Myocardial bridging in obstructive hypertrophic cardiomyopathy: a risk factor for myocardial fibrosis.

BACKGROUND: Myocardial bridging (MB) is common in patients with hypertrophic cardiomyopathy (HCM). There are sparse data on the impact of MB on myocardial fibrosis in HCM. This study was designed to evaluate the relationship between MB and myocardial fibrosis in patients with obstructive HCM. METHODS: In this cohort study, retrospective data were collected from a high-volume HCM center. Patients with obstructive HCM who underwent septal myectomy and preoperative cardiac magnetic resonance (CMR) were screened from 2011 to 2018. RESULTS: Finally, 492 patients were included in this study, with an average age of 45.7 years. Of these patients, 76 patients had MB. MB occurred mostly in the left anterior descending artery (73/76). The global extent of late gadolinium enhancement (LGE) was correlated with the degree of systolic compression (r = 0.33, p = 0.003). Multivariable linear regression analysis revealed that the degree of systolic compression was an independent risk factor for LGE (ß = 0.292, p = 0.007). The LGE fraction of basal and mid anteroseptal segments in patients with severe MB (compression ratio ≥ 80%) was significantly greater than that in patients with mild to moderate MB (compression ratio < 80%). During a median follow-up of 28 (IQR: 15-52) months, 15 patients died. Kaplan-Meier analysis did not identify differences in all-cause death (log-rank p = 0.63) or cardiovascular death (log-rank p = 0.72) between patients undergoing MB-related surgery and those without MB. CONCLUSIONS: MB with severe systolic compression was significantly associated with a high extent of fibrosis in patients with obstructive HCM. Concomitant myotomy or coronary artery bypass grafting might provide excellent survival similar to that of patients without MB. Identification of patients with severe MB and providing comprehensive management might help improve the prognosis of patients with HCM.

Acute myocardial infarction or Takotsubo syndrome in a patient with stunned myocardium due to myocardial bridging? A case report of diagnostic dilemma clarified after serial workup.

BACKGROUND: Myocardial bridging is a cardiac anomaly where a segment of epicardial coronary arteries runs through the myocardium and can rarely cause MI. Takotsubo syndrome is a stress-induced cardiomyopathy that can mimic MI. Catecholamine surge during stress can contribute to Takotsubo syndrome, but whether this surge can trigger an inconspicuous myocardial bridging to manifest symptomatically remains unclear, and alternately, whether a myocardial bridge might cause worsening of Takotsubo syndrome is also a matter that needs further research. CASE PRESENTATION: We report the case of a patient who initially presented with features of acute exacerbation of bronchiectasis and subsequently developed symptoms and ECG features suggestive of acute myocardial infarction. Echocardiography revealed features of takotsubo syndrome, and complete myocardial bridging was revealed via coronary angiography. The patient was managed conservatively with pharmacological treatment, and after a few days, echocardiographic features were reversed. As such, the diagnosis shifted toward Takotsubo syndrome with myocardial stunning due to co-existent myocardial bridging. CONCLUSION: We report a rare case of a patient with acute bronchiectasis exacerbation with features suggestive of acute myocardial infarction who had findings of Takotsubo syndrome and complete myocardial bridging. In the beginning, it was difficult to determine whether the symptoms arose due to acute MI resulting from myocardial bridging or were solely due to takotsubo syndrome because of stress from bronchiectasis. Although myocardial bridging is often overlooked as an etiology for acute MI, this case highlights the importance of expanding the differential diagnosis to myocardial bridging in the work-up for the cause of acute MI and how Takotsubo syndrome can mimic acute MI and pose a diagnostic challenge.

Myocardial ischemia caused by the synergistic effect of myocardial bridge and moderate stenosis: case report.

BACKGROUND: Clinical events such as angina pectoris, acute coronary syndrome, and sudden death caused by myocardial bridge (MB) have attracted increasing attention. It is still a challenge to diagnose whether MB can cause the symptoms of patients with MB. For most MB patients, medication remains the primary treatment. CASE PRESENTATION: This article reports a case of chest pain in a patient with MB in the middle segment of the left anterior descending artery (LADm) with moderate stenosis in the proximal segment (LADp). Through functional assessment, we found that neither MB nor fixed stenosis had sufficient effect on coronary blood flow to cause myocardial ischemia, but their synergistic effect resulted in myocardial ischemia. Finally, a stent was implanted in LADp and good clinical results were achieved. CONCLUSIONS: For symptomatic patients with MB combined with fixed stenosis, functional evaluation may be necessary, which has significant guiding significance for treatment strategy selection. For asymptomatic patients, early detection of myocardial ischemia may also improve the prognosis of patients.

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.

Nomogram to predict recurrent chest pain in patients with myocardial bridging.

OBJECTIVE: Patients with myocardial bridging (MB) frequently experience recurrent chest pain, even in those without coronary heart disease. This study aims to predict the risk of recurrent chest pain in patients with MB by using a novel predictive nomogram. METHODS: This retrospective study enrolled 250 patients with acute chest pain who underwent coronary computed tomography angiography (CCTA) between January and December 2018, including 111 patients with MB and 139 control patients. Least absolute shrinkage and selection operator (LASSO) and multivariable Cox regression analyses were used to screen for significant parameters that were included to develop a novel predictive nomogram model. Receiver operating characteristic curve, calibration curve, and decision curve analyses were used to evaluate the performance and clinical utility of the nomogram. RESULTS: A predictive nomogram was constructed in 111 patients with MB, 34 of whom (30.9%) had recurrent chest pain. The significant predictors screened out by the LASSO regression included age, sex, branch type MB, and systolic compression index. The area under the curves (AUCs) for recurrent chest pain at 12, 24, and 36 months were 0.688, 0.742, and 0.729, respectively, indicating remarkable accuracy of the nomogram. The calibration curve and decision curve analyses indicated a good agreement with the observations and utility of the nomogram. CONCLUSIONS: This study presents a high-accuracy nomogram to predict recurrent chest pain in patients with MB. This model incorporates clinical risk factors and CT imaging features and can be conveniently used to facilitate the individualised prediction. KEY POINTS: • Symptomatic patients with myocardial bridging often present with recurrent chest pain. • The potential predictors of recurrent chest pain in patients with myocardial bridging were age, sex, branch type MB, and systolic compression index. • Nomogram based on clinical CT imaging features is valuable to predict recurrent chest pain in patients with myocardial bridging.

Dynamic perfusion SPECT for functional evaluation in symptomatic patients with myocardial bridging.

BACKGROUND: The aim of this study was to investigate the feasibility and diagnostic value of myocardial flow reserve (MFR) assessed by rest/stress myocardial perfusion imaging with dynamic single-photon emission computed tomography (SPECT) in the functional evaluation of myocardial bridge (MB). METHODS: From May 2017 to July 2021, patients with angiographically confirmed isolated MB on the left anterior descending artery (LAD) who underwent dynamic SPECT myocardial perfusion imaging were retrospectively included. The assessment of semiquantitative indices of myocardial perfusion (summed stress scores, SSS) and quantitative parameters (MFR) was performed. RESULTS: A total of 49 patients were enrolled. The mean age of the subjects was 61.0 ± 9.0 years. All of the patients were symptomatic, and 16 cases (32.7%) presented with typical angina. SPECT-derived MFR showed a borderline significantly negative correlation with SSS (r = 0.261, P = .070). There was a trend of higher prevalence of impaired myocardial perfusion defined as MFR < 2 than as SSS ≥ 4 (42.9% vs 26.5%; P = .090). CONCLUSION: Our data support that SPECT MFR may be a useful parameter for the functional assessment of MB. In patients with MB, the use of dynamic SPECT could be a potential method for hemodynamic assessment.

Assessment of myocardial bridging and the pericoronary fat attenuation index on coronary computed tomography angiography: predicting coronary artery disease risk.

BACKGROUND: The fat attenuation index (FAI) is a radiological parameter that represents pericoronary adipose tissue (PCAT) inflammation, along with myocardial bridging (MB), which leads to pathological shear stress in the coronary vessels; both are associated with coronary atherosclerosis. In the present study, we assessed the predictive value of FAI values and MB parameters through coronary computed tomography angiography (CCTA) for predicting the risk of coronary atherosclerosis and vulnerable plaque in patients with MB. METHODS: We included 428 patients who underwent CCTA and were diagnosed with MB. FAI values, MB parameters, and high-risk coronary plaque (HRP) characteristics were recorded. The subjects were classified into two groups (A and B) according to the absence or presence of coronary plaque in the segment proximal to the MB. Group B was further divided into Groups B1 (HRP-positive) and B2 (HRP-negative) according to the HRP characteristic classification method. The differences among the groups were analysed. Multiple logistic regression analysis was performed to determine the independent correlation between FAI values and MB parameters and coronary atherosclerosis and vulnerable plaque risk. RESULTS: Compared to the subjects in Group A, those in Group B presented greater MB lengths, MB depths and muscle index values, more severe MB systolic stenosis and higher FAIlesion values (all P < 0.05). In multivariate logistic analysis, age (OR 1.076, P < 0.001), MB systolic stenosis (OR 1.102, P < 0.001) and FAIlesion values (OR 1.502, P < 0.001) were independent risk factors for the occurrence of coronary atherosclerosis. Compared to subjects in Group B2, those in Group B1 presented greater MB lengths and higher FAI values (both P < 0.05). However, only the FAIlesion value was an independent factor for predicting HRP (OR 1.641, P < 0.001). CONCLUSION: In patients with MB, MB systolic stenosis was associated with coronary plaque occurrence in the segment proximal to the MB. The FAI value was not only closely related to coronary atherosclerosis occurrence but also associated with plaque vulnerability. FAI values may provide more significant value in the prediction of coronary atherosclerosis than MB parameters in CCTA.

Relationship between myocardial bridging and fatal ventricular arrhythmias in patients with hypertrophic cardiomyopathy: the HCM-MB study.

BACKGROUND: Myocardial bridging (MB) and hypertrophic cardiomyopathy (HCM) are associated with the risk of fatal ventricular arrhythmias (VAs). The goal of the study was to determine the relationship between MB and fatal VAs in HCM patients with implantable cardiac defibrillators (ICD). METHODS: A total of 108 HCM patients (mean age: 46.6 ± 13.6 years; male: 73) were enrolled in this retrospective study. All patients underwent transthoracic echocardiography and coronary computed tomography angiography. Fatal VAs including sustained ventricular tachycardia and ventricular fibrillation were documented in ICD records. RESULTS: There were documented fatal VAs in 29 (26.8%) patients during a mean follow-up time of 71.3 ± 30.9 months. Compared with the other groups, the fatal VA group had a higher incidence of the following: presence of MB (82.8 vs. 38%, p < 0.001), deep MB (62.1 vs. 6.3%, p < 0.001), very deep MB (24.1 vs. 0%, p < 0.001), long MB (65.5 vs. 11.4%, p < 0.001), presence of > 1 MB (17.2 vs. 0%, p = 0.001), and MB of the left anterior descending artery (79.3 vs. 17.7%, p < 0.001) . Sudden cardiac death (SCD) risk score (hazard ratio: 1.194; 95% CI: 1.071-1.330; p = 0.001) and presence of MB (hazard ratio: 3.815; 95% CI: 1.41-10.284; p = 0.008) were found to be independent predictors of fatal VAs in HCM patients. CONCLUSIONS: The current data suggest that the SCD risk score and presence of MB were independent risk factors for fatal VAs in patients with HCM. In addition to conventional risk factors, the coronary anatomical course can provide clinicians with valuable information when assessing the risk of fatal VAs in HCM patients.

Congenital morphological patterns of myocardial bridges.

BACKGROUND: Myocardial bridging (MB) is a coronary anomaly in which a segment of the coronary artery is overlapped by a layer of myocardial tissue. Nowadays, there is no scientific agreement on if the MB are congenital or acquired or on the factors that determine their presence and/or absence. OBJECTIVE: This study is performed to analyze the anatomical characteristics of adult and children's hearts regarding the shape of the left coronary artery branching, presence of pre-bridge arterial branch, coronary dominance and its correlations to MB formation. METHODS: We analyzed 240 adults heart specimens and 63 children's specimens. The frequency of the myocardial bridges (MB) occurrence was performed through observational study of the anatomical specimens. The shape of the left coronary artery (LCA) branching, presence of pre-bridge arterial branch (PBB) and coronary dominance was determined superficial dissection of the epicardial adipose tissue and careful evaluation of the hearts. RESULTS: A relation between the trifurcated pattern of the LCA and the presence of MB (P<0.0001, odds ratio=3.74) was found in adults heart and in children's hearts (P=0.003, odds ratio=16.0), as well as a relation between the presence of PBB and the presence of MB in adult hearts (P<0.0001) and children's hearts (P<0.0001). CONCLUSION: Our findings suggest for the first time that the myocardial bridges are related to the presence of trifurcation of the left coronary artery and the pre-bridge arterial branch in adult and children's hearts.

Acute coronary syndrome caused by myocardial bridging.

Myocardial bridging (MB) is a phenomenon that occurs when coronary arteries course through myocardial tissue rather than, as is normal, on the surface of the myocardium. Although often asymptomatic, contraction of the myocardium in the presence of a myocardial bridge can sometimes occlude the lumen of coronary arteries that penetrate the myocardium, resulting in symptoms, signs, and electrocardiographic changes indistinguishable from those associated with acute coronary syndromes (ACS) caused by intraluminal narrowing of coronary arteries or coronary artery plaque rupture. In this monograph, we present the case of a 45-year-old man who presented to the emergency department with typical chest pain accompanied by electrocardiographic changes consistent with acute occlusion of the left anterior descending artery. During percutaneous coronary intervention, fluoroscopically-obtained cine image loops revealed evidence of dynamic coronary artery narrowing due to myocardial bridging. There was no evidence of static coronary artery occlusion. Myocardial bridging is typically managed medically when symptomatic, although refractory cases may ultimately require invasive or surgical intervention. Given that emergency physicians are frequently the first providers to evaluate patients with acute coronary syndromes, myocardial bridging as an etiology for ACS is a clinical entity of which emergency physicians should be aware.

Morphological analysis of myocardial bridges and coronary arterial dominance in northeast Brazil.

BACKGROUND: Coronary arterial dominance and myocardial bridges have clinical implications, since a left dominant pattern associated to the presence of myocardial bridges is often associated to a higher incidence of arteriosclerosis and higher mortality by myocardial infarction. OBJECTIVE: To determine the presence and position of myocardial bridges and their relation with coronary arterial dominance. METHODS: Fifty-seven human cadaveric hearts were analyzed into three groups, as follows: right dominance; left dominance; codominance. Each group was then divided into two subgroups: with or without myocardial bridges. Finally, each subgroup with myocardial bridges was classified according to the position of the myocardial bridge according to the main axis of the heart (proximal, middle and distal third). RESULTS: The right dominance occurred in most hearts (30 hearts-52,6%). Twenty-three myocardial bridges (40,3%) were identified and mostly occurred on left dominant hearts (22,8%). The pattern of coronary dominance presented a statistically significant correlation with the presence of myocardial bridges (P=0.048). The middle third of the heart axis showed the highest occurrence of myocardial bridges. CONCLUSION: These findings suggest there is a clear relationship between the presence of myocardial bridges and left dominant pattern. Middle third of the heart axis present the higher occurrence of myocardial bridges. Knowledge of the myocardial bridges morphology is of great clinical significance, improving patient care.

[Surgical treatment of obstructive hypertrophic cardiomyopathy combined with muscle bridging of the left anterior descending artery]. / Khirurgicheskoe lechenie obstruktivnoi gipertroficheskoi kardiomiopatii v sochetanii s miokardial'nym mostikom perednei niskhodyashchei arterii.

Myocardial bridging is often detected during diagnostic coronary angiography in patients with congenital and acquired heart defects. In most cases, muscle bridging does not require surgical treatment. Myocardial bridging and tunnels causing compression of one or more major coronary arteries is a potential cause of myocardial ischemia in patients with hypertrophic cardiomyopathy. The authors report surgical treatment of a patient with obstructive hypertrophic cardiomyopathy and myocardial bridging of the left anterior descending artery.

Myocardial bridging presenting as myocardial ischaemia induced cardiac arrest: a case report.

BACKGROUND: Myocardial bridging is a congenital anomaly defined as a segment of epicardial coronary arteries running through the myocardium. Various complications related to myocardial bridging have been reported, but at present, cardiac arrest has rarely been reported. CASE PRESENTATION: We report one case of a patient who was successfully resuscitated from ventricular fibrillation cardiac arrest and was diagnosed with myocardial bridging accompanied by myocardial ischaemia. A 50-year-old woman who had been resuscitated from cardiac arrest transferred to our institution for evaluation and management of out-of-hospital cardiac arrest. We confirmed the diagnosis of significant myocardial bridging with evident myocardial ischaemia by coronary angiography, resting echocardiography and heart MRI. Vasospasm was thought to be a trigger factor judging from the transient ST elevation on electrocardiography. In addition, the finding of septal buckling was detected for the first time throughout the whole cardiac cycle by resting echocardiography in MB. CONCLUSION: We report a rare case of survival after out-of-hospital cardiac arrest that might be caused by significant myocardial bridging-induced myocardial ischaemia, which was objectively confirmed by echocardiography and heart MRI. Although myocardial bridging is often overlooked as an aetiology for sudden cardiac death, this case highlights the importance of expanding the differential diagnosis to myocardial bridging in the work-up for the cause of sudden cardiac death.

Myocardial bridging of the left anterior descending coronary artery as a risk factor for atrial fibrillation in patients with hypertrophic obstructive cardiomyopathy: a matched case-control study.

BACKGROUND: Myocardial bridging (MB) is associated with various forms of arrhythmia. However, whether MB is a risk factor for atrial fibrillation (AF) in patients with hypertrophic obstructive cardiomyopathy (HOCM) remains unknown. This study aimed to identify the relationship between myocardial bridging of the left anterior descending coronary artery (MB-LAD) and AF in patients with HOCM. METHODS: We reviewed the medical records of 1925 patients diagnosed with HOCM at Fuwai Hospital from January 2012 to March 2019. Patients with coronary artery disease, a history of heart surgery, and those who had not been subjected to angiography were excluded. Finally, 105 patients with AF were included in this study. The control group was matched in a ratio of 3:1 based on age and gender. RESULTS: Forty-three patients were diagnosed with MB-LAD in this study. The presence of MB was significantly higher in patients with AF than in those without AF (19.0% vs. 7.3%; p = 0.001), although MB compression and MB length did not differ between the two groups. In conditional multivariate logistic analysis, MB (odds ratio [OR] 2.33; 95% confidence interval [CI] 1.08-5.01; p = 0.03), pulmonary arterial hypertension (OR 2.63; 95% CI 1.26-5.47; p = 0.01), hyperlipidemia (OR 1.83; 95% CI 1.12-3.00; p = 0.016), left atrial diameter (OR 1.09; 95% CI 1.05-1.13; p < 0.001), and interventricular septal thickness (OR 1.06; 95% CI 1.003-1.12; p = 0.037) were independent risk factors for AF in patients with HOCM. CONCLUSIONS: The presence of MB is an independent risk factor for AF in patients with HOCM. The potential mechanistic link between MB and the development of AF warrants further investigation.

A Hemodynamic Comparison of Myocardial Bridging and Coronary Atherosclerotic Stenosis: A Computational Model With Experimental Evaluation.

Myocardial bridging (MB) and coronary atherosclerotic stenosis can impair coronary blood flow and may cause myocardial ischemia or even heart attack. It remains unclear how MB and stenosis are similar or different regarding their impacts on coronary hemodynamics. The purpose of this study was to compare the hemodynamic effects of coronary stenosis and MB using experimental and computational fluid dynamics (CFD) approaches. For CFD modeling, three MB patients with different levels of lumen obstruction, mild, moderate, and severe were selected. Patient-specific left anterior descending (LAD) coronary artery models were reconstructed from biplane angiograms. For each MB patient, the virtually healthy and stenotic models were also simulated for comparison. In addition, an in vitro flow-loop was developed, and the pressure drop was measured for comparison. The CFD simulations results demonstrated that the difference between MB and stenosis increased with increasing MB/stenosis severity and flowrate. Experimental results showed that increasing the MB length (by 140%) only had significant impact on the pressure drop in the severe MB (39% increase at the exercise), but increasing the stenosis length dramatically increased the pressure drop in both moderate and severe stenoses at all flow rates (31% and 93% increase at the exercise, respectively). Both CFD and experimental results confirmed that the MB had a higher maximum and a lower mean pressure drop in comparison with the stenosis, regardless of the degree of lumen obstruction. A better understanding of MB and atherosclerotic stenosis may improve the therapeutic strategies in coronary disease patients and prevent acute coronary syndromes.

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.

Midterm results of different treatment methods for myocardial bridging in patients after septal myectomy.

BACKGROUND: Myocardial bridging (MB) is commonly treated in patients with hypertrophic cardiomyopathy. However, whether and how MB should be treated in patients with hypertrophic obstructive cardiomyopathy (HOCM) who underwent septal myectomy remain unclear. METHODS: A total of 823 adults with HOCM who underwent septal myectomy at the Fuwai Hospital from 2011 to 2017 were retrospectively studied. RESULTS: Overall, 31 events occurred: 24 patients died and 7 had nonfatal myocardial infarction (MI). The 3-year cumulative event-free survival of all-cause death (97.9% vs. 100% vs. 100% vs. 98.4%, p = .89) and cardiovascular death (98.3% vs. 100% vs. 100% vs. 98.4%, p = .63) were similar among the four groups (non-MB, coronary artery bypass grafting [CABG], unroofing, untreated, respectively). However, the 3-year cumulative event-free survival of nonfatal MI (100% vs. 97.5% vs. 98.0% vs. 89.9%, p < .001) and combined endpoints (97.9% vs. 97.5% vs. 98.0% vs. 88.4%, p = .02) were significantly lowest in untreated MB (non-MB, CABG, unroofing, untreated, respectively). Cox regression analysis indicated that untreated MB was a significant independent predictor of combined endpoints (hazard ratio: 4.06, 95% confidence interval: 1.60-10.32, p < .001). Moreover, 49 patients underwent coronary artery computed tomography 1 year after surgery. The patency rate of the saphenous vein graft was significantly higher than that of the left internal mammary artery (13.3% vs. 84.2%, p < .001). No MB was detected in the unroofing group. CONCLUSIONS: Surgical MB treatment could be beneficial and performed safely during septal myectomy. Myocardial unroofing is the recommended treatment for MB, and unroofing when technically possible may be preferable for long-term outcomes.

Myocardial bridges: A meta-analysis.

Myocardial bridges are anatomical entities characterized by myocardium covering segments of coronary arteries. In some patients, the presence of a myocardial bridge is benign and is only incidentally found on autopsy. In other patients, however, myocardial bridges can lead to compression of the coronary artery during systolic contraction and delayed diastolic relaxation, resulting in myocardial ischemia. This ischemia in turn can lead to myocardial infarction, ventricular arrhythmias and sudden cardiac death. Myocardial bridges have also been linked to an increased incidence of atherosclerosis, which has been attributed to increased shear stress and the presence of vasoactive factors. Other studies however, demonstrated the protective roles of myocardial bridges. In this study, using systematic review and a meta-analytical approach we investigate the prevalence and morphology of myocardial bridges in both clinical imaging and cadaveric dissections. We also discuss the pathophysiology, clinical significance, and management of these anatomical entities.

Clinical characteristics and factors associated with coronary stenosis proximal to a myocardial bridge: a retrospective study.

BACKGROUND: The association of myocardial bridge (MB) with cardiovascular risk and the possible cardiovascular risk factors remain unclear. This study aimed to explore the clinical characteristics and related factors of coronary stenosis proximal to an MB. METHODS: This was a retrospective study of patients with symptoms of coronary atherosclerotic heart disease admitted between 10/2011 and 12/2014 to the Emergency and Cardiology Department of Bayannur Hospital, who underwent selective coronary angiography (SCAG). The patients were assigned to the non-stenosis and stenosis groups according to whether coronary stenosis was proximal to the MB. RESULTS: Among 244 patients with MB and cardiovascular symptoms, 91 (37.3%) had stenosis proximal to the MB. Compared with the non-stenosis group, there were more males (80.2% vs. 55.6%, P < 0.001) and smokers (including those who had quit smoking) (P < 0.001) in the stenosis group. There were no significant differences in blood lipid-related indexes (TG, TC, HDL-C, LDL-C, and VLDL-C) between the two groups. Multivariable analysis suggested that MB location in the middle distal or distal segment of the left anterior descending artery (LAD) increased the odds of coronary stenosis proximal to the MB (OR = 0.439, 95% CI: 1.57-7.532, P = 0.002), which was then considered an independent factor associated with coronary stenosis proximal to the MB. CONCLUSIONS: In patients diagnosed with an MB by SCAG, only MB located in the middle distal or distal segment of the LAD is independently associated with coronary stenosis proximal to the MB.

Myocardial bridging is an independent predictor of positive spasm provocation testing by intracoronary ergonovine injections: a retrospective observational study.

The relationship between myocardial bridging (MB) and coronary spasms during spasm provocation testing (SPT) remains unclear. We aimed to investigate whether MB was correlated with the SPT by ergonovine (ER) injections in a retrospective observational study. Of the 3340 patients who underwent a first coronary angiography, 166 underwent SPT using ER injections and were divided into 2 groups: MB(+) (n = 23), and MB(-) (n = 143). MB was defined as an angiographic reduction in the diameter of the coronary artery during systole. The patients who had severe organic stenosis in the left anterior descending coronary artery were excluded. The MB(+) group more frequently had diabetes mellitus and chronic kidney disease, and a thicker interventricular septum thickness. The rate of SPT-positivity was higher in the MB(+) group than MB(-) group (56.5% vs. 22.4%, P = 0.001). A multivariate regression analysis showed that the presence of MB was independently associated with SPT-positivity (odds ratio 5.587, 95% confidence interval 2.061-15.149, P = 0.001). In conclusion, coronary spasms during provocation tests with ER independently correlated with the MB. MB may predict coronary spasms.