Comparison of Biological and Mechanical Prostheses for Heart Valve Surgery: A Systematic Review of Randomized Controlled Trials

Abstract Background: The choice of a mechanical (MP) or biological prosthesis (BP) for patients with valvular heart disease undergoing replacement is still not a consensus. Objective: We aimed to determine the clinical outcomes of MP or BP placement in those patients. Methods: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) that compared biological prostheses and mechanical prostheses in patients with valvular heart diseases and assessed the outcomes. RCTs were searched in the MEDLINE, EMBASE, LILACS, CENTRAL, SCOPUS and Web of Science (from inception to November 2014) databases. Meta-analyses were performed using inverse variance with random effects models. The GRADE system was used to rate the quality of the evidence. A P-value lower than 0.05 was considered significant. Results: A total of four RCTs were included in the meta-analyses (1,528 patients) with follow up ranging from 2 to 20 years. Three used old generation mechanical and biological prostheses, and one used contemporary prostheses. No significant difference in mortality was found between BP and MP patients (risk ratio (RR = 1.07; 95% CI 0.99-1.15). The risk of bleeding was significantly lower in BP patients than MP patients (RR = 0.64; 95% CI 0.52-0.78); however, reoperations were significantly more frequent in BP patients (RR = 3.60; 95% CI 2.44-5.32). There were no statistically significant differences between BP and MP patients with respect to systemic arterial embolisms and infective endocarditis (RR = 0.93; 95% CI 0.66-1.31, RR = 1.21; CI95% 0.78-1.88, respectively). Results in the trials with modern and old prostheses were similar. Conclusions: The mortality rate and the risk of thromboembolic events and endocarditis were similar between BP and MP patients. The risk of bleeding was approximately one third lower for BP patients than for MP patients, while the risk of reoperations was more than three times higher for BP patients.

摘要 背景：针对接受瓣膜置换术的心脏瓣膜病患者，选择机械瓣膜假体（mechanical prosthesis, MP）还是生物瓣膜假体（biological prosthesis, BP）目前仍未达成共识。目的：本研究旨在明确此类患者植入机械瓣膜假体或生物瓣膜假体后的临床结局。方法：本研究对比较心脏瓣膜病患者使用生物瓣膜假体与机械瓣膜假体的随机对照试验（randomized controlled trial, RCT）开展系统综述与荟萃分析，并对结局指标进行评估。检索了MEDLINE、EMBASE、LILACS、CENTRAL、SCOPUS及Web of Science数据库（建库至2014年11月），采用逆方差法结合随机效应模型开展荟萃分析，使用GRADE系统对证据质量进行评级，以P值<0.05作为具有统计学显著性的判定标准。结果：本荟萃分析共纳入4项随机对照试验，涉及1528例患者，随访时长为2至20年。其中3项试验使用第一代机械瓣膜与生物瓣膜假体，1项试验使用当代瓣膜假体。生物瓣膜假体组与机械瓣膜假体组患者的死亡率无显著差异（风险比（risk ratio, RR）=1.07；95%置信区间（confidence interval, CI）0.99~1.15）。生物瓣膜假体组患者的出血风险显著低于机械瓣膜假体组（RR=0.64；95%CI 0.52~0.78）；但生物瓣膜假体组患者的再手术率显著更高（RR=3.60；95%CI 2.44~5.32）。两组患者在系统性动脉栓塞与感染性心内膜炎方面无统计学显著差异（分别为RR=0.93；95%CI 0.66~1.31，RR=1.21；95%CI 0.78~1.88）。使用现代瓣膜假体与使用老式瓣膜假体的试验结果相似。结论：生物瓣膜假体组与机械瓣膜假体组患者的死亡率、血栓栓塞事件风险及心内膜炎风险均无显著差异。生物瓣膜假体组患者的出血风险较机械瓣膜假体组降低约三分之一，而再手术风险则较机械瓣膜假体组高出三倍以上。