Bortolotti U, Milano A, Mazzucco A, Callucci V, Valente M, Del Maschio A, Valfrè C, Thiene G
G Ital Cardiol. 1980;10(11):1520-5.
Conservative management is the treatment of choice for either congenital or acquired valvular disease in children. However, prosthetic valve replacement may sometimes be required and in this situation the surgeon is faced with the problem of which valvular substitute is the best for this particular patient. The glutaraldehyde-preserved Hancock porcine xenograft has been considered the safest one to use in the pediatric age group since the risks of thromboembolism as well as the mortality and morbidity related to anticoagulant treatment are reduced with this device. However durability of porcine bioprostheses at this time is still unknown, and it remains one of its major concerns. Recent reports have highlighted that porcine heterografts implanted in children undergo early and severe fibrocalcific degeneration. After having reviewed our pathological collection of explanted Hancock valves we have summarized our experience with pathology of porcine bioprostheses in young patients in the present report. Five Hancock heterografts were available for gross and histologic examination. They came from 3 children, 2 females and 1 male, who died or were reoperated upon because of prosthetic dysfunction. Both girls, aged 8 and 10 years, had undergone total correction of complete a-v canal which required mitral valve replacement in the first and mitrotricuspid valve replacement in the second. The first one was reoperated 2.10 years after surgery because of severe prosthetic stenosis and died in the 1st postoperative day of low output syndrome. The second, who developed the signs of mitral stenosis 3.4 years later, was successfully reoperated, but died in severe heart failure 2.9 years following mitral prosthetic re-replacement. The third patient, a 11-year-old boy, underwent mitral valve replacement because of mitral incompetence due to bacterial endocarditis; 5.4 years after surgery he necessitated reoperation because of mitral prosthetic stenosis. He is currently asymptomatic. Pathologic examination of the 5 explants (4 mitral, 1 tricuspid) which had been in place from 34 to 72 months (average 49 mos), showed a severe stenosis with impairment of the effective prosthetic orifice in all. The stenosis was due to coarse calcific deposits of the cusps and commissures and was worsened in 3 cases by fibrous tissue overgrowth on the inflow aspect of the leaflets. In 2 cases an atrial thrombosis was observed, as a consequence of prosthetic stenosis. Histologic examination together with microradiographic investigation showed in all cases the presence of diffuse calcifications of commissures and leaflets. Our pathological experience confirms that the Hancock bioprostheses, when implanted in children, undergoes structural changes early and severe enough so as to discourage their employment in this group of patients.
保守治疗是儿童先天性或后天性瓣膜疾病的首选治疗方法。然而，有时可能需要进行人工瓣膜置换，在这种情况下，外科医生面临着为该特定患者选择最佳瓣膜替代品的问题。自使用戊二醛保存的汉考克猪异种移植物以来，血栓栓塞风险以及与抗凝治疗相关的死亡率和发病率均降低，因此被认为是儿科年龄组中最安全的一种。然而，目前猪生物瓣膜的耐用性仍然未知，这仍然是其主要问题之一。最近的报告强调，植入儿童体内的猪异种移植物会发生早期严重的纤维钙化变性。在回顾了我们的植入汉考克瓣膜的病理标本后，我们在本报告中总结了我们在年轻患者中猪生物瓣膜病理学方面的经验。有5个汉考克异种移植物可供大体和组织学检查。它们来自3名儿童，2名女性和1名男性，这些儿童因人工瓣膜功能障碍死亡或接受了再次手术。两名女孩，年龄分别为8岁和10岁，均接受了完全性房室通道的根治术，第一名女孩首次手术需要置换二尖瓣，第二次手术需要置换二尖瓣和三尖瓣。第一名女孩在术后2.10年因严重的人工瓣膜狭窄接受再次手术，并在术后第1天死于低心排血量综合征。第二名女孩在3.4年后出现二尖瓣狭窄症状，成功接受了再次手术，但在二尖瓣再次置换术后2.9年死于严重心力衰竭。第三名患者是一名11岁男孩，因细菌性心内膜炎导致二尖瓣关闭不全而接受二尖瓣置换术；术后5.4年，他因人工二尖瓣狭窄需要再次手术。他目前无症状。对5个植入时间为34至72个月（平均49个月）的外植体（4个二尖瓣，1个三尖瓣）进行病理检查，结果显示所有外植体均存在严重狭窄，有效人工瓣口受损。狭窄是由于瓣叶和瓣环的粗大钙化沉积所致，3例因瓣叶流入面纤维组织过度生长而加重。2例观察到心房血栓形成，这是人工瓣膜狭窄的结果。组织学检查和微放射学研究均显示，所有病例均存在瓣环和瓣叶的弥漫性钙化。我们的病理经验证实，汉考克生物瓣膜植入儿童体内后，会发生早期且严重的结构变化，因此不建议在该组患者中使用。
