Pulmonary valve: contradictions in terminology and anatomy

Data on the anatomy of human heart valves is of a great importance for cardiac surgery, X-ray and ultrasound diagnostics, and additive technologies in bioengineering. This review analyzed Russian and English-written papers and presented contradictions of terminology, macroscopic and microscopic structure, topography of the normal pulmonary valve. The article compared such terms as «pulmonary valve» and «pulmonary root», the approaches of different scientific sources for naming the sinuses and leaflets and analyzed constituents of the pulmonary valve complex. Pulmonary root appearedus to be a distinct structure that includes the distal part of right ventricular outlet and proximal part of the pulmonary trunk. Interleaflet triangles and valvular commissures as well as semilunar leaflets and sinuses of Valsalva are thought to be parts of pulmonary valve complex. According to modern concepts, interleaflet triangles and valvular commissures are not the same and should be distinguished. The mouth of the pulmonary root is not surrounded with planar fibrous ring which anybody could reveal by dissection or histology technics, so the “fibrous ring” of the pulmonary artery is nothing more than an anatomical myth. The paper cited morphometrical data on the perimeter, valve diameters, sizes of semilunar leaflets and sinuses, revealed various models of regression and correlation between the size of the valve and body parameters. We summarized data on cell and fiber architectonics of the valve. Terminological and morphometric consensus in heart valves anatomy is the mandatory step on the way to the evidence-based morphology

Anatomical and morphometric variation of the orifice of the left atrial appendage

Background. Knowledge of the anatomical variations of the shape and size of the left atrial appendage orifice, along with the relationship of its size with the number of left atrial appendage lobes, the size of its neck, the left atrioventricular orifice, the left atrioventricular fibrous ring and the distance to it, as well as with the overall dimensions of the heart is important in personalized surgical planning for the installation of occluder device and left atrial appendage clipping to prevent thromboembolic complications. Aim. To identify anatomical variations in the shape and size of the left atrial appendage orifice and analyze the dependence of these parameters on the number of left atrial appendage lobes, cardiac dimensions, mitral orifice area and the distance from the orifice to the left atrioventricular fibrous ring. Material and methods. We studied 37 heart specimens fixed in 10% formalin in adults who died of non-cardiac causes. Morphometry was performed by an ShTsTs-1-200 digital calliper, drawing needle calliper and 4UM goniometer. We used nonparametric analysis of variance, Spearman correlation coefficient (Rs), univariate regression analysis, cross-tabulation analysis. The results are presented as the mean and standard deviation. The significance of differences was assessed by using the Mann–Whitney U-test. Results. The left atrial appendage was single-lobed in 16.2% of cases, two-lobed in 62.2%, and three-lobed in 18.9%. The length of the orifice was 12.7±4.03 mm, and the width was 9.5±3.62 mm. The elliptical shaped orifices were 3.1 times more common than round ones (28/37 and 9/37, p=0.0027). In 17 of 28, oval orifices were located predominantly horizontally, in nine predominantly vertical, in one case obliquely. Vertically oriented orifices were significantly longer and slightly wider compared with others. The number of the left atrial appendage lobes was not a reliable predictor for the orifice shape (p=0.055). The size of the appendage orifice, variants of its shape and the distance to the left atrioventricular opening were unrelated to each other. The length and width of the orifice were correlated with each other (Rs 0.68) and correlated with the diameters of the left atrioventricular fibrous ring size. The orifice length correlated with the length of the ventricular complex (Rs 0.47) and heart width (Rs 0.53). The orifice width correlated only with the heart width (Rs 0.4) but not with other dimensions. As the length and width of the ventricular complex increased, the orifice length increased exponentially. The distance from the left atrial appendage orifice to the left atrioventricular opening did not depend on either the orifice shape or its orientation. Conclusion. In a normal human adult heart, the shape of the left atrial appendage orifice was oval, less often round, and the size of the orifice depends on the length and the width of the ventricles. © Eco-Vector, 2022. All rights reserved

Morphometric characteristics and histotopography of the left atrium walls

Background. Knowledge of the anatomical features of the left atrium walls will minimize complications during the “Cox-Maze” surgery. Aim. To clarify common features and local anatomical specificities of the anterosuperior, lateral and inferior walls of the left atrial body of the heart of an adult. Material and methods. From 60 preparations of the hearts of men and women aged 35-89 years who died from non-cardiac causes, 61 histotopograms and 180 anatomical sections of the left atrium walls were made. A stereoscopic microscope (×4.7-15 magnification), a histological microscope (×40 magnification), and an image recognition program were used. Nonparametric dispersion, correlation, one-way regression analysis were applied. The significance of differences was assessed by the Mann-Whitney U-test. The results were presented as medians. Results. Anatomical markers of the anterosuperior wall were a compact group of transverse myocardial fibers (anterior interatrial Bachmann bundle) and a thinned section of the lower third of the medial half of the wall. A feature of the lateral wall was a group of oblique myocardial fibers (left lateral ridge). The inferior wall was characterized by well-developed subepicardial tissue. Anteroposterior wall in the medial area (5130 µm) and lateral wall (5243 µm) were thin. The epicardium with subepicardial tissue in the medial part of the inferior wall was thicker (4750 µm) than in the lateral (2651 µm) and anterosuperior (2535 µm) walls. The myocardium of the anteroposterior wall (2714 µm) was thicker than the myocardium of both the lateral (2213 µm) and inferior wall in its central (1947 µm) and lateral (1913 µm) sections. The median thickness of the endocardium of different walls varied from 335 to 426 µm. The wall thickness in the upper third mostly depended primarily on the myocardium thickness, and in the inferior third on the epicardium and subepicardial tissue thickness. Conclusion. For the walls of the left atrium, their thickening towards the coronary sulcus was common due to the subepicardial adipose tissue. The peculiarities were the differences of the left atrium walls in thickness and their unique pattern of myocardial anatomy. © Eco-Vector, 2022. All rights reserved

Morphometric topography of the left atrial appendage in human adult heart

Topography of the left atrial appendage is of importance for supraventricular arrhythmias surgery and sealing of the appendage orifice to prevent thromboembolism in cryptogenic strokes. The aim was to explore the common position of the appendage and delineate variants of its adjacent anatomy in human adults by means cadaveric morphometrics. Material and methods. We studied 54 silicone-filled heart specimens of 200–400 g. With the caliper, we measured the distances from the base of the left atrial appendage to the cardiac apex, to the structures of the atrial complex, nearest large blood vessels, as well as to the left coronary artery. Results. The base of the appendage was 87 ± 13.1 mm from the cardiac apex and 49.7 ± 7.0 mm from the right appendage. The distance from the appendage to the superior caval vein (36.4 ± 8.1 mm) was 16 % longer than the distance to the ascending aorta (30.4 ± 6.4 mm), 1.25 times less than the distance to the oval fossa (45.2 ± 6.0 mm), 1.5 times less than the distance to the inferior caval vein (55.5 ± 8.7). The smallest median value (9.6 mm) and the largest variation (1.4–15.2 mm) were found for the distance to the pulmonary trunk. Four pulmonary veins inflowed to the atrium at different distances from the appendage opening. In 59.6 %, we revealed the left upper pulmonary vein to be closest to the auricle. The mouth of that was 43 % higher and 57 % at the same level with the appendage opening (p = 0.07). The left coronary artery ran 2.63–18.74 mm inferiorly to the appendage. Interrelations of average strength were found for the parameters of atrial complex. The study showed the length of the ventricular complex as being an unpredictable parameter for determining the adjacent anatomy of left atrial appendage. Conclusions. The morphometric parameters and their interrelations are proposed to use as reference values and criteria for determining the normal atrial complex

Вариантная анатомия формы полости и внутреннего рельефа стенок левого ушка сердца

Introduction. The evaluation of the shape of the left atrial appendage into interconnection with the internal relief of its wall is of an importance for discovering anatomical patterns of the left atrium, which appears to be the most thrombogenic and are associated with a high thromboembolic risk from this chamber.The objective was to study features of the internal relief of the walls of the left atrial appendage of the adult heart and to find the dependence of these features on the size and shape of the appendage.Methods and material. We studied 68 left atrial silicone casts prepared from the hearts of 35–89 years men and women died from non-cardiac causes. By means a caliper, we measured the length and width of the cavity of the left atrial appendage, determined the shape, the number of lobes and intertrabecular spaces. With Image J program, we estimated the proportion of the area occupied by these spaces and pectinate muscles in pixels from photographs of the anterosuperior surface of the appendage. We used correlation analysis, Mann–Whitney U-test.Results. We found two-lobed appendages commonly than single-lobed and three-lobed. The number of intertrabecular spaces was 4–41 (median 21), with one-lobed appendages having fewer than twoand three-lobed. The same parameter was higher in the «chicken wing» than in the «arrowhead» specimens (23 vs 18, p=0.004). The proportion of the area occupied by the pectinate muscles and intertrabecular spaces in the left atrial appendage was 47 % (16–83 %) and showed none association with the shape of the cavity and the number of lobes.Conclusion. The number of intertrabecular spaces in the walls of the left atrial appendage correlated with its length and width and was the smallest in single-lobed specimens and in the appendages of the «arrowhead» shape. The abundant intertrabecular spaces were common for «chicken wing» variant of the left atrial appendage.Введение. Необходимость сопоставления формы полости левого ушка сердца с особенностями его внутреннего рельефа связана с поиском анатомических паттернов левого предсердия, наиболее вероятных по тромбообразованию в ушке и ассоциированных с высоким тромбоэмболическим риском из этой камеры.Цель – изучить особенности внутреннего рельефа стенок левого ушка сердца взрослого человека и выявить зависимость этих особенностей от размеров и формы полости ушка.Методы и материалы. На 68 силиконовых слепках левого предсердия мужчин и женщин 35–89 лет, умерших от причин, не связанных с болезнями сердца, штангенциркулем измеряли длину и ширину левого ушка сердца, определяли форму его полости, число долей и межтрабекулярных пространств. Долю площади, занятой этими пространствами и гребенчатыми мышцами, оценивали в пикселах по фотографиям передне-верхней поверхности левого ушка сердца в программе «Image J» (2019). Использовали корреляционный анализ, U-критерий Манна – Уитни.Результаты. Двухдолевые ушки были отмечены чаще, чем однодолевые и трехдолевые. Число межтрабекулярных пространств варьировало от 4 до 41 (медиана – 21), у однодолевых ушек было меньше, чем у двухдолевых и трехдолевых. Этот параметр у ушек в форме куриного крыла был больше, чем на препаратах в форме наконечника стрелы (23 vs 18, р=0,004). Доля площади, занятой гребенчатыми мышцами и межтрабекулярными пространствами, в левом ушке сердца составила 47 % (16–83 %) и не зависела от формы полости и числа долей ушка.Заключение. Число межтрабекулярных пространств стенок левого ушка сердца коррелировало с его длиной и шириной и было наименьшим в однодолевых ушках и в ушках формы наконечника стрелы. Максимальное число межтрабекулярных пространств было характерно для левого ушка сердца, имевшего форму куриного крыла

Does the wall thickness of the left atrial appendage and its isthmus depend on their macroscopic characteristics?

Knowledge in interrelations between gross anatomy of the left atrial appendage (LAA) and thickness of the walls of LAA and periauricular area enables decreasing operational risks in LAA ostium occluding and «Cox-Maze» surgery for atrial fibrillation. The aim of the study was to identify significant interrelations between the macroscopic characteristics of the LAA (size, shape, number of lobes) and the parameters of the wall thickness of the LAA and its isthmus. Material and methods. The study includes 50 heart specimens of patients died from non-cardiac diseases. We examined 60 anatomical sections from 30 hearts by means Olympus SZX2-ZB10 microscope, and histological slices from 20 hearts. Results. The layers of the LAA wall were thinner than those in the isthmus. The thickness of LAA walls did not show direct correlation with the external dimensions of LAA. We found inverse correlation (Rs = – 0.4, p < 0,05) between the thickness of the myocardium, endocardium and some external sizes of LAA. The wall thickness of «chicken wing», «cauliflower» and «arrowhead» was the same. The wall of single-lobe LAA was thinner than that of two-lobed LAA (p = 0.036). The LAA isthmus wall was thinner (p = 0.03) in hearts with «cauliflower» LAA compared to hearts with LAA resembled a «chicken wing». Differences in wall thickness in LAA of various shapes were due to the degree of subepicardial fatty tissue development. Intracardiac operations should be done with the utmost care in patients with «cauliflower» LAA and single-lobe LAA to avoid damage of the LAA and periauricular area. Conclusions. The research found clinically significant interrelations between the LAA wall thickness and the number of its lobes as well as between the LAA isthmus wall thickness and LAA shape variants

The Coronary Sinus and Adjacent Structures in Human Adult Hearts: Morphometrical Cadaveric Anatomy

The aim of this study was to explore the anatomy and morphometry of the coronary sinus in hearts of adult humans, clarify position of the sinus to left atrium, left fibrous ring and adjacent arteries and describe topographic variants for adjacent anatomy of the coronary sinus in hearts of various types of coronary dominance. We studied 40 hearts weighing 200-420 g, obtained from patients who died from non-cardiac causes. We dissected 30 non-injected macroscopic specimens preserved into 4% PBS formalin to reveal and measure coronary sinus and neighboring coronary arteries. The rest 10 hearts we used for preparing histological slices from the points of the beginning of the sinus, in the middle, and near the "crux cordis". We measured large and small diameters, circumference, wall thickness of the coronary sinus, as well as explored relative position of the coronary sinus, adjacent arteries, left atrium and left fibrous ring.The reference range of coronary sinus length was 33.76-48.4 mm. The median (Me) of the circumference of the coronary sinus increased from 13.87 mm at the beginning of the sinus to 23.99 mm at the "crux cordis". In some specimens, the cross section of the sinus looked flattened in the anteroposterior direction; in others, it appeared to be flattened basoapically. We distinguished two anatomical patterns of the coronary sinus: Subepicardial and intramyocardial. The first we proposed to term myocardialless or, simply, "naked", and the second type we named muscularized. We proposed to divide the latter into partially and completely muscularized. Lack of adventitia between the myocardial sheet and tunica media of the coronary sinus allowed us to consider myocardial sleeves as an integral structure of the intramyocardial sinus wall. The wall thickness value of the coronary sinus at the point of origin, in the middle, and at the point of its turning anterosuperiorly toward the right atrium had no differences, but significantly depended on the myocardial cover and on the position of the coronary sinus in the left atrioventricular sulcus. The distance from the sinus to the posterior wall of the left atrium was 0.15-7.66 mm (Me 0.91 mm); the distance to the left fibrous ring was 2.9-13.7 mm (Me 7.9 mm). We found four variants of topographic and anatomical relations of the sinus and its adjacent arteries. Commonly, arteries were located below the coronary sinus. The ranges of variability of morphometric values of the coronary sinus and neighboring structures may be considered as reference values of the anatomy of the coronary sinus in the normal human adult heart. © 2022 Sociedad Anatomica Espanola. All rights reserved

Size confinement effect in graphene grown on 6H-SiC (0001) substrate

We have observed the energy structure in the density of occupied states of graphene grown on n-type 6H-SiC (0001). The structure revealed with photoelectron spectroscopy is described by creation of the quantum well states whose number and the energy position (E1 = 0.3 eV, E2 = 1.2 eV, E3 = 2.6 eV ) coincide with the calculated ones for deep (V = 2.9 eV) and narrow (d = 2.15 A) quantum well formed by potential relief of the valence bands in the structure graphene/n-SiC. We believe that the quantum well states should be formed also in graphene on dielectric and in suspended graphene.Comment: 7 pages, 4 figure