Hanet C, Robert A, Wijns W
Division of Cardiology, University of Louvain, Brussels, Belgium.
Circulation. 1992 Nov;86(5 Suppl):II210-6.
In vitro studies have shown that the vasomotor response of internal mammary artery to vasoactive agents differs from that of saphenous vein.
To assess whether the response in vivo to methylergometrine and to nitrates differs in saphenous vein grafts, internal mammary artery grafts, and coronary arteries, 25 patients were studied more than 6 months (range, 6-96 months) after surgery. Angiograms of saphenous vein grafts (n = 11) or mammary artery grafts (n = 14) were obtained in basal conditions, after intravenous infusion of 0.4 mg methylergometrine, and after intragraft infusion of 1 mg isosorbide dinitrate. Computerized quantitative angiography was used to assess the changes in luminal diameter of the bypass graft and of the grafted coronary artery (n = 11). Methylergometrine reduced the diameter of saphenous vein grafts by 6.9 +/- 7.4%, from 3.26 +/- 0.71 to 3.05 +/- 0.76 mm (p < 0.01), and that of grafted coronary arteries by 9.3 +/- 7.2% (NS compared with saphenous vein grafts), from 2.08 +/- 0.49 to 1.89 +/- 0.49 mm (p < 0.005). The diameter of internal mammary artery grafts did not change significantly, from 3.27 +/- 0.42 to 3.25 +/- 0.44 mm (-0.3 +/- 5.1%, p < 0.02 compared with saphenous vein grafts and p < 0.002 compared with coronary arteries). After isosorbide dinitrate, the diameter of both grafted coronary arteries and mammary artery grafts increased significantly (respectively to 2.46 +/- 0.62 mm and 3.44 +/- 0.43 mm), the vasodilatation being greater (p < 0.002) in coronary arteries (+17.8 +/- 9.8% in proportion to basal diameter, p < 0.001) than in mammary grafts (+5.5 +/- 3.3%, p < 0.001). The diameter of saphenous vein grafts returned to control values (3.28 +/- 0.70 mm, NS compared with basal); the changes in luminal diameter after nitrates (+0.7 +/- 3.1%, NS) were significantly smaller than for mammary artery grafts (p < 0.01) and for grafted coronary arteries (p < 0.001).
Unlike internal mammary artery grafts, saphenous vein grafts constrict in response to methylergometrine and do not dilate in response to nitrates. These differences in vasomotor response could reflect heterogeneity in the sensitivity of vascular smooth muscle to these agents or differences in the basal level of vasomotor tone.
体外研究表明，乳内动脉对血管活性药物的血管舒缩反应与大隐静脉不同。
为评估大隐静脉移植血管、乳内动脉移植血管和冠状动脉在体内对甲基麦角新碱和硝酸盐的反应是否存在差异，对25例患者在术后6个月以上（范围为6 - 96个月）进行了研究。在基础状态下、静脉输注0.4毫克甲基麦角新碱后以及在移植血管内输注1毫克硝酸异山梨酯后，获取大隐静脉移植血管（n = 11）或乳内动脉移植血管（n = 14）的血管造影图像。采用计算机化定量血管造影术评估旁路移植血管和移植的冠状动脉（n = 11）的管腔直径变化。甲基麦角新碱使大隐静脉移植血管的直径从3.26±0.71毫米缩小至3.05±0.76毫米，缩小了6.9±7.4%（p < 0.01），使移植的冠状动脉直径从2.08±0.49毫米缩小至1.89±0.49毫米，缩小了9.3±7.2%（与大隐静脉移植血管相比无显著差异）（p < 0.005）。乳内动脉移植血管的直径无显著变化，从3.27±0.42毫米变为3.25±0.44毫米（-0.3±5.1%，与大隐静脉移植血管相比p < 0.02，与冠状动脉相比p < 0.002）。硝酸异山梨酯输注后，移植的冠状动脉和乳内动脉移植血管的直径均显著增加（分别增至2.46±0.62毫米和3.44±0.43毫米），冠状动脉的血管舒张程度更大（p < 0.002）（相对于基础直径增加17.8±9.8%，p < 0.001），大于乳内移植血管（+5.5±3.3%，p < 0.001）。大隐静脉移植血管的直径恢复至对照值（3.28±0.70毫米，与基础值相比无显著差异）；硝酸盐输注后管腔直径的变化（+0.7±3.1%，无显著差异）显著小于乳内动脉移植血管（p < 0.01）和移植的冠状动脉（p < 0.001）。
与乳内动脉移植血管不同，大隐静脉移植血管对甲基麦角新碱有收缩反应，对硝酸盐无舒张反应。这些血管舒缩反应的差异可能反映了血管平滑肌对这些药物敏感性的异质性或血管舒缩张力基础水平的差异。
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