Single coronary artery with transeptal anterior interventricular artery: a rare anatomical feature

A case of a single coronary artery is described in a 50-year-old male, who died of asphyxia. The artery originated in the right aortic sinus and from it another artery emerged which crossed the crista supraventricularis and the interventricular septum and returned to occupy a subepicardial position in the lower half of the anterior interventricular sulcus. This partially intramyocardial artery was considered as the anterior interventricular artery. A literature survey showed only five cases with similar characteristics. The importance of this anomaly derives from the risk of damage occurring to the intramyocardial artery during a manipulation of the infundibulum of the right ventricle in a cardiac surgery or from problems of perfusion during coronary bypass procedures.     

Vascular supply of the anterior interventricular epicardial nerves and ventricular Purkinje fibers in the porcine hearts

The aim of this study was to perform a pilot histological and quantitative analysis of the blood vessels accompanying the epicardial nerves (vasa nervorum) in the porcine hearts. Twenty healthy porcine hearts were used in this study. The blood vessels were analyzed by light microscopy using four different staining techniques in transverse sections taken from the upper, middle, and lower segments of the anterior part of the interventricular region and the adjacent parts of the right and left ventricles containing epicardial nerves and the endocardial peripheral parts of the Purkinje fibers. In total, 317 epicardial nerves were detected. The vasa nervorum were present in 75.7% of these nerves. The vasa nervorum resembled arterioles and postcapillary and collecting venules. One hundred and forty nine epicardial nerves were perivascular, located in the adventitia of the anterior interventricular artery and vein. The remaining 168 nerves ran freely through the epicardial interstitium. The presence of the vasa nervorum was not related to topographical location or nerve diameter. Additionally, from a total of 33 analyzed ventricular complexes of Purkinje fibers small blood vessels located in their proximity were identified in only two cases. It can be concluded that the majority of the anterior epicardial nerves of porcine heart possess well-developed vasa nervorum. In contrast, similar blood vessels are rarely present in the vicinity of the Purkinje fibers. The data obtained contribute to a better understanding of the nutrition of the cardiac nerves.     

Diameter-dependent axial prestretch of porcine coronary arteries and veins

The pressure-diameter relation (PDR) and the wall strain of coronary blood vessels have important implications for coronary blood flow and arthrosclerosis, respectively. Previous studies have shown that these mechanical quantities are significantly affected by the axial stretch of the vessels. The objective of this study was to measure the physiological axial stretch in the coronary vasculature; i.e., from left anterior descending (LAD) artery tree to coronary sinus vein and to determine its effect on the PDR and hence wall stiffness. Silicone elastomer was perfused through the LAD artery and coronary sinus trees to cast the vessels at the physiologic pressure. The results show that the physiological axial stretch exists for orders 4 to 11 (> 24 μm in diameter) arteries and orders -4 to -12 (>38 μm in diameter) veins but vanishes for the smaller vessels. Statistically, the axial stretch is higher for larger vessels and is higher for arteries than veins. The axial stretch λ(z) shows a linear variation with the order number (n) as: λ(z) = 0.062n + 0.75 (R(2) = 0.99) for artery and λ(z) = -0.029n + 0.89 (R(2) = 0.99) for vein. The mechanical analysis shows that the axial stretch significantly affects the PDR of the larger vessels. The circumferential stretch/strain was found to be significantly higher for the epicardial arteries (orders 9-11), which are free of myocardium constraint, than the intramyocardial arteries (orders 4-8). These findings have fundamental implications for coronary blood vessel mechanics.     

Morphological study on the thebesian veins of the right cavities of the heart in the dog.

The authors studied 48 dog hearts, using the injection-corrosion-fluorescence method to study the topography of thebesian veins in all the walls of the cardiac cavities. The thebesian veins are small, situated deep in the myocardium, opening after a short course into the cardiac cavities, by small openings with diameters in general not exceeding 1 mm, known 'foraminula'. They have a centripetal course, while every other vein in the heart has a centrifugal one, to reach the subepicardial zone. In the heart of the dog five types of thebesian veins were served: arboriform, sinuous, brush-like, canaliculated and stellate. The thebesian veins are almost regularly found in every wall of the cardiac cavities. The authors also observed that they predominated in the right ventricle (81.24%) and in the right atrium (77.43%).     

Subepicardial endothelial cells invade the embryonic ventricle wall to form coronary arteries

Coronary arteries bring blood flow to the heart muscle. Understanding the developmental program of the coronary arteries provides insights into the treatment of coronary artery diseases. Multiple sources have been described as contributing to coronary arteries including the proepicardium, sinus venosus (SV), and endocardium. However, the developmental origins of coronary vessels are still under intense study. We have produced a new genetic tool for studying coronary development, an AplnCreER mouse line, which expresses an inducible Cre recombinase specifically in developing coronary vessels. Quantitative analysis of coronary development and timed induction of AplnCreER fate tracing showed that the progenies of subepicardial endothelial cells (ECs) both invade the compact myocardium to form coronary arteries and remain on the surface to produce veins. We found that these subepicardial ECs are the major sources of intramyocardial coronary vessels in the developing heart. In vitro explant assays indicate that the majority of these subepicardial ECs arise from endocardium of the SV and atrium, but not from ventricular endocardium. Clonal analysis of Apln-positive cells indicates that a single subepicardial EC contributes equally to both coronary arteries and veins. Collectively, these data suggested that subepicardial ECs are the major source of intramyocardial coronary arteries in the ventricle wall, and that coronary arteries and veins have a common origin in the developing heart.     

Adaptive structures of the venous bed of the heart in normal state and in congenital defects

By means of a complex of anatomical, morphometrical and histological methods in 45 normally formed and in 179 abnormally developed hearts from persons of both sex died at various age, various links of the venous blood outflow from the myocardium have been investigated. Various parts, differing in a number of morphological signs, have been distinguished: coronary sinus, subepicardial veins, paired sinusoid veins, sinusoids of the myocardium and endocardial eversions. Regulation of their blood stream is performed by a system of simple muscular and infundibular valves, by intimal and muscular cushions, by connective tissue and muscular bridges. These adaptive structures occur in the normal heart also, but at congenital heart diseases, however, they reach an essentially greater development. Their localization is predominantly in the area of venular, vein, sinusoid bifurcations and endocardial eversions. Regular functioning of some parts of them is performed not by nonstriated, but by the cardiac muscular tissue. The coordinating work of the formation in question is one of the factors, that ensures the state of compensation in the defectively formed heart.     

Outflow pathways of venous blood from the myocardium in the dog and structures participating in their regulation

The intramural pathways of the venous blood outflow from the cardiac wall have been studied histologically, histochemically and micrometrically in 20 control and 84 experimental dogs with an artificially produced circulatory disturbances, peculiar for congenital heart disease (open arterial canal, coarctation of the aorta and stenosis of the pulmonary trunk). The experimental animals have been observed for 6-12 months. In the venous line of the coronary basin several morphologically differed parts, anatomically and functionally connected between themselves and ensuring blood outflow from the myocardium, are distinguished: coronary sinus, subepicardial veins, paired sinusoid veins, myocardial sinusoids and endocardial cushions. In each of them there are their own adaptive structures, participating in regulation of the venous blood stream. In the cardial sinus, in the subepicardial and paired sinusoid veins--these are valves of various complexity. In the myocardial sinusoids, the regulatory function, together with the valves, are performed by the intimal and muscle cushions, connective tissue and muscle bridges. In the endocardial cushions they are realized by the valves, muscle sphincters, bundles of obliquely and longitudinally oriented leiomyocytes. All the adaptive structures mentioned are also found in the hearts of the control animals. Under modelling various hemodynamic disturbances, the degree of their development increases sharply. The latter ensures the maintenance of an optimal regimen of blood circulation in the myocardium of a functionally loaded heart and prevents development of decompensation in the organ.     

New morphological aspects of blood islands formation in the embryonic mouse hearts

Vasculogenesis in embryonic hearts proceeds by formation of aggregates consisting of erythroblasts and endothelial cells. These aggregates are called blood-islands or blood-island-like structures. We aimed to characterize blood islands in mouse embryonic hearts at stages spanning from 11 dpc through 13 dpc, i.e. prior to the establishment of the coronary circulation. Our observations suggested that there are two types of blood islands. One formed by migrating nucleated erythroblasts, which associated with migrating endothelial cell and the second by in situ emergence of two kinds of cells belonging to separate populations: one resembling an erythroblast progenitor and the second resembling an endothelial-cell progenitor. The subepicardial blood islands contain nucleated erythroblasts, undifferentiated mesenchymal cells, platelets, and early lymphocytes. The subepicardial blood islands resemble vesicles with protruding prongs directed toward the myocardium. Ahead of the prongs, angiogenic sprouting and degradation of fibronectin is observed. Vesicles gradually change their shape from spherical to tubular at 13 dpc and grow and extend along the interventricular sulcuses forming vascular tubes. We presume that the vascular tubes located within the interventricular sulcuses are precursors of coronary veins. Our data seems to indicate that embryonic heart vasculogenesis is accompanied by hematopoiesis     

Valvular apparatus of the cardiac veins in the pig]

The valvular apparatus of the subepicardial venous network has been studied in reflected light of the diaphragmated source. Structure, form and variations of the valvular apparatus have been determined in different parts of the coronary sinus, in the large cardiac vein, in the median cardiac and in the posterior veins of the left ventricle and their main branches.     

Venous valves in the large branches of superior vena cava

In 97 human cadavers the valves of the following blood vessels were investigated with regard to their cusps and their sizes and positions: the internal jugular veins, the subclavian veins, the brachiocephalic veins, and the superior vena cava. The cusps of each of the valves, which consist of two or three parts, are neither always of equal size nor obligatorily sufficient. Unipartite valves may be sufficient as well as insufficient. Internal jugular veins: The inferior bulb of the internal jugular vein is provided with valves which in 6% of the cases consist of three parts, in 66% of two parts, and in 15% of only one cusp. The concave margins of most of them go down as far as the venous angle. The convex edges attached to the wall of the vein extend to a higher level on the right side than on the left. In 13% there do not exist any valves. Varieties are described separately in this paper. Subclavian veins: Valves are found along the length of the vessel. Only few of them reach the venous angle. In rare cases there exist two valves: one at the beginning, the other at the end of the subclavian vein. In 4% of the cases the valves consist of three, in 75% of two cusps. In 12% they are unipartite. In 9% there are no valves to be found. The right side is more often without valves than the left. Brachiocephalic veins: Only a minority of these vessels is provided with valves. Most of these consist of one cusp, are insufficient, and are situated in the left innominate vein.(ABSTRACT TRUNCATED AT 250 WORDS)     

Catheter-based antegrade intracoronary viral gene delivery with coronary venous blockade

The purpose of this study is to evaluate the feasibility of percutaneous antegrade myocardial gene transfer (PAMGT). A consistent and safe technique for in vivo gene transfer is required for clinical application of myocardial gene therapy. PAMGT with concomitant coronary venous blockade was performed in 12 swine. The myocardium was preconditioned with 1 min of occlusion of the left anterior descending and left circumflex arteries. The anterior interventricular vein was occluded during left anterior descending artery delivery, and the great cardiac vein at the entrance of the middle cardiac vein was occluded during left circumflex artery delivery. With arterial and venous balloons inflated (3 min) and after adenosine (25 mug) injection, PAMGT was performed by antegrade injection of an adenoviral solution (1 ml of 10(11) plaque-forming units in each coronary artery) carrying beta-galactosidase or saline through the center lumen of the angioplasty balloon. In one set of animals, PAMGT was performed with selective coronary vein blockade (n = 9); in another set of animals, PAMGT was performed without coronary vein blockade (n = 5). At 1 wk after gene delivery, the animals were killed. Quantitative beta-galactosidase analysis was performed in the left and right ventricular walls. PAMGT was successfully performed in all animals with and without concomitant occlusion of the coronary veins. Quantitative beta-galactosidase analysis showed that PAMGT with coronary blockade was superior to PAMGT without coronary blockade. beta-Galactosidase activity increased significantly in the beta-galactosidase group compared with the saline group: 1.34 +/- 0.18 vs. 0.81 +/- 0.1 ng (P 相似文献   

Assessment of the Coronary Venous System Using 256-Slice Computed Tomography

Purpose

To investigate the coronary venous system and its relation to adjacent structures using 256-slice computed tomography (CT).

Materials and Methods

The study consisted of 102 patients who underwent coronary CT angiography (CTA) using 256-slice CT. For each patient, the coronary venous system and its relation to adjacent structures were evaluated. The appropriate locations and diameters of the posterior interventricular vein (PIV), posterior vein of the left ventricle (PVLV) and the left marginal vein (LMV) were detected. The paired student''s t test was used to evaluate the difference between the diameter of the coronary sinus (CS) ostium in anteroposterior direction and that in superoinferior direction.

Results

The CS, great cardiac vein (GCV), PIV, and anterior interventricular vein (AIV) were visualized in all cases. It was possible to evaluate at least one main vein with adequate caliber and regular course for cardiac resynchronization therapy (CRT) in 96.1% of these cases. The diameter of the CS ostium in superoinferior direction (11.7±2.1 mm) was larger than that in anteroposterior direction (9.0±2.0 mm) (t = 13.511, P<0.05). For the majority of the cases, the CS-GCV was located above the level of the mitral valve annulus (MVA), while the left circumflex coronary artery (LCX) was coursed between the CS-GCV and the MVA. LMV had more intersection with the circumflex or circumflex marginal than PVLV.

Conclusion

256-slice CT provides superior noninvasive evaluation of the coronary venous system which has important clinical implications.     

Increased expression of bradykinin type-1 receptors in endothelium of intramyocardial coronary vessels in human failing hearts

In experimental animals, bradykinin type-1 receptors (BK-1Rs) are induced during inflammation and ischemia, and, by exerting either cardioprotective or cardiotoxic effects, they may contribute to the pathogenesis of heart failure. Nothing is known about the expression of BK-1Rs in human heart failure. Human heart tissue was obtained from excised hearts of patients undergoing cardiac transplantation (n = 13), due to idiopathic dilated cardiomyopathy (IDC; n = 7) or to coronary heart disease (CHD; n = 6), and from normal hearts (n = 6). The expression of BK-1Rs was analyzed by means of competitive RT-PCR, Western blot analysis, and immunohistochemistry. Expression of BK-1R mRNA was increased in both IDC (2.8-fold) and CHD (2.1-fold) hearts compared with normal hearts. The observed changes were verified at the protein level. Expression of BK-1Rs in failing hearts localized to the endothelium of intramyocardial coronary vessels and correlated with an increased expression of TNF-alpha in the vessel wall. Treatment of human coronary artery endothelial cells with TNF-alpha increases their BK-1R expression. These novel results show that BK-1Rs are induced in the endothelium of intramyocardial coronary vessels in failing human hearts and so may participate in the pathogenesis of heart failure.     

Autonomic nervous system regulation of epicardial coronary vein systolic and diastolic blood velocity as measured by a laser Doppler velocimeter

The velocity of blood in a major epicardial coronary vein accompanying the left anterior descending coronary artery of dogs was measured by means of a 140-micron fiber optic probe connected to a laser Doppler velocimeter. Right atrial pressure, left ventricular intramyocardial and cavity pressures, aortic pressure, as well as peripheral and central coronary venous pressures were compared with the velocity of blood measured in the epicardial coronary vein midway between the sites of the catheters measuring proximal and distal coronary vein pressures. During control conditions, coronary vein velocity was 14-18 cm/s during systole and 1.0-2.1 cm/s during diastole. Right stellate ganglion stimulation, norepinephrine or isoproterenol increased diastolic coronary vein velocity significantly, whereas left stellate ganglion stimulation did not. Average peak systolic velocity was not affected by these interventions. During these positive inotropic interventions, the peak coronary vein velocity usually occurred later in the cardiac cycle than during control conditions. Positive inotropic interventions appeared to decrease coronary vein velocity during systole and increase it during diastole. Left vagosympathetic trunk stimulation decreased diastolic but not systolic coronary vein velocity and usually caused peak coronary vein velocity to occur earlier in the cardiac cycle than during control states. Changes induced by vagosympathetic trunk stimulation usually occurred within one cardiac cycle. It is concluded that coronary vein blood velocity can be influenced by the autonomic nervous system.     

So-called muscular "bridges" and their interrelationship with blood vessels]

Fifty hearts of corpses of humans of different age groups were studied by means of macro-microscopical anatomical dissection of muscle fibres and cardiac blood vessels. The muscle bridges were found over the coronary arteries in all preparations of the heart. They were most frequently met on the anterior interventricular branch of the left coronary artery. The topography of muscle bridges is described and the miocardium muscle bundles participating in their formation are revealed. The character of the course of fibres in the muscle bridge is related to the course of the fibres of the muscle bundle forming it.     

Alternative venous drainage of heart ventricles in rabbits

The objective of this study was to describe the uncommon connections between cardiac veins, alternative pathways within cardiac venous circulation and complex variability of the venous system in the heart ventricles. The study was carried out on 30 adult New Zealand White rabbits. The arrangement of the cardiac veins was studied by using the corrosion casts prepared with the Spofacryl® and by perfusion of coloured latex. The presence and organization of principal veins of the heart ventricles was relatively constant with a great variability in the mode of opening and forming a common trunk. The highest variations were observed in the region of the paraconal interventricular vein, the left and right marginal vein and the left distal ventricular vein. The left proximal ventricular vein was an inconstant tributary of the left circumflex vein and was seen in 17% of cases. The left distal ventricular vein was visible as one (13% of cases) or two veins (87% of cases). Angular vein was observed in 20% of cases. Numerous anastomosis were found among cardiac veins.     

The cardiac muscle in the pulmonary vein of the rat: A morphological and electrophysiological study

The pulmonary veins of albino Wistar rats were studied by means of light and electron microscopy. The media of larger veins consists of cardiac muscle fibers which extend until the vessels attain about 100 μ in diameter. This coat consists of external longitudinal fibers and internal circular fibers. The vasa vasorum are well developed and the capillaries show pseudofenestrations. The numerous adrenergic and cholinergic nerve endings do not form typical motor end-plates as seen in skeletal muscles. The ultrastructure of these media muscle fibers is similar to that of rat hearts. The smooth muscle layer of larger pulmonary veins is not continuous as it is in smaller veins where it forms cushions. Comparisons of albino rats and other rodents reveal striking differences. Action potential shape and propagation velocity (0.5–1.2 m/s) along the myocardial coat of the pulmonary vein were similar to those observed in the left atrium and so was their sensitivity to locally applied acetylcholine. The physiological direction of propagation in rat pulmonary veins is toward the lung. This finding lends support to the hypothesis of a rhythmic, valve-like action of the striated musculature of the pulmonary venous wall during the systole and a possible role in the capacitance of the pulmonary circulation.     

SEA ICE DIATOMS (BACILLARIOPHYCEAE) OF THE CANADIAN ARCTIC. I. THE GENUS STENONEIS1

Ice diatom assemblages in the Canadian Arctic are dominated by the Naviculaceae, a family which includes the genus Stenoneis Cleve. A taxonomic history of S. inconspicua var. baculus (Cleve) Cleve (including type material of Navicula baculus Cleve) is presented with morphological data including the first SEM views of the genus. Stenoneis inconspicua var. baculus was compared with S. obtuserostrata (Hustedt) comb. nov. (basionym: Navicula obtuserostrata Hustedt). In the SEM, external, short, flattened siliceous ridges were revealed beside the proximal parts of the raphe branches and central pores. This may be a significant taxonomic feature of the genus. Valves of S. inconspicua var. baculus ranged from 40–103 μm in length, 7–11 μm in width and had 17–20 striae in 10 μm, whereas valves of S. obtuserostrata were shorter (27–53 μm), narrower (6–7.5 μm) and more finely striated (24–30 in 10 μm). Both taxa have a circumpolar Arctic distribution.