| Objective: Coronary artery disease(CAD) was getting popular at the beginning of the 20 th century in industrialized countries. It is “the first killer” in developed countries and developing countries now. It is also a leading cause of morbidity and mortality in the general population. Therefore, human has never stopped studying on the treatment of CAD. The first coronary artery bypass grafting(CABG) operation, which was finished by Sabiston in 1962, half a century ago. Despite many people highly incline to accept the interventional therapy in today’s world, CABG technique remains an important position.Great saphenous vein(GSV) becomes the main vascular graft material in CABG because of its easy to harvest, enough length, and smaller impacts on human body. But the patency rate of GSV grafts after 15 years is only 50%, which greatly influences the postoperative living quality and safety of life in patients with CAD. Based on clinical practice experience, from GSV is harvested to it is used as a graft, it should take at least 30 to 60 minutes, when the vein should be plunged into preservative solution. The protection of veins, while this period of time, can only rely on an appropriate preservative solution. The previous studies found that the preservative solution has an important influence on short-term and long-term patency rate of the CABG.GV solution is a mixture of verapamil and nitroglycerin. In 1993, Guowei He et al used GV solution in the protection of the great saphenous vein, and they achieved good results. In recent ears, a lot of researches have shown the effect of GV preservative solution. Meanwhile, it is easy to prepare and the price is lower. In conclusion, GV solution may be an ideal venous protective fluid.The animal study model we designed in the experiment was to use an external jugular vein of rabbit as a graft by anastomosing with ipsilateral carotid artery. The study aimed to find out GV solution’s short-term and long-term protective effect on veins as grafts. We hope to obtain useful data for clinical practice.Methods: 30 adult big ears New Zealand rabbits’ external jugular veins were harvested and randomly divided into 3 groups in this experiment: A. blank control group; B. papaverine saline group; C. GV solution group. Rabbits’ weight ranged from 2.5 to 3.0 kg. Harvested one side external jugular vein and stored in the corresponding preservation solution at room temperature for 30 minutes. Then cut it into two sections, one for morphological observation, endothelial cell coverage was calculated after HE staining and the protective effect on intimae was observed under transmission electron microscopy, the other section was used and anastomosed with the ipsilateral carotid artery. The content of ET-1 in preservative solution was measured with Elisa. 2 weeks later, the vein graft was taken for HE staining to observe intimae thickness and calculate the ratio of intimae to media, namely I/M.Data analysis was performed with SPSS13.0 for windows software(SPSS Inc, Chicago, III). Continuous data was reported as means±standard deviation. Independent samples t tests were performed on normal continuous data to test for any significant difference between two groups. Nonparametric tests were applicable if data does not fit the normal distribution. The statistical significant level was set at P<0.05 in a 2-sided test.Results: In the short-term results, the endothelial cell coverage in the blank group scored 1.556±0.416, the control group scored 1.850±0.264 and the experimental group scored 2.550±0.430. The endothelial cell coverage of GV solution group was obviously higher than that of the former two groups, and the difference was statistically significant(P<0.05). Papaverine saline severely damaged endothelial cells, and there was no statistically significant difference with the blank group(P>0.05). With transmission electron microscopy, it was found that endothelial cells of experimental group connected completely with basement membrane and closely connected with each other, moreover, the structure of their organelles was preserved well. In contrast, endothelial cells of papaverine group and blank group separated from the basement membrane with serious cytoplasm edema and the tight junctions between cells were opened, at the same time, mitochondria became vacuoles and crests fused. The ET-1 result of Elisa showed that 152.172±14.427 ng/L in group A, 144.880±10.149 ng/L in group B, and 61.032±10.849 ng/L in group C. The content of ET-1 in GV solution was statistical significantly lower than that in the blank group or control group(P<0.05). I/M of grafts after two weeks of operation were 1.469±0.159 in group A, 1.478±0.160 in group B, and 0.539±0.123 in group C. GV solution had the best function of preventing intimae from thickening. Compared with other two groups the difference was statistically significant(P<0.05).Conclusion: In the experiment of protection on rabbit vein grafts,GV solution performed better at protecting intimae, releasing vascular endothelin, and inhibiting restenosis two weeks after operation than papaverine saline and heparin saline. Meanwhile there were no significant differences between the two latter solutions in the above data. |
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