国产双叶二尖瓣植入绵羊体内的慢性实验研究

Chronic Sheep Model for Domestic Bileaflet Mitral Valves

目的 :建立国产双叶二尖瓣植入绵羊体内的慢性存活实验模型。 方法 :2 0 0 1年 12月到 2 0 0 2年 12月 ,选择 5只成年绵羊 ,体重 40～ 63kg ,平均 (5 2 6± 9 5 )kg。在体外循环并行下 ,心脏不停跳 ,经左心耳途径进行两种新型国产双叶二尖瓣的植入 (2 5号 4枚和 2 7号 1枚 )。其中 2只缝合在瓣环水平 ,同时将前叶切开固定到后瓣环保留全部二尖瓣 ;另 3只改缝在瓣环上水平 ,并原位完整保留全部二尖瓣。通过术后抗凝处理和细致的管理使成年绵羊长期存活。 结果 :5只成年绵羊手术死亡 1只 ,死亡原因主要是由于瓣膜与二尖瓣环失匹配 ,使主动脉瓣变形 ,从而导致低心排血量。存活的 4只成年绵羊生存时间 2 8～ 2 2 7天 ,平均为 (10 0± 94)天 ,平均抗凝时间 (78± 5 7)天。在此期间成年绵羊未发现血栓栓塞和出血并发症。晚期死亡 2只 :1只于术后 3 0天 ,按计划处死 ,另 1只于术后 2 2 7天时 ,体质差 ,被迫处死 ,2只尸解均未见异常 ,但后 1只处死前血标本显示严重贫血。其它 2只成年绵羊迄今仍然存活 ,存活时间已超过 2 8～ 115天 ,平均 (72± 62 )天。 结论 :成年绵羊是适合作为人工二尖瓣植入慢性存活实验的动物。绵羊体重大于 5

Objective: The purpose of this study was to establish the chronic sheep model using domestic bileaflet prosthetic mitral valves. Methods: From December 2001 to December 2002, five adult sheep[mean body weight(52.6±9.5)kg,range 40-63*!kg ] underwent mitral valve implantation using cardiopulmonary bypass with beating heart. By way of the left atrial appendage incision, the animals were implanted 25*!mm (n=4) and 27*!mm(n=1)domestic bileaflet prosthetic mitral valves (two kinds of new type). Mitral apparatuses were preserved in all 5 animals. The prostheses were sutured to the mitral annulus in 2 with anterior leaflets transposed onto posterior annulus and to the mitral super-annulus with intact anterior leaflets in situ in 3 .The animals surived for a long time by reasonable anticoagulant treatment. Results: There was one operation death. The cause of death was low cardiac output syndrome mainly due to the aortic valve disorder from prosthetic annular size disproportional to mitral annulus. The average survival time of the 4 sheep was (100±94)days,and the average anticoagulation time was (78±57) days. There were no complications of thrombolisim or bleeding during the period. There were 2 late deaths. One was sacrificed at 30 days postoperatively with no anomalous finding at autopsy. The other one was killed 227 days later because of poor condition. There was no anomalous finding at autopsy except severe anemia before killed. The remaining 2 have survived for 28 and 115 [mean(72±62)]days. Conclusion: Sheep is the best candidate for chronic animal model of implanted prosthetic mitral valve. The body weight of sheep over 50 kg and the modified implanting technique may be beneficial for testing the commonly used prosthetic valves. Two new types of domestic bileaflet prosthetic mitral valves preliminarily demonstrate a better biocompatability.