Myocardial Bridge: a clinical review

Integrating Coronary Plaque Information from CCTA by ML Predicts MACE in Patients with Suspected CAD

Conventional prognostic risk analysis in patients undergoing noninvasive imaging is based upon a limited selection of clinical and imaging findings, whereas machine learning (ML) algorithms include a greater number and complexity of variables. Therefore, this paper aimed to explore the predictive value of integrating coronary plaque information from coronary computed tomographic angiography (CCTA) with ML to predict major adverse cardiovascular events (MACEs) in patients with suspected coronary artery disease (CAD). Patients who underwent CCTA due to suspected coronary artery disease with a 30-month follow-up for MACEs were included. We collected demographic characteristics, cardiovascular risk factors, and information on coronary plaques by analyzing CCTA information (plaque length, plaque composition and coronary artery stenosis of 18 coronary artery segments, coronary dominance, myocardial bridge (MB), and patients with vulnerable plaque) and follow-up information (cardiac death, nonfatal myocardial infarction and unstable angina requiring hospitalization). An ML algorithm was used for survival analysis (CoxBoost). This analysis showed that chest symptoms, the stenosis severity of the proximal anterior descending branch, and the stenosis severity of the middle right coronary artery were among the top three variables in the ML model. After the 22nd month of follow-up, in the testing dataset, ML showed the largest C-index and AUC compared with Cox regression, SIS, SIS score + clinical factors, and clinical factors. The DCA of all the models showed that the net benefit of the ML model was the highest when the treatment threshold probability was between 1% and 9%. Integrating coronary plaque information from CCTA based on ML technology provides a feasible and superior method to assess prognosis in patients with suspected coronary artery disease over an approximately three-year period.

Surgical intervention and outcome for treatment of myocardial bridging refractory to medication

INTRODUCTION

Myocardial bridging (MB) is a common and usually benign inborn coronary abnormality that may lead to anginal symptoms, acute coronary syndrome, arrhythmias, and rarely sudden cardiac death. MB are most commonly localized in the middle segment of the left anterior descending coronary artery (LAD). The treatment of LAD-MB is still challenging. Our objective was to assess the short- and long-term results of surgical procedures in patients with LAD-MB who had chest pain refractory to medical therapy.

METHODS

Between March 2005 and January 2020, 26 patients (19 males and 7 females; mean 55.8 ± 12.4 years) with MB underwent surgery. All MB was located in the mid-segment of the LAD with a mean length of 4.2 ± 1.7 cm. Coronary angiography before surgery demonstrated LAD-MB with systolic compression more than or equal to 70% in all patients.

RESULTS

Twenty-five patients underwent myotomy and one patient underwent coronary artery bypass grafting (CABG). All patients survived and recovered uneventfully. Neither hospital or late death nor major complications occurred. Follow-up time was 3-173 months (mean 55.7 months). Follow-up of coronary angiography or computed tomography scan performed in 16 patients demonstrated restoration of coronary blood flow and myocardial perfusion without significant residual compression of the artery. All patients were symptom-free and are currently in NYHA Class I.

CONCLUSION

The symptomatic LAD-MB patients who are refractory to medication should actively undergo the surgical intervention such as myotomy and CABG to eliminate the clinical symptoms and achieve satisfactory results by follow-up findings. Myotomy is a preferred procedure because of its safety and satisfactory results.

Coronary artery aneurysm combined with myocardial bridge: A case report

BACKGROUND

Coronary artery aneurysm combined with myocardial bridge is a very rare clinical situation. The prognosis of this clinical situation is not yet clear.

CASE SUMMARY

A coronary artery aneurysm and myocardial bridge in the same segment of the coronary artery were found in a 54-year-old female patient who underwent coronary angiography and intravascular ultrasound examination. Through conservative treatment, the patient was discharged from the hospital smoothly, and she was in good condition during 5 mo of follow-up.

CONCLUSION

Coronary artery aneurysm combined with myocardial bridge seems to have a good prognosis, but due to the rarity of this clinical situation, further research and follow-up are needed.

CT evaluation of unrepaired/incidental congenital cardiovascular diseases in adults

Congenital heart disease (CHD) affects approximately one million people in the USA with the number increasing by 5% each year. Patients are usually both diagnosed and treated in infancy, however many of them may have subclinical CHD that remains undiagnosed until late adulthood. Patients with complex CHD tend to be symptomatic and are diagnosed at a younger age than those with a single defect. CHDs can be divided into three categories, including cardiac, great vessels and coronary artery anomalies. Recent advances in computed tomography (CT) technology with faster acquisition time and improved spatial resolution allow for detailed evaluation of cardiac morphology and function. The concomitant increased utilization of CT has simultaneously led to more sensitive detection and more thorough diagnosis of CHD. Recognition of and understanding the imaging attributes specific to each anomaly is important for radiologists in order to make a correct and definite diagnosis. This article reviews the spectrum of CHDs, which persist into adulthood that may be encountered by radiologists on CT.

An Updated Review on Myocardial Bridging

Myocardial bridging is a congenital coronary anomaly with normal epicardial coronary artery taking an intra-myocardial course also described as tunneled artery. The majority of patients with this coronary anomaly are asymptomatic and generally it is a benign condition. However, it is an important cause of myocardial ischemia, which may lead to anginal symptoms, acute coronary syndrome, cardiac arrhythmias and rarely sudden cardiac death. There are numerous studies published in the recent past on understanding the pathophysiology, diagnostic and management strategies of myocardial bridging. This review highlights some of the recent updates in the diagnosis and management of patients with myocardial bridging. We discuss the role of various non-invasive and invasive diagnostic methods to evaluate functional significance of bridging. In addition, role of medical therapy such as beta-blockers, percutaneous coronary intervention with stents/bioresorbable scaffolds and surgical unroofing in patients unresponsive to medical therapy is highlighted as well.

Comparison of detection percentage and morphology of myocardial bridge between conventional coronary angiography and coronary CT angiography

Introduction: Myocardial bridge (MB) is a congenital anomaly in which a segment of a coronary artery is surrounded by myocardium. In our study, we want to use conventional coronary angiography (CCA) to describe morphologic characteristics of MB (unidentified or identified) in the patients with documented evidence of MB in coronary computed tomography angiography (CCTA). Methods: The present study was designed as cross-sectional and was conducted on 47 patients with documented evidence of MB in CCTA, who were referred to Nemazee and Faghihi hospitals for performing coronary angiography during a one year period. We compared the morphologic characteristics of tunneled segments, which were missed at CCA (unidentified), and the tunneled segments which were identified with CCA. Results: In sum, MB was found in 16 (34%) patients at CCA (identified), and it was not found in 31 (66%) patients (unidentified) based on compression sign. No significant correlation was found between the percentage of systolic compression and the length and depth of the tunneled segment in identified group (r=0.73, P = 0.18; r=1.09, P = 0.15; respectively). Degree of atherosclerotic plaque formation (diameter stenosis, percentage) (mean, 0.25 (25%) ±0.29; range, 0-0.98) of the tunneled segments in unidentified group was significantly more than the same degree (mean, 0.07 (7%) ±0.13; range, 0-0.41) of the identified group (P = 0.03). The measurement of the trapezoid area under the tunneled segment with this formula [(MB length+ intramyocardial segment) ×depth/2] had significant relation with systolic compression (r=0.304, P = 0.03) and defined the cut-off value of 250 mm² as the value of significant difference in detecting myocardial bridging with CCA. Conclusion: Our results showed that in most of identified MBs in CCA the tunneled segment area was equal and more than 250 mm². In addition, the degree of atherosclerotic plaque of the tunneled segments at CCA was significantly more in unidentified group.

In vitro simulation research on the hoop stress of myocardial bridge--coronary artery

Aims

The aim of this study is to investigate how the myocardial bridge oppression affects the hoop stress of mural coronary artery.

Methods

The “myocardial bridge – coronary artery” simulative device records the hoop stress which is changed by adjusting the external pressure of the simulated coronary artery and the oppression degree of the respectively.

Results

Simulation experiment in vitro indicates that the abnormal hoop stress mainly occurs in the proximal end of mural coronary artery. As the oppression degree of myocardial bridge increases, the mean and the oscillatory value (maximum-minimum) of hoop stress in the proximal end increase markedly.

Conclusions

The “myocardial bridge – coronary artery” simulation device can provide an experiment method of studying the hoop stress influence on mural coronary artery in vitro.

Prediction of coronary plaque location on arteries having myocardial bridge, using finite element models

This study was performed to evaluate the influences of the myocardial bridges on the plaque initializations and progression in the coronary arteries. The wall structure is changed due to the plaque presence, which could be the reason for multiple heart malfunctions. Using simplified parametric finite element model (FE model) of the coronary artery having myocardial bridge and analyzing different mechanical parameters from blood circulation through the artery (wall shear stress, oscillatory shear index, residence time), we investigated the prediction of "the best" position for plaque progression. We chose six patients from the angiography records and used data from DICOM images to generate FE models with our software tools for FE preprocessing, solving and post-processing. We found a good correlation between real positions of the plaque and the ones that we predicted to develop at the proximal part of the myocardial bridges with wall shear stress, oscillatory shear index and residence time. This computer model could be additional predictive tool for everyday clinical examination of the patient with myocardial bridge.

Myocardial Bridging in a Child With Hypertrophic Obstructive Cardiomyopathy

Myocardial bridging (MB) is a rare coronary anomaly in children which is typically associated with hypertrophic obstructive cardiomyopathy (HCM) or left ventricular hypertrophy. Hypertrophic obstructive cardiomyopathy is the leading cause of sudden cardiac death in young patients, and the association of myocardial ischemia with sudden death has been recognized in patients with HCM. In this report, we describe an 11-year-old boy presented with a history of exertional, nonspecific chest pain and palpitations. Cardiac catheterization revealed MB of the left anterior descending coronary artery with evidence of intramyocardial obstruction during systole. Surgical unroofing of the affected coronary artery segment resulted in complete recovery. Myocardial bridging should be included in the differential diagnosis of children presenting with signs of ischemia.

Morphological aspects of myocardial bridges

Although some myocardial bridges can be asymptomatic, their presence often causes coronary disease either through direct compression of the "tunnel" segment or through stimulation and accelerated development of atherosclerosis in the segment proximally to the myocardial bridge. The studied material contained 30 human hearts received from the Department of Anatomy. The hearts were preserved 3 to 5 days in 10% formalin solution. Thereafter, the fatty tissue was removed and arterial blood vessels prepared by careful dissection with special reference to the presence of the myocardial bridges. Length and thickness of the bridges were measured by the precise electronic caliper. The angle between the myocardial bridge fibre axis and other axis of the crossed blood vessel was measured by a goniometer. The presence of the bridges was confirmed in 53.33% of the researched material, most frequently (43.33%) above the anterior interventricular branch. The mean length of the bridges was 14.64 ± 9.03 mm and the mean thickness was 1.23 ± 1.32 mm. Myocardial bridge fibres pass over the descending blood vessel at the angle of 10-90 degrees. The results obtained on a limited sample suggest that the muscular index of myocardial bridge is the highest for bridges located on RIA, but that the difference is not significant in relation to bridges located on other branches. The results obtained suggest that bridges located on other branches, not only those on RIA, could have a great contractive power and, consequently, a great compressive force, which would be exerted on the wall of a crossed blood vessel.

A clinical-angiographic risk scoring system for coronary artery anomalies

Congenital coronary anomalies remain a debated issue. On the basis of a critical review of the literature and our historical series, we propose a simple clinical profile scoring system for congenital coronary anomalies. A review of literature over the past 30 years was performed, searching for a relationship between the worst coronary anomaly presentation and manifestations and the anatomical and functional features. A risk scoring system was created based on these features, and retrospectively applied to our historical series of 140 consecutive patients (52 females; mean age, 60.1±19.3 years; mean follow-up, 60±23 months). Origin from the pulmonary artery, intramural course, intramyocardial course, coronary fistula with a significant pulmonary-to-systemic flow ratio, superimposed coronary artery disease, and associated congenital heart disease were associated with the worst clinical presentation. The risk scoring system gave 2 points to anatomical features and 1 point to the association with clinical and functional characteristics: 3 risk classes were identified: >3, 2-3, and <2 points. The system showed good correlation with presentation and manifestations on follow-up. Although not exhaustive, the proposed scoring system may simplify the clinical evaluation of patients with such abnormalities, being a model for decision making.

(1) coronary events caused by myocardial bridge

Myocardial bridge (MB), which covers a part of the left anterior descending coronary artery (LAD), is a normal anatomical variant structure (45% in frequency by autopsy) in LAD. MB contraction plays the role of a "double-edged sword" on the coronary events, suppressing coronary atherosclerosis under the MB, yet generating abnormal blood flow associated with coronary heart diseases (CHDs). High shear stress driven by MB compression causes the suppression of vascular permeability and vasoactive protein expression such as e-NOS and endothelin-1, which leads to the suppression of atherosclerosis in the LAD segment under the MB. However, despite the prevalent view of MB as benignancy by conventional coronary angiography (5-6% in frequency), with advance of imaging technique such as multislice spiral computed tomography [(MSCT); 16% in frequency], cardiologists are now frequently aware of symptomatic MB occurring not only in hospitalized patients, but also in young athletes free from atherosclerosis. Moreover, the large mass volume of MB muscle induces atherosclerosis evolution at the settled site in LAD proximal to MB and contributes to the occurrence of myocardial infarction. These events upon the coronary events result from the different pathophysiological mechanisms induced by contractile force of MB, which is solely determined just by the integration of anatomical properties of MB, such as the location, length and thickness of MB in an individual LAD. A recent MSCT provides the objective quantification of the anatomical variables that correlate with the histopathological results in relation to the occurrence of CHD. In this review, we therefore discuss the necessity to explore MB as a inherent chance anatomical risk factor for CHD.

Myocardial bridging: evaluation using single- and dual-source multidetector cardiac computed tomographic angiography

OBJECTIVE

To evaluate the prevalence and characteristics of myocardial bridging in patients who underwent single- or dual-source multidetector cardiac computed tomographic angiography (MDCTA).

METHODS

Retrospective review of the imaging characteristics of 57 myocardial bridges in 53 patients who underwent cardiac MDCTA examinations was performed.

RESULTS

The prevalence of myocardial bridges was 10.4%, most of which were located in the mid-left anterior descending coronary artery. The average myocardial bridge length was 23.4 mm, and the average tunneled artery depth was 2.6 mm.

CONCLUSIONS

Myocardial bridges are commonly found in patients who undergo cardiac multidetector computed tomographic angiograms on both single- and dual-source computed tomographic scanners and are most frequently located in the mid-left anterior descending coronary artery. Increasing utilization of cardiac MDCTA for noninvasive evaluation of coronary artery disease permits recognition, characterization, and functional assessment of this entity in a single examination.

Self-expanding intracoronary stent for symptomatic myocardial bridging

Myocardial bridging has been recognized as a potential cause of symptoms of angina, arrhythmias and even infarction. Various treatment strategies including beta-blockers, surgery and more recently intra-coronary stents have been used to manage bridging. We report a novel case of use of self-expanding stent for myocardial bridging in a patient with symptoms of angina and ischemia on nuclear imaging. We further present the 18-month follow up showing minimal in-stent stenosis. To our knowledge, this is the first report of using a self-expanding stent in myocardial bridging. The use of self-expanding stents could be a potential treatment for symptomatic myocardial bridging.

Symptomatic myocardial bridging in a child without hypertrophic cardiomyopathy

Myocardial bridging (MB) is a rare coronary anomaly in children that is typically associated with hypertrophic cardiomyopathy or left ventricular hypertrophy. Several reports, mainly in adults, have suggested an association between MB and sudden death or ischemia without other cardiac abnormalities. In this report, we describe an 11-year-old girl with syncope and manifestations of cardiac ischemia associated with MB of the middle segment of the left anterior descending artery. The coronary anomaly was not associated with left ventricular hypertrophy. Surgical unroofing of the affected coronary artery segment resulted in complete recovery. MB should be included in the differential diagnosis of children presenting with syncope and signs of ischemia even in the absence of ventricular hypertrophy.

Diastolic coronary artery compression in a cardiac transplant recipient: Treatment with a stent

Myocardial bridges, with resultant systolic compression of the coronary artery, are common inborn anomalies that generally have a benign course. Diastolic compression of the coronary artery, however, is a rare finding that is believed to be an acquired lesion. It can be hypothesized that during diastole, when left ventricular filling occurs, the coronary artery is compressed against epicardial scar tissue or a noncompliant pericardium. This can then lead to diminished intracoronary blood flow. We present a case of functionally significant diastolic coronary artery compression in a cardiac transplant recipient who was successfully treated with intracoronary stent placement.

Validation of a clinical-significance-based classification of coronary artery anomalies

The clinical significance and subsequent management of the various types of coronary artery anomalies (CAAs) are different, as is the relationship to sudden death, coronary artery disease, and myocardial ischemia. A practical global classification based on clinical significance has not yet been proposed. This retrospective study was aimed at evaluating the current clinical significance of CAAs and the effectiveness of a clinical-significance-based classification. In a single-center retrospective study at a public hospital, a review of the last 5,100 coronary angiographies was performed in order to select patients with CAAs. The CAAs were classified into 4 categories on the basis of a literature review according to angiographic appearance and clinical significance: benign (class I); relevant-associated with fixed myocardial ischemia (class II); severe-related to sudden death (class III); and critical-associated with superimposed coronary artery disease (CAD) (class IV). Clinical and instrumental records of the selected patients were reviewed as well as the occurrence of cardiovascular events from the date of diagnosis to July 2002. Sixty-two patients (1.2%, women/men 20/42, mean age 65.3 +/-10.6 years) had CAA on coronary angiography. From the above-described classification, 40 patients were categorized in class I (64.5%), 9 in class II (14.5%), 7 in class III (11.3%), and 6 in class IV (9.7%). During the follow-up (mean duration 60.4 +/-12.3 months) most cardiovascular events and death occurred in class III and IV patients (71.3% and 100% respectively). A high correlation was found between significance level and percentage of patients with cardiovascular events (r = 0.99). Actuarial survival at 5 years was 82.9%. CAAs can be practically classified on the basis of clinical presentation and significance. This clinical classification may be useful in managing patients with CAA and personalizing their follow-up and therapeutic options according to their class and case histories.