生物瓣膜失功能原因分析

目的对植入人体内1年以上损坏的生物瓣膜作损坏原因的临床分析。方法1993年6月至2004年6月,共41例(47只)生物瓣膜失功能病人行再次手术换瓣。两次换瓣间隔时间1~16年,平均(9.7±4.1)年。对失功能生物瓣膜进行标本观察及病理学检测。结果47只带支架生物瓣膜中,瓣架无一损坏,42只瓣膜发生瓣叶撕裂或穿孔,35只有不同程度的钙化现象,且在瓣环表面和瓣脚周围有纤维组织增生,2只瓣膜有赘生物及血栓形成;47只生物瓣膜中损坏较重的瓣膜送病理学检查发现大量吞噬细胞和单核细胞浸润。结论生物瓣膜早期损坏以破损撕裂为主,晚期以钙化和破损撕裂等多种因素的复合病损结果出现。     

The Chemical Protecting Group Concept Applied in Crosslinking of Natural Tissues with Glutaraldehyde Acetals

This work describes the results of the controlled crosslinking of collagen matrices by glutaraldehyde based on a double protection strategy, glutaraldehyde acetals and lysine protonation due to the acidic conditions of acetal formation. Materials crosslinked by this approach were characterized by thermal stability comparable to those obtained by conventional procedures with mechanical properties expected for bioprosthesis manufacture and with a higher stability toward collagenase hydrolysis. The integrity of the microfibrillar structure was confirmed by optical and scanning electronic microscopy. The results indicate that the glutaraldehyde acetals procedure may be of potential use for the crosslinking of bovine pericardium used in the manufacture of bioprosthetic devices. Advantages may be related to the production of materials with homogeneous crosslinking distributions, associated with better definition in the nature of the chemical link that they introduce, due to a better distribution of glutaraldehyde within the tissue matrix before the crosslinking reaction is allowed to occur. As a result, materials with improved biological and mechanical properties are expected.     

Surgical therapy in patients with active infective endocarditis: seven-year single centre experience in a subgroup of 255 patients treated with the Shelhigh stentless bioprosthesis

OBJECTIVE: We investigated outcomes after surgical therapy in patients with active infective endocarditis (AIE) with regard to survival in relation to surgical urgency, valve position, number of valves implanted and abscess formation. We aimed to identify independent risk factors for early mortality. METHODS AND RESULTS: Two hundred and fifty-five patients received Shelhigh bioprostheses between February 2000 and March 2007. A total of 74.1% had native and 25.9% prosthetic AIE. Surgery was regarded as urgent in 57.3% and as an emergency procedure in 38.4%. There was a highly significant difference in survival rate between patients who were operated on urgently versus in an emergency (p<0.0001), between single and double valve replacement (p=0.0206) and between patients with and without abscess formation (p=0.0245). There were two cases of early reinfection (0.78%) and six of late reinfection (2.35%) leading to re-operation. CONCLUSIONS: The survival of patients differs significantly in dependence on their surgical urgency. Better outcome could have been achieved if patients had been referred earlier for surgery and operated upon before heart failure or septic shock developed. Long-term survival was better in patients without abscess formation. The low reinfection rate of Shelhigh bioprostheses in AIE is promising and the early and mid-term results achieved need to be verified in the long-term course.     

Minimally immunogenic decellularized porcine valve provides in situ recellularization as a stentless bioprosthetic valve

Currently used bioprosthetic valves have several limitations such as calcification and functional deterioration, and revitalization through cellular ingrowth is impossible. To overcome these obstacles, we have developed a minimally immunogenic tissue-engineered valve that consists of an unfixed, decellularized porcine valve scaffold capable of being spontaneously revitalized in vivo after implantation. Porcine aortic root tissue was decellularized using detergents such as sodium lauryl sulfate and Triton X-100. The porcine valve was treated very gently and plenty of time was allowed for constituents to diffuse in and out of the matrix. In a preliminary study, a piece of decellularized porcine valve tissue was implanted into the rat subdermal space for 14 and 60 days and the structural integrity and calcification were evaluated. As an in vivo valve replacement model, the decellularized porcine valve was implanted in the pulmonary valve position in dogs and functional and histological evaluation was performed after 1, 2, and 6 months. Histological examination showed that the newly developed detergent treatment effectively removed cellular debris from the porcine aortic tissue. Decellularized porcine valve tissue implanted subdermally in rats showed minimal inflammatory cell infiltration and calcification. In the valve replacement model, spontaneous reendothelialization and repopulation of the medial cells were observed within 2 months, and good valve function without regurgitation was observed by echocardiography up to 6 months. The minimally immunogenic decellularized porcine valve proved effective in mitigating postimplant calcification and provided a suitable matrix for revitalizing prostheses through in situ recellularization, cellular ingrowth, and tissue remodeling.     

自体心包瓣“内皮化”的实验研究

目的 探讨有利于自体心包瓣内皮化的处理方法。方法 将体外培养小牛主动脉内皮细胞接种于不同方法处理的自体牛心包表面。采用＾３Ｈ－ＴｄＲ摄取量测定、扫描电镜及放射免疫法观察不同处理方法对接种后内皮细胞生长、前列环素（ＰＧＩ２）合成量和细胞内ｃＡＭＰ含量的影响。结果 三种不同浓度戊二醛短时间（１０ｍｉｎ）处理的心包表面内皮细胞均可生长,其中以体积分数为０．２％戊二种不同浓度戊二醛短时间（１０ｍｉｎ）处理     

An Experimentally Derived Stress Resultant Shell Model for Heart Valve Dynamic Simulations

In order to achieve a more realistic and accurate computational simulation of native and bioprosthetic heart valve dynamics, a finite shell element model was developed. Experimentally derived and uncoupled in-plane and bending behaviors were implemented into a fully nonlinear stress resultant shell element. Validation studies compared the planar biaxial extension and three-point bending simulations to the experimental data and demonstrated excellent fidelity. Dynamic simulations of a pericardial bioprosthetic heart valve with the developed shell element model showed significant differences in the deformation characteristics compared to the simulation with an assumed isotropic bending model. The new finite shell element model developed in the present study can also incorporate various types of constitutive models and is expected to help us to understand the complex dynamics of native and bioprosthetic heart valve function in physiological and pathological conditions.     

老年风湿性二尖瓣病变行二尖瓣修复术与生物瓣膜置换术中期效果比较

目的比较60岁以上老年患者风湿性二尖瓣修复(MVP)与生物瓣膜置换(MVR)的中期效果。方法选取2014年1月至2016年1月北京安贞医院瓣膜外科诊疗中心行风湿性二尖瓣修复或生物瓣置换手术的60岁以上老年风湿性二尖瓣病变患者,包括同期行三尖瓣修复术及房颤射频消融术患者;排除合并主动脉瓣手术、冠状动脉旁路移植手术、二次手术患者,最终纳入患者82例。根据二尖瓣手术方式分为二尖瓣修复组(MVP组,25例)和生物瓣置换组(MVR组,57例)。采用Kaplan-Meier法进行生存分析并绘制曲线,通过Log Rank方法比较两组患者5年生存率的差异。结果围手术期全组患者平均年龄(66.37±4.41)岁。54.9%的患者心功能(NYHA分级)Ⅲ级。两组患者在体外循环时间(P=0.99),主动脉阻断时间(P=0.88),术后住院时间(P=0.76)差异均无统计学意义。MVR组3例患者住院期间死亡,病死率5.3%;MVP组无住院期死亡(P=0.24)。随访5年,最长随访63个月,平均随访47.03个月。MVR组6例死亡,其中4例死于心脑血管不良事件,2例死于非心脑血管不良事件。MVP组无死亡。两组均无再手术病例。结论风湿性二尖瓣病变的老年患者采用二尖瓣修复手术治疗能够获得较好的中期效果。     

Biocompatibility of Ricinus communis polymer with addition of calcium carbonate compared to titanium. Experimental study in guinea pigs

Objective

The aim of the present investigation was to determine whether the difference in inflammatory tissue reaction between the Riccinus communis (castor) polymer with calcium carbonate and the titanium implant is statistically significant.

Methods

Thirty-two Cavia porcellus were allocated into four groups of eight animals each. We implanted the two types of materials in the retroperitoneal space of all the animals. They were euthanized at 7, 20, 30 and 40 days after surgery, and an histological study of the samples was conducted.

Results

All implants showed characteristics of chronic inflammation regardless of the material and timepoint of evaluation. There was no statistically significant difference between Pm+CaCO₃ and Ti with regard to the presence of granulation tissue, tissue congestion, histiocytes, lymphocytes, neutrophils, giant cells, and fibrosis (P> 0.05).

Conclusion

The castor oil polymer plus calcium carbonate implant was not statistically different from the titanium implant regarding inflammatory tissue reaction.