Vogt P R, Stallmach T, Niederhäuser U, Schneider J, Zünd G, Lachat M, Künzli A, Turina M I
Clinic for Cardiovascular Surgery, University Hospital Zurich, Switzerland.
Eur J Cardiothorac Surg. 1999 May;15(5):639-44; discussion 644-5. doi: 10.1016/s1010-7940(99)00053-6.
Life expectancy of cryopreserved allografts implanted in infants is different from those implanted in adults. A morphological study of explanted allograft heart valves was performed to determine the mechanism of deterioration and to compare cryopreserved arterial and heart valve allografts from adult patients with those explanted from infants.
Between 1987 and 1996, 209 cryopreserved allografts were implanted: 125 valved conduits or monocusps to reconstruct the right ventricular outflow tract in congenital heart disease, 50 allograft heart valves to treat native aortic and prosthetic aortic valve endocarditis and 34 cryopreserved arterial allografts to replace mycotic aortic aneurysms or infected aortic prosthetic grafts. Two months to 8 years after implantation, 23 heart valve allografts, 11 right-sided and 12 left-sided, and four arterial allografts had to be explanted for reasons such as degeneration, recurrent infection, aneurysm formation or rupture. Besides conventional staining, immunohistochemical detection of cell populations was performed as follows: CD45RO, CD3 and CD43 for T lymphocytes, CD20 for B lymphocytes, CD68 for macrophages, protein S100 for Langerhans-cells, vimentin for fibroblasts, alpha-actin for smooth muscle cells and factor VIII for endothelial cells.
Explanted cryopreserved allografts were all fibrotic, acellular, non-vital and without endothelial cells. The fibrous tissue was preserved. T lymphocytes, indicating rejection, were found in all right-sided allografts from the paediatric population, but only in 9% of left-sided valves explanted from adults and in one of the four of arterial allografts. Macrophages and Langerhans-cells were found only in right-sided allografts from paediatric patients.
Right-sided cryopreserved allografts from a paediatric population showed ongoing cellular rejection. By contrast, there was only a weak T-cell mediated rejection to adult heart valve and arterial allografts. Therefore, similar long-term results can be expected in adult arterial and heart valve allografts, whereas longevity of right-sided heart valve allograft in the paediatric age group seems endangered by cellular rejection.
植入婴儿体内的冷冻同种异体移植物的预期寿命与植入成人体内的不同。对取出的同种异体移植心脏瓣膜进行形态学研究,以确定其退化机制,并比较成年患者的冷冻动脉和心脏瓣膜同种异体移植物与从婴儿体内取出的同种异体移植物。
1987年至1996年间,植入了209个冷冻同种异体移植物:125个带瓣管道或单尖瓣用于重建先天性心脏病的右心室流出道,50个同种异体心脏瓣膜用于治疗原发性主动脉瓣和人工主动脉瓣心内膜炎,34个冷冻动脉同种异体移植物用于替换霉菌性主动脉瘤或感染的主动脉人工移植物。植入后2个月至8年,23个心脏瓣膜同种异体移植物(11个右侧和12个左侧)以及4个动脉同种异体移植物因退化、反复感染、动脉瘤形成或破裂等原因不得不被取出。除常规染色外,细胞群体的免疫组织化学检测如下进行:用CD45RO、CD3和CD43检测T淋巴细胞,用CD20检测B淋巴细胞,用CD68检测巨噬细胞,用蛋白S100检测朗格汉斯细胞,用波形蛋白检测成纤维细胞,用α-肌动蛋白检测平滑肌细胞,用因子VIII检测内皮细胞。
取出的冷冻同种异体移植物均为纤维化、无细胞、无活力且无内皮细胞。纤维组织得以保留。在儿科人群的所有右侧同种异体移植物中均发现了表明排斥反应的T淋巴细胞,但在从成人取出的左侧瓣膜中仅9%发现,在4个动脉同种异体移植物中的1个中发现。仅在儿科患者的右侧同种异体移植物中发现了巨噬细胞和朗格汉斯细胞。
儿科人群的右侧冷冻同种异体移植物显示出持续的细胞排斥反应。相比之下,成人心脏瓣膜和动脉同种异体移植物仅有较弱的T细胞介导的排斥反应。因此,成人动脉和心脏瓣膜同种异体移植物有望获得相似的长期结果,而儿科年龄组右侧心脏瓣膜同种异体移植物的寿命似乎因细胞排斥反应而受到威胁。