Myocardial bridging of the left anterior descending coronary artery: depiction rate and morphologic features by dual-source CT coronary angiography

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.

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.

Complications associated with myocardial bridging in four children without underlying cardiac disease: a case series

BACKGROUND

Myocardial bridging is largely considered to be a benign, symptomless congenital anomaly of the coronary arteries in which the intramyocardial coronary course is partially 'tunnelled' and leads to vessel compression during ventricular systole. There are few data regarding children.

OBJECTIVE

To report on myocardial bridging observed in children seeking medical help in the paediatric emergency room.

CASE PRESENTATION

A series of four children aged 6-13 years with symptomatic myocardial bridging but no other underlying cardiac abnormalities is reported. They were admitted to the paediatric emergency department during 2013-2016, three with chest pain after physical activity and one with septic shock.

RESULTS

Heart computed tomography scan in the first three demonstrated myocardial bridging of the left anterior descendent coronary artery's branches; their 2-year follow-up was uneventful. The fourth patient presented with ventricular fibrillation 24 hours after admission and at autopsy there was an intramyocardial tract 4 cm long on the left anterior descendent coronary artery.

CONCLUSIONS

This case series demonstrates that myocardial bridging can be symptomatic in children with no underlying cardiac disorders and should be included in the differential diagnosis of exertional chest pain and/or arrhythmias.Abbreviations: CRP, C-reactive protein; CT, computed tomography; D1, diagonal 1 artery; ECG, electrocardiogram; ED, emergency department; KD, Kawasaki disease; LAD, left anterior descending coronary artery; MB, myocardial bridging; RI, ramus intermedius artery; TN, troponin.

Evaluation of the morphological and clinical features of left anterior descending myocardial bridging with multi-detector computed tomography

Aim

The aim of the study was to assess the incidence, localization, depth, length of myocardial bridging (MB) with left anterior descending (LAD), systolic compression ratio, atherosclerotic plaque localization and degree of stenosis by 256-slice multi-detector computed tomography (MDCT).

Material and methods

Computed tomography (CT) scans from a total of 3947 patients who underwent MDCT were reviewed retrospectively for LAD MB. A diastolic and systolic dataset with the best image quality was selected. Myocardial bridge was defined as a coronary artery with an intra-myocardial course. Myocardial bridging was divided into “deep” or “superficial”. The length and depth of the bridging segment were calculated. For each bridging segment, the presence of atherosclerosis was saved in a 2-cm-long segment proximal to the entry of the bridging segment. The degree of stenosis made by atherosclerotic plaques was determined.

Results

LAD myocardial bridging was detected in 410 (10.4%) patients. Among these, 97 (23.7%) patients had a deep and 313 (76.3%) patients had a superficial course. The mean LAD MB length was 20.28 ±9.63 mm and the depth was 1.72 ±1.11 mm. The systolic and diastolic mean diameter difference was 0.193 mm and the average compression ratio was 9.44%. Atherosclerotic plaques were found in 167 (40.7%) of 410 LAD MB. Atherosclerotic plaques were found in 50.5% of deep MB and 37.7% of superficial MB.

Conclusions

256-slice MDCT coronary angiography has a high sensitivity to show myocardial bridging in LAD localization, to determine length, depth, compression ratio, atherosclerotic plaque localization and degree of stenosis.

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.

Dual-source computed tomography coronary artery imaging in children

Computed tomography (CT) has a well-established diagnostic role in the assessment of coronary arteries in adults. However, its application in a pediatric setting is still limited and often impaired by several technical issues, such as high heart rates, poor patient cooperation, and radiation dose exposure. Nonetheless, CT is becoming crucial in the noninvasive approach of children affected by coronary abnormalities and congenital heart disease. In some circumstances, CT might be preferred to other noninvasive techniques such as echocardiography and MRI for its lack of acoustic window influence, shorter acquisition time, and high spatial resolution. The introduction of dual-source CT has expanded the role of CT in the evaluation of pediatric cardiovascular anatomy and pathology. Furthermore, technical advances in the optimization of low-dose protocols represent an attractive innovation. Dual-source CT can play a key role in several clinical settings in children, namely in the evaluation of children with suspected congenital coronary artery anomalies, both isolated and in association with congenital heart disease. Moreover, it can be used to assess acquired coronary artery abnormalities, as in children with Kawasaki disease and after surgical manipulation, especially in case of transposition of the great arteries treated with arterial switch operation and in case of coronary re-implantation.

Prevalence and Spectrum of Coronary Anomalies Detected on Coronary Computed Tomography Angiography: A single centre experience in Oman

Objectives

Coronary artery anomalies (CAAs) are uncommon congenital abnormalities with a prevalence ranging from 0.2–2%. CAAs can be asymptomatic or less commonly present with life-threatening symptoms. This study aimed to investigate the prevalence and spectrum of CAAs in patients who underwent coronary computed tomography angiography (CCTA) in Oman.

Methods

This retrospective study was conducted at the National Heart Centre, Muscat, Oman between September 2012 and August 2018. All consecutive patients who had undergone CCTA were included.

Results

A total of 4,445 patients were included in this study. Of these, 59 patients (1.3%) were diagnosed with CAAs with a mean age of 52.6 years (range: 12–80 years) and an equal gender distribution. Among the patients with CAAs, the majority (69.5%) had anomalous origins from the opposite or non-coronary sinus. Right coronary artery arising from the left coronary sinus was the most common type (33.9%). Fewer patients (18.6%) had left circumflex arising from the right coronary sinus (RCS). Seven patients (11.9%) had left main arising from the RCS. Other CAAs were in the dual left anterior descending artery (8.5%), high coronary artery take-off (6.8%), single coronary ostia (6.8%) and coronary artery fistula (6.8%).

Conclusion

The prevalence of CAAs was 1.3% which is similar to the literature.

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

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

Morphological Features on Myocardial Bridges at the Anterior Interventricular Artery

Are described morphological features of myocardial bridges at the anterior interventricular artery obtained from the analysis of 274 cases with 312 myocardial bridges detected by angioCT performed over a period of 3.5 years on a total of 2857 subjects. CT examinations were performed on 1496 females, aged 56-79 years, and 1361 male subjects aged 34-74 years. At the level of the anterior interventricular artery we encountered 231 cases with myocardial bridges (84.31% of the total number of cases), being 267 myocardial bridges (85.58% of the total bridges analyzed). In the case of single myocardial bridges of the anterior interventricular artery, in 65 cases (33.33% of the 195 cases) they were located in the upper third of the artery, 32 cases were female (31.68% of female myocardial bridges) and 33 in male sex (35.11% of male myocardial bridges). In 129 cases (66.67%) were located in the middle third of the artery, 69 cases were female (63.30% female myocardial bridges) and 60 cases in male (64.89% of male myocardial bridges). In one case with three myocardial bridges, the inferior myocardial bridge was located in the lower third of the anterior interventricular artery. The length of the myocardial bridge was between 11.9 and 73.1 mm, for the female gender being 11.9-28.7 mm, and male 9.4-73.1 mm. The thickness of the myocardial bridge was found between 0.9-5.7 mm, for the female gender being 0.9-5.2 mm, and for the male the thickness was 1.7-5.7 mm. The caliber of the tunneling artery was found between 1.2-2.5 mm in female gender, for the male gender 1.3-4 mm.

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.

Assessment of Myocardial Bridge by Cardiac CT: Intracoronary Transluminal Attenuation Gradient Derived from Diastolic Phase Predicts Systolic Compression

Objective

To study the predictive value of transluminal attenuation gradient (TAG) derived from diastolic phase of coronary computed tomography angiography (CCTA) for identifying systolic compression of myocardial bridge (MB).

Materials and Methods

Consecutive patients diagnosed with MB based on CCTA findings and without obstructive coronary artery disease were retrospectively enrolled. In total, 143 patients with 144 MBs were included in the study. Patients were classified into three groups: without systolic compression, with systolic compression < 50%, and with systolic compression ≥ 50%. TAG was defined as the linear regression coefficient between intraluminal attenuation in Hounsfield units (HU) and length from the vessel ostium. Other indices such as the length and depth of the MB were also recorded.

Results

TAG was the lowest in MB patients with systolic compression ≥ 50% (-19.9 ± 8.7 HU/10 mm). Receiver operating characteristic curve analysis was performed to determine the optimal cutoff values for identifying systolic compression ≥ 50%. The result indicated an optimal cutoff value of TAG as -18.8 HU/10 mm (area under curve = 0.778, p < 0.001), which yielded higher sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy (54.1, 80.5, 72.8, and 75.0%, respectively). In addition, the TAG of MB with diastolic compression was significantly lower than the TAG of MB without diastolic compression (-21.4 ± 4.8 HU/10 mm vs. -12.7 ± 8 HU/10 mm, p < 0.001).

Conclusion

TAG was a better predictor of MB with systolic compression ≥ 50%, compared to the length or depth of the MB. The TAG of MB with persistent diastolic compression was significantly lower than the TAG without diastolic compression.

Myocardial bridging as one of the causes of atypical chest pain in young women

Introduction

Myocardial bridging is congenital anomaly which usually has benign prognosis but there are also reports suggesting that it can be associated with ischemic clinical syndromes presenting with chest pain. Coronary computed tomography angiography is a well-established method for detecting myocardial bridging. However, clinical significance of this anomaly still remains unclear.

Methods

We studied 977 patients who presented with recurrent typical or atypical chest pain in outpatient clinic. All patients have undergone detailed clinical examination, ECG stress testing and coronary computed tomography angiography.

Results

Highest positive prediction for having myocardial bridging was for patients presenting with atypical chest pain with negative ECG stress test and who were younger women.

Conclusion

Coronary computed tomography angiography may be preferable method for evaluation of chest pain in younger women presenting with atypical chest pain.

Systolic Compression of a Myocardial Bridged Coronary Artery and its Morphologic Characteristics: A Combination Study of Computed Tomography Angiography and Invasive Angiography

Background

Myocardial bridging (MB) is a congenital anomaly in which a segment of a major epicardial coronary artery courses through the myocardium. This anomaly can lead to myocardial ischemia, arrhythmia, and even death. The effectiveness of coronary computed tomographic angiography (CCTA) in the detection of MB and its morphological features, and the accuracy of invasive coronary angiography (ICA) in the evaluation of systolic compression have been shown in some prior studies.

Objectives

The present study aimed to evaluate the correlation between the depth and the length of MB as determined using CCTA, and the degree of luminal narrowing of the involved tunneled segment as calculated using the ICA.

Patients and Methods

For this study, 109 consecutive patients diagnosed with myocardial bridging using CCTA, and who had already undergone ICA, were studied. The depth and length of the MB was determined in the CCTA, while the degree of systolic compression was calculated in the ICA. The correlation between the depth and length of the MB and the systolic compression were then evaluated.

Results

The degree of systolic compression was found to be correlated with the depth of the MB. However, there was no correlation between the length of the MB and the degree of systolic compression.

Conclusion

The systolic compression of the MB was influenced by the depth of the tunneled segment, not by its length.

Sudden cardiac death from structural heart diseases in adults: imaging findings with cardiovascular computed tomography and magnetic resonance

Sudden cardiac death (SCD) is defined as the unexpected natural death from a cardiac cause within an hour of the onset of symptoms in the absence of any other cause. Although such a rapid course of death is mainly attributed to a cardiac arrhythmia, identification of structural heart disease by cardiovascular computed tomography (CCT) and cardiovascular magnetic resonance (CMR) imaging is important to predict the long-term risk of SCD. In adults, SCD most commonly results from coronary artery diseases, coronary artery anomalies, inherited cardiomyopathies, valvular heart diseases, myocarditis, and aortic dissection with coronary artery involvement or acute aortic regurgitation. This review describes the CCT and CMR findings of structural heart diseases related to SCD, which are essential for radiologists to diagnose or predict.

Multimodality Imaging in the Assessment of the Physiological Significance of Myocardial Bridging

In myocardial bridging (MB) a segment of the coronary artery is covered by the myocardium. MB can be seen as a systolic compression by invasive coronary angiography (ICA) or as an intramural course by computed tomography angiography (CTA). Intramural course is a common incidental finding in CTA studies. Only minority of the bridging segments are associated with systolic compression causing a possible impairment of myocardial perfusion. The relationship between myocardial blood flow and MB is complex and poorly evaluated by anatomic imaging. Furthermore, provocation tests are frequently needed to uncover systolic compression. Fractional flow reserve can be used to assess the hemodynamic significance of MB. Nuclear perfusion imaging can demonstrate flow abnormalities associated with MB. Stress echocardiography can demonstrate ischemic wall motion abnormalities. They can be complemented by hybrid imaging with CTA to distinguish epicardial coronary artery disease and MB. This article will review different imaging modalities for the evaluation of the physiologic significance of MB.

Coronary artery perforation in a patient with STEMI and a myocardial bridge: an increased risk for coronary artery perforation?

We present the case of a patient with ST-elevation myocardial infarction (STEMI) due to subtotal occlusion of the left anterior descending coronary artery caused by an atherosclerotic lesion and a myocardial bridge (MB). Stenting of the MB caused coronary artery perforation resulting in a fistula to the right ventricle that was closed by implantation of a PTFE-covered stent. Follow-up coronary angiography showed persistent shunting, which was sealed by inflation of a high-pressure balloon over the site of extravasation guided by intravascular ultrasound. Additionally, we provide a short review of cases with coronary artery perforation after stenting of an MB.

Myocardial bridging analysis by coronary computed tomographic angiography in a Saudi population

AIM: To assess the incidence, location, morphology and clinical association of myocardial bridging in a Saudi population using coronary computed tomographic angiography (CCTA).

METHODS: A total of 350 CCTA of Saudi patients were included in this study (236 men, 114 women) with a mean age of 56.3 years. All patients were examined for appropriateness criteria of CCTA indications (typical chest pain, recent onset cardiomyopathy, left bundle branch block, etc.). The scans were retrospectively reviewed for the presence of myocardial bridging and any other pathological association.

RESULTS: Myocardial bridging was found in 89 of 350 (22.5%) patients. Most of the intramuscular segments were of the superficial type and found in the mid left anterior descending (LAD) (24.6%), followed by distal LAD (3.7%), diagonal branches (2%), ramus intermedius artery (1.4%) and obtuse marginal artery (0.8%). No myocardial bridging was detected in the right coronary or circumflex arteries. No significant differences were found between males and females (P = 0.14). Coronary artery atherosclerosis was found in 51 of 89 (57.3%) patients with MB. Atherosclerotic plaques were not detected in the intramuscular or distal segment of bridging arteries. Dynamic compression was observed in 35 (94.5%) patients with full encasement. No evidence of myocardial hypoperfusion was found in the territories supplied by the bridging arteries.

CONCLUSION: CCTA is excellent in analyzing myocardial bridging in a Saudi population and the results are comparable to other populations. However, finding the real incidence may need a large multicenter study.

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.

Clinical value of the correlations of mural coronary artery compression extent with myocardial bridge length and thickness evaluated by 128-slice CT

This study aimed to investigate the correlations between the detection rate of mural coronary artery (MCA) by 128-slice CT and the MCA compression extent in systole with myocardial bridge (MB) length and thickness. A retrospective analysis was conducted for 580 patients receiving multislicespiral CT coronary angiography (MSCTCA). In addition, the MCA incidence rate and position were detected, and the MB length and thickness in the left anterior descending branch (LAD) and MCA compression extent in systole were measured to compare the differences between MB-MCA length and thickness among the mild, moderate and severe groups. A total of 140 cases of MB-MCA (24.14%) were involved in the study. Among them, 104 cases occurred in the middle segment of the LAD (74.3%), 16 cases (11.4%) occurred in the distal segment of the LAD, 8 cases (5.7%) occurred in the left circumflex-obtuse marginal branch (LCX-OM), 7 cases (5.0%) occurred in the first diagonal branch (1st D), 3 cases (2.1%) in the intermediate branch (M) and 2 cases (1.5%) occurred in the posterior descending branch of the right coronary artery (RCA-PD). The mean length of the MB in the LAD was 21.80±5.98 mm, the mean thickness was 2.15±0.74 mm and the mean compression extent was 38.5±19.6%. Among the different groups, there were no significant difference in MB length (P>0.05) but there were significant differences in MB thickness (P<0.05). In addition, the extent of MCA compression in systole was linearly and positively correlated with MB thickness (r=0.408, P<0.05) but was not correlated with MB length (r=0.076, P>0.05). 128-slice CT coronary angiography (SCTCA) is able to accurately detect MB-MCA and evaluate the correlations of MCA compression extent in systole with MB length and thickness which provides a basis for its clinical use.

Myocardial bridging: what have we learned in the past and will new diagnostic modalities provide new insights?

The clinical significance of myocardial bridging has been a subject of discussion and controversy since the introduction of coronary arteriography (CAG) in the early 1960s. More recently computed tomography coronary angiography (CTCA) has made it possible to visualise the overlying muscular bands and appears to have a higher sensitivity for detecting myocardial bridging than CAG. Combining CTCA with invasive techniques such as CAG should make it possible to improve our understanding of the pathophysiology of myocardial bridging and to provide answers to hitherto unresolved questions. This paper critically reviews the outcomes of previous studies and defines remaining questions that should be answered to optimise the management of the presumably fast growing number of patients in whom a diagnosis of myocardial bridging has been made.

The prevalence of coronary artery variations on coronary computed tomography angiography

BACKGROUND

Coronary computed tomography angiography (CCTA) can delineate the coronary artery anatomy precisely. Basic knowledge of the normal coronary artery anatomy and familiarity with its common variations are essential in order to assess CCTA accurately.

PURPOSE

To determine the prevalence of coronary artery variations detected by 64-slice mutidetector CT.

MATERIAL AND METHODS

CCTA images of 2096 patients were evaluated retrospectively. Relatively unusual coronary artery morphological features that were seen in greater than 1% of the study population were classified as variations.

RESULTS

Coronary artery circulation was right dominant in 86.6%, left dominant in 9.6%, and balanced in 3.8% of patients. The conus artery arose from the right coronary artery in 83%, or directly from the aorta with a separate ostium in 17% of cases which was much more common in men than women. The sinoatrial node artery originated from the right coronary artery (65.6%) or the circumflex artery (33.7%). The atrioventricular node artery originated from the right coronary artery in 86.4% or the circumflex artery in 13.6% of cases. The left main coronary artery was shorter than 0.5 cm in 4.7% of cases and trifurcated into the intermediate artery in 31.3% of cases. A myocardial bridge was observed in 21.6%, coronary ectasia-aneurysm in 2%, dual left anterior descending artery (LAD) type 1 in 1.38%, and a variant of type 1 in 0.1% of cases. The presence of coronary atherosclerosis was higher in patients with coronary ectasia-aneurysm than the patients who did not have coronary ectasia-aneurysm (90.5% vs. 72.2%, P = 0.000).

CONCLUSION

CCTA is a non-invasive imaging modality for the depiction of variations of the coronary arteries. The incidence of coronary artery variations is high and various, and readers should be familiar and looking for these conditions during interpretation of CCTA examinations.