Myocardial bridges and ischemic heart disease

A Rare Presentation of Myocardial Bridging With Heart Failure Symptoms

Myocardial bridging is an under-recognized cause of angina. This congenital anomaly occurs when a segment of the epicardial coronary artery has a short intra-myocardial course. A significant intra-myocardial course may lead to ischemia, causing anginal symptoms. In this case report, we discuss a rare presentation of myocardial bridging with symptoms of heart failure. The pathology led to a marked degree of ventricular dysfunction and a significant drop in cardiac output (CO), and the patient had severe exertional dyspnea and functional limitations. The ischemic workup with diagnostic imaging and angiograms failed to explain the severity of symptoms, which were only evident in hemodynamic studies and cardiopulmonary exercise testing.

Update review on myocardial bridging: New insights

Myocardial bridging (MB) is a common congenital abnormality that remains asymptomatic in a large proportion of patients. The peak of clinical manifestation occurs during the third and fourth decades of life. MB provokes myocardial ischemia through different mechanisms including supply-demand mismatch, endothelial dysfunction, coronary microvascular dysfunction and external mechanical compression. The association between MB and atherosclerotic disease is controversial. Recent studies established a significant association of MB with myocardial infarction and non-obstructive coronary artery disease. The first line medical treatment is based on beta-blockers and calcium channel blockers. Ivabradine is used in second line therapy. Invasive approaches involving percutaneous coronary intervention, coronary artery bypass graft and myotomy are performed in patients with symptoms refractory to maximally tolerated medical treatment. The choice of revascularization technique depends on anatomical characteristics, clinical condition and physician experience. Available data derived from anecdotal evidence view the lack of randomized clinical trials.

Acute Myocardial Infarction Due to Myocardial Bridge Treated With Surgery: a Case Report

Myocardial bridging is congenital anomaly characterized by segment of epicardial coronary arteries passing through the myocardium. Various ischemic conditions are related with this pathology. We report a case of myocardial bridging that was complicated with acute anterior myocardial infarction and a review of the literature. The patient was treated successfully with coronary bypass graft surgery after unsuccessful percutaneous intervention.

Coronary Artery Anomalies - State of the Art Review

Coronary artery anomalies (CAAs) comprise a wide spectrum of anatomic entities, with diverse clinical phenotypes. We present a case of an anomalous right coronary artery arising from the left aortic sinus with an interarterial course, a potentially fatal condition that can precipitate ischemia and sudden cardiac death. CAAs are increasingly detected in adults, mostly as incidental findings in the course of cardiac evaluation. This is due to the expanding use of invasive and noninvasive cardiac imaging, usually in the work-up for possible CAD. The prognostic implications of CAAs in this group of patients remain unclear. In AAOCA patients, appropriate work-up with anatomical and functional imaging should be performed for risk stratification. An individualized approach to management should be adopted, considering symptoms, age, sporting activities and the presence of high-risk anatomical features and physiologic consequences (such as ischemia, myocardial fibrosis, or cardiac arrhythmias) detected on multimodality imaging or other functional cardiac investigations. This comprehensive and up to date review seeks to crystallize current data in the recent literature, and proposes a clinical management algorithm for the clinician faced with the conundrum of managing such conditions.

Prominent myocardial bridging as a first clue to recognize haemorrhagic shock during percutaneous coronary intervention: a case report

Background

Haemorrhage at the puncture site is a serious complication of percutaneous coronary intervention (PCI).

Case summary

A 73-year-old man underwent transfemoral intervention because of stable angina pectoris. After a rotational atherectomy, an everolimus-eluting stent was implanted from the left main trunk to the proximal site of the left anterior descending (LAD) artery. We also recognized that myocardial bridging was significantly induced at the middle portion of the LAD, which was not evident before the PCI. We suspected puncture-related haemorrhage and immediately performed lower limb arteriography. As a result, contrast media extravasation was observed at the branch of the right inferior epigastric artery. Finally, we performed coil embolization into the left common femoral artery, and the extravasation successfully disappeared. Four months later, he underwent coronary angiography. There were no findings of myocardial bridging.

Discussion

Myocardial bridging during a PCI procedure may indicate hypercontraction because of haemorrhage.

A Young Adult With Myocardial Bridging: A Case Report

Myocardial bridging (MB) is a condition where the coronary artery is intramural instead of its natural course through the epicardium. Here, we present a case of a 25-year-old male without any medical history who presented with intermittent substernal chest discomfort on exertion. EKG was suggestive of ST changes in leads V1-V4 with right axis deviation. A left heart catheterization revealed myocardial bridging of the midportion of the left anterior descending artery. Myocardial bridging is commonly not associated with severe complications. However, it is imperative to diagnose it appropriately, especially in cases of chest pain, and provide immediate treatment to prevent mortality and morbidity.

Clinical Implication and Optimal Management of Myocardial Bridging: Role of Cardiovascular Imaging

Myocardial bridging (MB) was historically considered a benign structure as most people with MB are clinically asymptomatic. Recently, however, mounting evidence indicates that MB can cause adverse cardiac events owing to arterial systolic compression/diastolic restriction, atherosclerotic plaque progression upstream from MB, and/or vasospastic angina. In MB patients with refractory angina, the optimal treatment strategy should be determined individually based on versatile anatomic and hemodynamical assessments that often require multidisciplinary diagnostic approaches. The present review summarizes the clinical implication and management of MB, highlighting the role of imaging modalities currently available in this arena.

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.

Use of Novel Blunt Dissection Technique for Surgical Unroofing in Myocardial Bridging Patients

Background

Myocardial bridging (MB) is a congenital anomaly involving the myocardial tissue encasement of a segment of the coronary artery. The purpose of the present study was to assess safety and efficacy of two surgical methods used for treating MB patients at our institute.

Methods

Off-pump MB unroofing was performed in 45 adult patients between January 2016 and December 2021 by traditional surgical unroofing techniques (conventional group, n = 26) and blunt dissection techniques (blunt dissection group, n = 19). We retrospectively reviewed our patients by examining the baseline clinical characteristics, risk factors, medications, and diagnostic data for coronary artery disease. The Seattle Angina Questionnaire (SAQ) was used to assess angina symptoms both preoperatively and 6 months postsurgery.

Results

No significant difference in preoperative clinical characteristics was observed between the two groups. The blunt dissection group had shorter unroofed period (14.69 vs. 18.91 mins, P=0.001), less ventilator time (16.26 vs. 24.62 hours, P < 0.001), and a shorter hospital stay (8.74 vs. 12.89 days, P < 0.001). Although both traditional and blunt dissection techniques significantly improved postoperative SAQ scores including physical limitation due to angina, anginal stability, anginal frequency, treatment satisfaction, and quality of life (P < 0.001), no significant difference was observed between the traditional and blunt dissection techniques for SAQ. No cases of left anterior descending (LAD) injury in the blunt dissection group were observed although seven patients in the conventional group had LAD injuries.

Conclusions

In our single-center experience of MB unroofing, the blunt dissection technique is a safe, effective technique that significantly reduces surgical and ventilator time and hospital stay. MB patients with severe angina who underwent the blunt dissection for surgical unroofing experienced significant improvements in anginal symptoms and quality of life six months after the surgery.

Comparison of Framingham risk score and atherogenic indices as a predictor of atherosclerosis in patients with myocardial bridge in left anterior descending artery

BACKGROUND

Myocardial bridge (MB) is generally considered as a benign condition, but it may trigger atherosclerosis, especially in the adjacent proximal coronary artery segment. In this study, we aimed to investigate whether the Framingham risk score (FRS) or atherogenic indices are risk factors for coronary atherosclerosis in patients with MB in the left anterior descending coronary artery (LAD).

METHODS

We performed a retrospective study evaluating 155 patients who have MB in LAD. The patients were evaluated in two groups according to the presence of atherosclerosis (74 patients in atherosclerotic group vs. 81 patients in non-atherosclerotic group). Baseline characteristics, FRS and atherogenic indices were reviewed between groups. Significant independent risk factors for coronary atherosclerosis were investigated by logistic regression analysis.

RESULTS

Patients in atherosclerotic group were significantly older (58.15 ± 10.04 vs. 50.22 ± 9.27 years, p < .001) and 74.3% of the patients were male. While the mean FRS in the atherosclerotic group was 21.20 ± 8.81, it was 12.79 ± 8.61 in the non-atherosclerotic group (p < .001). Among the atherogenic indices, only LDL-c/HDL-c ratio was significantly higher in the atherosclerotic group (3.49 ± 1.2 vs. 3.11 ± 0.98, p:.033). Multivariable analysis showed that age (OR: 1.08, 95% CI 1.03-1.13, p < .001) and FRS (OR: 1.06, 95% CI 1.01-1.11, p:.012) were independently associated with the presence of atherosclerotic lesion.

CONCLUSIONS

FRS is an easily applicable predictor in clinical practice that indicates the presence of coronary atherosclerosis in patients with MB in LAD.

Therapeutic Dilemmas Faced When Managing a Life-Threatening Presentation of a Myocardial Bridge

Background. Myocardial bridges are congenital abnormalities, where a segment of coronary artery travels intramyocardially, rather than the typical epicardial course. The overlying muscle segment is termed “the bridge”. Most myocardial bridges are asymptomatic, but some can result in myocardial ischaemia, arrhythmias, and sudden cardiac death. Case Presentation. A 31-year-old male with no past medical history presented to our tertiary cardiac centre following an out-of-hospital ventricular fibrillation arrest. Coronary angiography and computed tomography of the coronary arteries revealed a 2 cm myocardial bridge overlying the left anterior descending (LAD) artery. An exercise echocardiogram demonstrated severe apical ballooning and hypokinesis during peak exercise, with corresponding ST-segment elevation, resolving on rest. Options for medical therapy of a symptomatic myocardial bridge include beta blockers, calcium channel blockers, ivabradine, or a combination thereof. Surgical interventions include deroofing the bridge and revascularisation of the affected region with bypass grafting. However, a lack of trial data comparing medical regimens and surgical interventions makes it difficult to ascertain the most effective management strategy for each patient. There was disagreement between experts at different tertiary centres over the optimal management of this patient. He was treated with multiple regimes of medical therapy with ongoing ischaemia on stress testing, before undergoing a negative stress test on amlodipine, diltiazem, and isosorbide mononitrate. It was felt that no further intervention was necessary at this time given his exercise test was now negative for ischaemia. However, after seeking a second opinion, he underwent surgical intervention with bypass grafting of his left anterior descending artery, followed by implantation of an implantable cardiac defibrillator. Subsequently, an angiogram postsurgery demonstrated concomitant spasm of the LAD and he was resumed on medical therapy with calcium channel blockers and nitrates. Discussion. Without randomised trials, it is impossible to determine the optimal management strategy for each patient. It is possible that some patients with myocardial bridges are not being trialled on optimal medical therapy prior to undergoing invasive and irreversible interventions.

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.

Is myocardial bridge more frequently detected on radial access coronary angiography?

Background

Although the incidence of myocardial bridge (MB) has been defined in different femoral access conventional coronary angiography (FACCA) studies, the frequency of MB on radial access coronary angiography (RACA) is unknown. The aim of this study was to determine the difference in the incidence of MB between patients undergoing RACA and FACCA.

Method

A total of 2500 consecutive patients who underwent RACA and a total of 1455 consecutive patients who underwent FACCA were retrospectively investigated to detect the presence of MB. The incidences of the groups were calculated separately and compared. The clinical and angiographic features of the patients with MB were analyzed.

Results

MB was detected at an incidence of 10.2%, in 255/2500 patients who underwent RACA, and 1.8% in 27/1455 patients who underwent FACCA (p < 0.001). In both RACA and FACCA patients, the most involved coronary artery was the left anterior descending artery (LAD) (86.9% and 93.1%) and the mid-segment (84.9% and 88.9%) was the most affected section. Co-involvement of multiple coronary arteries by MB was 7.8% in patients who underwent RACA and 7.4% in patients who underwent FACCA. Coronary artery disease (CAD) was determined in 111 (35.7%) of the coronary arteries with MB, of which 81.9% were proximal to the MB. No significant CAD was detected in any of the vessels of 69.8% (178/255) of the patients who underwent RACA for different clinical indications.

Conclusion

These data demonstrated that the incidence of myocardial bridge able to be detected on RACA was much higher than FACCA.

Coronary Artery Anomalies

Coronary artery anomalies (CAAs) are a group of congenital conditions characterized by abnormal origin or course of any of the 3 main epicardial coronary arteries. Although CAAs have been identified as a common underlying condition in young athletes with sudden cardiac death, the widespread use of invasive and noninvasive coronary imaging has led to increased recognition of CAAs among adults. CAAS are often discovered as an incidental finding during the diagnostic workup for ischemic heart disease. The clinical correlates and prognostic implication of CAAs remain poorly understood in this context, and guideline-recommended therapeutic choices are supported by a low level of scientific evidence. Several studies have examined whether assessment of CAA-related myocardial ischemia can improve risk stratification in these patients, suggesting that multimodality imaging and functional tests may be key in the management of CAAs. The aim of this review is to outline definitions, classification, and epidemiology of the most relevant CAAs, highlighting recent advances and the potential impact of multimodality evaluation, and to discuss current therapeutic opportunities.

Left anterior descending artery myocardial bridge manifesting as episodic, symptomatic exertional non-sustained ventricular tachycardia

A 48-year-old man presented to the emergency department (ED) with exertional chest pressure associated with palpitations and lightheadedness. He was found to have non-sustained ventricular tachycardia (NSVT) in the ED, which resolved spontaneously. Given his history of hyperlipidaemia, unknown family history due to being adopted and episode of NSVT in the ED, he underwent cardiac catheterisation, which showed non-obstructive coronary artery disease and distal left anterior descending artery myocardial bridge (MB). The patient subsequently underwent ECG treadmill stress test with reproduction of chest pressure and NSVT. The patient was referred to cardiac surgery for definitive management of symptomatic MB and underwent resection of MB.

Left anterior descending myocardial bridge: Angiographic prevalence and its association to atherosclerosis

OBJECTIVE

Left anterior descending Myocardial Bridge (LADMB) is considered a benign condition and actually becomes a forgotten cause of serious cardiac events. This study was conducted to estimate the prevalence of LADMB and its association to atherosclerosis.

METHODS

An observational retrospective study was conducted on patients referred for coronary angiography between June 2012 and June 2020. Coronary angiography database was revisedand studied population was divided into 2 groups: LADMB group versus Non-LADMB group.

RESULTS

LADMB was detected in 510 patients out of 35813 included in the study resulting in a prevalence at 1.42%. The mean age was 66.5 years. Male gender was more common than female (70vs30%). The prevalence of significant atherosclerotic LAD disease was more than two times higher in the non-LADMB group compared to the LADMB group. Statistical analysis revealed a significant negative association between LADMB and atherosclerosis (p < 0.001). A significant greater rate of MINOCA cases was observed in acute coronary syndrome LADMB patients.

CONCLUSIONS

LADMB is an inborn anatomic variation associated to atherosclerotic risk reduction in LAD. Physicians must be aware about the potential complications and pay attention to those classified at high risk for cardiovascular events.

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.

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.

Coronary Flow in Patients With Myocardial Bridges, Coronary Fistulae in the Setting of Unstable Non-Obstructive Coronary Disease

Оbjective

Our aim was to describe the difference in epicardial coronary flow at baseline on background anti-ischaemic therapy and following intracoronary glyceryl trinitrate in patients with acute coronary syndrome and non-obstructive coronary disease with and without myocardial bridges and coronary artery fistulae.

Materials and methods

Coronary flow was characterized in a group of 88 patients with coronary stenoses <50% diagnosed with acute coronary syndrome using the corrected Thrombolysis in Myocardial Infarction frame count (cTFC) method at coronary angiography at baseline and after the application of 200 µg glyceryl trinitrate.

Results

Тhe patients with myocardial bridges and coronary artery fistulae accounted for 4.4% (n=4) and 2.2% (n=2), respectively, of the patients with acute coronary syndrome. Sixty-two (70%) of all patients demonstrated slow progression of the contrast media (cTFC>25 frames) in at least one coronary artery. Coronary flow was similarly impaired in the patients with myocardial bridges, coronary artery fistulae, and those without coronary anomalies and variants. After the intracoronary infusion of glyceryl trinitrate, the epicardial flow improved in the patients with myocardial bridges and to a lesser degree in the cases with coronary fistulae. Most of the patients who responded to glyceryl trinitrate were on background therapy with calcium channel blockers.

Conclusion

The epicardial coronary flow of patients with non-obstructive coronary disease with myocardial bridges and acute coronary syndrome showed less impairment compared to baseline in response to intracoronary glyceryl trinitrate applied at background anti-ischaemic therapy that included calcium channel blockers.

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.

Prevalence of myocardial bridge in angiographic population-A study from rural part of western India

Introduction:

Intramural course of coronary artery is known as myocardial bridge (MB). Its prevalence is highly variable. Very few studies have been conducted in India, mostly from southern state and that too covering urban population. There are no studies from western India. In this study we aimed to estimate the prevalence of MB in coronary angiogram from rural part of western India.

Methods and Results:

A total of 4,438 patients underwent coronary angiography for various indications during the study period of 69 months. Mean age of the study population was 53.6 ± 11.2 years. MB was found in 212 (4.77%) of patients, predominantly in males. Unstable angina was the most common presentation among males (28.7%), whereas chronic stable angina was being the most common presentation among females (22.6%). Majority of MBs were seen in left anterior descending artery in its mid part (61%). Mean diameter compression of the affected segment was 32.6% ± 11.8%, with no significant difference seen among males and females or between mid and distal left anterior descending artery.

Conclusion:

Our study showed the prevalence of MB similar to other Indian studies. Left anterior descending artery was most common artery involved. Mean compression was not statistically significant among either sex.

A case report of a coronary myocardial bridge with impaired full-cycle ratio during dobutamine challenge

Background

A myocardial bridge (MB) is a coronary variant in which an epicardial coronary artery tunnels through the myocardial band. Although MBs have been reported to cause ischaemia, physiological assessment of an MB has not been fully established.

Case summary

We encountered a case with exertional chest pain who underwent coronary angiography showing an MB at the mid-left anterior descending artery with systolic compression. Optical coherence tomography showed an MB defined as a homogeneous intermediate intensity surrounding the epicardial artery. The full-cycle ratio, defined as the lowest ratio of distal coronary pressure (P_d) to aortic pressure (P_a) during the entire cardiac cycle, measured 0.89 at rest and 0.73 with intravenous dobutamine of 20 µg/kg/min with a distinctive waveform pattern (early diastolic P_d drop) during a dobutamine challenge. Metoprolol succinate dosage was increased. The patient has been free from chest pain for 7 months after the discharge.

Discussion

Optical coherence tomography may contribute to anatomical detections of MBs. Because a systolic compression of the MB and release of the vascular lumen during early diastole leads to an early steep pressure loss, early diastolic P_d drop should be one of the specific haemodynamic characteristics of MBs. On the other hand, in a severe atherosclerotic stenosis, P_d drop is typically observed in late diastole, which could be differentiated from that of MBs. Because full-cycle ratio reflects the whole cardiac cycle including early diastole, this might be more useful than other physiological indices for detection of MB-related ischaemia induced by a dobutamine challenge.

Associations of myocardial bridging with adverse cardiac events: a meta-analysis of published observational cohort studies involving 4,556 individuals

Background

Data derived from small series have demonstrated an association of myocardial bridge (MB) with adverse cardiac events, while MB has been traditionally considered as a benign condition. Hence, the precise clinical implications of MB on prognosis remains inconsistent. Our purpose is to perform a meta-analysis to assess the clinical implications of MB on prognosis.

Methods

We performed an extensive search of PubMed and reference lists of relevant articles. Studies which compared prognosis between subjects with and without MB were identified from 1960 to 31 March 2018. Studies selection was limited to human data and restricted to English language.

Results

Six eligible studies were included in current meta-analysis. Of 4,556 subjects, 1,389 (30.5%) presented MB. MB was associated with an increased risk of adverse cardiac events [odds ratio (OR), 1.71; 95% confidence interval (CI): 1.29 to 2.26; P=0.0002], non-fatal myocardial infarction (OR: 3.17; 95% CI: 1.21 to 8.31; P=0.02), and angina requiring hospitalization (OR: 2.31; 95% CI: 1.55 to 3.45; P<0.0001), respectively, compared with subjects without MB.

Conclusions

This meta-analysis of currently available observational cohort studies suggests that MB has an association with adverse cardiac events. Further prospective multicenter studies with large sample size are needed to confirm current findings. Moreover, studies refining the impact of different types of MB on cardiac events, myocardial ischemia, and symptoms requiring therapy, may provide more insights to this issue.

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.

The prevalence of myocardial bridging on multidetector computed tomography and its relation to coronary plaques

PURPOSE

To test the hypothesis that the prevalence of myocardial bridging varies between ethnic groups, and that the segment proximal to the myocardial bridge is more prone to plaque formation.

MATERIAL AND METHODS

A total of 4500 patients who had undergone computerised tomography (CT) coronary angiography at our institute were studied for myocardial bridging. Data on the clinical profile and indication for CT coronary angiography in myocardial bridging were collected. Patients with and without proximal disease were compared using the chi-square test for ordinal variables and Student's t-test for continuous variables. The length to depth ratio (RA-MA ratio) of the bridged segment was determined.

RESULTS

The prevalence of atherosclerotic plaques in the segment proximal to the bridged segment was 37.8%, which was lower than the prevalence of 48.7% for plaques in the corresponding segments among patients without myocardial bridging. The average length of the bridged segment was 15.5 ± 5 mm, and that for patients with and without proximal plaques was 13 ± 4 and 16 ± 6 mm (p = 0.1), respectively. Similarly, the average depth of the segments with and without proximal plaques was 1.8 ± 0.6 mm and 1.4 ± 0.5 mm (p = 0.06), respectively. Only the RA-MA ratio (8 ± 3 vs. 13 ± 6, p = 0.01) was significantly lower in patients with atherosclerotic plaques.

CONCLUSIONS

The prevalence in our study population was 10%, with mid left anterior descending artery (LAD) being the most common segment involved. Moreover, the prevalence and distribution of coronary plaques in LAD were similar in patients with and without myocardial bridging.

Unmasking Myocardial Bridge-Related Ischemia by Intracoronary Functional Evaluation

BACKGROUND

Invasive physiological assessment of myocardial bridges (MBs) is largely unsettled. Unlike fractional flow reserve (FFR), instantaneous wave-free ratio (iFR) is a diastole-specific index. As such, its value might not be hampered by systolic pressure overshooting and negative systolic pressure gradient caused by the compression of the tunneled coronary artery.

METHODS AND RESULTS

We prospectively enrolled 20 patients with angina and/or positive noninvasive stress test, absence of significant coronary artery stenosis, and angiographic suspicion/evidence of MB in the left anterior descending artery. According to a prespecified protocol, all patients underwent functional intracoronary evaluation with FFR at rest and after dobutamine (up to 20 μg kg^-1 min^-1) and atropine (1 mg) intravenous infusion. iFR at baseline and dobutamine-induced hyperemic wave-free period pressure ratio were also recorded. FFR values ≤0.80 and iFR values ≤0.89 were considered indicative of hemodynamic significance of MB. At baseline, no MB was hemodynamically significant according to FFR, whereas iFR was below the cutoff value in all but 7 patients. During inotropic challenge, median FFR did not change significantly (0.87-0.86, P=0.59).

CONCLUSIONS

Physiological evaluation of MBs with iFR seems to be more consistent with patients' symptoms and noninvasive test results compared with FFR.

Optical coherence tomography and intravascular ultrasound assessment of the anatomic size and wall thickness of a muscle bridge segment

OBJECTIVE

To use optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in assessing myocardial bridging (MB) vessel size and wall thickness.

BACKGROUND

During stent implantation, MB is associated with complications, especially perforation.

METHODS

OCT and IVUS were performed in 56 patients with typical angiographic "milking" from November 2016 to May 2017. The vessel area and thickness in the MB segments and adjacent proximal and distal reference segments were measured and compared with eight normal left anterior descending (LAD) segment (no atherosclerosis in a segment that was at least 20 mm long and that began ~40 mm distal to the LAD ostium).

RESULTS

Compared with the reference vessel size distal to the MB segment (6.3 ± 1.8 mm² ), the IVUS-measured size of the tunneled vessel during diastole was significantly smaller (6.0 ± 1.9 mm² , p < 0.05) (remodeling index = 0.79 ± 0.18). The minimum intramyocardial arterial wall thickness was 0.16 ± 0.02 mm, significantly thinner than that of the mean reference (0.22 ± 0.03 mm, p < 0.001). The location of the thinnest arterial wall was in the distal and middle MB segments in 45 (80.4%) and 11 (19.6%) patients, respectively, and was not related to the degree of systolic compression or remodeling index. The walls of the middle and distal MB subsegments, but not of the proximal MB subsegment, were thinner than that of the comparison group of normal LADs.

CONCLUSION

The coronary vessel involved in an MB is both smaller and thinner than that of the adjacent non-MB segment. This may explain the increased frequency and severity of coronary perforation during stent implantation.

Assessment of the Relationship between Monocyte to High-Density Lipoprotein Ratio and Myocardial Bridge

BACKGROUND

Assessing the monocyte to high-density lipoprotein ratio (MHR) is a new tool for predicting inflamation, which plays a major role in atherosclerosis. Myocardial bridge (MB) is thought to be a benign condition with development of atherosclerosis, particularly at the proximal segment of the brigde.

OBJECTIVE

To evaluate the relationhip between MHR and the presence of MB.

METHODS

We consecutively scanned patients referred for coronary angiography between January 2013- December 2016, and a total of 160 patients who had a MB and normal coronary artery were enrolled in the study. The patients' angiographic, demographic and clinic characteristics of the patients were reviewed from medical records. Monocytes and HDL-cholesterols were measured via complete blood count. MHR was calculated as the ratio of the absolute monocyte count to the HDL-cholesterol value. MHR values were divided into three tertiles as follows: lower (8.25 ± 1.61), moderate (13.11 ± 1.46), and higher (21.21 ± 4.30) tertile. A p-value of < 0.05 was considered significant.

RESULTS

MHR was significantly higher in the MB group compared to the control group with normal coronary arteries. We found the frequency of MB (p = 0.002) to increase as the MHR tertiles rose. The Monocyte-HDL ratio with a cut-point of 13.35 had 59% sensitivity and 65.0% specificity (ROC area under curve: 0.687, 95% CI: 0.606-0.769, p < 0.001) in accurately predicting a MB diagnosis. In the multivariate analysis, MHR (p = 0.013) was found to be a significant independent predictor of the presence of MB, after adjusting for other risk factors.

CONCLUSION

The present study revealed a significant correlation between MHR and MB.

Surgical unroofing of hemodynamically significant myocardial bridges in a pediatric population

BACKGROUND

Although myocardial bridges (MBs) are traditionally regarded as incidental findings, it has been reported that adult patients with symptomatic MBs refractory to medical therapy benefit from unroofing. However, there is limited literature in the pediatric population. The aim of our study was to evaluate the indications and outcomes for unroofing in pediatric patients.

METHODS

We retrospectively reviewed all pediatric patients with MB in our institution who underwent surgical relief. Clinical characteristics, relevant diagnostic data, intraoperative findings, and postoperative outcomes were evaluated.

RESULTS

Between 2012 and 2016, 14 pediatric patients underwent surgical unroofing of left anterior descending artery MBs. Thirteen patients had anginal symptoms refractory to medical therapy, and 1 patient was asymptomatic until experiencing aborted sudden cardiac arrest during exercise. Thirteen patients underwent exercise stress echocardiography, all of which showed mid-septal dys-synergy. Coronary computed tomography imaging confirmed the presence of MBs in all patients. Intravascular ultrasound imaging confirmed the length of MBs: 28.2 ± 16.3 mm, halo thickness: 0.59 ± 0.24 mm, and compression of left anterior descending artery at resting heart rate: 33.0 ± 11.6%. Invasive hemodynamic assessment with dobutamine confirmed the physiologic significance of the MBs with diastolic fractional flow reserve: 0.59 ± 0.13. Unroofing was performed with the patient under cardiopulmonary bypass (CPB) in the initial 9 cases and without CPB in the subsequent 5 cases. All patients were discharged without complications. The 13 symptomatic patients reported resolution of symptoms on follow-up, and improvement in symptoms and quality of life was documented using the Seattle Angina Questionnaire version 7.

CONCLUSIONS

Unroofing of MBs can be safely performed in pediatric patients, with or without use of CPB. In symptomatic patients, unroofing can provide relief of symptoms refractory to medical therapy.

What is the optimal treatment for symptomatic patients with isolated coronary myocardial bridge? A systematic review and pooled analysis

BACKGROUND

Myocardial bridging is a common coronary anomaly, with few severe adverse events but a relevant symptom burden. Myocardial bridging treatment, however, remains uncertain because of the lack of randomized trials.

MATERIAL

MEDLINE/PubMed was systematically screened for studies reporting on isolated myocardial bridging diagnosed at coronary angiography or with coronary computed tomography in patients admitted for suspected angina or with an acute coronary syndrome. Baseline, treatment and outcome data were appraised and pooled according to treatment (medical therapy, bypass surgery/myotomy or stenting).

RESULTS

A total of 899 patients in 18 studies were included with a low prevalence of traditional risk factors, especially diabetes (15.6%, interquartile range 2.5-21.5). After a median of 31.0 months (interquartile range 12.4-37.1), major cardiovascular events (composite of death, myocardial infarction or target vessel revascularization) occurred in only 3.4% of the study patients and 78.7% [70.5-86.9; 95% confidence intervals (CI)] were managed conservatively and free of symptoms. When an invasive strategy was planned, freedom from angina was higher in patients treated with surgery [84.5% (78.4-90.7; 95% CI)] than in those treated with stenting [54.7% (38.9-70.6; 95% CI)]. Patients in the stenting group experienced a high incidence of major cardiovascular events related to target vessel revascularization [40.07% (19.83-60.32; 95% CI)]. Meta-regression showed that patients treated with beta-blockers or with a history of hypertension were more likely to remain free from angina (B -0.6, P = 0.013; B -0.66, P = 0.006).

CONCLUSION

Patients with symptomatic isolated myocardial bridging generally have a good long-term prognosis. Pharmacological treatment alone, especially with beta-blockers, is able to improve angina in most cases. Surgical treatment appears to be more effective than stenting in nonresponders.

Myocardial Bridging: A Meta-Analysis of Prevalence

The main objective of this article was to analyze prevalence data about myocardial bridging (MB) in published studies. To this purpose, we performed a meta-analysis of studies published in English literature that contained data about the prevalence of MB and its anatomical characteristics. The overall prevalence was 19% (CI: 17-21%); autopsy studies revealed an overall prevalence of 42% (CI: 30-55%), CT studies 22% (CI: 18-25%), and coronary angiography 6% (CI: 5-8%). Most bridges were located on the left anterior descending artery (82% overall, 63% on autopsy studies), had a mean thickness of 2.47 mm and a mean length of 19.3 mm. In conclusion, autopsy studies should be the gold standard in evaluating the actual prevalence of myocardial bridges, while in vivo high-resolution CT scanning should be preferred to coronary angiography studies.

Relation between severity of myocardial bridge and vasospasm

BACKGROUND

Myocardial bridge (MB) has been reported to induce cardiac complications including coronary vasospasm. Although MB has some anatomical and morphological variations, the association of these variations with vasospasm is unclear. The aim of this study was to investigate the relation between morphological severity of MB and vasospasm induced by acetylcholine (ACh) provocation test.

METHODS

A total of 392 patients without coronary stent in the left anterior descending artery (LAD) undergoing intracoronary ACh provocation test were included. Angiographic coronary artery vasospasm was defined as total or subtotal occlusion induced by ACh provocation. MB was identified on coronary angiography as a milking effect. Total bridged length and maximum percent systolic compression of MB in the LAD were analyzed quantitatively.

RESULTS

MBs in the LAD were identified in 140 patients (36%), mostly in the mid segment. Patients with MB in the LAD had greater number of provoked vasospasm in the LAD and positive ACh provocation test compared to those without. The bridged length positively correlated with percent systolic compression of MB (r=0.37, p<0.001). In the receiver operating characteristic curve analysis, both bridged length and percent systolic compression of MB significantly predicted the provoked LAD spasm (AUC 0.74, p<0.001, and AUC 0.68, p<0.001). Multivariate regression analysis demonstrated these factors as independent predictors for provoked LAD spasm.

CONCLUSION

MB, especially morphologically severe MB, may induce greater coronary vasospasm.

Left Anterior Descending Artery Myocardial Bridging: A Clinical Approach

A myocardial bridge (MB) is the term for the muscle overlying the intramyocardial segment of the epicardial coronary artery (referred to as a tunneled artery). Although MBs can be found in any epicardial artery, most of them involve the left anterior descending artery. These congenital coronary anomalies have long been recognized anatomically, and are traditionally considered a benign condition; however, the association between myocardial ischemia and MBs has increased their clinical relevance. This review summarizes the prevalence, pathophysiology, and diagnostic findings, including morphological, functional assessment, and treatment of patients with MB involving the left anterior descending artery, suggesting a pragmatic clinical approach to this entity.

Coronary anatomy, anatomic variations and anomalies: a retrospective coronary angiography study

INTRODUCTION

The incidence of coronary artery anomalies (CAAs) varies from 0.2% to 8.4%. Knowledge of such anatomical variations is important as coronary procedures are regularly performed these days. We aimed to find the coronary dominance pattern, intermediate artery (IMA) frequency and CAA incidence in our clinic, and compare them to those in the literature.

METHODS

The medical reports of 5,548 patients who had undergone coronary angiography (CAG) between 2005 and 2009 were retrospectively investigated. Dominance pattern and presence of IMA and CAA were recorded. CAAs were described using two different classifications: Angelini and Khatami's classification, and a new modified classification that was derived from Angelini and Khatami's classification. Some procedural details and clinical features of the patients with CAA were also investigated.

RESULTS

Coronary dominance pattern was: 81.6% right coronary artery, 12.2% circumflex artery and 6.2% co-dominant. IMA was present in 613 (11.0%) patients. The incidences of overall anomaly were 2.7% and 1.4%, according to the different classifications. Absent left main coronary artery, which was the most common anomaly in the present study, was found in 51 (0.9%) patients. Incidences of myocardial bridge, coronary arteriovenous fistulae and aneurysms were 1.1%, 0.2% and 0.3%, respectively.

CONCLUSION

CAAs are generally asymptomatic, isolated lesions. Some may lead to anginal symptoms, myocardial infarction or sudden death. We found that CAA was associated with increased radiation and contrast exposure in patients who underwent CAG. This risk could be reduced if appropriate catheters were designed and training programmes on ostial cannulation were developed.

Noninvasive assessment of myocardial bridging by coronary flow velocity reserve with transthoracic Doppler echocardiography: vasodilator vs. inotropic stimulation

BACKGROUND

To consider hemodynamic assessment of myocardial bridging (MB) adequate, it is believed that inotropic stimulation with dobutamine should be estimated because its dynamic nature depends on the degree of extravascular coronary compression. This study evaluated comparative assessment of hemodynamic relevance of MB using coronary flow velocity reserve (CFVR) measurements by transthoracic Doppler echocardiography (TTDE) with vasodilatative and inotropic challenges.

METHODS

This prospective study included forty-four patients with angiographic evidence of isolated MB of the left anterior descending coronary artery (LAD) and systolic compression of ≥50% diameter stenosis. All patients were evaluated by exercise stress-echocardiography (ExSE) test for signs of myocardial ischemia, and CFVR of the distal segment of LAD during iv.infusion of adenosine (ADO:140μg/kg/min) and iv.infusion of dobutamine (DOB:10-40μg/kg/min), separately.

RESULTS

Exercise-SE was positive for myocardial ischemia in 8/44 (18%) of patients. CFVR during ADO was significantly higher than CFVR during peak DOB (2.85±0.68 vs. 2.44±0.48, p=0.002). CFVR during peak DOB was significantly lower in SE-positive group in comparison to SE-negative group (2.01±0.16 vs. 2.54±0.47, p<0.001), but not for ADO (2.47±0.51 vs. 2.89±0.70, p=0.168), respectively. Multivariable logistic analysis showed that CFVR peak DOB was the most significant predictor of functional significant MB (OR 0.011, 95%CI: 0.001-0.507, p=0.021). Receiver-operating characteristic curves have shown that TTDE-CFVR obtained by high-dose of dobutamine infusion is better than those by adenosine regarding to functional status of MB (AUC 0.861, p=0.004; AUC 0.674, p=0.179, respectively).

CONCLUSIONS

Non-invasive CFVR measurement by TTDE during inotropic stimulation, in comparison to vasodilation, provides more reliable functional evaluation of MB.

Evaluation of left ventricular function by three-dimensional speckle-tracking echocardiography in patients with myocardial bridging of the left anterior descending coronary artery

BACKGROUND

To understand the influence of myocardial bridging (MB) on left ventricular (LV) function, myocardial function was studied in patients with MB of the left anterior descending coronary artery (LAD) using three-dimensional speckle-tracking echocardiography (STE).

METHODS

Left anterior descending coronary artery MB was diagnosed by coronary angiography in 82 subjects. Patients were divided into three groups according to the percentage of systolic narrowing of the compressed segment: 30% to 49% was defined as group I (24 patients), 50% to 74% as group II (28 patients), and ≥75% as group III (30 patients). Thirty gender- and age-matched normal subjects were included as controls. Left ventricular myocardial deformation was estimated by three-dimensional STE.

RESULTS

Left ventricular ejection fractions were normal in all patients, but diastolic function was impaired in groups II and III (E/E' ratio, 9 ± 3 and 10 ± 3, respectively). The amplitudes of longitudinal strain (LS) and area strain (AS) of the LAD territory was significantly reduced in groups II and III compared with controls and group I (LS, -15 ± 2% and -12 ± 1% vs -19 ± 2% and -18 ± 2%; AS, -22 ± 2% and -13 ± 2% vs -33 ± 4% and -33 ± 3%; P < .0001), but the amplitudes of circumferential and radial strain showed no intergroup differences. Longitudinal strain and AS were significantly lower in patients with fractional flow reserve < 0.75 than in those with fractional flow reserve ≥ 0.75 (P < .0001), with relative preservation of circumferential and radial strain. The severity of LAD compression was significantly associated with AS and LS of the LAD territory (r = -0.92 and r = -0.84, respectively, P < .0001), but the correlations with circumferential and radial strain were modest (r = -0.36 and r = -0.32, respectively, P < .05).

CONCLUSIONS

With the increasing severity of systolic compression of the mural coronary artery, LV diastolic function and regional systolic deformation (AS and LS) of the MB perfusion territory were reduced. Three-dimensional STE can detect subtle myocardial dysfunction in patients with MB.

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.

Congenital coronary anomalies detected by coronary computed tomography compared to invasive coronary angiography

Background

As coronary computed tomography angiography (CCTA) has emerged as a non-invasive alternative for evaluation of coronary anatomy with a lower referral threshold than invasive coronary angiography (ICA), the prevalence of coronary anomalies in CCTA may more closely reflect the true prevalence in the general population. Morphological features of coronary anomalies can be evaluated more precisely by CCTA than by ICA, which might lead to a higher identification of congenital coronary anomalies in CCTA compared to ICA.

To evaluate the incidence, clinical and morphological features of the anatomy of patients with coronary anomalies detected either by coronary computed tomography angiography (CCTA) with prospective ECG-triggering or invasive coronary angiography (ICA).

Methods

Consecutive patients underwent 64-slice CCTA (n = 1′759) with prospective ECG-triggering or ICA (n = 9′782) and coronary anatomy was evaluated for identification of coronary anomalies to predefined criteria (origin, course and termination) according to international recommendations.

Results

The prevalence of coronary anomalies was 7.9% (n = 138) in CCTA and 2.1% in ICA (n = 203; p < 0.01). The most commonly coronary anomaly detected by CCTA was myocardial bridging 42.8% (n = 59) vs. 21.2% (n = 43); p < 0.01, while with ICA an absent left main trunk was the most observed anomaly 36.0% (n = 73; p < 0.01). In 9.4% (n = 13) of identified coronary anomalies in CCTA 9.4% were potentially serious coronary anaomalies, defined as a course of the coronary artery between aorta and pulmonary artery were identified.

Conclusion

The prevalence of coronary anomalies is substantially higher with CCTA than ICA even after exclusion of patients with myocardial bridging which is more frequently found with CCTA. This suggests that the true prevalence of coronary anomalies in the general population may have been underestimated based on ICA.

Myocardial bridge as a structure of "double-edged sword" for the coronary artery

Myocardial bridge (MB) is a chance anatomical structure, comprised of the myocardial tissue, with which the coronary artery running in epicardial adipose tissue is partly covered. It is predominantly present in the left anterior descending artery (LAD) and recognizable through imaging techniques as changes in blood flow within the LAD that arises from MB contraction at cardiac systole. Such changes in blood flow influence the pathophysiology of coronary circulation and atherosclerosis development, thus generating controversy as to whether MB predisposes individual to myocardial infarction (MI). However, recent histomorphometric studies have shown that the individual anatomic properties of MB, such as location, length and thickness, consistently play a critical role in the occurrence of MI. This review article comprehensively addresses the pathophysiological mechanisms of MI occurrence together with the benign suppressive effect of coronary atherosclerosis by MB.

Results of coronary artery bypass grafting in myocardial bridging of left anterior descending artery

BACKGROUND

We aimed to evaluate the graft patency rate following coronary artery bypass grafting (CABG) to the left anterior descending artery (LAD) with proximal myocardial bridging (MB). While MB is generally a benign coronary abnormality, ischemia, stunning, and sudden death have been reported. In symptomatic patients with proximal LAD systolic compression of >50%, positive for ischemic noninvasive testing and noneffective optimal medical therapy, coronary intervention could be indicated. Few studies of CABG in myocardial bridging have been reported. The influence of high flow in coronaries with MB on graft patency is cause for concern.

METHODS

We retrospectively studied 39 patients operated on for isolated MB of proximal LAD with >50% systolic compression. All patients were severely symptomatic despite optimal medical therapy and positive noninvasive tests for myocardial ischemia. CABG was performed through the midsternotomy with cardiopulmonary bypass and cardioplegia. Patients were divided into two groups: in 20 patients, LAD was bypassed with left internal mammary artery (LIMA) (Group 1) and in 19 patients with saphenous vein graft (SVG) (Group 2). All patients underwent follow-up coronary angiography.

RESULTS

Demographics and degree of systolic compression of the LAD were similar in both groups. There was no mortality or major morbidity. Freedom from angina was 68% in Group 1 and 94% in Group 2 at 18 months postoperatively (p = 0.58). Twelve LIMA grafts and three SVGs were found occluded (p = 0.002).

CONCLUSIONS

LIMA patency in myocardial bridging of the LAD can be low. SVGs should be considered in cases of CABG for myocardial bridging.

Sudden death and physical exercise: timely diagnosis of congenital anomalies of the coronary arteries with the new 320-slide multi-detector computed tomography

Congenital abnormalities of the coronary arteries here described are an uncommon form of structural heart disease. Nevertheless, they deserve attention because may cause chest pain and, in some cases, sudden cardiac death even during exercise. Traditional angiography has limitations due to its projectional and invasive nature. The recent development of the 320-slide multi-detector computer tomography with low radiation exposure has the potential to modify the current diagnostic work-up, as it allows even in young people a timely identification of clinical significant coronary anomalies minimizing the risks related to radiation exposure.

Prevalence and predictors of bridging of coronary arteries in a large Indonesian population, as detected by 64-slice computed tomography scan

BACKGROUND

Multislice computed tomography (MSCT) can be used to detect myocardial bridging (MB) of coronary arteries. However, most published studies included small cohorts and did not collect data about predictors. We investigated prevalence and predictors of MB in an Indonesian population.

METHODS

All patients who had MSCT at Cinere Hospital, Jakarta, Indonesia between 2006 and 2009 were included in a prospective registry. MB was defined when at least half of the coronary artery was imbedded within the myocardium with a normal epicardial course of the proximal and distal portion.

RESULTS

Of the 934 patients (mean age 53 years, 37.8 % female), MB could be observed in 152 patients (16.3 %). Patients with MB were younger compared with those without MB. Coronary risk factors were not different between the two groups. Coronary calcifications and moderate to severe coronary stenoses were less prevalent in patients with MB, also after adjusting for differences in age. At the time of diagnosis, only a few patients with MB were treated with beta-blockers (35 %) or calcium channel blockers (13 %).

CONCLUSIONS

Prevalence of myocardial bridging as detected by MSCT is relatively high. Patients with MB were younger and had a lower prevalence of coronary sclerosis. MB could be the cause of their unexplained symptoms. Follow-up studies are necessary to assess the symptoms of these patients, their response to treatment and the incidence of (coronary) events. MSCT can be used to identify patients for potential new treatment strategies.

Myocardial bridging: A 'forgotten' cause of acute coronary syndrome - a case report

During a stress test, an asymptomatic 40-year-old man showed an ST depression above 4 mm and a horizontal ST depression above 2 mm in the V3 to V6 precordial leads during the recovery phase, without symptoms related to myocardial ischemia. After several days, he experienced recurrent episodes of oppressive retrosternal pain with radiation to the interscapular region, associated with stress dyspnea. Stress myocardial scintigraphy using technetium sestamibi was performed, which showed a modest push-pull deficit of perfusion in the septal-anterior basal area associated with a small deficit of perfusion in the apical region.The patient was admitted to hospital with a diagnosis of unstable angina. Repeated episodes of chest pain appeared during this period, which were partially relieved with the administration of sublingual nitrate. There were no significant changes in the electrocardiogram or cardiac enzyme levels. Coronary angiography showed initial parietal hypertrophy with normal segmentary kinesis and global systolic function and, most importantly, the presence of a systolic narrowing (myocardial bridging) of the middle one-third of the left anterior descending artery from the likely intramyocardial route. There was no significant stenosis of the remaining coronary tracts.Myocardial bridges have traditionally been considered a benign condition, but recent studies have demonstrated that the clinical complications can be dangerous; these complications include acute coronary syndromes, arrhythmias (including supraventricular tachycardia and ventricular tachycardia), exercise-induced atrioventricular conduction blocks, transient ventricular dysfunction and sudden death.