Gerosa G, Ross D N, Brucke P E, Dziatkowiak A, Mohammad S, Norman D, Davies J, Sbarbati A, Casarotto D
Department of Cardiovascular Surgery, University of Padova School of Medicine, Italy.
J Thorac Cardiovasc Surg. 1994 Feb;107(2):424-36; discussion 436-7.
The increasing use of the aortic homograft as aortic valve substitute and the limited availability of donor valves prompted us to consider the pulmonary homograft as an alternative substitute for aortic valve replacement. The aim of our study is to compare the ultrastructural and biomechanical properties of pulmonary homograft leaflets with those of their aortic counterpart and to present the early results of using the pulmonary homograft for aortic valve replacement. Light and transmission electron microscopy have shown that pulmonary homograft leaflets are thinner than the aortic with a lesser content of elastic tissue in the ventricularis layer. However there were no substantial differences in the ultrastructure. Uniaxial tensile tests were done on 69 cusps from human pulmonary and aortic valves using an Instron testing machine. The strain at 200 KPa was found to be similar for both pulmonary and aortic leaflets (8.20% +/- 2.87% versus 8.98% +/- 1.90%) cut circumferentially. Radial strips appear to be more extensible in pulmonary leaflets than in aortic (32.6% +/- 7.5% and 28.6% +/- 11.1%, respectively). The ultimate tensile strength for circumferential strips was found to be similar for both aortic and pulmonary valves (1460 +/- 857 kPa versus 1450 +/- 689 kPa), but there was relatively little difference between the radial strips (295 +/- 95 kPa versus 252 +/- 104 kPa). A total of 123 patients whose ages ranged between 13 and 78 years received either fresh antibiotic sterilized or cryopreserved pulmonary homografts for aortic valve replacement. The pulmonary homograft was inserted in place of the patient's diseased aortic valve by using one of two different techniques: freehand in the subcoronary position or as a "short cylinder" inside the aortic root. There was three hospital deaths (2.43%; 70% confidence limits = 1.08% to 4.83%). Cumulative follow-up was 184 patient-years (range 1 to 39 months). All surviving patients have been followed up with serial color flow Doppler echocardiography. There were no late deaths. Actuarial late survival was 97.5% (70% confidence limits = 95.7% to 98.6%) at 3 years. Four patients (2.2%/pt-yr) underwent reoperation because of severe aortic regurgitation (1, 4, 12, and 15 months after the operation) because of technical problems (mismatch in size between the pulmonary homograft and aortic anulus) in three patients and probably because of graft rejection in one patient. At 3 years the actuarial rate of freedom from reoperation was 95.5% (70% confidence limits = 92.7% to 97.3%). Mild aortic regurgitation has been detected in three patients (2.6%). No patients incurred thromboembolic episodes or infective endocarditis.(ABSTRACT TRUNCATED AT 400 WORDS)
主动脉同种异体移植物作为主动脉瓣替代物的使用日益增加，以及供体瓣膜供应有限，促使我们考虑将肺动脉同种异体移植物作为主动脉瓣置换的替代物。我们研究的目的是比较肺动脉同种异体移植物瓣叶与其主动脉对应瓣叶的超微结构和生物力学特性，并展示使用肺动脉同种异体移植物进行主动脉瓣置换的早期结果。光镜和透射电镜显示，肺动脉同种异体移植物瓣叶比主动脉瓣叶薄，心室层弹性组织含量较少。然而，超微结构上没有实质性差异。使用Instron测试机对69个人类肺动脉瓣和主动脉瓣的瓣尖进行了单轴拉伸试验。发现对于沿圆周切割的肺动脉瓣和主动脉瓣叶，在200千帕时的应变相似（分别为8.20%±2.87%和8.98%±1.90%）。径向条带在肺动脉瓣叶中似乎比在主动脉瓣叶中更具延展性（分别为32.6%±7.5%和28.6%±11.1%）。发现主动脉瓣和肺动脉瓣的圆周条带的极限拉伸强度相似（分别为1460±857千帕和1450±689千帕），但径向条带之间的差异相对较小（分别为295±95千帕和252±104千帕）。共有123例年龄在13至78岁之间的患者接受了新鲜抗生素灭菌或冷冻保存的肺动脉同种异体移植物进行主动脉瓣置换。通过两种不同技术之一将肺动脉同种异体移植物植入患者病变主动脉瓣的位置：在冠状动脉下位置徒手操作或作为主动脉根部内的“短圆柱体”。有3例医院死亡（2.43%；70%置信区间=1.08%至4.83%）。累积随访为184患者年（范围1至39个月）。所有存活患者均通过连续彩色血流多普勒超声心动图进行随访。无晚期死亡。3年时的精算晚期生存率为97.5%（70%置信区间=95.7%至98.6%）。4例患者（2.2%/患者年）因严重主动脉瓣反流（术后1、4、12和15个月）接受再次手术，其中3例是由于技术问题（肺动脉同种异体移植物与主动脉瓣环尺寸不匹配），1例可能是由于移植物排斥。3年时再次手术的精算免再手术率为95.5%（70%置信区间=92.7%至97.3%）。3例患者（2.6%）检测到轻度主动脉瓣反流。无患者发生血栓栓塞事件或感染性心内膜炎。（摘要截断于400字）
