Prosthetic choice in mitral valve replacement for severe chronic ischemic mitral regurgitation: Long-term follow-up

BackgroundProsthetic choice for mitral valve replacement is generally driven by patient age and patient and surgeon preference, and current guidelines do not discriminate between different etiologies of mitral valve disease. Our objective was to assess and compare short- and long-term outcomes after mitral valve replacement among patients with biological or mechanical prostheses in the setting of severe ischemic mitral regurgitation.MethodsBetween 2000 and 2016, 424 patients underwent mitral valve replacement for severe ischemic mitral regurgitation at our institution, using biological prosthesis in 188 (44%) and mechanical prosthesis in 236 (56%). A 1:1 propensity score match (n = 126 per group) and inverse probability of treatment weighting were used to compare groups. Short-term outcomes included in-hospital mortality and other cardiovascular adverse events. Long-term outcomes included survival and hospital readmission for cardiovascular causes, stroke, and major bleeding.ResultsIn-hospital mortality and early postoperative adverse events were similar between groups in the propensity score match and inverse probability of treatment weighting cohorts. Overall long-term survival was similar at 5 and 9 years, but mechanical prosthesis recipients were more frequently readmitted to hospital for cardiovascular causes, including stroke and non-neurological bleeding in propensity score matching and inverse probability of treatment weighting analyses (all P values < .004). Type of prosthesis did not independently influence all-cause mortality (hazard ratio, 1.01; 95% confidence interval, 0.71-1.43; P = .959), but placement of a mechanical prosthesis was associated with increased risk of readmission for cardiovascular events (hazard ratio, 1.65; 95% confidence interval, 1.17-2.32; P = .004) among matched patients.ConclusionsThe type of prosthesis has no influence on long-term survival among patients with severe ischemic mitral regurgitation undergoing mitral valve replacement. There may be an increased risk of neurologic events and serious bleeding associated with mechanical prostheses.     

个体化假体复合组织工程技术修复兔下颌骨缺损

目的研究快速成型（RP）技术辅助下制作的个体化假体复合珊瑚羟基磷灰石（CHA）、重组人骨形成蛋白2（rhBMP-2）修复兔下颌骨缺损的成骨效果。 方法以27只新西兰大白兔为实验对象，随机数字表法平均分成3组（每组9只），全部建立下颌骨连续性缺损模型，并在兔下颌骨缺损区分别植入个体化假体+自体骨（A组）、个体化假体+CHA（B组）、个体化假体+CHA+rhBMP-2（C组）。分别于术后4、12、24周3个时间点处死动物取材，进行大体标本观察，以及骨钙素（OC）、Ⅰ型胶原（COL-1）的免疫组化观察，分别比较各组修复骨缺损的能力，并对实验数据进行重复测量设计资料的单因素方差分析。 结果术后24周各组实验兔外形均对称，通过OC及COL-1的吸光度检测，骨缺损区均有大量新骨形成，A组（0.537 ± 0.010）、C组（0.530 ± 0.010）可见大量骨小梁及编织骨结构，缺损区的新骨OC、COL-1的免疫组化观察基本一致，差异无统计学意义（t = 0.007，P>0.05）；但A组强于B组（0.415 ± 0.009，t = 0.122，P<0.001）；C组也强于B组（t = 0.121，P<0.001），差异均有统计学意义。 结论在兔下颌骨缺损修复中，通过RP技术和组织工程技术相结合，CHA复合rhBMP-2后成骨能力明显增强，成骨效能肯定，为后期的临床应用提供可靠的实验基础。     

Fatigue resistance of yttria‐stabilized tetragonal zirconia polycrystal clasps for removable partial dentures

With the rapid development of computer‐aided design/computer‐aided manufacturing (CAD /CAM ) systems, the application of zirconia in removable partial dentures is expected to expand. Clasps composed of zirconia should improve esthetics without inducing the risk of metal allergy. The aim of this study was to examine the fatigue resistance of yttria‐stabilized tetragonal zirconia polycrystal (Y‐TZP) clasps for removable partial dentures. Yttria‐stabilized tetragonal zirconia polycrystal and cobalt‐chromium (Co‐Cr) alloy were prepared using CAD /CAM systems. Specimens were either of the semicircular type or of the flat type, with cross‐sectional areas of taper ratios of 0.50, 0.75, and 1.00. All specimens were tested using the cantilever test and the constant displacement fatigue test, and data were analyzed using ANOVA . During the cantilever test, the maximum displacement prior to fracture was greater than the required undercut, and the semicircular‐type specimen exhibited a higher fracture load than the flat type. None of the specimens displayed permanent deformation and showed almost the same degree of deformation after fatigue testing. A lower taper ratio was associated with lower average load values and greater displacement. Within the limitations of this study, it was possible to conclude that Y‐TZP provides the required undercut and adequate retentive force for removable partial denture clasps. Additionally, Y‐TZP and Co‐Cr alloy had almost the same degree of deformation even after the simulated lifespan of removable partial dentures.     

植入物乳房重建一步法和二步法临床对比研究

目的:探讨即刻乳房假体重建（一步法）和应用扩张器的假体重建（二步法）两种不同手术方式在术后并发症、美容效果和成本效益的差异。方法:回顾性分析我院乳腺外科2015年5月至2018年5月收治的285例乳腺癌植入物重建患者，依据手术方式不同分为一步法组（145例）和二步法组（140例），比较两组患者临床资料的差异。结果:一步法组术后出血发生率（6.8%）高于二步法组（1.4%），差异有统计学意义（P=0.021）。一步法组术后伤口皮瓣坏死率（6.2%）高于二步法组（1.4%），差异有统计学意义（P=0.036）。二步法组乳房满意度评分（81.5±7.1）分高于1步法组（78.6±6.2）分，差异有统计学意义（P=0.035）。二步法组住院总花费（80 334.8±6 149.8）元高于一步法组（60 966.5±5 544.9）元，差异有统计学意义（P=0.049）。二步法组住院天数（34.3±3.2）天多于一步法组（17.5±3.9）天，差异有统计学意义（P=0.014）。结论:在植入物乳房重建两种手术方式中，二步法相较于一步法，其并发症少，美容效果好，但在成本效益上并不优于一步法。