The normal and abnormal anatomy of the coronary arteries

Rare origin of the sinoatrial node artery: an anatomic report and a brief review of the literature

Several studies reported anatomical variations in the sinoatrial node artery (SANa). Here, we report a rare variation in the origin of the SANa on a human adult male cadaver. During dissection, we identified the SANa originating from a large atrial branch of the right coronary artery (RCA). This branch originates at the level of the inferior border of the heart and courses upwards. The initial part of this vessel is tortuous, and then it follows a straight path parallel to the RCA along the anterior surface of the right atrium. After this part, the artery curves posteriorly and to the left until it reaches the lower border of the right auricle, where it closely approaches the RCA. Finally, the artery runs posteriorly and to the right to follow a course along the medial wall of the right auricle and right atrium to reach a location close to the region of the junction of the superior vena cava and right atrium, where it follows its path buried in the myocardium. After perforating the myocardium, this vessel gives rise to branches that are distributed to both atria in addition to the SANa. The SANa runs to the sinoatrial node in a precaval (anterior to the superior vena cava) course. We also tried to characterize the vessels radiologically. The knowledge of the anatomical variations of the SANa is of the utmost importance for cardiologists and heart surgeons to better understand cardiac disease and accurately plan and execute cardiac interventions and surgical procedures.

Pathophysiology of spontaneous coronary artery dissection: hematoma, not thrombus

Spontaneous coronary artery dissection (SCAD) accounts for 1.7%-4% of all acute coronary syndrome presentations, particularly among young women with an emerging awareness of its importance. The demarcation of acute SCAD from coronary atherothrombosis and the proper therapeutic approach still represents a major clinical challenge. Certain arteriopathies and triggers are related to SCAD, with high variability in their prevalence, and often, the cause remains unknown. The objective of this review is to provide contemporary knowledge of the pathophysiology of SCAD and possible therapeutic solutions.

Vieussens' Arterial Ring: Historical Background, Medical Review and Novel Anatomical Classification

In coronary artery disease, the presence of Vieussens' arterial ring (VAR), a ring-shaped anastomosis between the conus branch of the right coronary artery with the left anterior descending artery (LAD), will allow blood flow to return to the obstructed coronary system. We have conducted a literature review, aiming to collect all the existing information about the documented VAR cases and any related pathological conditions. A total of 54 studies entered the review, including 56 patients. The mean age of the patients was 56.12 ± 16.2 years. Angina was present in 53.6% of the patients, with 7.2% of the cases being asymptomatic. Coronary artery disease outweighed (58.9%) as the patients' most frequent diagnosis. We propose a novel VAR anatomical classification, based on the sites of origin and termination of its course, with six distinct types, for a better understanding and surgical management of VAR. Type IA, originating from the conus branch and terminating in the proximal segment of the LAD was most frequently reported (51.8%). The recognition and the subsequent evaluation of the ring's anatomy and course are crucial for a customized clinical intervention. When right and left coronary angiographies fail to reveal any collateral circulation, selective conus artery catheterization should be in order. The proposed classification offers a manageable and comprehensive context for the assessment, evaluation and planning of therapeutic strategies of VAR and sets a new terminology frame for treatment guidelines.

Intravascular imaging for left main stem assessment: An update on the most recent clinical data

Left main (LM) stem has different structural and anatomical characteristics compared to all of the other segments of the coronary tree, thus its management through percutaneous coronary intervention (PCI) is a challenge and is associated with worse clinical outcome and higher need for revascularization as compared to other lesion settings. Intravascular imaging, by means of intravascular ultrasound (IVUS) or optical coherence tomography (OCT), is an important tool for LM PCI guidance, aiming at improving the immediate performance and the long term outcome of this procedure. Following current guidelines and recent scientific findings, IVUS becomes important to firstly assess, and finally evaluate the result of LM stenting, according to the experience and preferences of the operator. The role of OCT still remains to be defined, but recent data is shedding light also on this imaging technique. The aim of this review is to highlight the latest scientific advancements regarding intravascular imaging in LM coronary artery disease.

3D Bioprinting-Based Vascularized Tissue Models Mimicking Tissue-Specific Architecture and Pathophysiology for in vitro Studies

A wide variety of experimental models including 2D cell cultures, model organisms, and 3D in vitro models have been developed to understand pathophysiological phenomena and assess the safety and efficacy of potential therapeutics. In this sense, 3D in vitro models are an intermediate between 2D cell cultures and animal models, as they adequately reproduce 3D microenvironments and human physiology while also being controllable and reproducible. Particularly, recent advances in 3D in vitro biomimicry models, which can produce complex cell structures, shapes, and arrangements, can more similarly reflect in vivo conditions than 2D cell culture. Based on this, 3D bioprinting technology, which enables to place the desired materials in the desired locations, has been introduced to fabricate tissue models with high structural similarity to the native tissues. Therefore, this review discusses the recent developments in this field and the key features of various types of 3D-bioprinted tissues, particularly those associated with blood vessels or highly vascularized organs, such as the heart, liver, and kidney. Moreover, this review also summarizes the current state of the three categories: (1) chemical substance treatment, (2) 3D bioprinting of lesions, and (3) recapitulation of tumor microenvironments (TME) of 3D bioprinting-based disease models according to their disease modeling approach. Finally, we propose the future directions of 3D bioprinting approaches for the creation of more advanced in vitro biomimetic 3D tissues, as well as the translation of 3D bioprinted tissue models to clinical applications.

Anatomy of the septal perforating arteries of the heart

The septal perforating arteries of the heart usually branch off from the anterior and inferior interventricular arteries and supply the interventricular septum and the conduction system therein. Since the septal perforating arteries are not directly visible from the outside of the heart, their anatomy and variations might be overlooked. However, the septal perforating arteries have their unique anatomy that needs to be recognized to avoid the damage of the vessels especially during common cardiac procedures such as the coronary artery bypass graft, percutaneous coronary intervention, and aortic valve replacement. A better understanding of these important arteries will help physicians to enhance the overall cardiac care for their patients. Therefore, this article discusses the anatomy, the relationship to the conduction system of the heart and the clinical significance of the septal perforating arteries.

Anatomical study of length and branching pattern of main trunk of the left coronary artery

The left coronary artery is responsible for the irrigation of important heart structures. The objective of this study was to analyze the morphological characteristics of the main trunk of left coronary artery in the Brazilian population and its clinical implications. The study was carried out by using 63 adult human hearts of the human anatomy laboratory of the Federal university of Ceará, Brazil. The hearts were dissected for exposure and analysis of the left coronary artery and its branches. The data collected were statistically analyzed. The main trunk arose from the left aortic sinus under the left atrial auricle in all the 63 hearts. The mean length of the main trunk was 8.53±4.03mm. According to the criteria for the classification of the main trunk length, about 78% were medium-sized. The majority of the hearts (52.38%) showed trifurcation of the main trunk. Anova test followed by the Tukey's post hoc test showed that the main trunk length of hearts with trifurcation was significantly longer when compared with hearts with bifurcation (9.77±4.31mm vs. 6.44±3.01mm; P=0.0029). Similar findings were observed in the main trunk length of the hearts with tetrafurcation in comparison with hearts with bifurcation (10.78±1.4mm vs. 6.44±3.01mm; P=0.0387). This study showed that there is a correlation between the branching pattern and the length of the main trunk. Additionally, we showed that the most common branching pattern of the main trunk is the trifurcation, differing from other Brazilian studies and providing additional information to professionals of cardiology, cardiovascular surgery, and radiology.

Anatomical and radiological angiographic study of the coronary ostia in the adult human hearts and their clinical significance

This study was carried out to investigate the morphometric parameters and variations of coronary ostia in the hearts of adult human cadavers and coronary angiographs. The hearts of 60 adult human cadavers and 400 coronary angiographs were used in this study. The root of the aorta was carefully dissected to clear aortic sinuses, coronary ostia, and sinutubular junction (STJ). Number, locations, internal diameter distance between coronary ostia and their corresponding STJ, sinus bottom, and valve commissures were investigated. The anterior aortic sinus (AAS) revealed a single ostium for right coronary artery (RCA) in 77.5% of male and 80% of female hearts. This ostium gave a common origin for RCA and third coronary artery (TCA) in 15% of male and 20% of female hearts. However, two separate ostia for RCA and TCA origin were seen in 20% of male and 15% of female hearts. Moreover, three ostia were seen in one male and one female hearts within AAS. Meanwhile, the left posterior aortic sinus showed a single ostium for left coronary artery (LCA) in 97.5% of male and 95% of female hearts and two ostia in one male and one female hearts. The ostia were commonly seen below STJ and less commonly were observed above STJ. The distance between the bottom of aortic sinus and LCA ostium was longer than that of RCA. The internal diameter of RCA ostium was significantly (P<0.05) narrower than that of LCA but with no significant sex difference. Moreover, anomalous of coronary ostia was observed in seven out 400 angiographs and in two cadaveric hearts. Knowledge the morphometric parameters and anatomical variations of coronary ostia helps the cardiac surgeons to overcome the possible difficulties that could occur during surgical and radiological coronary interventions.

Anatomy of the coronary artery and cardiac vein in the quail ventricle: patterns are distinct from those in mouse and human hearts

Coronary vessel development has been investigated in avian and mouse embryonic hearts. Quail embryos are a useful tool to examine vascular development, particularly because the QH1 antibody and transgenic quail line, Tg (tie1:H2B-eYFP), are useful to trace endothelial cells. However, there are only a few descriptions of the quail coronary vessels. Using ink injection coronary angiography, we examined the course of coronary vessels in the fetal quail heart. The major coronary arteries were the right and left septal arteries, which, respectively, branched off from the right and left coronary stems. The right septal artery ran posteriorly (dorsally) and penetrated the ventricular free wall to distribute to the posterior surface of the ventricles. The left septal artery ran anteriorly (ventrally) and penetrated the ventricular free wall to distribute to the anterior surface of the ventricles. The right and left circumflex arteries were directed posteriorly along the atrioventricular sulci. The cardiac veins consisted of three major tributaries: the middle, great, and anterior cardiac veins. The middle cardiac vein ascended along the posterior interventricular sulcus and emptied into the right atrium. The great cardiac vein ran along the anterior interventricular sulcus, entered the space between the left atrium and conus arteriosus and emptied into the right atrium behind the aortic bulb. The anterior cardiac vein drained the anterior surface of the right ventricle and connected to the anterior base of the right atrium. The course of coronary vessels in the quail heart was basically the same as that observed in chick but was different from those of mouse and human.

Acute Thrombotic Coronary Occlusion in a Patient with Coronary Artery Anomaly

Patients with coronary artery anomalies are more susceptible to develop acute thrombotic coronary occlusions due to the abnormal anatomy of these arteries and the disturbance of the pathophysiological mechanisms that lead to an accelerated atherosclerosis development. The following article presents the case of a 64-year-old female patient diagnosed with anterior ST-segment elevation myocardial infarction. The patient underwent primary percutaneous coronary intervention, which revealed the absence of the right coronary artery and separated origins of the left anterior descending artery and the left circumflex artery from the aorta.

Coronary Artery Anomalies in Animals

Coronary artery anomalies represent a disease spectrum from incidental to life-threatening. Anomalies of coronary artery origin and course are well-recognized in human medicine, but have received limited attention in veterinary medicine. Coronary artery anomalies are best described in the dog, hamster, and cow though reports also exist in the horse and pig. The most well-known anomaly in veterinary medicine is anomalous coronary artery origin with a prepulmonary course in dogs, which limits treatment of pulmonary valve stenosis. A categorization scheme for coronary artery anomalies in animals is suggested, dividing these anomalies into those of major or minor clinical significance. A review of coronary artery development, anatomy, and reported anomalies in domesticated species is provided and four novel canine examples of anomalous coronary artery origin are described: an English bulldog with single left coronary ostium and a retroaortic right coronary artery; an English bulldog with single right coronary ostium and transseptal left coronary artery; an English bulldog with single right coronary ostium and absent left coronary artery with a prepulmonary paraconal interventricular branch and an interarterial circumflex branch; and a mixed-breed dog with tetralogy of Fallot and anomalous origin of all coronary branches from the brachiocephalic trunk. Coronary arterial fistulae are also described including a coronary cameral fistula in a llama cria and an English bulldog with coronary artery aneurysm and anomalous shunting vessels from the right coronary artery to the pulmonary trunk. These examples are provided with the intent to raise awareness and improve understanding of such defects.

Case report: a common trunk of the coronary arteries

We describe the heart from a 79-year-old woman with no medical history of cardiac complaints. Her heart shows a regular right coronary artery (RCA) and a variant left coronary artery (LCA) arising from the right sinus of Valsalva. The common stem of the RCA and the LCA is extremely short. The LCA depicts a preinfundibular course with a cranial-anterior loop and reaches the intersection of the anterior interventricular sulcus and the left coronary sulcus, where it divides into the regular branches, the anterior interventricular branch (left anterior descending, LAD) and the circumflex branch (left circumflex, LCx). All further branching resembles a normal distribution with the posterior interventricular branch coming for the RCA. Such a variant LCA is extremely rare with a reported incidence of 0.17 %. However, recognition and angiographic demonstration of such a variation assume the highest priority in a patient undergoing, for instance, direct coronary artery surgery or prosthetic valve replacement.

A computational framework to characterize and compare the geometry of coronary networks

This work presents a computational framework to perform a systematic and comprehensive assessment of the morphometry of coronary arteries from in vivo medical images. The methodology embraces image segmentation, arterial vessel representation, characterization and comparison, data storage, and finally analysis. Validation is performed using a sample of 48 patients. Data mining of morphometric information of several coronary arteries is presented. Results agree to medical reports in terms of basic geometric and anatomical variables. Concerning geometric descriptors, inter-artery and intra-artery correlations are studied. Data reported here can be useful for the construction and setup of blood flow models of the coronary circulation. Finally, as an application example, similarity criterion to assess vasculature likelihood based on geometric features is presented and used to test geometric similarity among sibling patients. Results indicate that likelihood, measured through geometric descriptors, is stronger between siblings compared with non-relative patients. Copyright © 2016 John Wiley & Sons, Ltd.

The clinical anatomy of high take-off coronary arteries

A number of criteria are used in the literature to describe high take-off coronary arteries, which can in part, explain the divide in the literature on the pathological significance of this anomaly. This study presents the anatomical variations of high take-off coronary arteries to draw attention to the possible clinical implications they may cause during angiography and other surgical procedures. The English Literature was searched to review high take-off coronary arteries. A high take-off coronary artery arising at least 1 cm in adults or 20% the depth of the sinus in children above the sinutubular junction, is considered of greater clinical relevance and was included in our meta-analysis. High take-off coronaries by other criteria was also included as part of the comprehensive review. Exclusion criteria were reports made in case studies or case reviews. The prevalence of high take-off coronary arteries in our study was 26 of 12,899 (0.202%). High take-off coronary arteries were found to originate up to 5 cm above the sinutubular junction. Right coronary arteries made up 84.46% of high take-off coronary arteries reported in the literature. Three (0.023%) cases that originated more than one centimeter above the sinutubular junction was associated with sudden cardiac death. This is a higher reported association than in studies that used other criteria for classification. It is important for clinicians to recognize the importance of correctly diagnosing high take-off coronary arteries in patients with coexisting cardiac morbidities so that suitable management plans can be developed.

Coronary arterial development: a review of normal and congenitally anomalous patterns

Coronary artery development is a delicate, complex, and finely tuned process that includes multiple interactions among many pathways, especially in the pericardium and the developing myocardium. There still exists some controversy on the exact origin of certain cellular components. Nevertheless, an understanding of this extremely important developmental process is paramount in identifying some of the causes of anomalous coronary development. There are different patterns of anomalous coronary arteries, with variable risk of myocardial ischemia, malignant arrhythmias, and sudden cardiac death. These anomalies can be broadly categorized into 2 basic anatomic subsets: those with origin of the anomalous coronary artery from the opposite aortic sinus, and those with origin of the anomalous coronary artery from the pulmonary artery. Diagnosis and management of such patterns continues to be challenging. A good knowledge of the normal and abnormal coronary artery development could potentially help us explore new avenues in the treatment of ischemic heart disease as well as anomalous coronary arteries.

Arterial system of the atrium in the human heart

We dissected the atrial arterial system of 22 adult human hearts from donated cadavers. Atrial branches (ABs) of coronary arteries, more than 0.5 mm in diameter at their origin, were selected to trace systematically their origin and course. A total of 135 ABs were observed, of which 68 were from the circumflex branch, and 67 from the right coronary artery. The origins of ABs were classified into the following five regions where they arose from coronary arteries: (A) from the left aortic bulb to the one-third of the left auricle, (B) from the end of region A to the point of anastomosis of the coronary sinus (CS) with an oblique vein of the left atrium (OVLA), (C) from the end of region B to the opening of the CS, (D) from the end of region C to two-thirds of the right auricle, (E) from the end of region D to the right aortic bulb. With regard to the course of the ABs, they were classified according to the following 8 areas where they passed: (I) underneath Bachmann's bundle (BB); (II) the area connecting the right and left superior pulmonary veins; (III) the dorsal part of the interatrial septum; (IV) beside the OVLA; (V) the atrial side beside the CS; (VI) the ventral part of the interatrial septum; (VII) the dorsal wall of the left atrium; (VIII) on the dorsal surface of the right atrium. Thus, ABs showed various combinations of regions and courses.

The anatomy of the aortic root

The aortic root is the anatomical bridge between the left ventricle and the ascending aorta. It is made up of the aortic valve leaflets, which are supported by the aortic sinuses (of Valsalva), and the interleaflet triangles interposed between the basal attachments of the leaflets. As such, it possesses significant length, and because of the semilunar attachment of the leaflets, there is no discrete proximal border to the root. It is limited distally, nonetheless, by the supravalvar ridge, or sinutubular junction. Descriptions of the aortic root over the years have been bedeviled by accounts of a valve anulus. There are at least two rings within the root, but neither serves to support the valve leaflets, each leaflets being attached in semilunar fashion from the sinutubular junction to a basal ventricular attachment Two leaflets are supported by muscle, and the third has an exclusively fibrous attachment. The root acts as a bridging structure not only anatomically, separating the myocardial and arterial components of the left ventricular pathway, but also functionally, since its proximal and distal components can withstand considerable changes in ventricular and arterial pressures. In this review, we describe the anatomy of this crucial cardiac component, emphasizing the current problems which have arisen due to indiscriminate descriptions of a nonexistent anulus.

Anomalous origin of the left coronary artery from the proper sinus with acute angulation and an intramural segment

This is the first report of a coronary artery with an anomalous origin from the proper sinus resulting in ischemic events in a child. Transthoracic echocardiogram, computed tomogram, and coronary angiogram revealed that, although the left main coronary trunk originated from the left sinus, its ostium was displaced horizontally and was located near the commissure between the left and noncoronary valve cusps. Moreover, it was associated with an acute take off angle and an intramural segment, which are known contributing features for ischemia in cases of anomalous origin of a coronary artery from the wrong sinus. Surgical intervention, involving the unroofing procedure, was employed successfully to eliminate the ischemic events. At the latest follow up, no chest pain was reported and the transthoracic echocardiogram showed no stenosis of the neo-ostium. Even in a coronary artery that originates from the proper sinus, an abnormal ostial location could be associated with an acute takeoff angle and an intramural segment. This finding is extremely rare but entails the risk of ischemia and sudden death.

The clinical anatomy of the coronary arteries

There are a manifold number of variations and anomalies of the origin and course of coronary arteries described in the literature. The incidence of such variations in the general population is reported to range between 0.3 and 1.6 %. Although uncommon, they may be benign or produce symptoms ranging from mild dyspnea to sudden cardiac death, and have been associated with an increased risk of accelerated atherosclerosis and perfusion defects. Thus, in order to effectively utilize the increasing number of therapeutic options available for treating coronary artery diseases, an appreciation of the likely normal and variable arrangements of the coronary arteries is essential. This review will describe the normal anatomy of the coronary arteries as well as the common variations with potential clinical effects.

Can we better understand the known variations in coronary arterial anatomy?

Coronary arterial anatomy is remarkably diverse. Identification of surgical risk factors, however, requires description in a uniform fashion. Such description mandates that account be given of both aortic sinusal origin and variability in aortopulmonary relationships. Currently, however, it is rare to find all this information provided either in clinical reports or published reviews. In this review, therefore, we summarize why both these features are important, emphasizing the marriage of convenience between the aortic root position within the cardiac base and the arrangement of the epicardial coronary arteries. The inductive approach accounts for all potential variations.

Theoretical models for coronary vascular biomechanics: progress & challenges

A key aim of the cardiac Physiome Project is to develop theoretical models to simulate the functional behaviour of the heart under physiological and pathophysiological conditions. Heart function is critically dependent on the delivery of an adequate blood supply to the myocardium via the coronary vasculature. Key to this critical function of the coronary vasculature is system dynamics that emerge via the interactions of the numerous constituent components at a range of spatial and temporal scales. Here, we focus on several components for which theoretical approaches can be applied, including vascular structure and mechanics, blood flow and mass transport, flow regulation, angiogenesis and vascular remodelling, and vascular cellular mechanics. For each component, we summarise the current state of the art in model development, and discuss areas requiring further research. We highlight the major challenges associated with integrating the component models to develop a computational tool that can ultimately be used to simulate the responses of the coronary vascular system to changing demands and to diseases and therapies.

Anomalous origin and course of the coronary arteries

In the normal heart, the right and left coronary arteries arise from the aortic valvar sinuses adjacent to the pulmonary trunk. The right coronary artery then directly enters the right atrioventricular groove, whereas the main stem of the left coronary artery runs a short course before dividing to become the anterior interventricular and circumflex arteries. These arteries can have an anomalous origin from either the aorta or pulmonary trunk; their branches can have various anomalous origins relative to arterial pedicles. Other abnormal situations include myocardial bridging, abnormal communications, solitary coronary arteries, and duplicated arteries. Understanding of these variations is key to determining those anomalous patterns associated with sudden cardiac death. In the most common variant of an anomalous origin from the pulmonary trunk, the main stem of the left coronary artery arises from the sinus of the pulmonary trunk adjacent to the anticipated left coronary arterial aortic sinus. The artery can, however, arise from a pulmonary artery, or the right coronary artery can have an anomalous pulmonary origin. The key feature in the anomalous aortic origin is the potential for squeezing of the artery, produced by either the so-called intramural origin from the aorta, or the passage of the abnormal artery between the aortic root and the subpulmonary infundibulum.

Origins of the coronary arteries and their significance

OBJECTIVE

To describe the normal and variant anatomy of the coronary artery ostia in Indian subjects.

INTRODUCTION

Anomalous coronary origins may cause potentially dangerous symptoms, and even sudden death during strenuous activity. A cadaveric study in an unsuspected population provides a basis for understanding the normal variants, which may facilitate determination of the prevalence of anomalies and evaluation of the value of screening for such anomalies.

METHODS

One hundred and five heart specimens were dissected. The number of ostia and their positions within the respective sinuses were observed. Vertical and circumferential deviations of the ostia were observed. The heights of the cusps and the ostia from the bottom of the sinus were measured.

RESULTS

No openings were present in the pulmonary artery or the non-coronary sinus. The number of openings in the aortic sinuses varied from 2-5 in the present series; multiple ostia were mostly seen in the anterior sinus. The majority of the ostia lay below the sinutubular ridge (89%) and at or above the level of the upper margin of the cusps (84%). Left ostial openings were mainly centrally located (80%), whereas the right coronary ostia were often shifted towards the right posterior aortic sinus (59%).

DISCUSSION

The preferential location of the ostia was within the sinus and above the cusps, but below the sinutubular ridge. On occasion, normal variants like multiple ostia, vertical or circumferential shift in the position, and slit-like ostia may create confusion in interpreting the images and pose a difficulty during procedures like angiography, angioplasty, and coronary artery bypass grafting.