Myocardial bridges: A meta-analysis

Myocardial Bridge and Atherosclerosis, an Intimal Relationship

PURPOSE OF REVIEW

This review investigates the relationship between myocardial bridges (MBs), intimal thickening in coronary arteries, and Atherosclerotic cardiovascular disease. It focuses on the role of mechanical forces, such as circumferential strain, in arterial wall remodeling and aims to clarify how MBs affect coronary artery pathology.

REVIEW FINDINGS

MBs have been identified as influential in modulating coronary artery intimal thickness, demonstrating a protective effect against thickening within the MB segment and an increase in thickness proximal to the MB. This is attributed to changes in mechanical stress and hemodynamics. Research involving arterial hypertension models and vein graft disease has underscored the importance of circumferential strain in vascular remodeling and intimal hyperplasia. Understanding the complex dynamics between MBs, mechanical strain, and vascular remodeling is crucial for advancing our knowledge of coronary artery disease mechanisms. This could lead to improved management strategies for cardiovascular diseases, highlighting the need for further research into MB-related vascular changes.

High Prevalence of Myocardial Bridging Detected in an Indonesian Population Using Multi-Detector Computed Tomography

Background and Objectives: Myocardial bridging (MB) is still not yet considered a significant finding in Indonesia both radiographically and clinically. Hence, this article aims to assess the prevalence of MB using multi-detector computed tomography (MDCT) and look at factors contributing to stenosis amongst patients with MB. Materials and Methods: This study is cross-sectional in a single centre, with consecutive sampling, looking at all patients who underwent a multi-detector computed tomography (MDCT) scan from February 2021 until February 2023. GraphPad Prism version 9.0.0 for Windows (GraphPad Software, Boston, MA, USA) was used to analyse the results. Results: There are 1029 patients with an MB, yielding a prevalence of 44.3% (95%CI 42.3-46.4). The left anterior descending vessel is the most commonly implicated, with 99.6%. Among those with stenosis, the middle portion of the bridging vessel is the most common site of stenosis (n = 269), followed by the proximal portion (n = 237). The severity of stenosis is more often moderate, with 30-50% (n = 238). Females (odds ratio [OR] of 1.8, 95%CI 1.4-2.3; p-value < 0.0001), older age (t-value 5.6, p-value < 0.0001), symptomatic patients (OR 1.4, 95% CI 1.1-1.9; p-value = 0.013), and higher mean coronary artery calcium score (t-value 11.3, p-value < 0.0001) are more likely to have stenosis. The degree of stenosis is significantly higher in the proximal stenosis group than in the middle stenosis group (t-value 27, p-value < 0.0001). Conclusions: Our research demonstrates that MB may prevent atheromatosis of the coronary segment distal to the MB and predispose the development of atherosclerosis in the section proximal to the bridge.

Quantitative analysis of the relationship between the myocardial bridge and the FAI of pericoronal fat on computed tomography

We performed this cohort study to investigate whether the myocardial bridge (MB) affects the fat attenuation index (FAI) and to determine the optimal cardiac phase to measure the volume and the FAI of pericoronary adipose tissue (PCAT). The data of 300 patients who were diagnosed with MB of the left anterior descending (LAD) coronary artery were retrospectively analyzed. All of patients were divided into the MB group and the MB with atherosclerosis group. In addition, 104 patients with negative CCTA results were enrolled as the control group. There was no significant difference between FAI values measured in systole and diastole (P > 0.05). There was no significant difference in FAI among the MB group, the MB with atherosclerosis group, and the control group (P > 0.05). In MB with atherosclerosis group, LAD stenosis degree (< 50%) (OR = 0.186, 95% CI 0.036-0.960; P = 0.045) and MB located in the distal part of LAD opening (OR = 0.880, 95% CI 0.789-0.980; P = 0.020) were protective factors of FAI value. A distance (from the LAD opening to the proximal point of the MB) of 29.85 mm had the highest predictive value for abnormal FAI [area under the curve (AUC), 0.798], with a sensitivity of 81.1% and a specificity of 74.6%.

Stress-rest dynamic-CT myocardial perfusion imaging in the management of myocardial bridging: A "one-stop shop" exam

Myocardial bridging (MB) is a congenital anomaly characterized by the intramyocardial coronary course that can cause coronary compression during systole leading to myocardial ischemia, often with the concomitant presence of endothelial dysfunction.Improvements in computed tomography (CT) technology have increased the burden of MB detection during coronary-CT (cCT) but their anatomical and functional assessment is often challenging. A stress-rest myocardial perfusion imaging (MPI) by single-photon emission CT (SPECT) is usually required to decide the correct patient management. However, SPECT has long acquisition protocols, poor spatial resolution, and significant radiation doses for the patient. The recent advances in CT scan technology have allowed the evaluation of stress-rest MPI, representing a promising alternative to SPECT.In this paper, we report six cases of MBs assessed with cCT examination and further evaluated with a stress-rest dynamic-CT MPI and SPECT. A reversible perfusion defect in the left anterior descending (LAD) territory segments potentially due to MB was detected in two of six patients, and they were referred for heart team evaluation.In conclusion, cCT and stress-rest dynamic-CT MPI allowed to detect MBs, evaluate their functional significance, and decide the patients' management in a "one-stop shop" examination.

Learning objective

Improvements in computed tomography (CT) technology have increased the burden of myocardial bridging (MB) detection during coronary-CT but their anatomical and functional assessment is often challenging.A stress-rest myocardial perfusion imaging (MPI) by single-photon emission CT (SPECT) is then usually required to decide the correct patient management.Recent advances in CT scan technology have allowed the evaluation of stress-rest MPI, that represent a promising alternative to SPECT.

Myocardial bridge in a child with cardiac arrest and ventricular fibrillation: a bridge over troubled water?

Resuscitated cardiac arrest in a child triggers a comprehensive workup to identify an aetiology and direct management. The presence of a myocardial bridge does not automatically imply causation. Careful determination of the haemodynamic significance of the myocardial bridge is critical to avoid an unnecessary sternotomy and to provide appropriate treatment.

Combined intra-cavitary course of left anterior descending artery and myocardial bridge of right coronary artery in right ventricle hypertrophy: a case report

Background

Intra-cavitary (IC) coronary course is a rare anatomical variant that has become more commonly reported in the last decade. While the condition is generally benign and often discovered incidentally during coronary computed tomography angiography (CCTA), these arteries are vulnerable to injury during cardiac interventions. It is unclear whether right ventricle (RV) pathology, such as dilatation or hypertrophy, plays a role in this condition.

Case summary

A patient in their fifties with a medical history of rheumatic heart disease and atrial fibrillation presented with dyspnoea and orthopnea but denied any previous chest pain. Upon examination, the patient exhibited slow atrial fibrillation and generalized anasarca. Echocardiography revealed severe mitral stenosis, tricuspid regurgitation, pulmonary hypertension, and a significantly dilated and impaired RV. Before surgery, a CCTA was performed and revealed an abnormal mid-left anterior descending (LAD) course through the RV cavity with complete systolic attenuation. This finding was later confirmed through invasive angiography. Additionally, the right coronary artery (RCA) showed a mid-segment myocardial bridge (MB). The patient was scheduled for mitral and tricuspid valves' surgery with no planned intervention to the LAD or RCA.

Discussion

Coronary IC course is a rare finding that poses a risk of arterial injury during invasive cardiac procedures. It is important for all cardiac interventionists to be familiar with this diagnosis and the potential hazards during cardiac interventions. Further research is needed to determine whether RV dilatation or hypertrophy can exacerbate coronary IC course or MB.

A framework of myocardial bridge detection with x-ray angiography sequence

BACKGROUND

Myocardial bridges are congenital anatomical abnormalities in which myocardium covers a segment of coronary arteries, leading to stenocardia, myocardial ischemia, and sudden cardiac death in severe cases. However, automatic diagnosis of myocardial bridge presents significant challenges.

METHOD

A novel framework of myocardial bridge detection with x-ray angiography sequence is proposed, which can realize automatic detection of vessel stenosis and myocardial bridge. Firstly, we employ a novel neural network model for coronary vessel segmentation, which consists of both CNNs and transformer structures to effectively extract both local and global information of the vessels. Secondly, we describe the vessel segment information, establish the vessel tree in the image, and fuse the vessel tree information between sequences. Finally, based on vessel stenosis detection, we realize automatic detection of the myocardial bridge by querying the blood vessels between the image sequence information.

RESULTS

In experiment, we evaluate the segmentation results using two metrics, Dice and ASD, and achieve scores of 0.917 and 1.39, respectively. In the stenosis detection, we achieve an average accuracy rate of 92.7% in stenosis detection among 262 stenoses. In multi-frame image processing, vessels in different frames can be well-matched, and the accuracy of myocardial bridge detection achieves 75%.

CONCLUSIONS

Our experimental results demonstrate that the algorithm can automatically detect stenosis and myocardial bridge, providing a new idea for subsequent automatic diagnosis of coronary vessels.

Identification of Genetic Variants Associated with Severe Myocardial Bridging through Whole-Exome Sequencing

Myocardial bridging (MB) is a congenital coronary artery anomaly and an important cause of angina. The genetic basis of MB is currently unknown. This study used a whole-exome sequencing technique and analyzed genotypic differences. Eight coronary angiography-confirmed cases of severe MB and eight age- and sex-matched control patients were investigated. In total, 139 rare variants that are potentially pathogenic for severe MB were identified in 132 genes. Genes with multiple rare variants or co-predicted by ClinVar and CADD/REVEL for severe MB were collected, from which heart-specific genes were selected under the guidance of tissue expression levels. Functional annotation indicated significant genetic associations with abnormal skeletal muscle mass, cardiomyopathies, and transmembrane ion channels. Candidate genes were reviewed regarding the functions and locations of each individual gene product. Among the gene candidates for severe MB, rare variants in DMD, SGCA, and TTN were determined to be the most crucial. The results suggest that altered anchoring proteins on the cell membrane and intracellular sarcomere unit of cardiomyocytes play a role in the development of the missed trajectory of coronary vessels. Additional studies are required to support the diagnostic application of cardiac sarcoglycan and dystroglycan complexes in patients with severe MB.

Use of Intravascular Ultrasound and Coronary Angiography to Measure the Prevalence of Myocardial Bridge in Heart Transplant Patients

Myocardial bridge (MB) detection rates vary across methods and most studies that have assessed MB include symptomatic patients. Intravascular ultrasound (IVUS) is a sensitive tool for MB detection and donor hearts may serve as a surrogate measure of asymptomatic patients. We used IVUS and coronary angiography to measure MB prevalence in heart transplant patients during routine follow-up invasive coronary assessments. This was a retrospective, single-center study of heart transplant patients who received follow-up coronary assessments at the University of Chicago Heart and Vascular Center between December 2014 and December 2021. A single experienced interventional cardiologist assessed incidental findings of MB in IVUS and coronary angiography. Detection rates were compared with meta-analysis-reported prevalence. Of 129 patients, IVUS-detected MB in 87 patients (67.4%), whereas coronary angiography detected 41 (31.8%). All MB found by coronary angiography were detected by IVUS. Some level of cardiac allograft vasculopathy was found in 92 patients (71.3%). Our IVUS-detected MB prevalence was greater than meta-analysis-reported pooled prevalence across all methods: autopsy, computed tomography angiography, and coronary angiography (67.4% [95% confidence interval [CI] 59.4 to 75.5] vs 42% [95% CI 30 to 55]; 22% [95% CI 18 to 25]; 6% [95% CI 5 to 8], p ≤0.005). The difference between our observed IVUS-detected MB prevalence and meta-analysis autopsy reported MB prevalence was 1.25 (95% CI 1.11 to 1.40). In conclusion, the high prevalence of MB recorded in donor hearts emphasizes the need to further investigate the causes of chest pain in patients who are found to have MB.

Plaque morphology and distribution in patients with and without myocardial bridge - an intravascular ultrasound study

BACKGROUND

Myocardial bridging (MB) is a common congenital cardiovascular anomaly. There are reported associations of MB with different clinical presentations like effort angina, acute coronary syndromes (ACS) and sudden cardiac death. Acceleration of atherosclerosis in proximal vessel is reported in patients with MB, while bridged segments are reported to be free of atherosclerosis.

METHODS

We assessed patients who underwent intravascular ultrasound (IVUS) guided percutaneous intervention (PCI) of left anterior descending (LAD) artery. Plaque characteristics derived from IVUS analysis were compared between those who displayed myocardial bridge versus those who did not harbour the anomaly.

RESULTS

One hundred and forty-seven (147) patients underwent IVUS guided PCI. Incidence of MB was 44/147 (29.9%). Mean age of patients who had MB {+} was higher (62.1 ± 10.3 vs. 57.8 ± 11.2 (p = .03). 142/147 (96.6%) patients presented with ACS. ST elevation myocardial infarction (STEMI) was the most common presenting diagnosis (110/147 to 74.8%). There were no differences in qualitative plaque characteristics - attenuated plaque, calcification or calcium score between two groups. Plaque burden and length of the lesion in the proximal vessel were not different. Among patients with MB {+}, atheromatous extension to segments underlying the bridge was seen in 31/44 (70.5%) cases.

CONCLUSIONS

In a series of patients who presented with advanced clinical atherosclerosis, plaque characteristics were not different in patients who harboured myocardial bridge vs. those who did not have the anomaly. Atheromatous involvement was seen extending into bridged segment contrary to previous reports.

Atheroprotective effect of myocardial bridge sustains in aging: Autopsy study on subjects with dual left anterior descending coronary artery type 3

BACKGROUND

The atheroprotective role of the myocardial bridge (MB) on a tunneled segment is already demonstrated in subjects with dual left anterior descending coronary artery (dual LAD) type 3 anomaly, but the dynamics of changes and whether this protective effect sustains during aging is unknown.

METHODS

The retrospective autopsy study included cases of dual LAD type 3 anomaly identified over 18 years. The severity grade of atherosclerosis in branches of dual LAD was estimated by microscopy. The Spearman's correlation test and Receiver operator characteristics (ROC) curve analyses were performed to determine the relation of subjects' age with a degree of the protective role of the myocardial bridge.

RESULTS

A total of 32 dual LAD type 3 cases were identified. The systematic heart examination revealed an anomaly prevalence of 2.1%. The age significantly positively correlated with the severity of atherosclerosis in the subepicardial dual LAD branch but not with the severity of atherosclerosis in the intramyocardial dual LAD branch. Subjects aged ≥38 years were likely to have a more severe degree of atherosclerosis in subepicardial than in intramyocardial LAD arteries (AUC 0.81 95% CI 0.59-1; sensitivity 100%, specificity 66.7%). In subjects aged ≥58 years, this difference was likely to be more pronounced (≥2 degree difference; AUC 0.75 95% CI 0.58-0.93; sensitivity 92.9%, specificity 66.7%).

CONCLUSION

The atheroprotective effect of the myocardial bridge on tunneled segments usually becomes evident throughout the second half of the fourth decade of life and is most pronounced after about 60 years and ceases only in some.

Incidence and Morphological Study of Myocardial Bridge in the State of Ceará: A Cadaveric Study

BACKGROUND

Myocardial bridges (MB) are anatomical anomalies with possible clinical repercussions; hence, their understanding deserves attention.

OBJECTIVE

To determinate the prevalence and characterize MB in human hearts from the state of Ceará. Methods: Fifty hearts of adult human cadavers from the Medicine School of Federal University of Ceará, Brazil. The hearts were dissected to identify MBs that pass over part of the coronary artery. The segment of the artery (proximal, middle, and distal) with a bridge was identified. The external diameter of the artery at the proximal and distal points of the MB was measured. The length and thickness of the MB were also measured with an electronic caliper. The muscle index (MMI) of the MB was calculated as the product of length and thickness expressed in millimeters. The significance level adopted in the statistical analysis was 5%.

RESULTS

MB was confirmed in 40% of sample. Approximately one third of the sample had only 1 MB. MB was most frequently found over the anterior interventricular branch of the left coronary artery (59.25%, p=0.02), and its prevalence in other branches was much lower (22.23%). The most affected segments of arteries were the superior (44.44%) and medium (40.74%). The mean diameter of arteries proximal to the MB was 2.38±0.97mm (range=0.78-5.15mm), and the diameter distal to the MB was 1.71±0.75mm (range=0.42-3.58mm). The length was measured as mean=8.55±5.27mm, while the mean thickness was 0.89±0.33mm.

CONCLUSION

A high prevalence of MB is more likely to affect the left coronary artery system with larger MMI than other affected branches.

MINOCA Associated with a Myocardial Bridge: Pathogenesis, Diagnosis and Treatment

Myocardial bridging (MB) is the most frequent congenital coronary anomaly characterized by a segment of an epicardial coronary artery that passes through the myocardium. MB is an important cause of myocardial ischemia and is also emerging as a possible cause of myocardial infarction with non-obstructed coronary arteries (MINOCA). There are multiple mechanisms underlying MINOCA in patients with MB (i.e., MB-mediated increased risk of epicardial or microvascular coronary spasm, atherosclerotic plaque disruption and spontaneous coronary artery dissection). The identification of the exact pathogenetic mechanism is crucial in order to establish a patient-tailored therapy. This review provides the most up-to-date evidence regarding the pathophysiology of MINOCA in patients with MB. Moreover, it focuses on the available diagnostic tools that could be implemented at the time of coronary angiography to achieve a pathophysiologic diagnosis. Finally, it focuses on the therapeutic implications associated with the different pathogenetic mechanisms of MINOCA in patients with MB.

A spatiotemporal analysis of the left coronary artery biomechanics using fluid-structure interaction models

Biomechanics plays a critical role in coronary artery disease development. FSI simulation is commonly used to understand the hemodynamics and mechanical environment associated with atherosclerosis pathology. To provide a comprehensive characterization of patient-specific coronary biomechanics, an analysis of FSI simulation in the spatial and temporal domains was performed. In the current study, a three-dimensional FSI model of the LAD coronary artery was built based on a patient-specific geometry using COMSOL Multiphysics. The effect of myocardial bridging was simulated. Wall shear stress and its derivatives including time-averaged wall shear stress, wall shear stress gradient, and OSI were calculated across the cardiac cycle in multiple locations. Arterial wall strain (radial, circumferential, and longitudinal) and von Mises stress were calculated. To assess perfusion, vFFR was calculated. The results demonstrated the FSI model could identify regional and transient differences in biomechanical parameters within the coronary artery. The addition of myocardial bridging caused a notable change in von Mises stress and an increase in arterial strain during systole. The analysis performed in this manner takes greater advantage of the information provided in the space and time domains and can potentially assist clinical evaluation.

Systematic Review and Meta-Analysis of Cardiovascular Consequences of Myocardial Bridging in Hypertrophic Cardiomyopathy

Myocardial bridging (MB) is a congenital variant in which a segment of a coronary artery follows an atypical intramural course under a "bridge" of myocardium and is notably common in hypertrophic cardiomyopathy (HCM). This systematic review and meta-analysis explored the clinical consequences of MB in patients with HCM. A total of 3 outcome domains were investigated: cardiovascular mortality, nonfatal adverse cardiac events, and investigative indicators of myocardial ischemia. A meta-analysis was performed on 10 observational studies comparing outcomes in patients with HCM with and without MB. Studies were identified through a systematic search of 4 databases (PubMed, Scopus, Medline Complete, and Web of Science). The quality of the studies was assessed using a modified version of the Downs and Black tool, from which studies could score a maximum of 23 points. The mean score was 17.5 ± 1.3 (good). The meta-analysis showed that MB was not associated with cardiovascular mortality (odds ratio [OR] 1.70, 95% confidence interval [CI] 0.56 to 5.15, p = 0.35) or nonfatal adverse cardiac events (OR 1.80, 95% CI 0.98 to 3.28, p = 0.06) but was associated with myocardial ischemia (OR 1.89, 95% CI 1.03 to 3.44, p = 0.04). In conclusion, the potential prognostic implications of MB in HCM, especially in those with hemodynamically significant bridges and/or severe underlying disease, should not be ignored. The focus of future studies should be to establish functional and morphologic thresholds, by which MB may adversely influence prognosis by corroborating imaging findings with clinical outcome data.

Benign incidental cardiac findings in chest and cardiac CT imaging

With the continuous expansion of the disease scope of chest CT and cardiac CT, the number of these CT examinations has increased rapidly. In addition to their common indications, many incidental cardiac findings can be observed when carefully evaluating the coronary arteries, valves, pericardium, ventricles, and large vessels. These findings may have clinical significance or risk of complications, but they are sometimes overlooked or may not be described in the final reports. Although most of the incidental findings are benign, timely detection and treatment can improve the management of chronic diseases or reduce the possibility of severe complications. In this review, we summarized the imaging findings, incidence rate, and clinical relevance of some benign cardiac findings such as coronary artery calcification, aortic and mitral valve calcification, aortic calcification, cardiac thrombus, myocardial bridge, aortic dilation, cardiac myxoma, pericardial cyst, and coronary artery fistula. Reporting incidental cardiac findings will help reduce the risk of severe complications or disease deterioration and contribute to the recovery of patients.

A chart review on surgical myocardial debridging in symptomatic patients: a safe procedure with good long-term clinical outcome and coronary computed tomographic angiography results

OBJECTIVES

Myocardial bridging is mostly diagnosed as an incidental imaging finding but can result in severe vessel compression and significant clinical adverse complications. Since there is still an ongoing debate when to propose surgical unroofing, we studied a group of patients where this was performed as an isolated procedure.

METHODS

In 16 patients (38.9 ± 15.7 years, 75% men) who had surgical unroofing for symptomatic isolated myocardial bridges of the left anterior descending artery, we retrospectively analysed symptomatology, medication, imaging modalities used, operative techniques, complications and long-term outcome. Computed tomographic fractional flow reserve was calculated to understand its potential value for decision-making.

RESULTS

Most procedures were performed on-pump (75%, mean cardiopulmonary bypass 56.5 ± 27.9 min, mean aortic cross-clamping 36.4 ± 19.7 min). Three patients needed a left internal mammary artery bypass since the artery dived inside the ventricle. There were no major complications or deaths. The mean follow-up was 5.5 years. Although there was a dramatic improvement in symptoms, still 31% experienced atypical chest pain at various moments during follow-up. Postoperative radiological control was performed in 88%, showing no residual compression or recurrent myocardial bridge and patent bypass if performed. All postoperative computed tomographic flow calculations (7) showed a normalization of coronary flow.

CONCLUSIONS

Surgical unroofing for symptomatic isolated myocardial bridging is a safe procedure. Patient selection remains difficult but introducing standard coronary computed tomographic angiography with flow calculations could be helpful in preoperative decision-making and during follow-up.

The myocardial bridge: incidence, diagnosis, and prognosis of a pathology of uncertain clinical significance

The myocardial bridge (MB) is a common anomaly of the coronary tree, very often clinically silent. The artery typically involved is the left anterior descending in its proximal and/or middle portion. MB can cause ischaemia with various mechanisms, directly proportional to the degree of compression of the intra-myocardial tract, which impairs the coronary flow. It is a dynamic phenomenon that is affected by the adrenergic tone and is therefore often brought by physical exercise. MB, when symptomatic, often begins with angina from exertion; some patients have more severe conditions such as unstable angina or myocardial infarction. Coronary vasospasm related to MB-induced endothelial dysfunction can explain a number of cases that come to observation even with catastrophic pictures such as ventricular fibrillation caused by ischaemia. The diagnostic workup includes the non-invasive study using computed tomography angiography and the invasive study of the haemodynamic impact using pressure and Doppler guides. In symptomatic cases, drug therapy with a beta-blocker is enough to manage angina. When it fails, there is the option of coronary angioplasty or surgical treatment techniques.

Implications of Myocardial Bridge on Coronary Atherosclerosis and Survival

Background: In this study, we aimed to describe the impact of MBs on atherosclerosis and survival, in patients with coronary artery disease (CAD). Methods: We retrospectively studied 1920 consecutive patients who underwent conventional coronary angiography for suspected CAD. Atherosclerotic load (AL), defined as the sum of degrees of stenosis, and general atherosclerotic load (GAL), representing the sum of AL, were compared between patients with MB and a control group without MB; patients in these groups were similar in age and sex. We assessed survival at 10 years after the last enrolled patient. Results: Prevalence of MB was 3.96%, predominantly in the mid-segment of left anterior descendent artery (LAD). In the presence of MB, GAL was lower (158.1 ± 93.7 vs. 205.3 ± 117.9, p = 0.004) with a lesser AL in the proximal (30.3 ± 39.9 vs. 42.9 ± 41.1, p = 0.038) and mid-segments (8.1 ± 20.0 vs. 25.3 ± 35.9, p < 0.001) of LAD. Based on a Multinominal Logistic Regression, we found that the presence of MB on LAD (regardless of its location on this artery) is a protective factor against atherosclerotic lesions, decreasing the probability of significant stenosis, especially of those ≥70%, on the entire artery (B −1.539, OR 4660; 95% CI = 1.873−11.595, p = 0.001) and on each of its segments as well: proximal LAD (B −1.275, OR 0.280; 95% CI = 0.015−5.073; p = 0.038), mid-LAD (B −1.879, OR 6.545; 95% CI = 1.492−28.712; p = 0.013) and distal LAD (B −0.900, OR 2.459, 95% CI = 2.459−2.459, p = 0.032). However, 10-year survival was similar between groups (76.70% vs. 74.30%, p = 0.740). Conclusion: The presence of MB on LAD proved to be a protective factor against atherosclerosis for the entire artery and for each of its segments, but it does not influence long-term survival in patients with CAD.

The Critical Appraisal Tool for Anatomical Meta-analysis (CATAM): A framework for critically appraising anatomical meta-analyses

The hallmark of evidence-based medicine is the meta-analysis (MA). For much of its rich history, the field of anatomy has been dominated by descriptive, cadaveric studies. In the last two decades, quantitative measurements and statistical analyses have frequently accompanied such studies. These studies have directly led to the publication of anatomical MAs, which have ushered in the exciting field of evidence-based anatomy. Although critical appraisal tools exist for clinical MAs, none of them are specifically tailored for anatomical MAs. Therefore, the purpose of this paper is to provide a framework by which clinical anatomists and others can critically appraise anatomical MAs using the Critical Appraisal Tool for Anatomical Meta-analysis (CATAM). Using a running example from a recently published MA, we show how to use the CATAM rubric in a step-by-step fashion. Each scored section of the CATAM rubric is summated into a total score (maximum 50 points). This score is then referenced to a conversion chart, which assigns a qualitative value to the MA in a range from "very good" to "poor." Future studies can investigate the interrater reliability of the instrument, and possibly subject the CATAM rubric to a Delphi panel. As anatomical MAs become more commonplace at surgical grand rounds and journal clubs in academic medical centers throughout the world, we hope that the CATAM rubric can help facilitate meaningful discussions about the quality and clinical relevance of anatomical MAs. This article is protected by copyright. All rights reserved.

Myocardial Bridging: Diagnosis, Functional Assessment, and Management: JACC State-of-the-Art Review

Myocardial bridging (MB) is a congenital coronary anomaly in which a segment of the epicardial coronary artery traverses through the myocardium for a portion of its length. The muscle overlying the artery is termed a myocardial bridge, and the intramyocardial segment is referred to as a tunneled artery. MB can occur in any coronary artery, although is most commonly seen in the left anterior descending artery. Although traditionally considered benign in nature, increasing attention is being given to specific subsets of MB associated with ischemic symptomatology. The advent of contemporary functional and anatomic imaging modalities, both invasive and noninvasive, have dramatically improved our understanding of dynamic pathophysiology associated with MBs. This review provides a contemporary overview of epidemiology, pathobiology, diagnosis, functional assessment, and management of MBs.

Left Ventricular Summit-Concept, Anatomical Structure and Clinical Significance

The left ventricular summit (LVS) is a triangular area located at the most superior portion of the left epicardial ventricular region, surrounded by the two branches of the left coronary artery: the left anterior interventricular artery and the left circumflex artery. The triangle is bounded by the apex, septal and mitral margins and base. This review aims to provide a systematic and comprehensive anatomical description and proper terminology in the LVS region that may facilitate exchanging information among anatomists and electrophysiologists, increasing knowledge of this cardiac region. We postulate that the most dominant septal perforator (not the first septal perforator) should characterize the LVS definition. Abundant epicardial adipose tissue overlying the LVS myocardium may affect arrhythmogenic processes and electrophysiological procedures within the LVS region. The LVS is divided into two clinically significant regions: accessible and inaccessible areas. Rich arterial and venous coronary vasculature and a relatively dense network of cardiac autonomic nerve fibers are present within the LVS boundaries. Although the approach to the LVS may be challenging, it can be executed indirectly using the surrounding structures. Delivery of the proper radiofrequency energy to the arrhythmia source, avoiding coronary artery damage at the same time, may be a challenge. Therefore, coronary angiography or cardiac computed tomography imaging is strongly recommended before any procedure within the LVS region. Further research on LVS morphology and physiology should increase the safety and effectiveness of invasive electrophysiological procedures performed within this region of the human heart.