The prevalence of coronary artery variations on coronary computed tomography angiography

Use of Intravascular Ultrasound and Coronary Angiography to Measure the Prevalence of Myocardial Bridge in Heart Transplant Patients

Myocardial bridge (MB) detection rates vary across methods and most studies that have assessed MB include symptomatic patients. Intravascular ultrasound (IVUS) is a sensitive tool for MB detection and donor hearts may serve as a surrogate measure of asymptomatic patients. We used IVUS and coronary angiography to measure MB prevalence in heart transplant patients during routine follow-up invasive coronary assessments. This was a retrospective, single-center study of heart transplant patients who received follow-up coronary assessments at the University of Chicago Heart and Vascular Center between December 2014 and December 2021. A single experienced interventional cardiologist assessed incidental findings of MB in IVUS and coronary angiography. Detection rates were compared with meta-analysis-reported prevalence. Of 129 patients, IVUS-detected MB in 87 patients (67.4%), whereas coronary angiography detected 41 (31.8%). All MB found by coronary angiography were detected by IVUS. Some level of cardiac allograft vasculopathy was found in 92 patients (71.3%). Our IVUS-detected MB prevalence was greater than meta-analysis-reported pooled prevalence across all methods: autopsy, computed tomography angiography, and coronary angiography (67.4% [95% confidence interval [CI] 59.4 to 75.5] vs 42% [95% CI 30 to 55]; 22% [95% CI 18 to 25]; 6% [95% CI 5 to 8], p ≤0.005). The difference between our observed IVUS-detected MB prevalence and meta-analysis autopsy reported MB prevalence was 1.25 (95% CI 1.11 to 1.40). In conclusion, the high prevalence of MB recorded in donor hearts emphasizes the need to further investigate the causes of chest pain in patients who are found to have MB.

Atheroprotective effect of myocardial bridge sustains in aging: Autopsy study on subjects with dual left anterior descending coronary artery type 3

BACKGROUND

The atheroprotective role of the myocardial bridge (MB) on a tunneled segment is already demonstrated in subjects with dual left anterior descending coronary artery (dual LAD) type 3 anomaly, but the dynamics of changes and whether this protective effect sustains during aging is unknown.

METHODS

The retrospective autopsy study included cases of dual LAD type 3 anomaly identified over 18 years. The severity grade of atherosclerosis in branches of dual LAD was estimated by microscopy. The Spearman's correlation test and Receiver operator characteristics (ROC) curve analyses were performed to determine the relation of subjects' age with a degree of the protective role of the myocardial bridge.

RESULTS

A total of 32 dual LAD type 3 cases were identified. The systematic heart examination revealed an anomaly prevalence of 2.1%. The age significantly positively correlated with the severity of atherosclerosis in the subepicardial dual LAD branch but not with the severity of atherosclerosis in the intramyocardial dual LAD branch. Subjects aged ≥38 years were likely to have a more severe degree of atherosclerosis in subepicardial than in intramyocardial LAD arteries (AUC 0.81 95% CI 0.59-1; sensitivity 100%, specificity 66.7%). In subjects aged ≥58 years, this difference was likely to be more pronounced (≥2 degree difference; AUC 0.75 95% CI 0.58-0.93; sensitivity 92.9%, specificity 66.7%).

CONCLUSION

The atheroprotective effect of the myocardial bridge on tunneled segments usually becomes evident throughout the second half of the fourth decade of life and is most pronounced after about 60 years and ceases only in some.

Influence of coronary dominance on coronary artery calcification burden

OBJECTIVE

To evaluate the influence of coronary artery dominance on observed coronary artery calcification burden in outpatients presenting for coronary computed tomography angiography (CCTA).

METHODS

A 12-month retrospective review was performed of all CCTAs at a single institution. Coronary arterial dominance, Agatston score and presence or absence of cardiovascular risk factors including hypertension (HTN), hyperlipidemia (HLD), diabetes and smoking were recorded. Dominance groups were compared in terms of calcium score adjusted for covariates using analysis of covariance based on ranks. Only covariates observed to be significant independent predictors of the relevant outcome were included in each analysis. All statistical tests were conducted at the two-sided 5% significance level.

RESULTS

1223 individuals, 618 women and 605 men were included, mean age 60 years (24-93 years). Right coronary dominance was observed in 91.7% (n = 1109), left dominance in 8% (n = 98), and codominance in 1.3% (n = 16). The distribution of patients among Agatston score severity categories significantly differed between codominant and left (p = 0.008), and codominant and right (p = 0.022) groups, with higher prevalence of either zero or severe CAC in the codominant patients. There was no significant difference in Agatston score between dominance groups. In the subset of individuals with coronary artery calcification, Agatston score was significantly higher in codominant versus left dominant patients (mean Agatston score 595 ± 520 vs. mean 289 ± 607, respectively; p = 0.049), with a trend towards higher scores in comparison to the right-dominant group (p = 0.093). Significance was not maintained upon adjustment for covariates.

CONCLUSIONS

While the distribution of Agatston score severity categories differed in codominant versus right- or left-dominant patients, there was no significant difference in Agatston score based on coronary dominance pattern in our cohort. Reporting and inclusion of codominant subsets in larger investigations may elucidate whether codominant anatomy is associated with differing risk.

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.

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.

Conus artery occlusion causing isolated right ventricular outflow tract infarction: novel application of cardiac magnetic resonance in anterior STEMI

Acute ST elevation in the anterior precordial leads typically suggests an anteroseptal infarction due to left anterior descending coronary artery obstruction, but the differential can be broad. Conus branch artery occlusion is a potentially overlooked cause of anteroseptal ST elevation myocardial infraction. Cardiac magnetic resonance (CMR) imaging is an emerging technology which can differentiate the etiology of anterior ST elevation in patients with no apparent coronary abnormalities on coronary angiography and normal echocardiography.

Anatomical Variations in the Sinoatrial Nodal Artery: A Meta-Analysis and Clinical Considerations

BACKGROUND AND OBJECTIVE

The sinoatrial nodal artery (SANa) is a highly variable vessel which supplies blood to the sinoatrial node (SAN). Due to its variability and susceptibility to iatrogenic injury, our study aimed to assess the anatomy of the SANa and determine the prevalence of its anatomical variations.

STUDY DESIGN

An extensive search of major electronic databases was performed to identify all articles reporting anatomical data on the SANa. No lower date limit or language restrictions were applied. Anatomical data regarding the artery were extracted and pooled into a meta-analysis.

RESULTS

Sixty-six studies (n = 21455 hearts) were included in the meta-analysis. The SANa usually arose as a single vessel with a pooled prevalence of 95.5% (95%CI:93.6-96.9). Duplication and triplication of the artery were also observed with pooled prevalence of 4.3% (95%CI:2.8-6.0) and 0.3% (95%CI:0-0.7), respectively. The most common origin of the SANa was from the right coronary artery (RCA), found in 68.0% (95%CI:55.6-68.9) of cases, followed by origin from the left circumflex artery, and origin from the left coronary artery with pooled prevalence of 22.1% (95%CI:15.0-26.2) and 2.7 (95%CI:0.7-5.2), respectively. A retrocaval course of the SANa was the most common course of the artery with a pooled prevalence of 47.1% (95%CI:36.0-55.5). The pooled prevalence of an S-shaped SANa was 7.6% (95%CI:2.9-14.1).

CONCLUSIONS

The SANa is most commonly reported as a single vessel, originating from the RCA, and taking a retrocaval course to reach the SAN. Knowledge of high risk anatomical variants of the SANa, such as an S-shaped artery, must be taken into account by surgeons to prevent iatrogenic injuries. Specifically, interventional or cardiosurgical procedures, such as the Cox maze procedure for atrial fibrillation, open heart surgeries through the right atrium or intraoperative cross-clamping or dissection procedures during mitral valve surgery using the septal approach can all potentiate the risk for injury in the setting of high-risk morphological variants of the SANa.

Prevalence of coronary artery ectasia in older adults and the relationship with epicardial fat volume by cardiac computed tomography angiography

OBJECTIVE

Coronary artery ectasia (CAE) refers to abnormal dilation of coronary artery segments to 1.5 times of adjacent normal ones. Epicardial fat is associated with cardiovascular risk factors. The relationship between CAE and epicardial fat has not yet been investigated. This study aimed to assess the relationship between CAE and epicardial fat volume (EFV) in older people by dual-source computed tomography coronary angiography (CTCA).

METHODS

We prospectively enrolled 1400 older adults who were scheduled for dual-source CTCA. Under reconstruction protocols, patients with abnormal segments 1.5 times larger than the adjacent segments were accepted as CAE. EFV was measured by semi-automated software. Traditional risk factors in CAE patients, as well as the extent of EFV, were analyzed and compared to non-CAE group.

RESULTS

A total of 885 male and 515 female older patients were enrolled. CAE was identified by univariable analysis in 131 patients and significantly correlated to hypertension, smoking, hyperlipidemia, prior percutaneous coronary intervention and ascending aorta aneurysm. EFV was shown to be significantly higher in CAE patients than patients without ectasia. In multivariable analyses, EFV (P = 0.018), hypertension (P < 0.001) and hyperlipidemia (P < 0.001) were significantly correlated to CAE. There was a significant negative correlation between EFV and Markis classification.

CONCLUSIONS

CAE can be reliably recognized by dual-source CTCA. Epicardial fat might play a role in etiopathogenesis and progression of CAE, providing a new target for treating ectasia.

Coronary ostium topography: an implication for transcatheter aortic valve implantation?

OBJECTIVES

Shorter distances from coronary ostia to the calcified aortic valve may result in occlusion with potential infarction during transcatheter aortic valve implantation. We hypothesized that preoperative CT-scan measurements might predict coronary occlusion.

METHODS

Distances from the coronary ostia to the calcified aortic valve were measured during open heart aortic valve replacement in 60 consecutive patients. Distances were compared to preoperative CT-scan measurements evaluating distance of the coronary ostia as well (n = 15).

RESULTS

The distances of the lower lip of the left and the right coronary artery ostia measured from the aortic annulus were 14.7 ± 3.9 mm and 13.4 ± 4.0 mm, respectively. The left, right and noncoronary cusp heights were 13.9 ± 2.5 mm, 12.8 ± 3.0 mm and 13.3 ± 3.1 mm, respectively. Coronary ostia topography indicated variations from the middle to the noncoronary commissure in 40% for the left and 63% for the right coronary ostium. CT-scan based measurements resulted in a distance of 12.8 ± 3.5 mm for the left and 13.9 ± 4.0 mm for the right coronary ostium, compared to 14.2 ± 4.2 mm and 13.5 ± 4.3 mm measured intraoperatively. A mild correlation between both measurements could be observed (r = 0.374, P = 0.188, left and r = 0.46, P = 0.09, n = 15).

CONCLUSIONS

CT-scan-based measurements differed from the intraoperative measurements, however preoperative CT-scan evaluation may be a useful tool to identify patients with short distance of coronaries.

Coronary artery ectasia diagnosed using multidetector computed tomography: morphology and relation to coronary artery calcification

Coronary artery ectasia (CAE) is usually considered a variant of coronary artery atherosclerosis; however, a definite link has not yet been confirmed. As not all patients with CAE are symptomatic, the real incidence is unknown. The aim of this study was to evaluate the prevalence of CAE and its clinical and angiographic characteristics as well as its relation to coronary artery calcification and any associated vascular abnormality by using multidetector computed tomography (MDCT). We prospectively enrolled 2,600 patients (mean age 55 ± 10 years) who were scheduled for computed tomography coronary angiography (CTCA). CTCA was performed using 64-MDCT with dedicated software for calcium measurement. CAE was defined as an arterial segment with a diameter of >1.5 times the diameter of the adjacent normal segment. The presence of ≥70 % diameter stenosis of any major epicardial vessel was considered an obstructive lesion. CAE was encountered in 192 (7.4 %) patients and showed gender predominance in men (88 %). Patients with CAE were more hypertensive but less diabetic. Left anterior descending artery was the most commonly affected vessel. Only 16 % of CAE patients had no atherosclerotic lesion. Coronary artery calcium score (CACS) and prevalence of ascending aorta aneurysm were shown to be significantly higher in CAE patients compared to patients having no ectasia. A significant negative correlation was noted between CACS and Markis classification. CTCA is a feasible technique to identify and evaluate morphology of CAE. The link between CACS and CAE may favor the consideration that ectasia is an advanced form of atherosclerosis.