。使用有限元方法确定病变中的应力分布，材料特性估计值来自先前对人体组织的测量。
大隐静脉病变的最大周向应力（中位数352 kPa[四分位间距161至475]）显著高于冠状动脉病变（中位数104 kPa[四分位间距75至185]）（p = 0.05）。薄壁圆柱公式预测应力与血管半径成正比，与最小壁厚成反比。在本研究中，26个病变中的最大应力与管腔面积平方根与最小纤维帽厚度之比之间存在良好的相关性（r = 0.83，p < 0.001）。
大隐静脉旁路移植血管狭窄处的最大周向拉应力高于冠状动脉粥样硬化狭窄处。这些数据表明，降低旁路移植血管粥样硬化病变应力的策略，如预防脂质积聚，可降低旁路移植血管斑块破裂的可能性。
