羊抗钙化预处理的同种带瓣大血管作右心室流出道重建

Anticalcification of conduit valve homograft by ethanol combined with aluminum chloride: an experimental right ventricular-pulmonary reconstruction sheep model

目的探讨乙醇和氯化铝溶液浸泡作抗钙化预处理,能否降低同种带瓣主动脉(CVH)的钙化。方法 18只幼羊,分别植入经乙醇和氯化铝溶液浸泡作抗钙化预处理(实验组)和用生理盐水浸泡(对照组)的CVH,作右心室流出道移植重建。移植后18个月(1年半),处死动物,取出CVH,作肉眼、光镜(HE染色及VonKossa法染色)观察,原子吸收火焰法测定组织钙含量。处死前均作心脏彩超检查(测定肺动脉瓣膜直径、平均跨瓣压差、跨瓣峰压、心排量及心排指数)。结果共完成CVH植入18例。其中,实验组1例术中吻合口出血死亡,1例术后16天死于胸腔内感染;对照组2例分别于随访9、12个月时死亡(尸体解剖见CVH瓣膜均钙化严重、明显狭窄),其余14例均成活到18个月。心脏超声:实验组CVH瓣膜柔软,光滑,无增厚及钙化,活动正常,跨瓣压差低(接近正常)。对照组CVH瓣膜增厚及钙化,管壁亦有钙化灶,瓣膜轻、中、重度返流及狭窄,跨瓣压差增高。两组均未见赘生物及血栓形成。CVH取出后见:实验组管道质地柔软,内膜光滑。瓣膜质地纤细,无退行性或钙化改变;对照组CVH管壁多处钙化,瓣膜不均匀增厚、钙化。Von Kossa染色见:实验组CVH管壁无黑色钙盐,对照组管壁及瓣膜有黑色钙盐。光镜:实验组见血管中层纤维细胞形态完整,细胞核无裂解和浓缩,胞浆均匀,平滑肌细胞呈梭状,排列整齐,结构完整,瓣膜细胞结构清楚;对照组血管中层纤维细胞及平滑肌细胞排列疏松,纤维结构有断裂,瓣膜细胞有少许呈死后自溶,主动脉管壁及瓣膜可见较多钙化灶。与实验组比较,对照组主动脉壁及瓣膜的钙含量均明显增加。实验组带瓣血管血流动力学明显优于对照组。结论以乙醇和氯化铝溶液浸泡作抗钙化预处理CVH,可降低其钙化,作右心室流出道重建,可获得更好的血流动力学效果,有可能成为新的CVH材料。

Objective To investigate the efficacy of anticalcification of conduit valve homograft by ethanol with aluminum chloride in a right ventricular-pulmonary reconstruction animal model.Methods Right ventricular-pulmonary reconstructions were carried out in eighteen juvenile sheep.Ethanol and aluminum chloride were applied to pretreat the conduit in experiment group,non pretreated conduit were used in control group.Animals were followed-up for 18 months,and hemodynamic parameters were achieved by echocardiography analysis,homograft was harvested for evaluation of calcification.Results Of the eighteen animals implanted with CVH,2 animals in experiment group died,included one operative death caused by anastomosis leakage,one died before 30 days postoperation due to introthoracic infection.Two deaths in control group on postoperative month 9 and 12.They were all associated with marked calcific stenosis of the implanted CVH as shown by autopsy.The remainders fourteen animals were survived to 18 months.Ethanol plus aluminum chloride complete inhibited calcification of homograft in experiment group（aortic wall calcium level,30.2±3.1 μg/mg tissue compared with control calcium level,63.3±7.2 μg/mg tissue;valve cusp calcium level,6.24.±2.21 μg/mg tissue compared with control calcium level,31.6.±10.32 μg/mg tissue）.There was no valve regurgitation and/or stenosis by the echocardiogram in experiment group,whereas in control group,valve regurgitation and/or stenosis were existed.Histological,all homografts in experiment group preserved their normal organization,without calcification,while significant calcification focuses were existed both in the aortic wall and valve cusp in control group.Conclusion Ethanol and aluminum chloride could provide desirable anticalcification efficacy,and conduit valve homograft pretreated by these agent might be an excellent homograft substitute.