Myocardial bridging evaluated with 128-multi detector computed tomography 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.

Impact of Clinical and Morphological Factors on Long-Term Mortality in Patients with Myocardial Bridge

Although myocardial bridging (MB) has been intensively investigated using different methods, the effect of bridge morphology on long-term outcome is still doubtful. We aimed at describing the anatomical differences in coronary angiography between symptomatic and non-symptomatic LAD myocardial bridges and to investigate the influence of clinical and morphological factors on long-term mortality. In our retrospective, long-term, single center study we found relevant MB on the left anterior descendent (LAD) coronary artery in 146 cases during a two-year period, when 11,385 patients underwent coronary angiography due to angina pectoris. Patients were divided into two groups: those with myocardial bridge only (LAD-MBneg, n = 78) and those with associated obstructive coronary artery disease (LAD-MBpos, n = 68). Clinical factors, morphology of bridge by quantitative coronary analysis and ten-year long mortality data were collected. The LAD-MBneg group was associated with younger age and decreased incidence of diabetes mellitus, as well as with increased minimal diameter to reference diameter ratio (LAD-MBneg 54.5 (13.1)% vs. LAD-MBpos 46.5 (16.4)%, p = 0.016), while there was a tendency towards longer lesions and higher vessel diameter values compared to the LAD-MBpos group. The LAD-MBpos group was associated with increased mortality compared to the LAD-MBneg group. The analysis of our data showed that morphological parameters of LAD bridge did not influence long-term mortality, either in the overall population or in the LAD-MBneg patients. Morphological parameters of LAD bridge did not influence long-term mortality outcomes; therefore, it suggests that anatomical differences might not predict long-term outcomes and should not influence therapy.

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.

Intra-Right Ventricle Course of the Coronary Arteries on Computed Tomography Angiography

BACKGROUND

The clinical relevance and anatomic characteristics of intracavitary coronary arteries coursing within the right ventricle (RV) are largely unknown.

OBJECTIVES

The aim of our study was to assess the clinical and computed tomographic characteristics of patients diagnosed with intracavitary coronary arteries coursing within RV (intra-RV coronaries).

METHODS

Electronic records from a single high-volume cardiac center were retrospectively screened for the presence of intra-RV coronaries among consecutive patients who underwent coronary computed tomography angiography (coronary CTA) from 2008 to 2019.

RESULTS

Overall, 31,748 coronary CTA reports were evaluated, and 17 subjects with intra-RV coronaries were identified. None of these patients was referred for subsequent invasive coronary angiography. One patient underwent coronary artery bypass grafting, 1 patient had a history of percutaneous coronary intervention, and 1 patient had a concomitant coronary anomaly: left circumflex coronary artery originating from the right coronary artery. All of the involved coronaries (n = 17) were the left anterior descending coronary arteries (LADs). Typical segmental coronary course within RV was along the border between free RV wall and interventricular septum (beneath interventricular groove), often within trabeculae carneae of the RV. Only the midsegment and distal segment of the LAD traversed within the RV. The mean ± SD distance from the aorta to the coronary entrance into the RV was 74.5 ± 17.1 mm, whereas the mean ± SD intra-RV coronary length was 25.1 ± 14.0 mm.

CONCLUSIONS

Intra-RV course of the coronaries in an adult CTA population is an infrequent anatomical variant involving LAD. It may require additional attention during interventional and surgical interventions.

Incidence, Characteristics and Atherosclerotic Involvement of Coronary Artery Anomalies in Adult Population Undergoing Catheter Coronary Angiography

Background

Coronary artery anomalies (CAAs) are rare disorders of coronary anatomy with varied clinical presentations. There are widespread geographic variations in incidence and patterns of these anomalies, with limited data from North Indian population. We performed a retrospective study to evaluate the incidence, characteristics and atherosclerotic involvement of CAAs in adult population undergoing catheter coronary angiography.

Methods

Serial coronary angiographies performed at our institution over a period of 2.5 years (from January 2017 to June 2019) were retrospectively analyzed. We identified patients with anomalous coronaries and studied their clinical characteristics and angiographic profiles.

Results

Among 3,233 coronary angiograms analyzed, CAAs were found in 99 patients with an incidence of 3.06%. Mean age of the patients was 56.2 ± 12.9 years (range: 20 - 86 years), with 74.75% being males and 25.25% females. Split right coronary artery (RCA) was the most common coronary anomaly, being seen in 27 patients; with an angiographic incidence of 0.84%. Dual left anterior descending artery (LAD) was the second most common anomaly and was seen in 22 cases with an angiographic incidence of 0.68%. Absent left main trunk was noted in 14 patients (0.43%). Ectopic origin of RCA from left sinus was seen in 12 patients (0.37%), while ectopic origin of RCA from ascending aorta was seen in four patients (0.12%). Ectopic origin of left circumflex artery (LCX) from right sinus or RCA was noted in 13 patients (0.40%). One patient (0.03%) had a superdominant LAD supplying the posterior descending artery (PDA). Coronary artery fistulae were seen in six patients (0.18%). Significant coronary artery disease (CAD) was seen in 89 of 268 (33.21%) normal vessels, whereas it was seen in 56 of 114 (49.12%) of anomalous vessels. This difference was statistically significant (P = 0.003).

Conclusions

The incidence of CAAs in our study was slightly higher than many of the previous angiographic series. The patterns of coronary anomalies in our study were different from most of the previous studies. Our study had higher incidence of atherosclerotic involvement of anomalous vessels as compared to normal vessels.

Prevalence and spectrum of coronary artery anomalies in 8021 patients: A single center study in South India

Objective

To identify the prevalence of coronary artery anomalies (CAAs) and their subtypes based on Angelini et al. classification in symptomatic yet stable population of South India using 64- slice dual source multi detector CT coronary angiography (MDCT-CA).

Methods

We retrospectively reviewed reports of 8021 symptomatic patients predominantly South Indians who were referred for CT coronary angiography (CT-CA) to our tertiary cardiac care center in Hyderabad, India from January 2011 to March 2017.

Results

We identified a total of 838 coronary artery anomalies in 812 patients with a prevalence of 10.09%. 96.9% of patients were older than 30 years of age with a M:F ratio of 1.39:1. Coronary artery disease (CAD) was seen in 61.5% of these patients. Among these anomalies, myocardial bridging (MB) was the most common anomaly followed by anomalous location of coronary ostium at improper sinus (ACOIS).

Conclusion

There is no significant difference in prevalence of CAAs (including and excluding MB) in Indian and World population. CAAs were more common in males than females and most of these patients remain asymptomatic during first three decades of their life. Myocardial bridging is the most common anomaly detected by MDCT-CA followed by ACOIS. Right coronary artery (RCA) arising from left coronary sinus (LCS) is the most commonly encountered ACOIS.

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.

Long-Term Prognosis of Patients With Intramural Course of Coronary Arteries Assessed With CT Angiography

OBJECTIVES

The aim of the present study was to evaluate, in low-to-intermediate pre-test probability patients who were referred for coronary computed tomography angiography (CTA) and did not show obstructive coronary artery disease (CAD), whether an intramural course of a coronary artery is associated with worse outcome compared with patients without an intramural course of the coronary arteries.

BACKGROUND

The prognostic value of an intramural course of the coronary arteries on coronary CTA in patients without obstructive CAD is not well-known.

METHODS

The study population consisted of 947 patients with a low-to-intermediate pre-test probability who were referred for coronary CTA and who did not have obstructive CAD. During follow-up, the occurrence of unstable angina pectoris that required hospitalization, nonfatal myocardial infarction, and all-cause mortality was evaluated.

RESULTS

On coronary CTA, 210 patients (22%) had an intramural course of a coronary artery. The median depth of the intramural course was 1.9 mm (interquartile range: 1.4 to 2.6 mm). In 84 patients (40%), the depth of the intramural course was considered deep (>2 mm surrounded by myocardium). During a median follow-up of 4.9 years (interquartile range: 3.2 to 6.9 years), a total of 43 events occurred: hospitalization due to unstable angina pectoris in 13 patients (1.4%); 7 patients (0.7%) had a nonfatal myocardial infarction; and 23 patients died (2.4%). The 6-year cumulative event rate of unstable angina pectoris requiring hospitalization (0.0% vs. 1.1%), nonfatal myocardial infarction (0.5% vs. 0.4%), all-cause mortality (1.9% vs. 2.2%) as well as the combined endpoint of all 3 events (2.4% vs. 3.7%) was similar in patients with and without an intramural course of a coronary artery.

CONCLUSIONS

In patients without obstructive CAD on coronary CTA, the presence of an intramural course of a coronary artery was not associated with worse outcome.

Multidetector computed tomography imaging of coronary artery anomalies

PURPOSE

The purpose of the study was to determine the prevalence of coronary artery anomalies and to demonstrate in which cases multidetector computed tomography has an additional clinical value compared with the conventional angiography.

MATERIAL AND METHODS

A total of 2375 multidetector computed tomography studies were retrospectively reviewed to determine the dominance of the coronary artery anomalies. The classification of coronary artery anomalies was made according to anatomical criteria--origin, course, intrinsic anatomy, and termination--and clinical relevance--benign versus malignant.

RESULTS

The coronary artery system was right dominant in 83.99%, left dominant in 8.0%, and co-dominant in 9.01% of the cases. The incidence of the origin and/or course anomalies was 1.76%, that of fistulas was 0.42%, and that of myocardial bridges was 10.82%. Multidetector computed tomography was performed after conventional angiography in 23 cases and it provided additional information regarding its origin and proximal course, as well as its relationship with the aortic root and main pulmonary trunk in 100% of the cases; eight malignant cases were found. In addition, in all of (100%) the six cases with coronary artery fistulas, conventional angiography failed to detect their terminations, which were clearly depicted by multidetector computed tomography.

CONCLUSION

Multidetector computed tomographic angiography is superior to conventional angiography in delineating the ostial origin and proximal course of anomalous coronary arteries. Furthermore, it reveals the exact relationship of anomalous coronary arteries with the aorta and the pulmonary artery. Anomalies of the intrinsic anatomy and the termination of coronary arteries are also better visualised with multidetector computed tomography.

Myocardial bridging on coronary CTA: an innocent bystander or a culprit in myocardial infarction?

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.

Screening for proximal coronary artery anomalies with 3-dimensional MR coronary angiography

Under 35 years of age, 14% of sudden cardiac death in athletes is caused by a coronary artery anomaly (CAA). Free-breathing 3-dimensional magnetic resonance coronary angiography (3D-MRCA) has the potential to screen for CAA in athletes and non-athletes as an addition to a clinical cardiac MRI protocol. A 360 healthy men and women (207 athletes and 153 non-athletes) aged 18–60 years (mean age 31 ± 11 years, 37% women) underwent standard cardiac MRI with an additional 3D-MRCA within a maximum of 10 min scan time. The 3D-MRCA was screened for CAA. A 335 (93%) subjects had a technically satisfactory 3D-MRCA of which 4 (1%) showed a malignant variant of the right coronary artery (RCA) origin running between the aorta and the pulmonary trunk. Additional findings included three subjects with ventral rotation of the RCA with kinking and possible proximal stenosis, one person with additional stenosis and six persons with proximal myocardial bridging of the left anterior descending coronary artery. Coronary CT-angiography (CTA) was offered to persons with CAA (the CAA was confirmed in three, while one person declined CTA) and stenosis (the ventral rotation of the RCA was confirmed in two but without stenosis, while two people declined CTA). Overall 3D MRCA quality was better in athletes due to lower heart rates resulting in longer end-diastolic resting periods. This also enabled faster scan sequences. A 3D-MRCA can be used as part of the standard cardiac MRI protocol to screen young competitive athletes and non-athletes for anomalous proximal coronary arteries.