Gulbins Helmut, Kreuzer E, Reichart B
Dept. of Cardiac Surgery, Univ. Hospital Grosshadern, LMU Munich, D-81366 Munich, Germany.
Expert Rev Cardiovasc Ther. 2003 Nov;1(4):533-9. doi: 10.1586/14779072.1.4.533.
Since their introduction into clinical practice in 1965 homografts have become established in clinical routine. The storing and sterilization procedures have been improved over time. Long-term results showed that homografts had a superior durability compared to xenogenic biological prostheses. Approximately 40% were still in place 20 years after implantation in aortic position. Their low rate of thromboembolic events made a life-time anticoagulative therapy unnecessary and their hemodynamics were superior to all other heart valve prostheses. There exist two implantation techniques, subcoronary or mini-root, both technically more demanding compared with implantation of stented valve prostheses. When using the subcoronary technique, the valve is suspended into the aortic root leaving the coronary arteries untouched. The success of this technique, however, depends on the relation of the recipients aortic root and the implanted valve. The mini-root technique requires reimplantation of the coronary arteries but left the morphology of the valve and its root unchanged. Especially in patients with endocarditis, the mini-root technique offered the advantage of allowing for excision of all affected tissue with subsequent replacement by the homograft. The Ross-procedure uses the patient's own pulmonary valve as aortic valve substitute with implantation of a homograft in pulmonary position. This proved to be advantageous in children, since in these patients the degeneration of an aortic homograft was faster compared to an older population. This was explained by the recipient's immunologic response to the graft which was more pronounced in younger patients. The advantages of homografts with regards to hemodynamics and thromboembolic risk make them a good alternative to mechanical prostheses in younger, active patients. In very young patients, a Ross-procedure was shown to be superior to aortic homografts due to slower degeneration of the autograft. The decision to use a homograft must be made individually according to the patients demands.
自1965年同种移植物引入临床实践以来，已成为临床常规使用的材料。随着时间的推移，其储存和灭菌程序得到了改进。长期结果表明，与异种生物假体相比，同种移植物具有更高的耐用性。在主动脉位置植入20年后，约40%的同种移植物仍在位。其血栓栓塞事件发生率低，无需终身抗凝治疗，且血流动力学优于所有其他心脏瓣膜假体。存在两种植入技术，即冠状动脉下植入或微根部植入，与带支架瓣膜假体植入相比，这两种技术在技术上要求更高。使用冠状动脉下技术时，瓣膜悬挂在主动脉根部，不触及冠状动脉。然而，该技术的成功取决于受体主动脉根部与植入瓣膜的关系。微根部技术需要重新植入冠状动脉，但瓣膜及其根部的形态保持不变。特别是在患有心内膜炎的患者中，微根部技术的优点是可以切除所有受影响的组织，随后用同种移植物进行置换。罗斯手术使用患者自身的肺动脉瓣作为主动脉瓣替代物，并在肺动脉位置植入同种移植物。这在儿童中被证明是有利的，因为在这些患者中，主动脉同种移植物的退变比老年人群更快。这可以通过受体对移植物的免疫反应来解释，这种反应在年轻患者中更为明显。同种移植物在血流动力学和血栓栓塞风险方面的优势使其成为年轻、活跃患者机械假体的良好替代品。在非常年轻的患者中，由于自体移植物退变较慢，罗斯手术被证明优于主动脉同种移植物。必须根据患者的需求单独决定是否使用同种移植物。
