Kobayashi H
Department of Surgery III, Nara Medical College, Kashihara, Japan.
Nihon Geka Gakkai Zasshi. 1990 Jul;91(7):889-900.
To evaluate the usefulness of the internal mammary artery (IMA) as a graft material for coronary artery bypass surgery, 1) the whole length of 26 bilateral IMAs and 13 left anterior descending coronary arteries (LADs) harvested at autopsies were comparatively examined on atherosclerosis from the histological point of view, and 2) the lipid (total cholesterol, triglyceride and phospholipid) contents of 12 IMA segments and 11 LAD segments excised at other autopsies were also comparatively examined from the biochemical standpoint. 1) The histologic index of atherosclerotic involvement was expressed as intima-to-media ratio (R) representing the severity of the intimal thickening. The severity of atherosclerosis was graded from I to IV according to the R value. Of all 274 IMA sections grade IV (R greater than or equal to 3.0) atherosclerosis was found in only one section (1/26 IMAs, 3.8%). The mean R value of all IMAs (0.30 +/- 0.36) was approximately one tenth of that of all LADs (3.01 +/- 2.05) (p less than 0.01). The histologic examination for whole segments of the IMAs revealed that atherosclerosis of the IMA was equally slight in every part of the IMA with no laterality. On the other hand, atherosclerosis of the LAD was characteristically severer in the proximal segment of the artery than the distal segment. 2) The contents of total cholesterol, triglyceride and phospholipid of the IMA and the LAD were 5.5 +/- 1.8 (IMA) vs 17.8 +/- 13.6 (LAD) micro g/mg wet wt. (p less than 0.05), 90.4 +/- 90.3 (IMA) vs 114.4 +/- 117.2 (LAD) micro g/mg wet wt. and 7.4 +/- 3.9 (IMA) vs 11.2 +/- 3.9 (LAD) micro g/mg wet wt. (p less than 0.05) respectively. The lipid content of the IMA was significantly smaller than that of the LAD. 3) The low incidence of atherosclerosis of the IMA in contrast to frequent atherosclerosis of the LAD was proven histologically as well as biochemically in the present study. This is the first report to describe the histologic examination of atherosclerosis on the whole length of the IMA and the biochemical analysis for the lipid content of the IMA in Japanese population.
为评估乳内动脉（IMA）作为冠状动脉搭桥手术移植物材料的效用，1）从组织学角度对26条双侧IMA和13条左前降支冠状动脉（LAD）在尸检时获取的全长进行动脉粥样硬化的比较检查，并且2）从生化角度对在其他尸检时切除的12段IMA和11段LAD的脂质（总胆固醇、甘油三酯和磷脂）含量也进行比较检查。1）动脉粥样硬化累及的组织学指标用代表内膜增厚严重程度的内膜与中膜比值（R）表示。根据R值将动脉粥样硬化的严重程度分为I至IV级。在所有274段IMA切片中，仅在1个切片（1/26条IMA，3.8%）中发现IV级（R大于或等于3.0）动脉粥样硬化。所有IMA的平均R值（0.30±0.36）约为所有LAD平均R值（3.01±2.05）的十分之一（p＜0.01）。对IMA全段的组织学检查显示，IMA的动脉粥样硬化在IMA的各个部位同样轻微，无左右侧差异。另一方面，LAD的动脉粥样硬化特征性地在动脉近端段比远端段更严重。2）IMA和LAD的总胆固醇、甘油三酯和磷脂含量分别为5.5±1.8（IMA）对17.8±13.6（LAD）μg/mg湿重（p＜0.05）、90.4±90.3（IMA）对114.4±117.2（LAD）μg/mg湿重以及7.4±3.9（IMA）对11.2±3.9（LAD）μg/mg湿重（p＜0.05）。IMA的脂质含量显著低于LAD。3）在本研究中，从组织学和生化方面均证实了IMA动脉粥样硬化发生率低，而LAD动脉粥样硬化常见。这是首篇描述日本人群中IMA全长动脉粥样硬化组织学检查及IMA脂质含量生化分析的报告。
