Pediatric Cardiology and Intensive Care, University Medical Center Göttingen, Germany; Department of Congenital Heart Disease and Pediatric Cardiology, German Heart Institute Berlin.
Pediatric Cardiology and Intensive Care, University Medical Center Göttingen, Germany.
Int J Cardiol. 2019 Apr 15;281:113-118. doi: 10.1016/j.ijcard.2019.01.095. Epub 2019 Jan 30.
Bioprosthetic pulmonary valve conduits have been reported with an increased risk of endocarditis. Thrombus formation is considered as source of these serious and life-threatening infections. We reviewed a series of explanted valved pulmonary conduits for histological evidence for thrombus formation.
Explanted bioprosthetic pulmonary valves were fixed in formalin and embedded in paraffin or in methylmethacrylate. Standard staining as well as immunohistochemical staining techniques were applied. Native pulmonary valves of German domestic pigs served as controls.
47 valved pulmonary conduits (Hancock n = 23, Homograft n = 7, Contegra n = 7, Melody n = 7, other n = 3) were analyzed histologically. Average time of implantation had been 63 months (6 to 342 months). Indications for explantation included significant obstruction (n = 45), regurgitation (n = 7), and/or endocarditis (n = 6). In 44/47 (93%) specimen, we found accumulation of thrombotic material at the basis of the semilunar valve sinus to a variable degree. 11 patients had been treated with antiplatelet agents, 2 had received anticoagulants at the time of explantation. There was no suspicion of thrombus formation clinically or echocardiographically prior to explantation in any of the patients. Control porcine pulmonary valves (n = 5) did not show any evidence of accumulation of thrombotic material.
In a large series of explanted valved pulmonary conduits, formation of subclinical, mostly non-infectious thrombotic material was an almost ubiquitous finding. We speculate that high incidence of endocarditis in bioprosthetic valves may in part be explained by thrombus apposition at the basis of conduit valve sinus.
生物瓣肺动脉管道已被报道有较高的心内膜炎风险。血栓形成被认为是这些严重且危及生命的感染的来源。我们回顾了一系列已植入的带瓣肺动脉管道，以寻找血栓形成的组织学证据。
已植入的生物瓣肺动脉瓣膜用福尔马林固定，然后嵌入石蜡或甲基丙烯酸甲酯中。应用标准染色和免疫组织化学染色技术。德国本地猪的天然肺动脉瓣膜作为对照。
对 47 个带瓣肺动脉管道（ Hancock 组 n=23，同种异体移植物组 n=7，Contegra 组 n=7，Melody 组 n=7，其他组 n=3）进行了组织学分析。平均植入时间为 63 个月（6 至 342 个月）。植入物取出的指征包括严重梗阻（n=45）、反流（n=7）和/或心内膜炎（n=6）。在 44/47（93%）标本中，我们发现瓣窦基底有不同程度的血栓物质堆积。11 名患者接受了抗血小板治疗，2 名患者在取出时接受了抗凝治疗。在任何患者中，在取出前，临床或超声心动图均未怀疑血栓形成。对照组猪肺动脉瓣膜（n=5）没有显示出任何血栓物质堆积的证据。
在一系列已植入的带瓣肺动脉管道中，亚临床的、主要是非感染性的血栓物质的形成是一种几乎普遍存在的发现。我们推测，生物瓣心内膜炎的高发生率部分可能是由于管道瓣窦基底血栓附壁。
