YPV—I型牦牛心包瓣替换二尖瓣术后远期的临床观察

ＹＰＶ－Ｉ型瓣膜是一种血流动力学优良的牦牛心包瓣，但其耐久性和长期结果尚不知道。从１９８５年５月至１９８７年９月，我科使用该种瓣作二尖瓣替换。对５５例出院患者进行了随访，共随访３７９．４病人－年（平均６．９）。随访期间９例死亡，除１例原因不明外，其余由于替换瓣膜心内膜炎、血栓栓塞、心衰和瓣膜毁损所致。替换瓣膜心内膜炎、血栓栓塞、瓣膜毁损及再手术发生率分别为：１．３２％、０．２６％、４．２２％及１．     

检测人工心瓣的参数和方法

前言全世界每年大约有100,000例心脏瓣膜修复替换手术。当然,用于替换的人工心脏瓣膜的结构和材料同自然的、健康的人体瓣膜相比还有些缺陷。被移植的生物瓣普遍的寿命不超过10年,而机械瓣却比较持久耐用。不过,在心瓣置换术后的早期发生的一些并发症应引起足够的重视。近年来,西德的研究和技术部提出了通过体外检测试验来保证人工心瓣质量的     

心脏瓣膜替换术后抗凝治疗的监护

严重的风湿性心瓣膜疾病均需进行瓣膜替换手术。目前人工瓣膜均采用机械瓣膜。瓣膜替换术后，进行抗凝治疗时，如药量不足易出现血栓；药量过大可引起出血。这是抗凝治疗中最易出现的并发症。因此抗凝治疗期间病人的监护具有非常重要的意义。现将我院1999年8月至2004年2月行瓣膜替换术94例病人抗凝监护情况报告如下。     

机械瓣血栓形成与国际标准化比率的调控

瓣膜血栓形成、血栓栓塞及抗凝有关的出血是机械瓣替换天然心脏瓣膜后最常见和最严重的并发症，也是术后的主要死亡原因。其发生涉及瓣膜本身的血流动力学特性和材料特性、患罹患的疾病状态，以及个体抗凝强度的控制水平等多个方面。因此，对不同个体、不同类型的人造心脏瓣膜，维持不同的抗凝强度，是预防瓣膜相关并发症的最重要措施。     

中国男性成人心瓣环径离体正常值及其相互关系分析

作为建立有活性同种瓣膜库的工作常规,我们测量了同种心脏瓣膜及大动脉的环直径。现报道如下,为涉及心脏瓣膜的研究和应用提供一些背景知识。     

同种带瓣心外管道的临床应用

目的 探讨同种带瓣主动脉和肺动脉心管道治疗复杂先天性心脏病的临床效果。方法 应用深低温保存同种带瓣主动脉或肺动脉心外管道重建右心室流出道治疗复杂先天性心脏病6例，其中，右心室双出口4例，法氏氏四联症1例，完全型大动脉位1例。应用同种带瓣主动脉4例，同种带带瓣动脉2例。结果 手术死亡1例，余5例术后同种管道吻合口通道，无压差、扭曲和受压，同种瓣膜活动良好。随访9个月－2．5年，效果良好。结论 同种带瓣主动脉和肺动脉心外管道具有生物活性和完整的瓣膜功能，是矫正复杂先天性心脏病的理想材料。     

带血管同种异体骨移植研究进展

如何解决肢体大段骨缺损是骨科领域的研究重点和难点，带血管同种异体骨移植是解决该难题颇具潜力的方法。本文着重探讨了带血管同种异体骨移植的抗原、免疫抑制剂的使用，带血管骨深低温冷冻技术及其临床运用，展示骨移植现状，为进一步研究和实践提供一定借鉴。     

血管冷冻保存的研究进展

随着心血管外科技术的发展,同种冷冻保存血管被广泛用于心血管疾病的手术纠治.因此,血管冷冻保存的技术和设备在近年来得到了进一步的研究和发展,本文对血管冷冻保存的基本操作和所需设备.以及一些影响因素的研究作一介绍.     

血管镜直视下股浅静脉多瓣膜壁外修复成形术

利用血管镜直视的先进性能，在成功设计和旅行了单瓣膜修复成形术的基础上，作者又进一步成功地施行了血管镜直视下股浅静脉多瓣膜壁外修复成形术，经２０例２４条下肢６１对瓣膜手术的初步临床应用，证明该手术优于传统的单瓣膜修复成形术，其优点具体体现为“壁外”和“多瓣膜”。“壁外”即指不切开静脉壁即可修复瓣膜，从而避免了瓣膜损伤和继发血栓形成。“多瓣膜”即指一次手术可同时修复两对以上瓣膜，以完善的多瓣膜的整合力     

颈部血管超声在脑梗塞合并颈动脉狭窄病变诊断中的应用

目的探讨颈部血管超声在脑梗塞合并颈动脉狭窄病变诊断中的应用价值。方法将我院自2013年1月至2016年12月间收治的脑梗塞患者220例作为研究组,随机挑选同期入院体检的健康者158例作为对照组,分别使用颈部血管超声检测各组患者颈动脉狭窄情况。结果研究组患者颈部血管狭窄程度明显高于对照组,其血管狭窄发生率为94.09%(185/220),明显高于对照组7.59%(12/158)(P0.05)。结论颈部血管超声诊断脑梗塞合并颈动脉狭窄病变可行性较好,可用于脑梗塞高危人群的早期筛查。     

Different types of aortic stenosis and simulation of their morphological-hydrodynamic interdependence--in vitro study with allografts and stenotic valve models

Biological valves display a dependence of valve resistance and valve area on flow and a phase shift between systolic flow through the valves and pressure difference across the valves. The pressure-flow relations of stenosed valves raise questions about the "best measure of stenosis". There is a need for quantitative evaluation of the hydrodynamic performance of homografts and allografts. In the present paper, we report on in vitro studies of the hydrodynamic behavior of homografts from human donors, allografts from different animal species as well as three valve models. Valve model I was designed to simulate flow-dependence of valve area, valve model II was designed to simulate restricted valve opening independent of flow, and valve model III was designed to simulate a flow-dependent movement of valve root in flow direction. Among other aspects, the effect of increased viscosity of the test fluid on the pressure difference and the effects of water absorption by valve tissue on valve characteristics were investigated. The results of the present studies clearly indicate that any biological valve may be modelled as a serial connection of a model I type valve and a model II type valve. From the results, the dependence of the characteristic pressure-flow relationship of a valve on valve size and valve distensibility can be clearly seen and the clinical significance of the characteristic coefficients of the pressure-flow relationship of a valve can be elucidated. Further, it was shown that the characteristic phase shift between flow and pressure difference displayed by biological valves is due to their movable valve plane similar to that of valve model III.     

A Bioreactor with Compliance Monitoring for Heart Valve Grafts

The drawbacks of state-of-the-art heart valve prostheses lead researchers to explore the prospect of using tissue-engineered constructs as possible valve substitutes. It is widely accepted that the mechanical properties of the construct are improved with mechanical stimulation during in vitro growth. We designed a new dynamic bioreactor with the perspective of using decellularized valve homografts as scaffolds in order to produce tissue-engineered valve substitutes. The design guidelines were (a) compatibility with the procedures for the treatment of homografts; (b) delivery of finely controlled pulsatile pressure loads, which induce strain stimuli that may drive cells toward repopulation of and integration with the natural scaffold; and (c) monitoring the construct’s biomechanical status through a comprehensive index, i.e., its compliance. The handling needs during the set-up of the homograft and the use of the bioreactor were minimized. The bioreactor and its automated control system underwent tests with a compliant phantom valve. The estimated compliances are in good agreement with the measured ones. Tests were also carried out with porcine aortic samples in order to assess the hydrodynamic and biomechanical reliability. In the future, monitoring the construct’s compliance might represent a key factor in controlling the recellularization of the valve homografts, which provides awareness of the construct’s biomechanical status by real-time, non-destructive, and non-invasive means.     

Blood flow and permeability changes in the immune lymphocyte transfer reaction.

Blood flow (133Xe clearance) and plasma exudation ([133I]HSA) have been measured in the immune lymphocyte transfer (ILT) reaction and skin grafts in rabbits. Injection of sensitised lymphocytes produced a dose-related increase in plasma exudation and blood flow at 48 hr, reached a maximum at day 3 and faded from day 5 to 8. There was an increased blood flow and plasma exudation on day 4 after grafting autografts and homografts, but the increase in plasma exudation was significantly higher in homografts. In the ILT reaction (48 hr) and the homografts (4 days) but not in autografts, prostaglandin synthetase inhibition caused a significant reduction in the increased blood flow, but did not abolish it nor did they affect the increased plasma exudation. It is concluded that the ILT reaction is a suitable model for the study of mediators of the vascular effects of the early phase of the skin graft reaction. The present experiments suggest that the vasodilatation is partly due to prostaglandin formation, but part of the vasodilatation and all the plasma exudation are mediated by substances other than prostaglandins.     

Aortic stenosis in the elderly: challenges in diagnosis and therapy

Severe aortic valve stenosis, remains the main cause of morbidity and mortality in the elderly, reaching a prevalence of 2–7% above the age of 65 years old.Despite its frequency and the development in invasive and noninvasive approach of the disease, several of its aspects remain controversial. This review is focused on the clinical aspects, the indices for assessment severity, newly markers related to prognosis and new therapeutic modalities for the elderly population. The term low flow, low gradient severe aortic stenosis with preserved LV systolic function has revealed a new modality in the field of diagnostic evaluation and therapeutic approach. Aortic valve replacement is the choice therapy for symptomatic severe aortic stenosis. Despite the recent advances in cardiac surgery, the overall operative mortality rate for isolated aortic valve replacement surgery ranges from 2.5% to 4.0% and is higher in octogenarians and can be up to 25% in patients with comorbid conditions. The fact that surgery is not being performed for 30% or more of patients requiring it, a great attention was attracted to the percutaneous transcatheter implantation of a stent-mounted aortic valve. The up to now experience of transcatheter valve implantation in more than 25,000 patients, has shown promising results in terms of mortality and quality of life. Echocardiography still plays the central role for the evaluation of the elderly patient, as it can illustrate the pathophysiological alterations during the course of aortic valve stenosis, and guide appropriate therapy.     

Aortic Stenosis in African Americans: Focus On Disparities in Treatment and Outcomes

Aortic stenosis (AS) is the third most common type of cardiovascular disease after hypertension and coronary artery disease, and it carries a high mortality rate when left untreated. Risk factors include male sex, hypertension, tobacco use, advanced age, elevated LDL cholesterol, and coronary atherosclerosis. Definitive treatment for AS includes valve repair, either percutaneously or surgically; however, in aging populations corrective surgery carries increased risk. While research suggests that patients of some non-White ethnic groups, including African-Americans, are less likely than their Caucasian counterparts to have AS, these minority patients may experience may experience differences in the way they receive and accept care. This paper seeks to explicate the mechanisms of racial disparities among the African-Americans affected by aortic stenosis as they pertain to healthcare utilization, referral for valve replacement, acceptance of therapy, and overall treatment outcomes.     

Lymph flow and changes in intracellular enzymes during healing and rejection of rabbit skin grafts

1. Autografts and homografts of full thickness skin were made on a hind limb of rabbits. During the following days the appearance and histological changes of the grafts were studied; the lymph flow from the limb, and the enzyme activities in the supernatant and cell pellet of the lymph after centrifugation were determined, as well as the enzyme activities in the graft roof and the underlying host tissue. It was further examined whether a lymphatic and vascular connexion occurred between graft and host tissue.2. During the first 5 days the grafts changed from pale blue to bright pink, became swollen, soft and had a mild cellular inflammatory exudate. Autografts then became pale, took on the appearance of normal skin with the inflammatory changes subsiding, whereas homografts became firm, showed heavy mononuclear cell infiltration, had a blotchy purple appearance due to thrombosis and haemorrhage, developed widespread necrosis and changed into a black hard scab which was eventually shed. With high dose homografts (6-8 grafts) these changes occurred 1-2 days earlier than with low dose (2-4) grafts.3. The flow of lymph increased during the first 5 days after grafting, then returned to normal with autografts but remained increased with homografts.4. In the supernatant of the lymph the activities of LDH and beta-glucuronidase did not change during the first 5 days but activities of cathepsin, acid phosphatase, GOT and GPT increased. With the autografts the increase in the activities of these four enzymes then subsided, but with the homografts they increased further and there was an increase in the activities of LDH and beta-glucuronidase, even greater than in those of the other four enzymes.5. In the cell pellets of the lymph the activities of the six enzymes did not increase during the first 5 days; with homografts, but not with autografts, they then increased. These increases occurred even though the cell count in the pellet remained unchanged. Thus some of the lymphocytes must have become ;activated' to contain higher enzyme activities.6. The enzyme activities in the roof tissue did not parallel those in lymph. They did not change during the first three days. During the following three days the activities of acid phosphatase, LDH, beta-glucuronidase and cathepsin increased, but not those of GOT and GPT which remained low. From then onwards the behaviour was different with auto- and homografts. With autografts only the activity of acid phosphatase continued to increase, those of LDH, beta-glucuronidase and cathepsin decreased and those of GOT and GPT remained low. With homografts the activities of LDH, beta-glucuronidase and cathepsin continued to increase and became even greater than in the supernatant of lymph, whereas the activities of acid phosphatase, GOT and GPT, remained low.7. In the bed tissue the activities of all six enzymes increased during the first 3 days after grafting, then the activities of GOT and GPT returned towards normal but those of the other four increased further. The only difference between auto- and homografts was that the increase in beta-glucuronidase and LDH activity was much greater with homografts.8. Lymph drainage became established with autografts on day 5 or 6 and then persisted. With homografts the dosage of grafts influenced the result. With low dosage (2-4 grafts) lymph drainage became established in a small percentage of the experiments, also on day 5 or 6, but it persisted for 2-3 days only. With high dosage, no lymph drainage became established. However, when the onset of rejection was delayed by treatment with cyclophosphamide lymph drainage became established also with high dosage homografts.9. Vascularization of the grafts was established on day 3 or 4, and persisted in autografts. In homografts a vascular shut down occurred at about the time of onset of rejection. It therefore occurred later with low than with high dosage and with high dosage on treatment with cyclophosphamide.10. It is concluded that the absence of lymph drainage from homografts is the cause of the small magnitude of increases in enzyme activities of lymph collected during and after their rejection. The increase results from ;activated' small lymphocytes which infiltrate the graft bed and junctional tissue and subsequently undergo necrosis, and that the establishment of a lymphatic connexion between the graft and host tissue is not a prerequisite for rejection.     

Diagnosing Aortic Valve Stenosis by Parameter Extraction of Heart Sound Signals

The objective of this study was to develop an automatic signal analysis system for heart sound diagnosis. This should support the general practitioner in discovering aortic valve stenoses at an early stage to avoid or decrease the number of surgical interventions. The applied analysis method is based on classification of heart sound signals utilising parameter extraction. From the wavelet decomposition of a representative heart cycle as well as from the Short Time Fourier Transform (STFT) and the Wavelet Transform (WT) spectra new time series were derived. In several segments, parameters were extracted and analysed. In addition, features of the Fast Fourier Transform (FFT) of the raw signal were examined. In this study, 206 patients were enrolled, 159 with no heart valve disease or any other heart valve disease but aortic valve stenosis and 47 suffering from aortic valve stenosis in a mild, moderate or severe stage. To separate the groups, a linear discriminant function analysis was applied leading to a reduced parameter set. The introduced two classification stage (CS) system for automatic detection of aortic valve stenoses achieves a high sensitivity of 100% for moderate and severe aortic valve stenosis and a sensitivity of 75% for mild aortic valve stenosis. A specificity of 93.7% for patients without aortic valve stenosis is provided. The developed method is robust, cost effective and easy to use, and could, therefore, be a suitable method to diagnose aortic valve stenosis by general practitioners.     

Frequent detection of viral nucleic acids in heart valve tissue

Due to a paucity of published data concerning the prevalence of viral nucleic acid in homografts, we analyzed tissue from 30 donor hearts for the presence of viral genome sequences of enteroviruses, adenoviruses, human cytomegalovirus, and influenza virus using different PCR techniques. Viral DNA was amplified in 64 and 52% of the subvalvular myocardial tissue and non-coronary valve samples, respectively. These findings, compared with clinical history and histologic and serologic analysis, demonstrate the importance of viral safety measures in heart valve banking.     

Dissecting cuspal hematomas. A rare form of porcine bioprosthetic valve dysfunction

Large dissecting cuspal hematomas (DCHs) were present in six (3%) of 193 porcine bioprostheses (PBs) explanted at reoperation. In four mitral PBs, the DCHs contributed to valve dysfunction; in one aortic PB, DCH was the only determinant of failure, causing stenosis by cusp thickening and rigidity. In another mitral PB, DCHs were occasionally found in the setting of valve incompetence due to commissural tears. While confirming that DCHs are a potential but infrequent cause of PB failure, these observations demonstrate that they may involve PBs implanted both in mitral and aortic position and might be a complication of anticoagulation.     

Decellularized homologous tissue-engineered heart valves as off-the-shelf alternatives to xeno- and homografts

Decellularized xenogenic or allogenic heart valves have been used as starter matrix for tissue-engineering of valve replacements with (pre-)clinical promising results. However, xenografts are associated with the risk of immunogenic reactions or disease transmission and availability of homografts is limited. Alternatively, biodegradable synthetic materials have been used to successfully create tissue-engineered heart valves (TEHV). However, such TEHV are associated with substantial technological and logistical complexity and have not yet entered clinical use. Here, decellularized TEHV, based on biodegradable synthetic materials and homologous cells, are introduced as an alternative starter matrix for guided tissue regeneration. Decellularization of TEHV did not alter the collagen structure or tissue strength and favored valve performance when compared to their cell-populated counterparts. Storage of the decellularized TEHV up to 18 months did not alter valve tissue properties. Reseeding the decellularized valves with mesenchymal stem cells was demonstrated feasible with minimal damage to the reseeded valve when trans-apical valve delivery was simulated. In conclusion, decellularization of in-vitro grown TEHV provides largely available off-the-shelf homologous scaffolds suitable for reseeding with autologous cells and trans-apical valve delivery.