Prevalence of myocardial bridging detected with 64-slice multidetector coronary computed tomography angiography in asymptomatic adults

doi:10.1016/j.jcct.2007.08.003

Journal of Cardiovascular Computed Tomography

Volume 1, Issue 2, October 2007, Pages 78-83

https://doi.org/10.1016/j.jcct.2007.08.003 Get rights and content

Abstract

Objective

Myocardial bridging is a congenital condition in which a segment of an epicardial artery has an intramural course within the myocardium. The aim of the present study was to evaluate the prevalence of myocardial bridging and the ability of 64-slice coronary computed tomography angiography to identify myocardial bridging in asymptomatic adults.

Methods

One hundred sixty-nine consecutive asymptomatic subjects underwent 64-row multidetector computed tomography (MDCT) of the coronary arteries. Two experienced CT radiologists identified myocardial bridging >1 mm in thickness, by consensus. We examined the frequency of myocardial bridging and evaluated the length, thickness, and coronary wall lesions.

Results

Myocardial bridges were found in 28 (17%) of 165 subjects. Twenty-one subjects (75%) had 1 bridge and 7 subjects (25%) had 2, for a total of 35 myocardial bridges. Twenty-one bridges (60%) were located in the left anterior descending, 8.5% in the diagonal branch, and 2.8% in the circumflex arteries. The segment beneath the myocardial bridge was always free of coronary wall plaques, but the arterial segment proximal to it had significant coronary wall plaques in 24 cases (68.6%).

Conclusion

We found that the incidence of myocardial bridging in asymptomatic adults is 7%, which is in agreement with some pathologic studies in the literature. Our study shows that MDCT of the coronary arteries is a reliable and noninvasive technique, which can accurately locate the site of myocardial bridging, and measure its thickness, course, and length.

Introduction

The coronary arteries are normally located on the epicardial surfaces of the heart, surrounded by epicardial fat. Myocardial bridging, first described by Reyman¹ in 1737, is a congenital condition in which a segment of an epicardial artery has an intramural course within the myocardium. It is typically confined to a single vessel, usually the mid left anterior descending (LAD) artery. The reported frequency at autopsy ranges from 5% to 86%.2, 3, 4, 5, 6, 7, 8, 9, 10, 11 Myocardial bridging is usually asymptomatic and is traditionally considered to be a normal variant or benign coronary anomaly. However, clinical interest has been triggered by the observation that myocardial bridging may be a contributory factor in the development of myocardial ischemia, angina pectoris, myocardial infarction, arrhythmias, and even sudden death.12, 13, 14, 15, 16, 17, 18, 19, 20 Those studies suggest that coronary compression by the myocardial bridge at systole could lead to a reduction in blood flow and subsequent ischemia. Furthermore, myocardial bridging may pose a technical challenge during coronary bypass surgery, because intraoperative echocardiography may be necessary to expose the intramuscular coronary artery.5, 6, 7, 21, 22 Although conventional angiography is recognized as the reference standard examination for the diagnosis of myocardial bridging, its detection rate is <5%, which is significantly lower than that of autopsy studies.2, 3 Detection has improved with the application of newer, more sensitive imaging techniques, such has intravascular ultrasound (IVUS), intracoronary Doppler (ICD) ultrasound, and multidetector computed tomography (MDCT).2, 3, 8, 9

The aim of the present study was to evaluate the prevalence of myocardial bridging and the ability of 64-slice coronary computed tomography angiography (CCTA) to identify myocardial bridging in asymptomatic adults. To the best of our knowledge, this is the first report in the English literature for the prevalence of myocardial bridging in asymptomatic adults using 64-slice MDCT.

Section snippets

Patients and methods

It was a retrospective single-centered analysis that was performed from November 2006 to January 2007 at “Mor” Institute for Cardiovascular Imaging in Bnei Brak, Israel. The study group consisted of 169 consecutive subjects, 132 men and 37 women, who underwent CCTA, ages ranged from 38 to 75 years (mean ± SD, 53.8 ± 7.9 years). All patients were asymptomatic before the examination and were self-referred. Exclusion criteria were allergy to contrast medium, irregular heart rate, and impaired

Results

Images appropriate for evaluation were obtained for 165 subjects. The other 4 subjects were excluded because of motion artifacts of arrhythmia or breathing. The demographic characteristics and cardiovascular risk factors of the 165 participants are shown in Table 1.

Myocardial bridges were found in 28 subjects (17%), with a higher prevalence in men (n = 25; 89.2%). Twenty-one subjects (75%) had 1 bridge and 7 subjects (25%) had 2 bridges, for a total of 35 myocardial bridges. Twenty-one bridges

Discussion

The current imaging standard of reference for the diagnosis of myocardial bridging is conventional coronary angiography, which shows the milking effect and step-down/step-up phenomenon induced by systolic compression of the tunneled segment.

In the present study, we used 64-slice MDCT to evaluate the presence and anatomical characteristics of myocardial bridging in 165 consecutive asymptomatic adults with ≥1 clinical risk factors for atherosclerosis. The incidence of myocardial bridging in our

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Cited by (17)

Coronary plaque burden of the left anterior descending artery in patients with or without myocardial bridge: A case-control study based on coronary CT-angiography
2021, International Journal of Cardiology
Citation Excerpt :
On average, MBs can be detected in about one-fourth of the adult population [3], however the prevalence varies depending on the diagnostic modality applied [4]. Using coronary CTA, the prevalence rate of MB varies between 5% and 58% in different cohorts [2,5–7] while it was 17% among asymptomatic adults [8]. Both MB and coronary plaque burden can reliably be investigated by coronary CTA as this method provides accurate visualization of the course of coronary arteries in the epicardial fat and within the myocardial wall [9].
The clinical significance of myocardial bridging (MB) on the left anterior descending artery (LAD) is debated. We aimed to assess the association between MB and LAD plaque volumes/compositions in a case-control set up.
In our retrospective analysis we investigated 50 cases with incidentally recognized LAD MB and 50 matched controls without LAD MB on coronary computed tomography angiography. We quantified plaque volumes proximal to the MB and beneath it in patients with MB and in the corresponding coronary segments in patients without MB.
In total, we have included 100 patients (mean age 60.6 ± 10.8 years, males: 80%). Plaque volume was similar in the LAD segments proximal to the MB in cases vs. controls (150.0 mm³ [IQR: 90.7–194.5 mm³] vs. 132.8 mm³ [IQR: 94.2–184.3 mm³], respectively; p = 0.95) while the plaque volume was smaller beneath LAD MB vs. control segment (16.2 mm³ [IQR: 12.6–25.8 mm³] vs. 21.1 mm³ [IQR: 14.0–42.4 mm³], respectively; p = 0.002). No significant differences were found regarding different plaque components in segments proximal to the MB while fatty plaque and necrotic core volumes were smaller or negligible in coronary segment beneath MB than in controls (0.07 mm³ [IQR: 0.005–0.27 mm³] vs. 12.7 mm³ [IQR: 7.4–24.4 mm³] and 0.00 mm³ [IQR: 0.00–0.04 mm³] vs. 0.06 mm³ [IQR: 0.03–2.8 mm³], respectively (p < 0.001).
Comparing patients with MB vs. matched controls without it, MB was not associated with increased plaque volumes in LAD segment proximal to MB and plaque quantity was smaller in the MB segment. Our data are supportive of benign nature of incidentally recognized LAD MB.
Myocardial bridging on coronary cta: An innocent bystander or a culprit in myocardial infarction?
2012, Journal of Cardiovascular Computed Tomography
Myocardial bridging describes the clinical entity whereby a segment of coronary artery is either partially or completely covered by surrounding myocardium. It represents the most frequent congenital coronary anomaly and has an estimated prevalence of ≤13% on angiographic series. With the emergence of cardiac computed tomography and its ability to simultaneously image the coronary arteries and also the myocardium, there has been an apparent increase in the detection rates of myocardial bridges (prevalence as high as 44%). It has now become important to evaluate their clinical significance. Myocardial bridging is generally considered a benign entity with survival rates of 97% at 5 years; however, there is now emerging evidence that certain myocardial bridge characteristics may be associated with cardiovascular morbidity. The length and depth of myocardial bridges have been associated with increased atherosclerosis, whereas the degree of systolic compression has been associated with ischemia on myocardial perfusion single-photon emission tomography. On the basis of current evidence, it appears that limiting further testing for ischemia to symptomatic patients with long and/or deep myocardial brides would be appropriate.
Left anterior descending coronary artery myocardial bridging by multislice computed tomography: Correlation with clinical findings
2010, European Journal of Radiology
Citation Excerpt :
The prevalence of LAD myocardial bridging by MSCT in our study was with 23% about 10–20 folds higher compared invasive angiography (0.5–2.5%) [1], and was similar to recently published data reporting 26% and 30.5% detection rates [15,16]. The highest prevalence of LAD myocardial bridges by MSCT with 44% (including patients with significant stenosis) was recently reported by Lubarsky et al. [17], but another study found only 17% LAD bridges in asymptomatic patients [24]. The lower prevalence of myocardial bridges identified on invasive angiography compared to MSCT may be related to the fact that the pathognomic “milking-phenomenon” is an indirect diagnostic criterion because invasive angiography does not allow direct visualization of the myocardium.
To assess the relationship between left anterior descending (LAD) coronary artery myocardial bridging detected by 64-slice computed tomography (CT) and clinical findings.
221 consecutive patients were examined with coronary 64-slice CT angiography. 21 patients with coronary stenosis >50% were excluded. The length, depth, and luminal narrowing of LAD myocardial bridges during systole and diastole were measured. CT findings were compared with the treadmill ECG-stress test, and clinical symptoms.
Myocardial bridges of the LAD were found in 23% of patients (51/221) (length, 14.9 ± 6.5 mm; depth, 2.6 ± 1.6 mm). A significant difference was noted between the LAD luminal diameter before the intramyocardial course and intramyocardially, for both diastole and systole (p < 0.001); with a higher diameter reduction of 27% for end-systole compared to end-diastole with 15% (p = 0.006). Systolic LAD intramyocardial luminal narrowing >50% was found in 3/25 (8%). 30/51 (59%) of bridges were “deep” (>2 mm myocardial depth), 21/51 (41%) were “superficial”. The prevalence of a positive ECG-stress tests for the anterior myocardial region was significantly higher in patients with LAD myocardial bridges (34/50; 68%) compared to those without (28/144; 19.4%) (p < 0.001). There was no difference between “superficial” and “deep” LAD myocardial bridges in regard to a positive treadmill ECG-stress test. Typical angina was rare with 6%.
LAD myocardial bridges are common findings and can possibly explain a positive exercise ECG-stress test for anterior myocardial ischemia. Intramyocardial LAD segments show mild-to-moderate luminal narrowing at rest, which is higher during end-systolic phase.
Myocardial Bridging, a Common Anatomical Variant Rather Than a Congenital Anomaly
2008, Seminars in Ultrasound, CT and MRI
Citation Excerpt :
In addition, only few reports in the cardiac surgery literature have suggested the presence of an intracavitary subtype with an estimated prevalence of 0.2 to 0.3%.25 In the past 2 years, several studies have evaluated the prevalence of myocardial bridging using MDCT.11-15,23 In most series the prevalence is similar to autopsy studies ranging between 3.5 and 39% (Table 1).
The recent introduction of coronary computed tomographic angiography into clinical use as a noninvasive tool for coronary artery evaluation has evoked a new interest in myocardial bridging. Recent studies using multidetector computed tomography for the evaluation of coronary anatomy have shown myocardial bridging to be more prevalent than previously reported in angiographic series. The purpose of this article was to provide an overview of the current knowledge on the prevalence and features of myocardial bridging as shown by multidetector computed tomography and to discuss the potential clinical implications of this entity.
Multidetector-row computed tomography is a powerful tool in detection of myocardial bridges but clinical significance remains uncertain
2007, Journal of Cardiovascular Computed Tomography
Assessment of Clinical Features and Morphological Characteristics of Myocardial Bridging Involving the Left Circumflex Artery Using Coronary Computed Tomography Angiography
2022, Research Square

View all citing articles on Scopus

: Conflict of interest: The authors report no conflicts of interest.

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Original Research ArticlePrevalence of myocardial bridging detected with 64-slice multidetector coronary computed tomography angiography in asymptomatic adults

Abstract

Objective

Methods

Results

Conclusion

Introduction

Section snippets

Patients and methods

Results

Discussion

Eur J Radiol

Ann Thoracic Surg

Thoracic Surg

J Am Coll Cardiol

Atherosclerosis

J Am Coll Cardiol

J Am Coll Cardiol

Incidence and clinical significance of bridges of myocardium over the coronary arteries and their branches

Surg Radiol Anat

Update on myocardial bridging

Circulation

Myocardial bridging

Eur Heart J

Original Research Article
Prevalence of myocardial bridging detected with 64-slice multidetector coronary computed tomography angiography in asymptomatic adults