He G W, Yang C Q
Department of Surgery, University of Hong Kong, Grantham Hospital, Aberdeen, Hong Kong.
Ann Thorac Surg. 1996 Feb;61(2):610-4. doi: 10.1016/0003-4975(95)00920-5.
The radial artery (RA) has been used as an alternative arterial graft for coronary artery bypass grafting. This artery has been reported to be spastic; therefore, use of spasmolytic drugs (vasodilators) during the preparation of the RA is recommended. The combination of calcium antagonists and nitroglycerin (verapamil plus nitroglycerin, VG solution) has been suggested to be effective in other bypass grafts. This study was designed to investigate (1) the effect of the VG solution during preparation of the RA for coronary artery bypass grafting and (2) whether the effect would last for a prolonged period after topical use.
Ring segments of the RA taken from coronary artery bypass grafting patients were studied in organ chambers at a physiologic pressure. The relaxation effect of VG (30 mumol/L verapamil and 30 mumol/L nitroglycerin, n = 5) or papaverine (30 mumol/L, n = 5) was recorded in K+ (25 mmol/L potassium chloride)-precontracted RA segments. Other segments taken from the RA were treated (n = 5) or not treated (n = 20, as the control) with the VG solution for 45 minutes before used for coronary artery bypass grafting. Both the VG-treated and nontreated segments were immersed in oxygenated Krebs solution and stored in a refrigerator at 4 degrees C for 24 hours. The contraction force to 100 mmol/L K+ was compared between the two groups.
The VG solution induced more rapid relaxation than papaverine (p < 0.05 from the first to the ninth minute). After 10 minutes, both solutions induced full relaxation. The contraction to K+ (100 mmol/L) in rings treated with VG solution for 45 minutes during operation was almost abolished 24 hours later (0.86 +/- 0.1 g). In contrast, the control segments (n = 20) taken from nontreated RA contracted with K+ to high force (5.0 +/- 0.6 g; p < 0.001).
The present study suggests that the combination of verapamil and nitroglycerin may provide a rapid onset, a complete relaxation, and a long-lasting vasorelaxant effect when used to prepare the RA for grafting. This study adds a new method to prevent RA spasm during coronary artery bypass grafting.
桡动脉（RA）已被用作冠状动脉旁路移植术的替代动脉移植物。据报道，该动脉会发生痉挛；因此，建议在桡动脉制备过程中使用解痉药物（血管扩张剂）。钙拮抗剂和硝酸甘油的组合（维拉帕米加硝酸甘油，VG溶液）已被认为在其他旁路移植术中有效。本研究旨在调查：（1）VG溶液在冠状动脉旁路移植术桡动脉制备过程中的作用；（2）局部使用后该作用是否会持续较长时间。
从冠状动脉旁路移植术患者获取的桡动脉环段在生理压力下于器官腔中进行研究。在钾离子（25 mmol/L氯化钾）预收缩的桡动脉段中记录VG（30 μmol/L维拉帕米和30 μmol/L硝酸甘油，n = 5）或罂粟碱（30 μmol/L，n = 5）的舒张作用。取自桡动脉的其他段在用于冠状动脉旁路移植术前，用VG溶液处理45分钟（n = 5）或不处理（n = 20，作为对照）。将经VG处理和未处理的段均浸入含氧的 Krebs 溶液中，并在4℃冰箱中保存24小时。比较两组对100 mmol/L钾离子的收缩力。
VG溶液比罂粟碱诱导更快的舒张（从第1分钟到第9分钟，p < 0.05）。10分钟后，两种溶液均诱导完全舒张。术中用VG溶液处理45分钟的环段对钾离子（100 mmol/L）的收缩在24小时后几乎消失（0.86±0.1 g）。相比之下，取自未处理桡动脉的对照段（n = 20）对钾离子收缩至高强度（5.0±0.6 g；p < 0.001）。
本研究表明，维拉帕米和硝酸甘油组合在用于制备移植用桡动脉时，可能提供快速起效、完全舒张和持久的血管舒张作用。本研究为冠状动脉旁路移植术中预防桡动脉痉挛增添了一种新方法。
