Nataf P, Hadjiisky P, Bourbon A, Peuchmaurd M, Leprince P, Regan M, Escolano S, Gandjbakhch I
Department of Cardiovascular Surgery, La Pitié Hospital, Paris, France.
Eur J Cardiothorac Surg. 1996;10(11):965-70. doi: 10.1016/s1010-7940(96)80398-8.
Elastic arteries were found to be less prone to intimal hyperplasia than muscular arteries. The internal mammary artery (IMA), which is elastic in its proximal segment, presents a gradual decrease of media elastic fibers along its downstream course. Metabolic and morphometric studies of the distal end of the IMA with regard to its local susceptibility to develop intimal changes were undertaken in order to evaluate the reliability of its use as an anastomotic site for bypass grafting.
Twenty distal segments of IMA were harvested from patients who had undergone myocardial revascularization. Histologic, enzyme-histochemical and morphometric studies were undertaken on these arterial segments.
Histologic examinations indicated an elastomuscular structure in 13 patients, a muscular structure in 6 and an elastic structure in 1. Of the 20 IMAs, none was found to have intimal thickening of greater than 25% of the diameter of the lumen. The enzyme-histochemical profile of the proliferating cells found in the intimal thickening differed from normal contractile smooth muscle medial cells in the loss of myosin and mitochondrial ATPase, plasma membrane 5' nucleotidase, moderately decreased aerobic dehydrogenase and increased lactate dehydrogenase activity and ribonucleoprotein-linked pyroninophilia. Lysosomal beta-glucuronidase and sulfatase were strongly active. This enzyme behavior is unfavorable to contractile function and favorable to cell proliferation and lipid accumulation, two events strongly involved in the atherogenic process.
Intimal proliferative changes were observed in the distal segment of the IMA. Although there was no histologic evidence of atherosclerotic plaque, the enzyme-histochemical profile of this intimal thickening was favorable to cell proliferation and lipid accumulation. These findings suggest that it may be beneficial to avoid coronary anastomoses with the distal end of the IMA and to use a more proximal/elastic segment.
研究发现弹性动脉比肌性动脉更不易发生内膜增生。胸廓内动脉（IMA）近端为弹性结构，其下游段中膜弹性纤维逐渐减少。对IMA远端进行代谢和形态学研究，以评估其作为旁路移植吻合部位的可靠性。
从接受心肌血运重建术的患者中获取20段IMA远端。对这些动脉段进行组织学、酶组织化学和形态学研究。
组织学检查显示，13例为弹性肌性结构，6例为肌性结构，1例为弹性结构。20段IMA中，未发现内膜增厚超过管腔直径25%的情况。内膜增厚处增殖细胞的酶组织化学特征与正常收缩性平滑肌中膜细胞不同，表现为肌球蛋白和线粒体ATP酶缺失、质膜5'核苷酸酶缺失、需氧脱氢酶适度降低、乳酸脱氢酶活性增加以及核糖核蛋白相关的嗜派洛宁性增加。溶酶体β-葡萄糖醛酸酶和硫酸酯酶活性较强。这种酶的表现不利于收缩功能，有利于细胞增殖和脂质蓄积，这两个过程在动脉粥样硬化形成过程中起重要作用。
在IMA远端观察到内膜增殖性改变。尽管没有动脉粥样硬化斑块的组织学证据，但这种内膜增厚的酶组织化学特征有利于细胞增殖和脂质蓄积。这些发现表明，避免将IMA远端用于冠状动脉吻合，而使用更靠近近端的弹性段可能是有益的。
