Age-Related Histological Changes in Vena Caval System of Human Foetus and Adult: A Comparative Study.

BACKGROUND: It has been documented that cardiac musculature is present in both venae cavae, and they contract together with the atrium, contributing to the pumping mechanism of the heart. So, in the present study, we measured the relative thicknesses of the three histological layers at formation, termination and intermediate levels of the venae cavae along with their histological characteristics. MATERIALS AND METHODS: Ten foetal and 10 adult cadavers were used. The Superior and Inferior Venae Cavae from all three regions were excised and processed for histology. The qualitative and quantitative features of the vessels were observed and recorded. The data thus obtained was then assessed statistically. RESULTS: In superior vena cava, the tunica intima grows actively especially during late gestation. The tunica media shows active growth. The tunica adventitia growth is significant at the middle and termination levels. In inferior vena cava, the tunica intima grows actively at the level of formation. The tunica media shows the active overall growth during early gestation. The tunica adventitia shows active growth during late gestation. In qualitative analysis the plump, spindle-shaped primitive mesenchymal cells were observed. Muscle and collagen fibers show reciprocal abundance with increasing age, with the former being lesser in amount than the latter in earlier stages. Appearance of vasa vasorum was notable from 2nd trimester. The cardiac myocytes were located in the middle and outer tunics of the superior vena cava. CONCLUSION: Cardiac musculature was absent in the inferior vena; however, the vessel shows advanced rate of overall development.

Caudal vena cava collapsibility index in healthy cats by ultrasonography / [Índice de colapsibilidade da veia cava caudal em gatos domésticos Saudáveis, obtido por meio de ultrassonografia]

The objective of this study was to calculate the collapsibility index (CI) in a group of 15 healthy adult mixed breed cats via right hepatic intercostal ultrasound view. The minimal and the maximal diameters of the caudal vena cava (CVC) were obtained during inspiration and expiration, respectively, then CI was calculated. The mean diameter of the CVC was 0.5cm. The mean CI was 28±3% and CI was not significantly associated with gender. As in human medicine, there is a growing need for less invasive monitoring in small animal practice. The CI enables the assessment of estimated volemia without the need for a central venous catheter. This is the first reported study investigating CI in cats.(AU)

O objetivo deste estudo foi calcular o índice de colapsabilidade (IC) em um grupo de 15 gatos adultos, saudáveis e SRD, por meio da janela ultrassonográfica hepática intercostal direita. Os diâmetros mínimo e máximo da veia cava caudal (VCC) foram obtidos durante a inspiração e a expiração, respectivamente. O IC foi calculado, posteriormente. O diâmetro médio da VCC foi de 0,5cm. O diâmetro médio do IC foi de 28±3%, e o IC não foi significativamente associado ao gênero. Como na medicina humana, há uma necessidade crescente de monitoramento menos invasivo na prática de pequenos animais. O IC possibilita a avaliação da volemia estimada sem a necessidade de um cateter venoso central. Este é o primeiro estudo relatado sobre IC em gatos domésticos.(AU)

Anatomy of the cavotricuspid isthmus for radiofrequency ablation in typical atrial flutter.

BACKGROUND: Radiofrequency (RF) catheter ablation is one of the most common strategies for the current management of cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL). The interindividual anatomic variability can influence the duration and outcome of ablation procedure. OBJECTIVE: The purpose of this study was to establish complication rates in patients undergoing RF catheter ablation for CTI-dependent AFL, assess the role of CTI morphology in procedural success, and determine the anatomic variability of CTI ex vivo. METHODS: RF catheter ablation for CTI-dependent AFL was performed in 337 consecutive patients. Angiographically determined CTI morphology was classified as either simple or complex due to pouchlike recesses. Macroscopic and histologic examination of the CTI was performed in 104 heart specimens from consecutive autopsies. RESULTS: Complex CTI anatomy was present in 10.9% of AFL patients. RF application time to achieve bidirectional isthmus block was longer in patients showing pouchlike recesses than in those without (10.7 vs 8.3 min; P= .025). Acute procedure failure or major complications occurred in 3 cases, all with complex CTI anatomy. A pouchlike recess of the CTI was present in 9.6% of autopsy hearts. Histomorphometric analysis of the CTI atrial wall demonstrated that the central level was the thinnest in the 3 sectors and the paraseptal level was the thickest. CONCLUSION: Although RF catheter ablation is a safe and effective procedure for AFL treatment, CTI anatomic complexity can affect ablation parameters and outcome. Standard definition of CTI morphologic variants is recommended. Preprocedural assessment of CTI anatomy might lead to personalized ablation preventing potential difficulties and complications.

Transthoracic echocardiographic evaluation of the heart and great vessels.

PURPOSE: Transthoracic examination of the heart and great vessels is an essential skill that allows the anesthesiologist to evaluate cardiac function. In this article, we describe a pragmatic technique to obtain the essential views to evaluate normal or abnormal cardiac function and to appreciate great vessel anatomy and physiology. PRINCIPAL FINDINGS: The cardiac anatomy and function can be described using standard parasternal, apical, and subcostal views. These windows can also be used to assess the aorta, pulmonary artery, and vena cavae; however, other transthoracic and abdominal windows can be used to complete the evaluation of the great vessels. CONCLUSIONS: The integration of the echocardiographic information particularly from the heart and great vessels with the case story, physical examination, laboratory data, and other relevant clinical information should become the way of the future, and this will benefit the patients under our care.

The collateral venous system in late pregnancy: A systematic review of the literature.

Recent literature has reported an association between maternal supine sleep position and stillbirth during late pregnancy. In this position the gravid uterus almost completely obstructs the inferior vena cava. A small number of women experience supine hypotension, thought to be due in part to inadequate collateral venous circulation. The aim of this paper is to review the literature describing the anatomy of the collateral venous system and in particular the azygos system, the abdominal portion of which has not been well studied. A systematic review was conducted using the electronic databases: Medline, Embase, Scopus, and Google Scholar. Relevant anatomical and radiological literature concerning the azygos system in particular was reviewed. The search was limited to adult human studies only. The collateral venous system can be divided into superficial, intermediate and deep systems. The azygos system in particular provides immediate collateral venous circulation in the event of acute inferior vena caval obstruction. The abdominal portion of this pathway, including the ascending lumbar vein, has not been well studied and there are certain variations that can render it ineffective. In conclusion, the collateral venous system provides an alternative route for blood to flow back to the systemic circulation when acute occlusion of the inferior vena cava occurs in the supine position during late pregnancy. However, certain anatomical variations can render this pathway ineffective, and this could have implications for the development of supine hypotension and stillbirth in late pregnancy. Clin. Anat. 30:1087-1095, 2017. © 2017 Wiley Periodicals, Inc.

Vena Cava Responsiveness to Controlled Isovolumetric Respiratory Efforts.

OBJECTIVES: Respirophasic variation of inferior vena cava (IVC) size is affected by large variability with spontaneous breathing. This study aims at characterizing the dependence of IVC size on controlled changes in intrathoracic pressure. METHODS: Ten healthy subjects, in supine position, performed controlled isovolumetric respiratory efforts at functional residual capacity, attaining positive (5, 10, and 15 mmHg) and negative (-5, -10, and -15 mmHg) alveolar pressure levels. The isovolumetric constraint implies that equivalent changes are exhibited by alveolar and intrathoracic pressures during respiratory tasks. RESULTS: The IVC cross-sectional area equal to 2.88 ± 0.43 cm2 at baseline (alveolar pressure = 0 mmHg) was progressively decreased by both expiratory and inspiratory efforts of increasing strength, with diaphragmatic efforts producing larger effects than thoracic ones: -55 ± 15% decrease, at +15 mmHg of alveolar pressure (P < .01), -80 ± 33 ± 12% at -15 mmHg diaphragmatic (P < .01), -33 ± 12% at -15 mmHg thoracic. Significant IVC changes in size (P < .01) and pulsatility (P < .05), along with non significant reduction in the response to respiratory efforts, were also observed during the first 30 minutes of supine rest, detecting an increase in vascular filling, and taking place after switching from the standing to the supine position. CONCLUSIONS: This study quantified the dependence of the IVC cross-sectional area on controlled intrathoracic pressure changes and evidenced the stronger influence of diaphragmatic over thoracic activity. Individual variability in thoracic/diaphragmatic respiratory pattern should be considered in the interpretation of the respirophasic modulations of IVC size.

Valor pronóstico de la medición del diámetro y colapso inspiratorio de la vena cava inferior en la insuficiencia cardiaca aguda / Prognostic value of measuring the diameter and inspiratory collapse of the inferior vena cava in acute heart failure

Objetivos. Valorar la utilidad de la medición del diámetro y colapso de la vena cava inferior (VCI) en la insuficiencia cardiaca aguda (ICA), su relación con el pronóstico y con biomarcadores séricos de congestión. Pacientes y métodos. Estudio prospectivo observacional que incluyó 85 pacientes con ICA, clasificándolos en 4 grupos según el diámetro de la VCI (≤ o >20mm) y su colapso inspiratorio (< o ≥50%) al ingreso. Las variables de valoración fueron la mortalidad por IC y el evento combinado de mortalidad y reingreso por IC a los 180días. Resultados. El 24,7% de los pacientes presentó una VCI no dilatada y colapso ≥50% (grupo 1); el 20% VCI no dilatada y colapso <50% (grupo 2); el 5,9% VCI dilatada y colapso ≥50% (grupo 3); el 49,4% VCI dilatada y colapso <50% (grupo 4). La ausencia de colapso inspiratorio, pero no la dilatación de la VCI, se relacionó con concentraciones más elevadas de urea (p=0,007), creatinina (p=0,004), ácido úrico (p=0,008), NT-proBNP (p=0,009) y CA125 (p=0,005). La supervivencia libre de evento combinado a los 180días fue inferior en aquellos pacientes sin colapso de la VCI. Conclusiones. La dilatación y la ausencia de colapso inspiratorio de la VCI es frecuente en el contexto de la ICA. La ausencia de colapso inspiratorio de la VCI durante la fase de descompensación identifica un subgrupo de pacientes con peor pronóstico a los 6 meses (AU)

Objectives. To assess the utility of measuring the diameter and collapse of the inferior vena cava (IVC) in acute heart failure (AHF), its relationship with the prognosis and serum biomarkers of congestion. Patients and methods. An observational prospective study was conducted that included 85 patients with AHF, classifying them into 4 groups according to IVC diameter (≤ or >20mm) and inspiratory collapse (< or ≥50%) at admission. The endpoints were mortality due to HF and the combined event of mortality and readmission for HF at 180 days. Results. Some 24.7% of the patients had an undilated IVC and ≥50% collapse (group 1); 20% had an undilated IVC and <50% collapse (group 2), 5.9% had a dilated IVC and ≥50% collapse (group 3); and 49.4% had a dilated IVC and <50% collapse (group 4). The lack of inspiratory collapse but not IVC dilation was related to higher concentrations of urea (P=.007), creatinine (P=.004), uric acid (P=.008), NT-proBNP (P=.009) and CA125 (P=.005). Survival free of the combined event at 180 days was lower in those patients with no IVC collapse. Conclusions. Dilation and the absence of the inspiratory collapse of the IVC are common in the context of AHF. The lack of inspiratory collapse of the IVC during the decompensation phase identifies a subgroup of patients with poorer prognosis at 6 months (AU)

Venous cannula performance assessment in a realistic caval tree model.

OBJECTIVES: A new caval tree system was designed for realistic in vitro simulation. The objective of our study was to assess cannula performance for virtually wall-less versus standard percutaneous thin-walled venous cannulas in a setting of venous collapse in case of negative pressure. METHODS: For a collapsible caval model, a very flexible plastic material was selected, and a model with nine afferent veins was designed according to the anatomy of the vena cava. A flow bench was built including a lower reservoir holding the caval tree, built by taking into account the main afferent vessels and their flow provided by a reservoir 6 cm above. A cannula was inserted in this caval tree and connected to a centrifugal pump that, in turn, was connected to a reservoir positioned 83 cm above the second lower reservoir (after-load = 60 mmHg). Using the same pre-load, the simulated venous drainage for cardiopulmonary bypass was realized using a 24 F wall-less cannula (Smartcanula) and 25 F percutaneous cannula (Biomedicus), and stepwise increased augmentation (1500 RPM, 2000 and 2500 RPM) of venous drainage. RESULTS: For the thin wall and the wall-less cannulas, 36 pairs of flow and pressure measurements were realized for three different RPM values. The mean Q-values at 1500, 2000 and 2500 RPM were: 3.98 ± 0.01, 6.27 ± 0.02 and 9.81 ± 0.02 l/min for the wall-less cannula (P <0.0001), versus 2.74 ± 0.02, 3.06 ± 0.05, 6.78 ± 0.02 l/min for the thin-wall cannula (P <0.0001). The corresponding inlet pressure values were: -8.88 ± 0.01, -23.69 ± 0.81 and -70.22 ± 0.18 mmHg for the wall-less cannula (P <0.0001), versus -36.69 ± 1.88, -80.85 ± 1.71 and -101.83 ± 0.45 mmHg for the thin-wall cannula (P <0.0001). The thin-wall cannula showed mean Q-values 37% less and mean P values 26% more when compared with the wall-less cannula (P <0.0001). CONCLUSIONS: Our in vitro water test was able to mimic a negative pressure situation, where the wall-less cannula design performs better compared with the traditional thin-wall cannula.

The anatomy of vena cava in the work of Aretaeus of Cappadocia.

Aretaeus of Cappadocia did not deal systematically with the study of anatomy, as it can be assumed from the thorough study of his remaining work, as well as the references to the topics and the fragments of his lost treatises. We could also extract useful information on anatomy through his analytical descriptions about the various diseases in his remaining work. A perfect example is the anatomy of the upper and inferior vena cava exposed in his work on acute diseases.

Brillouin spectroscopy: a new tool to decipher viscoelastic properties of biological scaffold functionalized with nanoscale films.

BACKGROUND: In tissue engineering, the endothelialization of vascular scaffold can be a crucial step to improve graft patency. A functional cellularization requires coating surfaces. Since 2003, our group used polyelectrolyte multilayer films (PEMFs) made of poly(allylamine hydrochloride) and polystyren sulfonate to coat luminal surface of blood vessel. Previous results showed that PEMFs have remarkable effect on cellular behavior: adhesion, proliferation, differentiation. However, no method seems adapted for in vitro measurement of the viscoelastic shift after PEMFs buildup. OBJECTIVE: In this present work, we proposed to use a new analytical method based on Brillouin spectroscopy (BS) to investigate the influence PEMFs coating on vessel intrinsic viscoelasticy. METHODS: On human umbilical arteries and rabbit vessels, PEMFs were buildup and the luminal surfaces viscoelasticy were measuring by BS. RESULTS: It seems that these films do not alter dynamic functionality and BS could be an interesting method for understanding the role of the tissue architecture, the interrelation between the different structures constituting the wall and the influence of this architecture on the tissue behavior, especially with the characterized components of the different vascular wall. CONCLUSION: The ability of BS to characterize biological samples opens potential applications in tissue engineering field, especially as a tool for a better understanding of vascular diseases.

Estrutura, ultraestrutura e morfometria da veia cava de paca (Cuniculus paca Linnaeus, 1766) criada em cativeiro / Structure, ultrastructure and morphometry of the Vena cava in the paca (Cuniculus paca Linnaeus, 1766) raised in captivity

A paca (Cuniculus paca) é o segundo maior roedor da fauna brasileira. Apresenta carne de excelente qualidade, o que incentiva a criação comercial. Além disso, este animal pode tornar-se uma opção válida em experimentação embora poucas sejam as informações detalhadas sobre sua morfologia. Assim, objetivou-se descrever a morfologia, morfometria e ultraestrutura de segmentos das porções cranial e caudal da veia cava de quatro pacas (Cuniculus paca) adultas excedentes do plantel do Setor de Animais Silvestres do Departamento de Zootecnia da FCAV-Unesp. Os segmentos venosos foram analisados à microscopia de luz e à microscopia eletrônica de varredura. Foram mensuradas as espessuras do complexo formado pelas túnicas íntima e média, além da túnica adventícia e analisou-se os resultados pela estatística descritiva, teste "T" pareado (p<0,05). Em relação à espessura das túnicas estudadas, comprovou-se que os valores da espessura das túnicas íntima, média e adventícia, para todos os animais, foram significativamente maiores no segmento cranial. As camadas das paredes dos vasos apresentaram variações entre si quanto à estrutura e espessura, supostamente devido a uma adaptação à exigência funcional.

The paca (Cuniculus paca) is the second largest rodent of the Brazilian fauna. The excellent meat quality of this specie encourages the development of their commercial production. Moreover, this animal can become a viable alternative for animal experimentation although there exists scarce detailed information concerning their morphology. Therefore the purpose of this study is to describe the morphology, morphometry and ultrastructure in segments of the cranial and caudal portions of vena cava in four adult males and females of Cuniculus paca from the squad of Wild Animals Sector of Animal Science Department of FCAV-Unesp. Parts of the segments were examined by light microscopy and part by scanning electron microscopy. Thickness measures of the tunica intima and media complex and tunica adventitia of the vena cava were taken and analyzed using "T" test (p<0.05). In vena cava the thickness values of the intima, media and adventitia, for all animals, were significantly higher in the cranial segment. The layers of the vessel walls showed variations in structure and thickness, presumably due to an adaptation to functional demand.

Radiographic evaluation of central venous catheter position: anatomic correlation using gated coronary computed tomographic angiography.

PURPOSE: To determine the best radiographic landmark for the cavoatrial junction (CAJ) using electrocardiographic-gated, 64-row multidetector coronary computed tomographic angiography (CTA). MATERIALS AND METHODS: Institutional Review Board approval was obtained. Patient age, sex, weight, and height were recorded. The CAJ was localized by 2 readers using multiplanar CTA, cross-referenced with a scout topogram. Designated radiographic landmarks (the carina, intersection between the bronchus intermedius and the right heart border, and the inflection of the right heart border) were assessed for visibility and vertical distance from the CAJ. RESULTS: Sixty consecutive CTA studies (39 men, 21 women; age range, 27 to 98 y; mean±SD, 55±15 y) were analyzed. The closest radiographic landmark to the CAJ was the intersection between the bronchus intermedius and the right heart border (0.9±0.8 cm above the CAJ), visible in 71% of patients. The second closest radiographic landmark was the inflection of the right heart border (1±0.8 cm above the CAJ), visible in 84% of patients. The carina was visible on 100% of topograms, 4.2±1.1 cm above the CAJ. There was no strong correlation between age, weight, height, or sex and the visibility or distance of landmarks from the CAJ. CONCLUSIONS: The intersection of the bronchus intermedius with the right heart border and the inflection of the right heart border are the closest radiographic landmarks to the CAJ. When these landmarks are not identifiable, the most uniformly visible radiographic landmark is the carina.

Evaluation of migration forces of a retrievable filter: experimental setup and finite element study.

The aim of this paper is to provide a computational study of migration forces of a retrievable filter (Günther Tulip inferior vena cava filter). Using an experimental setup and finite element simulation, the migration forces and stress at the end of the anchored hooks in the struts were estimated. After that, the estimation value of migration stress (τ(rup)) was used to analyze the effect of different mechanical factors (strut thickness, vena cava diameter) in the migration of the IVC filter. Our results show that the migration stress is τ(rup)=4.37 N/mm(2). Using this value we obtain that the filter with higher strut diameter (ϕ(strut)=0.45 mm) shows the maximal migration forces in every cava diameter. On the other hand, the value of the migration force decreases when the cava diameter increases. In addition, the finite element simulations also show that there are contact between the struts of the filter and the vein in regions close to the anchors.

The right inferior phrenic artery: path of its ascending branch at the vena caval foramen.

The ascending branch of the right inferior phrenic artery is generally understood to pass to the lateral side of the vena caval foramen, on the inferior surface of the diaphragm. A study of 16 cadavers shows that the artery may pass through the vena caval foramen to run on the superior surface of the diaphragm, before returning to the inferior surface by passing through the muscle of the diaphragm.

Morphology of haemal nodes in the roe deer (Capreolus capreolus).

The present study was aimed at the determination of the morphology of haemal nodes in the roe deer (Capreolus capreolus). The morphology of haemal nodes located in the abdominal and thoracic cavities of six roe deer (two adult male, two adult female and two foetuses) was studied by gross inspection and histological methods. Oval- and round-shaped haemal nodes with colours varying from pink to dark red were observed particularly between the abdominal aorta and caudal vena cava, and at the beginning of the main branches of the abdominal aorta. These nodes, having connection only with blood vessels, were covered with a thin or thick capsule of connective tissue in the foetus and the adult respectively. Trabeculae were not observed in foetal nodes. In adults, the capsule, trabeculae and, in particular, the sinuses were strongly supported by reticular fibres and cells. The morphology of these nodes displayed similarity to that of other ruminant species.

Prediction of the frictional behavior of mammalian tissues against biomaterials.

Frictional and adhesion properties are important characteristics to be assessed in the development of new materials for biological applications, particularly for medical devices such as catheters. In this work a new computational method that predicts frictional and adhesive forces is presented. A multi-asperities adhesion model, based on the JKR theory, coupled with a Monte Carlo method was employed, together with a three components friction model. This takes into account interfacial adhesion, asperities deformation and viscous lubricant film shearing action. We have estimated the frictional coefficients of silicone and polyurethane (common materials in catheters) against aorta and vena cava. In order to do this, we have measured the surface properties of the two blood vessels tissues, such as surface energy components, asperity height distribution and asperity radius of curvature. These data have not been previously reported. The predictions in both the dry and in lubricated (with blood) cases are in very good agreement with our published experimental data of the same materials/tissue combinations.

Histological assessment of selected blood vessels of the phocid seals (northern elephant and harbour seals).

Phocid seals exhibit vascular adaptations that allow them to undertake prolonged deep dives. These vascular adaptations are either unique to phocids, or are modified vascular equivalents to those present in terrestrial mammals. One such adaptation, the aortic bulb, is a spherical enlargement of the ascending aorta specific to phocid seals. Its histological make-up consists of a reinforced tunica media with circular and longitudinal layers of elastic fibres. This reinforcement enables multi-axial deformation of the aortic bulb, thus complementing its function as a prominent elastic reservoir or 'windkessel'. A second adaptation, the hepatic sinus, is an asymmetrical dilation of the abdominal portion of the caudal vena cava and accompanying hepatic veins. The hepatic sinus is comprised of a relatively thin tunica media, with a scant smooth muscle component. The bulk of the sinus wall is comprised of tunica adventitia. A third vascular adaptation distinctive to the phocids is the pericardial venous plexus, composed of convoluted veins circumnavigating the perimeter of the heart. Microscopically, these veins have a thick tunica media and also contain valves. Smaller arteries, venules and distinct capillary beds are observed interspersed in-between these veins. It can be hypothesized, that in seals, certain vascular embryonic development may be arrested at an earlier embryonic stage, resulting in these unusual vascular formations. These modifications play a vital role in blood pressure regulation and distribution of oxygenated blood during prolonged deep diving. The purpose of this work was to elucidate the histological aspects of these unique vascular modifications and relate them to specific function.