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engineering in the construction of numerical simulation oriented patient-specific model of stented aorticarch aneurysm

Xianlong MENG, Wenyu FU, Yun ZHANG, Aike QIAO,

《机械工程前沿（英文）》 2010年 第5卷 第3期   页码 328-335 doi: 10.1007/s11465-010-0026-9

摘要： Patient-specific models are widely used in hemodynamic simulations. The flow in the boundary layer changes so strongly that fine meshes in the boundary layer are required in numerical simulations, especially for the calculation of wall shear stress and its gradient. To precisely analyze hemodynamics, it is necessary to investigate the approaches to the reconstruction of a numerical simulation-oriented patient-specific model for aortic arch aneurysm that can perform particular meshing in the boundary layer. Based on a surface model of aortic arch aneurysm in STL format, reverse engineering concept was applied to reconstruct a solid model using CAD software Geomagic and Pro/E, and a simplified model of stent for the intervention of aortic arch aneurysm was also created. After these models were imported to ANSYS, a block modeling approach was employed to divide the whole model into several domain blocks to adopt different meshing strategies. Particular meshing was performed especially in the boundary layer and around the stents. The finite element model particularly suitable for numerical simulation of hemodynamics was obtained. Hemodynamic simulation was performed, using the constructed finite element model to verify its applicability. The results indicate that reverse engineering concept and the proposed block modeling approach can be used to divide the solid model of aortic arch aneurysm into multiple volumes, which can be meshed according to particular requirements in each volume; the finite element model of stented aortic arch aneurysm can be employed to simulate hemodynamics. The approaches of modeling were applicable not only for aortic arch aneurysm, but also for similar model reconstruction as a reference in hemodynamic simulation investigations.

关键词： reverse engineering     aortic arch aneurysm     surface model     meshing     finite element model    

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Aortic aneurysm and chronic disseminated intravascular coagulation: a retrospective study of 235 patients

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《医学前沿（英文）》 2017年 第11卷 第1期   页码 62-67 doi: 10.1007/s11684-017-0498-7

摘要：

Chronic disseminated intravascular coagulation (DIC) is a rare but devastating complication of aortic aneurysm (AA). This study investigated the clinical manifestations, laboratory findings, and treatment of patients with AA-associated chronic DIC (AA-DIC) and explored the mechanisms, duration, and therapeutic response of AA-DIC. We retrospectively reviewed the medical records of 235 AA patients admitted at the Peking Union Medical College Hospital between September 2009 and January 2015. The patients were classified as those with DIC (AA-DIC) and those without DIC (non-DIC). The AA-DIC group showed a significantly higher proportion of female patients and a significantly longer AA disease course than the non-DIC group did. The AA-DIC patients presented mural thrombi, dissecting aneurysms, a family history of AA, and diabetes significantly more frequently than the non-DIC patients did. Furthermore, multiple regression analyses revealed that sex, mural thrombus, aneurysm type, diabetes, and stent surgery are possible independent risk factors for AA-DIC patients. Fifty-two (22.1%) patients presented AA-DIC. Among these patients, 43 had non-typical DIC and 9 had typical DIC; the mortality rate of the latter was 22.2%. The mean age of the patients with typical DIC was significantly higher than of that of patients with non-typical DIC. The non-typical DIC patients also presented abnormal coagulation disorders of varying degrees. Furthermore, heparin or low-molecular-weight heparin improved the clinical symptoms and laboratory parameters in patients with AA and typical DIC. Thus, chronic DIC should be considered in patients with AA.

关键词： aortic aneurysm     disseminated intravascular coagulation     anticoagulation therapy    

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Evaluation of the harmonic scalpel in open surgery for abdominal aortic aneurysm

null

《医学前沿（英文）》 2012年 第6卷 第1期   页码 85-88 doi: 10.1007/s11684-012-0174-x

摘要：

The harmonic scalpel is a hemostatic device primarily designed for use in laparoscopic surgery. During the last few years, many surgeons have begun to use the harmonic scalpel in open surgery. Several papers have cited the benefits of the device compared with conventional knot-tying techniques; however, no evidence showing the advantages of using the harmonic scalpel in complicated abdominal aortic aneurysm (AAA) surgery has been presented. The aim of the present study is to determine the value of the harmonic scalpel in open operation for AAA. A total of 153 patients who underwent open surgery for AAA at the Department of Vascular Surgery of Guangdong General Hospital, China between January 2001 and December 2010, were retrospectively analyzed. Open surgery performed with the harmonic scalpel on 105 patients was compared with open operation using conventional knot-tying techniques on 48 patients. The operative time, intraoperative blood loss, total postoperative drainage fluid volumes, hospital stay, and postoperative complications between the two groups were compared. The harmonic scalpel group was associated with a shorter operation time (113.2±23.6 min vs. 232.1±39.2 min, P<0.01) and lower intraoperative blood loss (126.1±96.6 ml vs. 592.1±207.2 ml, P<0.01). Postoperative drainage fluid volumes were greater in the conventional surgery group than in the harmonic scalpel group (702.1±192.8 ml vs. 198.5±97.4 ml, P<0.01). The hospital stay was shorter for the harmonic scalpel group than for the conventional surgery group (10.7±3.3 d vs. 16.5±4.7 d, P<0.05). No differences between the postoperative complications or hospital mortality of the two groups were found. The harmonic scalpel is a safe and minimally invasive tool in open surgery for AAA and is associated with shorter operative time, shorter hospital stay, and lower intraoperative blood loss and postoperative drainage fluid volumes compared with conventional knot-tying techniques.

关键词： abdominal aortic aneurysm     harmonic scalpel     minimally invasive    

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The evolution of surgical and medical treatment of aortic root aneurysm

null

《医学前沿（英文）》 2014年 第8卷 第4期   页码 427-432 doi: 10.1007/s11684-014-0385-4

摘要：

Since first report of aortic root replacement in 1968, the surgical risk and long term outcome of patients with aortic root aneurysm have been continuously improving. In the last 30 years, the surgical approach is also evolving towards more valve conservation with prophylactical intervention at an earlier clinical stage. Translational research has also led to emerging surgical innovation and new drug therapy. Their efficacies are currently under vigorous clinical trials and evaluations.

关键词： aortic root aneurysm     aortic root replacement     valve sparing root replacement     personalised external aortic root support    

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Identification of variants associated with sporadic thoracic aortic dissection: a case--control study

《医学前沿（英文）》 2021年 第15卷 第3期   页码 438-447 doi: 10.1007/s11684-020-0826-1

摘要： Thoracic aortic dissection (TAD) without familial clustering or syndromic features is known as sporadic TAD (STAD). So far, the genetic basis of STAD remains unknown. Whole exome sequencing was performed in 223 STAD patients and 414 healthy controls from the Chinese Han population (N = 637). After population structure and genetic relationship and ancestry analyses, we used the optimal sequence kernel association test to identify the candidate genes or variants of STAD. We found that COL3A1 was significantly relevant to STAD (P = 7.35 × 10−6) after 10 000 times permutation test (P = 2.49 × 10−3). Moreover, another independent cohort, including 423 cases and 734 non-STAD subjects (N = 1157), replicated our results (P = 0.021). Further bioinformatics analysis showed that COL3A1 was highly expressed in dissected aortic tissues, and its expression was related to the extracellular matrix (ECM) pathway. Our study identified a profile of known heritable TAD genes in the Chinese STAD population and found that COL3A1 could increase the risk of STAD through the ECM pathway. We wanted to expand the knowledge of the genetic basis and pathology of STAD, which may further help in providing better genetic counseling to the patients.

关键词： sporadic thoracic aortic dissection     exome sequencing     gene COL3A1     case–control study     extracellular matrix    

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Aneurysmal dilatation of the aortic sinuses of Valsalva — beyond Marfan syndrome: a single centre experience

null

《医学前沿（英文）》 2014年 第8卷 第4期   页码 419-426 doi: 10.1007/s11684-014-0383-6

摘要：

Aneurysmal dilatation of the aortic sinuses of Valsalva has been most extensively documented in the setting of aortopathies, particularly Marfan syndrome. On the other hand, there is limited data in the literature about congenital sinus of Valsalva aneurysms outside this context. For the purpose of this review, we carried out a literature search on aneurysmal dilatation of the sinuses of Valsalva in Marfan syndrome, and compared this with congenital sinus of Valsalva aneurysms, also including data from a case series from our institution. In conclusion, there are differences in management of aortic dilatation in Marfan syndrome and congenital sinus of Valsalva aneurysms. Though less well-recognised, congenital aneurysms are often associated with significant morbidity and mortality and timely intervention is necessary.

关键词： sinus of Valsalva aneurysms     Marfan syndrome     aortic dissection    

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Right coronary occlusion following transcatheter aortic valve implantation: two case reports

null

《医学前沿（英文）》 2016年 第10卷 第3期   页码 351-355 doi: 10.1007/s11684-016-0465-8

摘要：

This paper discusses two male patients with severe aortic stenosis, whose right coronary arteries (RCA) were completely occluded during transcatheter aortic valve implantation (TAVI), leading to fatal hemodynamic disorder. Occlusions of RCA complicated by TAVI are rare. In addition, emergency cardiopulmonary bypass (CPB) played a critical role in rescuing our second patient. Both patients were admitted for “severe aortic stenosis,” and TAVIs were performed. The first patient’s blood pressure immediately dropped to 70/40 mmHg after the balloon expansion and did not increase much after the administration of aramine or fluid therapy. He did not receive emergency surgery and died after 1.5 h of resuscitation. The second patient’s blood pressure fluctuated greatly for several minutes after the valve implantation, ranging from 170/100 mmHg to 60/40 mmHg. Angiography revealed a total occlusion of RCA. Thoracic surgery with CPB was performed, and the patient survived.

关键词： aortic stenosis     transcatheter aortic valve implantation     right coronary occlusion     cardiac group    

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Clinical significance of para-aortic lymph node dissection and prognosis in ovarian cancer

null

《医学前沿（英文）》 2014年 第8卷 第1期   页码 96-100 doi: 10.1007/s11684-014-0316-4

摘要：

Lymph node metastasis has an important effect on prognosis of patients with ovarian cancer. Moreover, the impact of para-aortic lymph node (PAN) removal on patient prognosis is still unclear. In this study, 80 patients were divided into groups A and B. Group A consisted of 30 patients who underwent PAN+ pelvic lymph node (PLN) dissection, whereas group B consisted of 50 patients who only underwent PLN dissection. Analysis of the correlation between PAN clearance and prognosis in epithelial ovarian cancer was conducted. Nineteen cases of lymph node metastasis were found in group A, among whom seven cases were positive for PAN, three cases for PLN, and nine cases for both PAN and PLN. In group B, 13 cases were positive for lymph node metastasis. Our study suggested that the metastatic rate of lymph node is 40.0%. Lymph node metastasis was significantly correlated with FIGO stage, tumor differentiation, and histological type both in groups A and B (P<0.05). In groups A and B, the three-year survival rates were 77.9% and 69.0%, and the five-year survival rates were 46.7% and 39.2%, respectively. However, the difference was not statistically significant (P>0.05). The three-year survival rates of PLN metastasis in groups A and B were 68.5% and 41.4%, and the five-year survival rates were 49.7% and 26.4%, respectively. Furthermore, PLN-positive patients who cleared PAN had significantly higher survival rate (P=0.044). In group A, the three-year survival rates of positive and negative lymph nodes were 43.5% and 72.7%, and the five-year survival rates were 27.2% and 58.5%, respectively. The difference was statistically significant (P=0.048). Cox model analysis of single factor suggested that lymph node status affected the survival rate (P<0.01), which was the death risk factor. Consequently, in ovarian carcinoma cytoreductive surgery, resection of the para-aortic lymph node, which has an important function in clinical treatment and prognosis of patients with ovarian cancer, is necessary.

关键词： ovarian cancer     para-aortic lymph node     pelvic lymph node    

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in improving left ventricular remodelling and clinical outcome following surgical and trans-catheter aortic

《医学前沿（英文）》 2021年 第15卷 第3期   页码 416-437 doi: 10.1007/s11684-021-0852-7

摘要： Over the last half century, surgical aortic valve replacement (SAVR) has evolved to offer a durable and efficient valve haemodynamically, with low procedural complications that allows favourable remodelling of left ventricular (LV) structure and function. The latter has become more challenging among elderly patients, particularly following trans-catheter aortic valve implantation (TAVI). Precise understanding of myocardial adaptation to pressure and volume overloading and its responses to valve surgery requires comprehensive assessments from aortic valve energy loss, valvular-vascular impedance to myocardial activation, force-velocity relationship, and myocardial strain. LV hypertrophy and myocardial fibrosis remains as the structural and morphological focus in this endeavour. Early intervention in asymptomatic aortic stenosis or regurgitation along with individualised management of hypertension and atrial fibrillation is likely to improve patient outcome. Physiological pacing via the His-Purkinje system for conduction abnormalities, further reduction in para-valvular aortic regurgitation along with therapy of angiotensin receptor blockade will improve patient outcome by facilitating hypertrophy regression, LV coordinate contraction, and global vascular function. TAVI leaflet thromboses require anticoagulation while impaired access to coronary ostia risks future TAVI-in-TAVI or coronary interventions. Until comparable long-term durability and the resolution of TAVI related complications become available, SAVR remains the first choice for lower risk younger patients.

关键词： surgical aortic valve replacement     trans-catheter aortic valve implantation     left ventricular hypertrophy and fibrosis     myocardial force-velocity relationship     His-Purkinje pacing     renin-angiotensin system inhibitors     coronary access impairment    

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Modelling autogenous expansion for magnesia concrete in arch dams

JIN Feng, LUO Xiaoqing, ZHANG Chuhan, ZHANG Guoxin

《结构与土木工程前沿（英文）》 2008年 第2卷 第3期   页码 211-218 doi: 10.1007/s11709-008-0025-7

摘要： Magnesia Concrete is a kind of expansive concrete used in Chinese hydraulic engineering more and more widely. To evaluate the effects of autogenous expansion on the stresses of arch dams, a simple model of autogenous expansion for Magnesia Concrete in dam engineering is presented. This model is based on three assumptions: 1) the total amount of autogenous expansion of Magnesia Concrete is related only to the properties of materials and mixing of concrete; 2) the autogenous expansion of Magnesia Concrete is irreversible due to the irreversibility of hydration reaction of Magnesia in the concrete; 3) the autogenous expansion strain rates of Magnesia Concrete bear a relation between temperature and residual Magnesia per unit volume of concrete. The model is verified by some experimental data of autogenous expansion of Magnesia Concrete and field-measured data of an arch dam in China. Embedded into finite element arch dam simulation software, this model is employed to simulate the effects of autogenous expansion of Magnesia Concrete in hydraulic engineering.

关键词： field-measured     irreversibility     temperature     irreversible     element arch    

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Analysis of arch dam deformations

Franz PERNER, Pius OBERNHUBER,

《结构与土木工程前沿（英文）》 2010年 第4卷 第1期   页码 102-108 doi: 10.1007/s11709-010-0012-7

摘要： Predicting “regular” dam deformations for prevailing conditions and comparing them with observed deformations is an essential part of dam surveillance. In many cases prediction and comparison are carried out automatically and an alarm is triggered in the case of larger deviations.The main contributors to the deformations of arch dams are water loading and the fluctuation of concrete temperature. In general, the deformations exhibit an instantaneous elastic part, a time dependent reversible part and an irreversible part. Prediction of dam deformations can be based on deterministic models, purely statistical models or so-called hybrid models, which are a combination of the first two. Deterministic models rely on static analyses, statistical models on the statistical analysis of previous deformation data.For annual reservoirs, both water loading and temperature vary in cycles over a period of one year and it is extremely difficult to identify the various factors contributing to an observed deformation. This is particularly true for time-dependent reversible displacements due to the water loading and the portion caused by temperature variation.The present article deals with the analysis of arch dam deformations based on hybrid models. Particular attention is given to the analysis of the deformations due to temperature fluctuation and to the long-term deformations. The proposed procedure is employed for the analysis of the deformations of the 186 m high Zillergruendl arch dam.

关键词： arch dam     analysis     Zillergruendl     concrete temperature     hybrid model    

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Shape design of arch dams under load uncertainties with robust optimization

Fengjie TAN, Tom LAHMER

《结构与土木工程前沿（英文）》 2019年 第13卷 第4期   页码 852-862 doi: 10.1007/s11709-019-0522-x

摘要： Due to an increased need in hydro-electricity, water storage, and flood protection, it is assumed that a series of new dams will be build throughout the world. The focus of this paper is on the non-probabilistic-based design of new arch-type dams by applying means of robust design optimization (RDO). This type of optimization takes into account uncertainties in the loads and in the material properties of the structure. As classical procedures of probabilistic-based optimization under uncertainties, such as RDO and reliability-based design optimization (RBDO), are in general computationally expensive and rely on estimates of the system’s response variance, we will not follow a full-probabilistic approach but work with predefined confidence levels. This leads to a bi-level optimization program where the volume of the dam is optimized under the worst combination of the uncertain parameters. As a result, robust and reliable designs are obtained and the result is independent from any assumptions on stochastic properties of the random variables in the model. The optimization of an arch-type dam is realized here by a robust optimization method under load uncertainty, where hydraulic and thermal loads are considered. The load uncertainty is modeled as an ellipsoidal expression. Comparing with any traditional deterministic optimization method, which only concerns the minimum objective value and offers a solution candidate close to limit-states, the RDO method provides a robust solution against uncertainty. To reduce the computational cost, a ranking strategy and an approximation model are further involved to do a preliminary screening. By this means, the robust design can generate an improved arch dam structure that ensures both safety and serviceability during its lifetime.

关键词： arch dam     shape optimization     robust optimization     load uncertainty     approximation model    

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Numerical simulation of damage in high arch dam due to earthquake

Hong ZHONG , Gao LIN , Hongjun LI

《结构与土木工程前沿（英文）》 2009年 第3卷 第3期   页码 316-322 doi: 10.1007/s11709-009-0039-9

摘要： Based on the assumption that concrete is macroscopic homogeneous, the cracking evolution process and damage mode of high arch dams are studied in consideration of the heterogeneity of concrete in mesoscale. The bilinear damage evolution model and the damage evolution model expressed in power function with descending section are adopted to combine with the Mohr-Coulomb criterion to investigate the crack development and fracture mode of high arch dams under the action of an earthquake. The analysis result of a high arch dam in China under design shows that cracks that take place in concrete are caused by excessive tensile stress. The cracks initiate at the middle of the dam top and distribute at the upper half of the dam while the rest of the parts remain intact. This conclusion agrees with the model test result.

关键词： mesoscopic heterogeneity     damage simulation in earthquakes     arch dam    

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Key problems and solutions in arch dam heightening

Zuoguang FU, Yunlong HE, Sheng SU

《结构与土木工程前沿（英文）》 2011年 第5卷 第1期   页码 98-104 doi: 10.1007/s11709-010-0004-7

摘要： The dam heightening, which is an effective way to increase reservoir volume, has been paid close attention by engineers. Three problems should be dealt with when an arch dam needs to be heightened: stress state getting worse at dam heel, cracking on new added concrete dam surface, and weak bonding between new added concrete and old dam. Taking Geba arch dam as an example, these problems are examined in details through simulation analysis by the finite element method. The tensile stresses on dam’s surface and joint face that have certain relations to the dam heightening can be controlled by some measures.

关键词： arch dam     heighten     tensile stress     finite element method    

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Histopathological study of congenital aortic valve malformations in 32 children

HUANG Ping, WANG Hongwei, LI Yanping, CHENG Peixuan, LIU Qingjun, ZHANG Zhenlu, LIU Jianying

《医学前沿（英文）》 2007年 第1卷 第1期   页码 74-78 doi: 10.1007/s11684-007-0015-5

摘要： The histopathological characteristics of congenital aortic valve malformations in children were investigated. All the native surgically excised aortic valves from 32 pediatric patients suffering from symptomatic aortic valve dysfunction due to congenital aortic valve malformations between January 2003 and December 2005 were studied macroscopically and microscopically. The patients medical records were reviewed and the clinical information was extracted. The diagnosis was made by the clinical presentation, preoperative echocardiography, intraoperative examination, and postoperative histopathological study, excluding rheumatic or degenerative aortic valve diseases, infective endocarditis and primary connective tissue disorders, e.g. Marfan syndrome. Among 32 children with congenital aortic valve malformations, the age was ranged from six to 18 years, with a mean of 14.9 years, and there were 27 boys and five girls (male: female = 5.4:1). There were five cases of aortic stenosis (AS, 15.62%), 25 cases of aortic insufficiency (AI, 78.13%) and two cases of AS-AI (6.25%), without other valve diseases. Twenty cases still had other congenital heart diseases: ventricular septal defect (19 cases), patent ductus arteriosus (two cases), double-chambered right ventricle (one case), aneurysm of the right anterior aortic sinus of valsalva (three cases). Histopathological examination indicated that the cusps became thickening with unequal size, irregular shape (coiling and prolapse edge), enhanced hardness, and partly calcification. Microscopic investigation revealed the unsharp structure of valve tissue, fibrosis, myxomatous, reduced collagen fiber, rupture of elastic fibers, different degrees of infiltration of inflammatory cells, secondary calcareous and lipid deposit, and secondary fibrosis. Congenital aortic valve malformations in children involve males more than females, mostly associated with other congenital heart diseases. Aortic insufficiency is more common in children with congenital aortic valve malformations. Histopathologically, the leaflets of aortic valve are mainly myxomatous, thickening with unequal size, irregular shape (coiling and prolapse edge), reduced collagen fiber, rupture of elastic fibers, without small vessel proliferation and inflammatory cell infiltration, fibrosis and calcification rarely seen.
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标题 作者 时间 类型 操作

engineering in the construction of numerical simulation oriented patient-specific model of stented aorticarch aneurysm

Xianlong MENG, Wenyu FU, Yun ZHANG, Aike QIAO,

期刊论文

Aortic aneurysm and chronic disseminated intravascular coagulation: a retrospective study of 235 patients

null

期刊论文

Evaluation of the harmonic scalpel in open surgery for abdominal aortic aneurysm

null

期刊论文

The evolution of surgical and medical treatment of aortic root aneurysm

null

期刊论文

Identification of variants associated with sporadic thoracic aortic dissection: a case--control study

期刊论文

Aneurysmal dilatation of the aortic sinuses of Valsalva — beyond Marfan syndrome: a single centre experience

null

期刊论文

Right coronary occlusion following transcatheter aortic valve implantation: two case reports

null

期刊论文

Clinical significance of para-aortic lymph node dissection and prognosis in ovarian cancer

null

期刊论文

in improving left ventricular remodelling and clinical outcome following surgical and trans-catheter aortic

期刊论文

Modelling autogenous expansion for magnesia concrete in arch dams

JIN Feng, LUO Xiaoqing, ZHANG Chuhan, ZHANG Guoxin

期刊论文

Analysis of arch dam deformations

Franz PERNER, Pius OBERNHUBER,

期刊论文

Shape design of arch dams under load uncertainties with robust optimization

Fengjie TAN, Tom LAHMER

期刊论文

Numerical simulation of damage in high arch dam due to earthquake

Hong ZHONG , Gao LIN , Hongjun LI

期刊论文

Key problems and solutions in arch dam heightening

Zuoguang FU, Yunlong HE, Sheng SU

期刊论文

Histopathological study of congenital aortic valve malformations in 32 children

HUANG Ping, WANG Hongwei, LI Yanping, CHENG Peixuan, LIU Qingjun, ZHANG Zhenlu, LIU Jianying

期刊论文