Lüscher T F, Diederich D, Siebenmann R, Lehmann K, Stulz P, von Segesser L, Yang Z H, Turina M, Grädel E, Weber E
Department of Research, University Hospital, Basel, Switzerland.
N Engl J Med. 1988 Aug 25;319(8):462-7. doi: 10.1056/NEJM198808253190802.
Both the internal mammary artery and the saphenous vein are used to construct coronary-artery bypass grafts. We hypothesized that the release or production of endothelium-derived relaxing factor, which regulates blood flow and inhibits platelet function, may differ in venous and arterial grafts. We therefore studied endothelium-dependent relaxation in internal mammary arteries, internal mammary veins, and saphenous veins obtained from 58 patients undergoing coronary bypass surgery. Vascular rings with and without endothelium were suspended in organ chambers, and isometric tension was recorded. Acetylcholine (10(-8) to 10(-4) M), thrombin (1 U per milliliter), and adenosine diphosphate (10(-7) to 10(-4) M) evoked potent endothelium-dependent relaxation in the mammary artery but weak response in the saphenous vein (P less than 0.005; n = 6 to 27). In the mammary artery, relaxation was greatest in response to acetylcholine (86 +/- 4 percent reduction in norepinephrine-induced tension), followed by thrombin (44 +/- 7 percent) and adenosine diphosphate (39 +/- 8 percent). In the saphenous and mammary veins, relaxation was less than 25 percent. Relaxation was unaffected by indomethacin but was inhibited by methylene blue and hemoglobin (P less than 0.005 and 0.01, respectively), which suggests that endothelium-derived relaxing factor was the mediator. Endothelium-independent relaxation in response to sodium nitroprusside was similar in arteries and veins. We conclude that endothelium-dependent relaxation is greater in the mammary artery than in the saphenous vein. The possibility that this contributes to the higher patency rate among arterial grafts than among venous grafts will require further study.
乳内动脉和大隐静脉都可用于构建冠状动脉旁路移植术。我们推测，调节血流并抑制血小板功能的内皮源性舒张因子的释放或产生在静脉移植物和动脉移植物中可能有所不同。因此，我们研究了58例接受冠状动脉搭桥手术患者的乳内动脉、乳内静脉和大隐静脉中的内皮依赖性舒张。将有内皮和无内皮的血管环悬挂在器官浴槽中，记录等长张力。乙酰胆碱（10⁻⁸至10⁻⁴M）、凝血酶（每毫升1U）和二磷酸腺苷（10⁻⁷至10⁻⁴M）在乳内动脉中引起强烈的内皮依赖性舒张，但在大隐静脉中引起的反应较弱（P<0.005；n = 6至27）。在乳内动脉中，对乙酰胆碱的舒张反应最大（去甲肾上腺素诱导的张力降低86±4%），其次是凝血酶（44±7%）和二磷酸腺苷（39±8%）。在大隐静脉和乳内静脉中，舒张小于25%。吲哚美辛对舒张无影响，但亚甲蓝和血红蛋白可抑制舒张（分别为P<0.005和0.01），这表明内皮源性舒张因子是介质。对硝普钠的非内皮依赖性舒张在动脉和静脉中相似。我们得出结论，乳内动脉中的内皮依赖性舒张大于大隐静脉。这是否有助于动脉移植物的通畅率高于静脉移植物，还需要进一步研究。
