Department of Cardiac Surgery, University Hospital of Ghent, Ghent, Belgium.
Department of Biostatistics, University of Ghent, Ghent, Belgium.
Eur J Cardiothorac Surg. 2017 Aug 1;52(2):272-278. doi: 10.1093/ejcts/ezx117.
Concerns have been raised about the durability of the first-generation Mitroflow aortic bioprosthesis (model 12 A-LX) due to the lack of anticalcification treatment. This study reflects a 10-year experience with this prosthesis for aortic valve replacement.
From June 2003 to May 2012, the Mitroflow prosthesis was used for aortic valve replacement in 510 patients, of whom only 467 with complete clinical follow-up were included for analysis. Study end-points were survival and incidence of structural valve degeneration (SVD). Analysis of SVD was based on cumulative incidence function and competing-risk Cox regression.
The mean patient age was 76.4 ± 6.1 years. Valve sizes from 23 to 25 were used in 70.4%, whereas sizes from 19 to 21 were used in only 19.2%, thereby avoiding patient-prosthesis mismatch in 89.1%. Within a median follow-up time of 6.6 years (interquartile range 4.4), a cumulative 2375 patient-years, the survival rate was 86.2%, 67.3% and 33.3% at 1, 5 and 10 years, respectively. The cumulative incidence of SVD, with death as a competing risk, was 0%, 0.7% and 6.2% at 1, 5 and 10 years, respectively. Only age <75 years tended to affect the late hazard of SVD (hazard ratio 0.50, 95% confidence interval 0.23-1.08, P = 0.08), regardless of valve-specific issues.
The data do not support the concerns about early accelerated structural degeneration of the first-generation Mitroflow bioprosthesis used for aortic valve replacement in patients older than 75 years. We postulate that limiting the number of small prostheses using a proper implantation technique has enhanced the reduction in risk of significant patient-prosthesis mismatch as the main determinant of early SVD.
由于缺乏抗钙化处理，第一代 Mitroflow 主动脉生物瓣（型号 12 A-LX）的耐用性受到质疑。本研究反映了该生物瓣用于主动脉瓣置换的 10 年经验。
2003 年 6 月至 2012 年 5 月，510 例患者接受了 Mitroflow 假体进行主动脉瓣置换，其中仅 467 例有完整临床随访的患者纳入分析。研究终点为生存率和结构性瓣膜退化（SVD）的发生率。SVD 的分析基于累积发生率函数和竞争风险 Cox 回归。
患者平均年龄为 76.4±6.1 岁。23 至 25 号瓣膜大小的使用率为 70.4%，而 19 至 21 号瓣膜大小的使用率仅为 19.2%，从而避免了 89.1%的患者-假体不匹配。中位随访时间为 6.6 年（四分位间距 4.4），2375 患者-年的累积随访时间内，1、5 和 10 年的生存率分别为 86.2%、67.3%和 33.3%。以死亡为竞争风险，SVD 的累积发生率分别为 0%、0.7%和 6.2%，1、5 和 10 年。只有年龄<75 岁的患者倾向于影响 SVD 的晚期风险（风险比 0.50，95%置信区间 0.23-1.08，P=0.08），与瓣膜特异性问题无关。
数据不支持对 75 岁以上患者使用第一代 Mitroflow 生物瓣行主动脉瓣置换术早期加速结构性瓣退化的担忧。我们推测，限制使用适当植入技术的小瓣膜数量，降低了严重患者-假体不匹配的风险，这是早期 SVD 的主要决定因素。
