Thrombosis, physical activity, and acute coronary syndromes

Acute coronary syndromes (ACS) are common, life-threatening cardiac disorders that typically are triggered by rupture or erosion of an atherosclerotic plaque. Platelet deposition and activation of the blood coagulation cascade in response to plaque disruption lead to the formation of a platelet-fibrin thrombus, which can grow rapidly, obstruct coronary blood flow, and cause myocardial ischemia and/or infarction. Several clinical studies have examined the relationship between physical activity and ACS, and numerous preclinical and clinical studies have examined specific effects of sustained physical training and acute physical activity on atherosclerotic plaque rupture, platelet function, and formation and clearance of intravascular fibrin. This article reviews the available literature regarding the role of physical activity in determining the incidence of atherosclerotic plaque rupture and the pace and extent of thrombus formation after plaque rupture.     

Rupture of Descemet's membrane secondary to presumed forceps trauma

Ruptures in Descemet's membrane can occur secondary to forceps injury at birth, prolonged labor, blunt trauma, keratoconus, and congenital glaucoma as well as other less frequent causes. The rupture initially causes acute comeal hydrops which resolves within weeks to leave permanent linear thickening of Descemet's membrane. It is important to differentiate Descemet's rupture from other entities like syphilitic interstitial keratitis, posterior polymorphous dystrophy and congenital hereditary endothelial dystrophy which may have a similar clinical presentation. Although treatment is rarely required, proper diagnosis is important to prevent unnecessary referrals and provide appropriate counseling. This case report examines a 66-year-old female with Descemet's rupture secondary to presumed forceps trauma at birth. Discussion of clinical presentation, differential diagnosis and clinical management are presented.     

A machine learning approach to investigate the relationship between shape features and numerically predicted risk of ascending aortic aneurysm

Geometric features of the aorta are linked to patient risk of rupture in the clinical decision to electively repair an ascending aortic aneurysm (AsAA). Previous approaches have focused on relationship between intuitive geometric features (e.g., diameter and curvature) and wall stress. This work investigates the feasibility of a machine learning approach to establish the linkages between shape features and FEA-predicted AsAA rupture risk, and it may serve as a faster surrogate for FEA associated with long simulation time and numerical convergence issues. This method consists of four main steps: (1) constructing a statistical shape model (SSM) from clinical 3D CT images of AsAA patients; (2) generating a dataset of representative aneurysm shapes and obtaining FEA-predicted risk scores defined as systolic pressure divided by rupture pressure (rupture is determined by a threshold criterion); (3) establishing relationship between shape features and risk by using classifiers and regressors; and (4) evaluating such relationship in cross-validation. The results show that SSM parameters can be used as strong shape features to make predictions of risk scores consistent with FEA, which lead to an average risk classification accuracy of 95.58% by using support vector machine and an average regression error of 0.0332 by using support vector regression, while intuitive geometric features have relatively weak performance. Compared to FEA, this machine learning approach is magnitudes faster. In our future studies, material properties and inhomogeneous thickness will be incorporated into the models and learning algorithms, which may lead to a practical system for clinical applications.     

Staged transcatheter closure of chronic postinfarction ventricular septal defects with the Amplatzer septal occluder

Ventricular septal rupture is a serious complication of myocardial infarction with an extremely poor outcome. There are single reports of transcatheter closure of postmyocardial septal defects and clinical experience is limited. This paper reports on a successful staged transcatheter closure of two chronic postmyocardial defects using the Amplatzer septal occluder in a 52-year-old male.     

未足月胎膜早破合并绒毛膜羊膜炎孕妇血清淀粉样蛋白A、血小板激活因子水平的表达及临床意义

目的:检测未足月胎膜早破合并绒毛膜羊膜炎(HCA)孕妇血清淀粉样蛋白A(SAA)、血小板激活因子(PAF)水平,并探讨其临床意义。方法:选择从2013年7月到2017年7月,在我院接受治疗的165例胎膜早破孕产妇作为研究对象。165例患者中,未足月胎膜早破者80例(未足月胎膜早破组),足月胎膜早破者85例(足月胎膜早破组),再根据是否合并HCA分为合并HCA胎膜早破组43例和未合并HCA胎膜早破组122例。另选取同期在我院体检的80例健康孕产妇志愿者作为正常组,对比各组血清SAA和PAF水平,分析合并与未合并HCA胎膜早破组的妊娠结局,利用受试者工作特征(ROC)曲线分析血清SAA和PAF对未足月胎膜早破是否合并HCA的诊断价值。结果:未足月胎膜早破组及足月胎膜早破组的血清SAA和PAF水平均明显高于正常组,且未足月胎膜早破组又高于足月胎膜早破组,差异有统计学意义(P0.05)。未足月胎膜早破组80例患者中HCA发生率为35.00%(28/80),明显高于足月胎膜早破组的17.65%(15/85),差异有统计学意义(P0.05)。合并HCA胎膜早破组的血清SAA和PAF水平均明显高于未合并HCA胎膜早破组,差异有统计学意义(P0.05)。合并HCA的未足月胎膜早破患者血清SAA和PAF水平高于未合并HCA的未足月胎膜早破患者(P0.05)。合并HCA的胎膜早破组的产后大出血、剖宫产以及新生儿肺炎的发生率均明显高于未合并HCA胎膜早破组,差异有统计学意义(P0.05)。根据ROC曲线分析可知,血清SAA和PAF对未足月胎膜早破是否合并HCA的诊断价值较高。结论:血清SAA、PAF水平在未足月胎膜早破合并HCA孕妇中明显升高,二者对此种合并症具有较高的诊断价值。临床诊疗过程中可将SAA及PAF纳入到指标监测体系中,从而为临床治疗提供指导。     

34例胎膜早破孕妇妊娠晚期阴道微生态及免疫因子变化状况分析

目的：胎膜早破是一种常见但发生机制十分复杂的妊娠并发症。在所有的早产儿中,孕妇胎膜早破的比例高达33％。本研究针对胎膜早破产妇妊娠晚期阴道微生态及免疫因子的变化情况,分析阴道内茵群失调或局部免疫反应与胎膜早破的关系,为临床研究提供实验数据。方法：回顾性分析我院于2010年7月-2013年3月收治的34例胎膜早破孕妇的临床资料,同时选取于我院进行健康体检的妇女及产前检查的健康孕妇各34例作为对照。采集所有研究对象的阴道分泌物,对比分析各组样本中病原微生物的分布及免疫因子的浓度。结果：胎膜早破组乳酸杆菌的检出率要明显低于健康妇女组与健康孕妇组（79．4％VS70．6％VS34．1,X2=8．438,P〈0．05）,三组研究对象其他茵属分布的差异比较无统计学意义（P〉0．05）;胎膜早破组阴道分泌物IL-6浓度与TNF．仪浓度要显著高于健康妇女组与健康孕妇组（P〈0．05）。结论：胎膜早破产妇阴道内的菌群分布与健康女性及孕妇有所不同,阴道内茵群失调及局部的免疫反应可能会导致胎膜旱破的发生。     

Modeling rupture of growing aneurysms

Growth and rupture of aneurysms are driven by micro-structural alterations of the arterial wall yet precise mechanisms underlying the process remain to be uncovered. In the present work we examine a scenario when the aneurysm evolution is dominated by turnover of collagen fibers. In the latter case it is natural to hypothesize that rupture of individual fibers (or their bonds) causes the overall aneurysm rupture. We examine this hypothesis in computer simulations of growing aneurysms in which constitutive equations describe both collagen evolution and failure. Failure is enforced in constitutive equations by limiting strain energy that can be accumulated in a fiber. Within the proposed theoretical framework we find a range of parameters that lead to the aneurysm rupture. We conclude in a qualitative agreement with clinical observations that some aneurysms will rupture while others will not.     

Spontaneous splenic rupture in patient with metastatic melanoma treated with vemurafenib

ABSTRACT: BACKGROUND: BRAF inhibitors such as vemurafenib are a new family of biological drugs, recently available to treat metastatic malignant melanoma. METHODS: We present the case of a 38-year-old man affected by metastatic melanoma who had been under treatment with vemurafenib for a few days. The patient suffered from sudden onset of abdominal pain due to intra-abdominal hemorrhage with profuse hemoperitoneum. An emergency abdominal sonography confirmed the clinical suspicion of a splenic rupture. RESULTS: The intraoperative finding was hemoperitoneum due to splenic two-step rupture and splenectomy was therefore performed. Histopathology confirmed splenic hematoma and capsule laceration, in the absence of metastasis. CONCLUSIONS: This report describes the occurrence of a previously unreported adverse event in a patient with stage IV melanoma receiving vemurafenib.     

A fluid–structure interaction-based numerical investigation on the evolution of stress,strength and rupture potential of an abdominal aortic aneurysm

An abdominal aortic aneurysm (AAA) is an irreversible dilation of the abdominal artery. Once an aneurysm is detected by doctors, clinical intervention is usually recommended. The interventions involve traditional open surgery repair and endovascular aneurysm repair with a stent graft. Both types of prophylactic procedures are expensive and not without any risk to the patient. It is very difficult to balance the risk of aneurysm repair and the chance of rupture. The reason lies in that the changing trend of characteristic physical quantities with the evolution of AAA and the mechanisms that give rise to it are still not completely clear. In this study, computational 3D patient-specific model for investigating AAA development was established based on computed tomography (CT) images. Results showed that as the aneurysm evolved, peak wall stress and time-averaged wall shear stress distribution patterns changed. The expansion of AAA wall resulted in the increment of peak stress. The AAA wall compliance not only showed different magnitudes at different cross-sections of the aneurismal body, but also changed with the development of the aneurysm. Furthermore, minimum wall strength and rupture potential index during the three stages of AAA evolution were also investigated in detail. This study might provide valuable information on how to further explore the mechanical basis and the rupture potential during AAA evolution, and that it may assist clinical diagnostic procedures and avoid the potential risk of unnecessary surgical intervention.     

Silicone breast implant rupture: pitfalls of magnetic resonance imaging and relative efficacies of magnetic resonance, mammography, and ultrasound

The objective of this study was to evaluate the relative efficacies of magnetic resonance (MR) imaging, ultrasonography, and mammography in implant rupture detection and to illustrate pitfalls in MR image interpretation. Thirty patients referred by plastic surgeons with suspected breast implant rupture were prospectively evaluated using MR, ultrasonography, and mammography. Imaging examinations were interpreted independently and blindly for implant rupture and correlated to operative findings. Surgical correlation in 16 patients (53 percent) with 31 implants showed 13 (42 percent) were intact, 5 (16 percent) had severe gel bleed, and 13 (42 percent) were ruptured. MR sensitivity was 100 percent and specificity was 63 percent. Accuracy for rupture was 81 percent with MR, higher than with ultrasonography and mammography (77 and 59 percent, respectively). We describe a specific pitfall in MR interpretation, the "rat-tail" sign, composed of a medial linear extension of silicone along the chest wall. Seen in eight cases (four intact, three ruptures, one gel bleed), the rat-tail sign may lead to misdiagnosis of implant rupture if seen in isolation. Magnetic resonance imaging is more accurate and sensitive than ultrasonography and mammography in detecting breast implant rupture. We describe a new sign (rat-tail sign) composed of medial compression of the implant simulating silicone extrusion as a potential false-positive MR finding for rupture. This article presents clinical experience with magnetic resonance, mammography, and ultrasound in the diagnosis of implant rupture and defines and illustrates potential pitfalls of MR interpretation, including the new rat-tail sign.     

Metalloproteinases promote plaque rupture and myocardial infarction: A persuasive concept waiting for clinical translation

Atherosclerotic plaque rupture provokes most myocardial infarctions. Matrix metalloproteinases (MMPs) have counteracting roles in intimal thickening, which stabilizes plaques, on the one hand and extracellular matrix destruction that leads to plaque rupture on the other. This review briefly summarizes the key points supporting the involvement of individual MMPs in provoking plaque rupture and discusses the barriers that stand in the way of clinical translation, which can be itemised as follows: structural and functional complexity of the MMP family; lack of adequate preclinical models partly owing to different expression patterns of MMPs and TIMPs in mouse and human macrophages; the need to target individual MMPs selectively; the difficulties in establishing causality in human studies; and the requirement for surrogate markers of efficacy. Overcoming these barriers would open the way to new treatments that could have a major impact on cardiovascular mortality worldwide.     

In vitro analysis of localized aneurysm rupture

In this study, bulge inflation tests were used to characterize the failure response of 15 layers of human ascending thoracic aortic aneurysms (ATAA). Full field displacement data were collected during each of the mechanical tests using a digital image stereo-correlation (DIS-C) system. Using the collected displacement data, the local stress fields at burst were derived and the thickness evolution was estimated during the inflation tests. It was shown that rupture of the ATAA does not systematically occur at the location of maximum stress, but in a weakened zone of the tissue where the measured fields show strain localization and localized thinning of the wall. Our results are the first to show the existence of weakened zones in the aneurysmal tissue when rupture is imminent. An understanding these local rupture mechanics is necessary to improve clinical assessments of aneurysm rupture risk. Further studies must be performed to determine if these weakened zones can be detected in vivo using non-invasive techniques.     

ADT、Lanchman试验与MRI对于诊断前交叉韧带断裂的可靠性研究

目的:回顾性分析因怀疑前交叉韧带断裂而住院行膝关节镜检查治疗术的患者当中,术前前抽屉试验(ADT)、Lanchman试验、核磁共振成像(MRI)检查提示韧带断裂的阳性率、敏感性以及特异性,讨论前交叉韧带断裂的最敏感非手术检查方法。方法:通过搜集近10年内我院骨科关节镜术中确诊的前交叉韧带损伤患者的临床病例资料,分析术前ADT、Lanchman试验及MRI检查数据,统计各种检查结果的阳性率、敏感性和特异性,比较各种检查方法的差异。结果:本次研究共搜集到210个关节镜手术病例,术前相关检查的确诊前交叉韧带断裂的阳性率依次为:ADT:61.4%;Lanchman试验:69.5%;MRI:87.1%。敏感性依次为:ADT:61.5%;Lanchman试验:69.5%;MRI:91.4%。特异性依次为:ADT:60.9%;Lanchman试验:69.6%;MRI:52.2%。结论:ADT、Lanchman试验、MRI对于诊断前交叉韧带断裂均存在偏差,临床诊疗过程中应将三种检查结果联合参考作为前交叉韧带断裂的诊断依据。     

Morphological Parameters Associated with Ruptured Posterior Communicating Aneurysms

The rupture risk of unruptured intracranial aneurysms is known to be dependent on the size of the aneurysm. However, the association of morphological characteristics with ruptured aneurysms has not been established in a systematic and location specific manner for the most common aneurysm locations. We evaluated posterior communicating artery (PCoA) aneurysms for morphological parameters associated with aneurysm rupture in that location. CT angiograms were evaluated to generate 3-D models of the aneurysms and surrounding vasculature. Univariate and multivariate analyses were performed to evaluate morphological parameters including aneurysm volume, aspect ratio, size ratio, distance to ICA bifurcation, aneurysm angle, vessel angles, flow angles, and vessel-to-vessel angles. From 2005–2012, 148 PCoA aneurysms were treated in a single institution. Preoperative CTAs from 63 patients (40 ruptured, 23 unruptured) were available and analyzed. Multivariate logistic regression revealed that smaller volume (p = 0.011), larger aneurysm neck diameter (0.048), and shorter ICA bifurcation to aneurysm distance (p = 0.005) were the most strongly associated with aneurysm rupture after adjusting for all other clinical and morphological variables. Multivariate subgroup analysis for patients with visualized PCoA demonstrated that larger neck diameter (p = 0.018) and shorter ICA bifurcation to aneurysm distance (p = 0.011) were significantly associated with rupture. Intracerebral hemorrhage was associated with smaller volume, larger maximum height, and smaller aneurysm angle, in addition to lateral projection, male sex, and lack of hypertension. We found that shorter ICA bifurcation to aneurysm distance is significantly associated with PCoA aneurysm rupture. This is a new physically intuitive parameter that can be measured easily and therefore be readily applied in clinical practice to aid in the evaluation of patients with PCoA aneurysms.     

Measurement of the transverse strain tensor in the coronary arterial wall from clinical intravascular ultrasound images

Atherosclerotic plaque rupture is the major cause of acute coronary syndromes. Currently, there is no reliable diagnostic tool to predict plaque rupture. Knowledge of plaque mechanical properties based on local artery wall strain measurements would be useful for characterizing its composition and predicting its vulnerability. Due to cardiac motion, strain estimation in clinical intravascular ultrasound (IVUS) images is extremely challenging. A method is presented to estimate cross-sectional coronary artery wall strain in response to cardiac pulsatile pressure using clinically acquired IVUS images, which are acquired in continuous pullback mode. First, cardiac phase information is retrieved retrospectively from an IVUS image sequence using an image-based gating method, and image sub-sequences at systole and diastole are extracted. Then, images at branch sites are used as landmarks to align the two image sub-sequences. Finally, the paired images at each site are registered to measure the 2D strain tensor of the coronary artery cross-section. This method has been successfully applied to IVUS images of a left anterior descending (LAD) coronary artery acquired clinically during a standard procedure. Such complete strain information should be useful for identifying vulnerable plaque.     

Automated methodology for determination of stress distribution in human abdominal aortic aneurysm

Knowledge of impending abdominal aortic aneurysm (AAA) rupture can help in surgical planning. Typically, aneurysm diameter is used as the indicator of rupture, but recent studies have hypothesized that pressure-induced biomechanical stress may be a better predictor Verification of this hypothesis on a large study population with ruptured and unruptured AAA is vital if stress is to be reliably used as a clinical prognosticator for AAA rupture risk. We have developed an automated algorithm to calculate the peak stress in patient-specific AAA models. The algorithm contains a mesh refinement module, finite element analysis module, and a postprocessing visualization module. Several aspects of the methodology used are an improvement over past reported approaches. The entire analysis may be run from a single command and is completed in less than 1 h with the peak wall stress recorded for statistical analysis. We have used our algorithm for stress analysis of numerous ruptured and unruptured AAA models and report some of our results here. By current estimates, peak stress in the aortic wall appears to be a better predictor of rupture than AAA diameter. Further use of our algorithm is ongoing on larger study populations to convincingly verify these findings.     

Growth rate and rupture rate of unruptured intracranial aneurysms: a population approach

Background  

Understanding aneurysm growth rate allows us to predict not only the current rupture risk, but also accumulated rupture risk in the future. However, determining growth rate of unruptured intracranial aneurysms often requires follow-up of patients for a long period of time so that significant growth can be observed and measured. We investigate a relationship between growth rate and rupture rate and develop a theoretical model that can predict average behavior of unruptured intracranial aneurysms based on existing clinical data.     

C- 反应蛋白检测在胎膜早破孕妇中的临床意义

目的:探讨C反应蛋白(CRP)检测在足月胎膜早破(PROM)孕妇中的临床意义。方法:选取足月胎膜早破(PROM)孕妇50例为实验组,并根据破膜时间将足月破膜孕妇分为3个亚组;并选取同期住院的正常孕妇30例为对照,采用高敏CRP试剂盒,测定不同组别孕妇中CRP水平。结果:入院时,胎膜早破各亚组中CRP水平明显高于对照组,具有显著统计学意义(P<0.05);同时随着破膜时间的增加,各亚组中的CRP水平及WBC计数也逐渐升高,且3个亚组之间也分别存在统计学差异(P<0.05)。在应用抗生素3d后,CRP出现显著下降,与正常组相比未见明显差异(P>0.05);WBC计数在应用抗生素后的3d时间出现下降,但与入院前相比未见明显统计学差异。结论:CRP检测在判断孕妇胎膜早破、指导临床用药方面具有较高的临床价值,可作为常规检查项目。     

Toward a biomechanical tool to evaluate rupture potential of abdominal aortic aneurysm: identification of a finite strain constitutive model and evaluation of its applicability

Knowledge of the wall stresses in an abdominal aortic aneurysm (AAA) may be helpful in evaluating the need for surgical intervention to avoid rupture. This must be preceded by the development of a more suitable finite strain constitutive model for AAA, as none currently exists. Additionally, reliable stress analysis of in vivo AAA for the purposes of clinical diagnostics requires patient-specific values of the material parameters, which are difficult to determine noninvasively. The purpose of this work, therefore, was three-fold: (1) to develop a finite strain constitutive model for AAA; (2) to estimate the variation of model parameters within a sample population; and (3) to evaluate the sensitivity of computed stress distribution in AAA due to this biologic variation. We propose here a two parameter, hyperelastic, isotropic, incompressible material model and utilize experimental data from 69 freshly excised AAA specimens to both develop the functional form of the model and estimate its material parameters. Parametric analyses were performed via repeated finite element computations to determine the effect of varying each of the two model parameters on the stress distribution in a three-dimensional AAA model. The agreement between experimental data and the proposed functional form of the constitutive law was very good (R2 > 0.9). Our finite element simulations showed that the computed AAA wall stresses changed by only 4% or less when both the parameters were varied within the 95% confidence intervals for the patient population studied. This observation indicates that in lieu of the patient-specific material parameters, which are difficult to determine the use of population mean values is sufficiently accurate for the model to be reasonably employed in a clinical setting. We believe that this is an important advancement toward the development of a computational tool for the estimation of rupture potential for individual AAA, for which there is great clinical need.     

The diagnosis of ruptured breast implants

This study is a retrospective review of 18 patients treated by the authors and 14 reported patients with ruptured breast implants. A history of trauma was absent in 11 patients; 17 patients had closed capsulotomies. The physical findings of ruptured implants were nodules, decreased breast size, asymmetry, tenderness, and a softer texture. Mammograms were 90 percent accurate when silicone had migrated. In seven of eight false-negative mammograms, silicone was contained within the fibrous capsule. Mammography signs of rupture are summarized. The diagnosis of ruptured implants should be facilitated by recognition of the clinical presentations and radiographic signs.