Butany Jagdish, Zhou Taylor, Leong Shaun W, Cunningham Kristopher S, Thangaroopan Molly, Jegatheeswaran Anusha, Feindel Christopher, David Tirone E
Department of Pathology, Toronto General Hospital/University Health Network, Toronto, Canada.
Cardiovasc Pathol. 2007 Sep-Oct;16(5):258-67. doi: 10.1016/j.carpath.2007.01.009. Epub 2007 Apr 2.
The Medtronic Freestyle valve is fixed in glutaraldehyde at zero pressure on the cusps and treated with alpha-amino oleic acid. This valve reportedly has excellent clinical and hemodynamic results, but little has been reported about its long-term pathology.
Nine Freestyle valves explanted between 2003 and 2005 were reviewed to assess the reasons for bioprosthesis failure (six implanted at our institution). All valves were examined in detail, using histochemistry and immunohistochemistry to identify the cellular response. One Freestyle valve, explanted for mitral valve endocarditis on the fifth postoperative day, was excluded from analysis. Average implant duration was 52.8+/-35.5 months. Four valves were explanted for infective endocarditis, three for aortic insufficiency, two for aortic stenosis with cusp calcification seen in five valves, pannus and thrombus in all valves and a chronic inflammatory reaction involving the xenograft arterial wall seen in eight of nine valves. This was associated with significant damage to the porcine aortic wall in seven cases, and cusp myocardial shelf damage in six cases.
In this series of valves, we found (1) infective endocarditis; (2) pannus, thrombus, and calcification; and (3) unusual and significant inflammatory reaction and aortic tissue damage, which could by itself lead to aortic incompetence.
美敦力自由式瓣膜在零压力下将瓣叶固定于戊二醛中，并用α-氨基油酸处理。据报道，这种瓣膜具有出色的临床和血流动力学效果，但关于其长期病理学的报道较少。
回顾了2003年至2005年间取出的9个自由式瓣膜，以评估生物假体失败的原因（6个在我们机构植入）。所有瓣膜均进行了详细检查，采用组织化学和免疫组织化学来识别细胞反应。一个因二尖瓣心内膜炎在术后第5天取出的自由式瓣膜被排除在分析之外。平均植入时间为52.8±35.5个月。4个瓣膜因感染性心内膜炎被取出，3个因主动脉瓣关闭不全，2个因主动脉瓣狭窄伴瓣叶钙化，在5个瓣膜中可见血管翳和血栓，在9个瓣膜中的8个可见涉及异种移植动脉壁的慢性炎症反应。这与7例猪主动脉壁的显著损伤以及6例瓣叶心肌附着处损伤有关。
在这一系列瓣膜中，我们发现（1）感染性心内膜炎；（2）血管翳、血栓和钙化；（3）异常且显著的炎症反应和主动脉组织损伤，其本身可能导致主动脉瓣关闭不全。
