Accuracy of Computed Tomographic Angiography and Single-Photon Emission Computed Tomography-Acquired Myocardial Perfusion Imaging for the Diagnosis of Coronary Artery Disease

Comparison of image quality, arterial depiction, and radiation dose between two rapid kVp-switching dual-energy CT scanners in CT angiography at 40-keV

PURPOSE

To compare the quantitative parameters and qualitative image quality of dual-energy CT angiography (CTA) between two rapid kVp-switching dual-energy CT scanners.

MATERIALS AND METHODS

Between May 2021 and March 2022, 79 participants underwent whole-body CTA using either Discovery CT750 HD (Group A, n = 38) or Revolution CT Apex (Group B, n = 41). All data were reconstructed at 40-keV and with adaptive statistical iterative reconstruction-Veo of 40%. The two groups were compared in terms of CT numbers of the thoracic and abdominal aorta, and the iliac artery, background noise, signal-to-noise ratio (SNR) of the artery, CT dose-index volume (CTDIvol), and qualitative scores for image noise, sharpness, diagnostic acceptability, and arterial depictions.

RESULTS

The median CT number of the abdominal aorta (p = 0.04) and SNR of the thoracic aorta (p = 0.02) were higher in Group B than in Group A, while no difference was observed in the other CT numbers and SNRs of the artery (p = 0.09-0.23). The background noises at the thoracic (p = 0.11), abdominal (p = 0.85), and pelvic (p = 0.85) regions were comparable between the two groups. CTDIvol was lower in Group B than in Group A (p = 0.006). All qualitative scores were higher in Group B than in Group A (p < 0.001-0.04). The arterial depictions were nearly identical in both two groups (p = 0.005-1.0).

CONCLUSION

In dual-energy CTA at 40-keV, Revolution CT Apex improved qualitative image quality and reduced radiation dose.

When too much closeness harms: circumflex artery injury during mitral valve surgery

Occlusion of the left coronary circumflex artery (LCX) during surgical procedures of the mitral valve is an infrequent but potentially life-threatening complication (1-3). Due to its close anatomical relationship to the posterior mitral valve annulus, there is a relevant risk of causing a stenosis or an occlusion of the left circumflex artery, especially by surgical annular sutures. The perioperative clinical course is heterogeneous, ranging from-initially-asymptomatic or solely electrocardiographic abnormalities to cardiogenic shock. Both severely impaired ventricular contractility or malignant arrhythmia may potentially lead to a weaning failure from cardiopulmonary bypass (CPB) and eventually result in chronic heart failure with persistently reduced ejection fraction. Possible therapeutic strategies include the immediate reopening of causal sutures, aortocoronary bypass grafting or percutaneous coronary intervention (PCI), yet PCI seems to be the preferred method at present.

Recent Advances of Using Exosomes as Diagnostic Markers and Targeting Carriers for Cardiovascular Disease

Cardiovascular diseases (CVDs) are the leading cause of human death worldwide. Exosomes act as endogenous biological vectors; they possess advantages of low immunogenicity and low safety risks, also providing tissue selectivity, including the inherent targeting the to heart. Therefore, exosomes not only have been applied as biomarkers for diagnosis and therapeutic outcome confirmation but also showed potential as drug carriers for cardiovascular targeting delivery. This review aims to summarize the progress and challenges of exosomes as novel biomarkers, especially many novel exosomal noncoding RNAs (ncRNAs), and also provides an overview of the improved targeting functions of exosomes by unique engineered approaches, the latest developed administration methods, and the therapeutic effects of exosomes used as the biocarriers of medications for cardiovascular disease treatment. Also, the possible therapeutic mechanisms and the potentials for transferring exosomes to the clinic for CVD treatment are discussed. The advances, in vivo and in vitro applications, modifications, mechanisms, and challenges summarized in this review will provide a general understanding of this promising strategy for CVD treatment.

Non-Contrast and Contrast-Enhanced Cardiac Computed Tomography Imaging in the Diagnostic and Prognostic Evaluation of Coronary Artery Disease

In recent decades, cardiac computed tomography (CT) has emerged as a powerful non-invasive tool for risk stratification, as well as the detection and characterization of coronary artery disease (CAD), which remains the main cause of morbidity and mortality in the world. Advances in technology have favored the increasing use of cardiac CT by allowing better performance with lower radiation doses. Coronary artery calcium, as assessed by non-contrast CT, is considered to be the best marker of subclinical atherosclerosis, and its use is recommended for the refinement of risk assessment in low-to-intermediate risk individuals. In addition, coronary CT angiography (CCTA) has become a gate-keeper to invasive coronary angiography (ICA) and revascularization in patients with acute chest pain by allowing the assessment not only of the extent of lumen stenosis, but also of its hemodynamic significance if combined with the measurement of fractional flow reserve or perfusion imaging. Moreover, CCTA provides a unique incremental value over functional testing and ICA by imaging the vessel wall, thus allowing the assessment of plaque burden, composition, and instability features, in addition to perivascular adipose tissue attenuation, which is a marker of vascular inflammation. There exists the potential to identify the non-obstructive lesions at high risk of progression to plaque rupture by combining all of these measures.

Imaging Early Life Cardiovascular Phenotype

The growing epidemics of obesity, hypertension, and diabetes, in addition to worsening environmental factors such as air pollution, water scarcity, and climate change, have fueled the continuously increasing prevalence of cardiovascular diseases (CVDs). This has caused a markedly increasing burden of CVDs that includes mortality and morbidity worldwide. Identification of subclinical CVD before overt symptoms can lead to earlier deployment of preventative pharmacological and nonpharmacologic strategies. In this regard, noninvasive imaging techniques play a significant role in identifying early CVD phenotypes. An armamentarium of imaging techniques including vascular ultrasound, echocardiography, magnetic resonance imaging, computed tomography, noninvasive computed tomography angiography, positron emission tomography, and nuclear imaging, with intrinsic strengths and limitations can be utilized to delineate incipient CVD for both clinical and research purposes. In this article, we review the various imaging modalities used for the evaluation, characterization, and quantification of early subclinical cardiovascular diseases.

Contemporary Chest Pain Evaluation: The Australian Case for Cardiac CT

Computed tomography coronary angiography (CTCA) is a non-invasive diagnostic modality that provides a comprehensive anatomical assessment of the coronary arteries and coronary atherosclerosis, including plaque burden, composition and morphology. The past decade has witnessed an increase in the role of CTCA for evaluating patients with both stable and acute chest pain, and recent international guidelines have provided increasing support for a first line CTCA diagnostic strategy in select patients. CTCA offers some advantages over current functional tests in the detection of obstructive and non-obstructive coronary artery disease, as well as for ruling out obstructive coronary artery disease. Recent randomised trials have also shown that CTCA improves prognostication and guides the use of guideline-directed preventive therapies, leading to improved clinical outcomes. CTCA technology advances such as fractional flow reserve, plaque quantification and perivascular fat inflammation potentially allow for more personalised risk assessment and targeted therapies. Further studies evaluating demand, supply, and cost-effectiveness of CTCA for evaluating chest pain are required in Australia. This discussion paper revisits the evidence supporting the use of CTCA, provides an overview of its implications and limitations, and considers its potential role for chest pain evaluation pathways in Australia.

Multimodality Imaging in the Detection of Ischemic Heart Disease in Women

Women with coronary artery disease tend to have a worse short and long-term prognosis relative to men and the incidence of atherosclerotic cardiovascular disease is increasing. Women are less likely to present with classic anginal symptoms when compared with men and more likely to be misdiagnosed. Several non-invasive imaging modalities are available for diagnosing ischemic heart disease in women and many of these modalities can also assist with prognostication and help to guide management. Selection of the optimal imaging modality to evaluate women with possible ischemic heart disease is a scenario which clinicians often encounter. Earlier modalities such as exercise treadmill testing demonstrate significant performance variation in men and women, while newer modalities such as coronary CT angiography, myocardial perfusion imaging and cardiac magnetic resonance imaging are highly specific and sensitive for the detection of ischemia and coronary artery disease with greater parity between sexes. Individual factors, availability, diagnostic performance, and female-specific considerations such as pregnancy status may influence the decision to select one modality over another. Emerging techniques such as strain rate imaging, CT-myocardial perfusion imaging and cardiac magnetic resonance imaging present additional options for diagnosing ischemia and coronary microvascular dysfunction.

Plasma Exosomal S1PR5 and CARNS1 as Potential Non-invasive Screening Biomarkers of Coronary Heart Disease

Background

Early diagnosis and treatment significantly improve the prognosis of coronary heart disease (CHD), but no convenient screening tools are available. This study aims to find potential non-invasive screening biomarkers of coronary heart disease.

Method

We performed microarray analysis to investigate the mRNA expression levels in Small extracellular vesicles (sEVs) and screen significantly differentially expressed mRNAs in CHD patients vs. non-CHD patients. We then performed quantitative real-time polymerase chain reaction (qRT-PCR) to validate the microarray results, and we calculated the correlations between expression levels and clinicopathological data. Microarray analysis identified 72 downregulated mRNAs and 31 upregulated mRNAs in CHD patients relative to non-CHD patients.

Results

From the study, we found that upregulated sphingosine-1-phosphate receptor 5 (S1PR5) and downregulated carnosine synthase 1 (CARNS1) had the most significant differences between the patient group and the control group. S1PR5 expression was correlated with diabetes, heart rate, triglycerides, total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, and fasting blood glucose (P < 0.05). CARNS1 level was correlated with uric acid (UA) (P < 0.05). Overexpressed S1PR5 and downregulated CARNS1 were independent risk factors for CHD. The area under the receiver operating characteristic curve (AUC) of S1PR5 was 0.838 for diagnosing CHD; the AUC of CARNS1 was 0.883 for non-CHD; and the AUC of S1PR5 plus CARNS1 was 0.921 for CHD.

Conclusions

Microarray analysis showed that upregulated S1PR5 and downregulated CARNS1 in sEVs have the potential to become non-invasive biomarkers for CHD screening.

Prediction of multivessel coronary artery disease and candidates for stress-only imaging using multivariable models with myocardial perfusion imaging

Purpose

Selecting patients with coronary multivessel disease (MVD) or no stenosis using myocardial perfusion imaging (MPI) is challenging. We aimed to create a model to predict MVD using a combination of quantitative MPI values and background factors of patients. We also assessed whether patients in the same database could be selected who do not require rest studies (stress-only imaging).

Methods

We analyzed data from 1001 patients who had been assessed by stress MPI at 12 centers and 463 patients who had not undergone revascularization in Japan. Quantitative values based on MPI were obtained using cardioREPO software, which included myocardial perfusion defect scores, left ventricular ejection fractions and volumes. Factors in MPI and clinical backgrounds that could predict MVD were investigated using univariate and multivariate analyses. We also investigated whether stress data alone could predict patients without coronary stenosis to identify candidates for stress-only imaging.

Results

We selected summed stress score (SSS), rest end-diastolic volume, and hypertension to create a predictive model for MVD. A logistic regression model was created with an area under the receiver operating characteristics curve (AUC) of 0.825. To more specifically predict coronary three-vessel disease, the AUC was 0.847 when SSS, diabetes, and hypertension were selected. The mean probabilities of abnormality based on the MVD prediction model were 12%, 24%, 40%, and 51% for no-, one-, two-, and three-vessel disease, respectively (p < 0.0001). For the model to select patients with stress-only imaging, the AUC was 0.78 when the model was created using SSS, stress end-systolic volume and the number of risk factors (diabetes, hypertension, chronic kidney disease, and a history of smoking).

Conclusion

A model analysis combining myocardial SPECT and clinical data can predict MVD, and can select patients for stress-only tests. Our models should prove useful for clinical applications.

Utilization of Non-Gated Chest Computed Tomography Scans in Predicting Acute Coronary Occlusion in Out-of-Hospital Cardiac Arrest

INTRODUCTION

Coronary artery disease is thought to be responsible for up to 60-80% of out-of-hospital cardiac arrests. The utility of Computed Tomography (CT) chest when it comes to identifying acute coronary occlusion in patients following an arrest has not been studied. We aim to we evaluate whether myocardial perfusion on a contrast-enhanced chest CT performed for a non-cardiac cause can predict culprit coronary occlusion as the cause of cardiac arrest, and if the absence of a perfusion defect can exclude an ischemic etiology.

METHODS

A retrospective cohort of 53 consecutive patients presenting with VT or VF arrest and successful resuscitation who had contrast chest CT before angiography. CT scans were reviewed for myocardial perfusion defects by a cardiologist and radiologist blinded to angiogram findings. CT results were then compared with angiograms.

RESULTS

On coronary angiography, 22(42%) of the patients presenting with out-of-hospital arrest had critical stenosis. Sensitivity and specificity of perfusion defect on CT in identifying critical stenosis on catheterization was 0.45, 95% CI [0.24, 0.68] and 0.77, 95% CI [59%, 90%], respectively. The positive likelihood ratio being 2.01 (0.91,4.46) and the negative likelihood ratio being 0.70 (0.46,1.08). The diagnostic accuracy was 64.2%.

CONCLUSIONS

Our study did not show much utility for the use of myocardial perfusion defect on an incidental pre-angiography contrast chest CT to predict acute thrombotic occlusion in out-of-hospital cardiac arrest patients. However, this shouldn't discourage further studies evaluating the utility of contrast-enhanced CT-images in predicting acute coronary occlusion.

A Narrative Review of the Classical and Modern Diagnostic Methods of the No-Reflow Phenomenon

The incidence of the no-reflow (NR) phenomenon varies depending on the diagnostic criteria used. If just the angiographic criteria are considered (i.e., a degree of thrombolysis in myocardial infarction ≤2), it will be found that the incidence of NR is quite low; on the other hand, when the myocardial NR is taken into account (i.e., a decrease in the quality of myocardial reperfusion expressed by the degree of myocardial blush), the real incidence is higher. Thus, the early establishment of a diagnosis of NR and the administration of specific treatment can lead to its reversibility. Otherwise, regardless of the follow-up period, patients with NR have a poor prognosis. In the present work, we offer a comprehensive perspective on diagnostic tools for NR detection, for improving the global management of patients with arterial microvasculature damage, which is a topic of major interest in the cardiology field, due to its complexity and its link with severe clinical outcomes.

Quantitative myocardial perfusion 82Rb-PET assessed by hybrid PET/coronary-CT: Normal values and diagnostic performance

PURPOSE

We aimed to assess normal values for quantified myocardial blood flow (MBF) on a hybrid PET/coronary-CT scanner and to test their diagnostic performance in patients with suspected CAD.

MATERIALS AND METHODS

Patients underwent 82Rb-PET/CT and integrated CT-based coronary angiography (CCTA) and were classified as normal (no stenosis), with non-obstructive stenosis (< 50%) and with CAD (≥ 50%). Global and regional stress MBF (sMBF), rest MBF and myocardial flow reserve (MFR) were calculated. Ischemia was defined as SDS ≥ 2, severe ischemia as SDS ≥ 7.

RESULTS

357 consecutive patients were included. Global sMBF and MFR were higher in normal patients than in patients with CAD (3.61 ± 0.71 vs 3.04 ± 0.77, P < 0.0001; 3.08 ± 0.84 vs 2.68 ± 0.79, P = 0.0001), but not different compared to patients with non-obstructive stenosis (3.61 ± 0.71 vs 3.43 ± 0.69, P = 0.052; 3.08 ± 0.84 vs 2.99 ± 0.82, P = 0.45). sMBF yielded superior accuracy over MFR in identifying both ischemia (AUC 0.74 vs 0.62, P = 0.003) and severe ischemia (AUC 0.88 vs 0.78, P = 0.012). Optimal threshold for global sMBF to rule out myocardial ischemia was 3.5 mL g-1 min-1.

CONCLUSIONS

Normal quantitative values are provided. Global sMBF provided higher diagnostic accuracy than MFR. Using sMBF-threshold of 3.5 mL·g-1·min-1 on 82Rb-PET/CT yielded similar NPV (96%) as CCTA to rule out CAD. Hence, resting scan could be omitted in patients with sMBF values above reference.

Cardiovascular risk stratification by coronary computed tomography angiography imaging: current state-of-the-art

Current cardiovascular risk stratification by use of clinical risk score systems or plasma biomarkers is good but less than satisfactory in identifying patients at residual risk for coronary events. Recent clinical evidence puts now further emphasis on the role of coronary anatomy assessment by coronary computed tomography angiography (CCTA) for the management of patients with stable ischaemic heart disease. Available computed tomography (CT) technology allows the quantification of plaque burden, identification of high-risk plaques, or the functional assessment of coronary lesions for ischaemia detection and revascularization for refractory angina symptoms. The current CT armamentum is also further enhanced by perivascular Fat Attenuation Index (FAI), a non-invasive metric of coronary inflammation, which allows for the first time the direct quantification of the residual vascular inflammatory burden. Machine learning and radiomic features' extraction and spectral CT for tissue characterization are also expected to maximize the diagnostic and prognostic yield of CCTA. The combination of anatomical, functional, and biological information on coronary circulation by CCTA offers a unique toolkit for the risk stratification of patients, and patient selection for targeted aggressive prevention strategies. We hereby provide a review of the current state-of-the art in the field and discuss how integrating the full capacities of CCTA into clinical care pathways opens new opportunities for the tailored management of coronary artery disease.

Coronary computed tomography angiography in patients with stable coronary artery disease

The treatment of coronary artery disease (CAD), which is defined by stable anatomical atherosclerotic and functional alterations of epicardial vessels or microcirculation, focuses on managing intermittent angina symptoms and preventing major adverse cardiovascular events with optimal medical therapy. When patients with known CAD present with angina and no acute coronary syndrome, they have historically been evaluated with a variety of noninvasive stress tests that utilize electrocardiography, radionuclide scintigraphy, echocardiography, or magnetic resonance imaging for determining the presence and extent of inducible myocardial ischemia. Patient event-free survival, however, is largely driven by the coronary atherosclerotic disease burden, which is not directly assessed by functional testing. Direct evaluation of coronary atherosclerotic disease by coronary computed tomography angiography (coronary CTA) has emerged as the first line noninvasive imaging modality as it improves diagnostic accuracy and positively influences clinical management. Compared to functional assessment of CAD, coronary CTA-guided management results in improved patient outcomes by facilitating prevention of myocardial infarction. Other strengths of coronary CTA include detailed atherosclerotic plaque characterization and the ability to assess functional significance of specific lesions, which may further improve risk assessment and prognosis and lead to more appropriate referrals for additional testing, such as invasive coronary angiography.

Coronary Computer Tomography Angiography in 2021-Acquisition Protocols, Tips and Tricks and Heading beyond the Possible

Recent technological advances, together with an increasing body of evidence from randomized trials, have placed coronary computer tomography angiography (CCTA) in the center of the diagnostic workup of patients with coronary artery disease. The method was proven reliable in the diagnosis of relevant coronary artery stenosis. Furthermore, it can identify different stages of the atherosclerotic process, including early atherosclerotic changes of the coronary vessel wall, a quality not met by other non-invasive tests. In addition, newer computational software can measure the hemodynamic relevance (fractional flow reserve) of a certain stenosis. In addition, if required, information related to cardiac and valvular function can be provided with specific protocols. Importantly, recent trials have highlighted the prognostic relevance of CCTA in patients with coronary artery disease, which helped establishing CCTA as the first-line method for the diagnostic work-up of such patients in current guidelines. All this can be gathered in one relatively fast examination with minimal discomfort for the patient and, with newer machines, with very low radiation exposure. Herein, we provide an overview of the current technical aspects, indications, pitfalls, and new horizons with CCTA, providing examples from our own clinical practice.

Coronary Artery Disease Evaluation and Management Considerations for High Risk Occupations: Commercial Vehicle Drivers and Pilots

Optimal treatment of stable ischemic heart disease for those in the transportation industry is considered in the context of the individual's health, as well as with the perspective that sudden impairment could have catastrophic consequences for others. This article focuses on two high risk occupations that one may encounter in practice: commercial motor vehicle drivers and commercial pilots. This article discusses coronary heart disease in patients in high risk occupations and covers current guideline recommendations for screening, treatment, and secondary prevention. The importance of the complimentary perspectives of the regulatory agency, medical examiners, physicians, and pilot or driver are considered in this narrative review, as are considerations for future guideline updates.

Standardizing the Definition and Analysis Methodology for Complete Coronary Artery Revascularization

Guideline‐based medical therapy is the foundation of treatment for individuals with coronary artery disease. However, revascularization with either percutaneous coronary intervention or coronary artery bypass grafting may be beneficial in patients with acute coronary syndromes, refractory symptoms, or in other specific scenarios (eg, left main disease and heart failure). While the goal of percutaneous coronary intervention and coronary artery bypass grafting is to achieve complete revascularization, anatomical and ischemic definitions of complete revascularization and their methodology for assessment remain highly variable. Such lack of consensus invariably contributes to the absence of standardized approaches for invasive treatment of coronary artery disease. Herein, we propose a novel, comprehensive, yet pragmatic algorithm with both anatomical and ischemic parameters that aims to provide a systematic method to assess complete revascularization after percutaneous coronary intervention or coronary artery bypass grafting in both clinical practice and clinical trials.

Circular RNA in cardiovascular disease: Expression, mechanisms and clinical prospects

Circular RNAs (circRNAs) are a group of covalently closed, endogenous, non‐coding RNAs, which exist widely in human tissues including the heart. Increasing evidence has shown that cardiac circRNAs play crucial regulatory roles in cardiovascular diseases (CVDs). In this review, we aimed to provide a systemic understanding of circRNAs with a special emphasis on the cardiovascular system. We have summarized the current research on the classification, biogenesis and properties of circRNAs as well as their participation in the pathogenesis of CVDs. CircRNAs are conserved, stable and have specific spatiotemporal expression; thus, they have been accepted as a potential diagnostic marker or an incremental prognostic biomarker for CVDs.

Coronary Computed Tomography Angiography Compared With Single Photon Emission Computed Tomography Myocardial Perfusion Imaging as a Guide to Optimal Medical Therapy in Patients Presenting With Stable Angina: The RESCUE Trial

Background

The RESCUE (Randomized Evaluation of Patients with Stable Angina Comparing Utilization of Noninvasive Examinations) trial was a randomized, controlled, multicenter, comparative efficacy outcomes trial designed to assess whether initial testing with coronary computed tomographic angiography (CCTA) is noninferior to single photon emission computed tomography (SPECT) myocardial perfusion imaging in directing patients with stable angina to optimal medical therapy alone or optimal medical therapy with revascularization.

Methods and Results

The end point was first major adverse cardiovascular event (MACE) (cardiac death or myocardial infarction), or revascularization. Noninferiority margin for CCTA was set a priori as a hazard ratio (HR) of 1.3 (95% CI=0, 1.605). One thousand fifty participants from 44 sites were randomized to CCTA (n=518) or SPECT (n=532). Mean follow‐up time was 16.2 (SD 7.9) months. There were no cardiac‐related deaths. In patients with a negative CCTA there was 1 acute myocardial infarction; in patients with a negative SPECT examination there were 2 acute myocardial infarctions; and for positive CCTA and SPECT, 1 acute myocardial infarction each. Participants in the CCTA arm had a similar rate of MACE or revascularization compared with those in the SPECT myocardial perfusion imaging arm, (HR, 1.03; 95% CI=0.61‐1.75) (P=0.19). CCTA segment involvement by a stenosis of ≥50% diameter was a better predictor of MACE and revascularization at 1 year (P=0.02) than the percent reversible defect size by SPECT myocardial perfusion imaging. Four (1.2%) patients with negative CCTA compared with 14 (3.2%) with negative SPECT had MACE or revascularization (P=0.03).

Conclusions

There was no difference in outcomes of patients who had stable angina and who underwent CCTA in comparison to SPECT as the first imaging test directing them to optimal medical therapy alone or with revascularization. CCTA was a better predictor of MACE and revascularization.

Registration Information

URL: https://www.clinicaltrials.gov/. Identifier: NCT01262625.

Plasma-Derived Exosomal Circular RNA hsa_circ_0005540 as a Novel Diagnostic Biomarker for Coronary Artery Disease

Background

Exosomes exist in almost all body fluid and contain diverse biological contents which may be reflective of disease state. Circular RNAs (circRNAs) are stable in structure and have a long half-life in exosomes without degradation, thus making them reliable biomarkers. However, the potential of exosomal circRNAs as biomarkers of coronary artery disease (CAD) remains to be established. Here, we aimed to investigate the expression levels and the potential use of exosomal circRNAs as diagnostic biomarkers for CAD.

Methods

CircRNA expression levels in exosomes obtained from three plasma samples of CAD patients and three paired controls were analyzed using RNA sequencing. Exosomal circRNAs obtained in the profiling phase were then verified in two-center validation cohorts. Finally, the ability of exosomal circRNAs, adjusting for Framingham Heart Study (FHS) risk factors, was determined to discriminate between CAD patients and non-CAD controls.

Results

355 circRNAs were differentially expressed between these two groups: 164 were upregulated, and 191 were downregulated. Here, we selected the potential circRNAs (fold change > 4, P < 0.05) as candidate biomarkers for further validation. Our data showed that only hsa_circ_0005540 was significantly associated with CAD (P < 0.0001). After adjustment for risk factors, hsa_circ_0005540 showed a high discriminatory power for CAD in ROC analyses (AUC = 0.853; 95%confidence interval (CI) = 0.799 - 0.906, P < 0.001).

Conclusion

Our results suggest that plasma exosomal hsa_circ_0005540 can be used as a promising diagnostic biomarker of CAD.

Myocardial Perfusion by Coronary Computed Tomography in the Evaluation of Myocardial Ischemia: Simultaneous Stress Protocol with SPECT

BACKGROUND

Functional assessment to rule out myocardial ischemia using coronary computed tomography angiography (CCTA) is extremely important and data on the Brazilian population are still limited.

OBJECTIVE

To assess the diagnostic performance of myocardial perfusion by CCTA in the detection of severe obstructive coronary artery disease (CAD) compared with single-photon emission computerized tomography (SPECT). To analyze the importance of anatomical knowledge to understand the presence of myocardial perfusion defects on SPECT imaging that is not identified on computed tomography (CT) scan.

METHOD

A total of 35 patients were evaluated by a simultaneous pharmacologic stress protocol. Fisher's exact test was used to compare proportions. The patients were grouped according to the presence or absence of significant CAD. The area under the ROC curve was used to identify the diagnostic performance of CCTA and SPECT in perfusion assessment. P < 0.05 values were considered statistically significant.

RESULTS

For detection of obstructive CAD, CT myocardial perfusion analysis yielded an area under the ROC curve of 0.84 [a 95% confidence interval (CI95%): 0.67-0.94, p < 0.001]. SPECT myocardial perfusion imaging, on the other hand, showed an AUC of 0.58 (95% CI 0.40 - 0.74, p < 0.001). In this study, false-positive results with SPECT are described.

CONCLUSION

Myocardial perfusion analysis by CTA displays satisfactory results compared to SPECT in the detection of obstructive CAD. CCTA can rule out false-positive results of SPECT.

Outcomes of non-invasive diagnostic modalities for the detection of coronary artery disease: network meta-analysis of diagnostic randomised controlled trials

OBJECTIVE

To evaluate differences in downstream testing, coronary revascularisation, and clinical outcomes following non-invasive diagnostic modalities used to detect coronary artery disease.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

Medline, Medline in process, Embase, Cochrane Library for clinical trials, PubMed, Web of Science, SCOPUS, WHO International Clinical Trials Registry Platform, and Clinicaltrials.gov.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Diagnostic randomised controlled trials comparing non-invasive diagnostic modalities in patients presenting with symptoms suggestive of low risk acute coronary syndrome or stable coronary artery disease.

DATA SYNTHESIS

A random effects network meta-analysis synthesised available evidence from trials evaluating the effect of non-invasive diagnostic modalities on downstream testing and patient oriented outcomes in patients with suspected coronary artery disease. Modalities included exercise electrocardiograms, stress echocardiography, single photon emission computed tomography-myocardial perfusion imaging, real time myocardial contrast echocardiography, coronary computed tomographic angiography, and cardiovascular magnetic resonance. Unpublished outcome data were obtained from 11 trials.

RESULTS

18 trials of patients with low risk acute coronary syndrome (n=11 329) and 12 trials of those with suspected stable coronary artery disease (n=22 062) were included. Among patients with low risk acute coronary syndrome, stress echocardiography, cardiovascular magnetic resonance, and exercise electrocardiograms resulted in fewer invasive referrals for coronary angiography than coronary computed tomographic angiography (odds ratio 0.28 (95% confidence interval 0.14 to 0.57), 0.32 (0.15 to 0.71), and 0.53 (0.28 to 1.00), respectively). There was no effect on the subsequent risk of myocardial infarction, but estimates were imprecise. Heterogeneity and inconsistency were low. In patients with suspected stable coronary artery disease, an initial diagnostic strategy of stress echocardiography or single photon emission computed tomography-myocardial perfusion imaging resulted in fewer downstream tests than coronary computed tomographic angiography (0.24 (0.08 to 0.74) and 0.57 (0.37 to 0.87), respectively). However, exercise electrocardiograms yielded the highest downstream testing rate. Estimates for death and myocardial infarction were imprecise without clear discrimination between strategies.

CONCLUSIONS

For patients with low risk acute coronary syndrome, an initial diagnostic strategy of stress echocardiography or cardiovascular magnetic resonance is associated with fewer referrals for invasive coronary angiography and revascularisation procedures than non-invasive anatomical testing, without apparent impact on the future risk of myocardial infarction. For suspected stable coronary artery disease, there was no clear discrimination between diagnostic strategies regarding the subsequent need for invasive coronary angiography, and differences in the risk of myocardial infarction cannot be ruled out.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registry no CRD42016049442.

Coronary CT Angiography: Use in Patients With Chest Pain Presenting to Emergency Departments

OBJECTIVE

Previously published reports have shown that coronary CT angiography (CCTA) is a more efficient method of diagnosis than myocardial perfusion imaging (MPI) and stress echocardiography for patients presenting to emergency departments (EDs) with acute chest pain. In light of this evidence, the objective of this study was to examine recent trends in the use of these techniques in EDs.

MATERIALS AND METHODS

The nationwide Medicare Part B databases for 2006-2015 were the data source. The Current Procedural Terminology, version 4, codes for CCTA, MPI, and stress echocardiography were selected. Medicare place-of-service codes were used to determine procedure volumes in EDs. Medicare specialty codes were used to ascertain how many of these examinations were interpreted by radiologists, cardiologists, and other physicians as a group.

RESULTS

From 2006 to 2015, there was essentially no change in the number of MPI examinations performed in EDs for patients using Medicare (22,342 in 2006, 22,338 in 2015) or in the number of stress echocardiograms (3544 in 2006, 3520 in 2015). By contrast, the number of CCTA examinations increased rapidly, from 126 in 2006 to 1919 in 2015 (compound annual growth rate, 35%). Despite this rapid growth, patients in EDs underwent 11.6 times as many MPI as CCTA examinations in 2015. In that last year of the study, radiologists interpreted 78% of ED MPI and 83% of ED CCTA examinations.

CONCLUSION

Use of CCTA in EDs has increased rapidly, but far more MPI examinations are still being performed. This finding suggests that recently acquired evidence is not yet being fully acted upon.

Impact of spatial characteristics in the left stenotic coronary artery on the hemodynamics and visualization of 3D replica models

Cardiovascular disease has been the major cause of death worldwide. Although the initiation and progression mechanism of the atherosclerosis are similar, the stenotic characteristics and the corresponding medical decisions are different between individuals. In the present study, we performed anatomic and hemodynamic analysis on 8 left coronary arterial trees with 10 identified stenoses. A novel boundary condition method had been implemented for fast computational fluid dynamics simulations and patient-specific three-dimensional printed models had been built for visualizations. Our results suggested that the multiple spatial characteristics (curvature of the culprit vessel multiplied by an angle of the culprit's vessel to the upstream parent branch) could be an index of hemodynamics significance (r = -0.673, P-value = 0.033). and reduction of the maximum velocity from stenosis to downstream was found correlated to the FFRCT (r = 0.480, p = 0.160). In addition, 3D printed models could provide accurate replicas of the patient-specific left coronary arterial trees compare to virtual 3D models (r = 0.987, P-value < 0.001). Therefore, the visualization of the 3D printed models could help understand the spatial distribution of the stenoses and the hand-held experience could potentially benefit the educating and preparing of medical strategies.

The Risk Continuum of Atherosclerosis and its Implications for Defining CHD by Coronary Angiography

Patients undergoing coronary angiography for suspected coronary heart disease who are found to have coronary atherosclerotic disease with <50% diameter stenosis may carry a risk of adverse cardiac events similar to that in patients with single-vessel obstructive disease. Yet clinical practice guidelines offer no direction for managing symptomatic patients with nonobstructive coronary atherosclerosis because current diagnostic criteria for coronary heart disease are not met. Accordingly, secondary preventive measures are not endorsed, and their role is not defined in this setting. Available data suggest that we are missing the opportunity to provide effective preventive measures in millions of patients with nonobstructive coronary heart disease. The emergence of noninvasive coronary angiography in patients with suspected coronary heart disease provides the opportunity to transition from a categorical perspective on the presence or absence of coronary heart disease to accepting the risk continuum from atherosclerosis and its implications for diagnosis and management.

Clinical evaluation of new automatic coronary-specific best cardiac phase selection algorithm for single-beat coronary CT angiography

The aim of this study was to evaluate the workflow efficiency of a new automatic coronary-specific reconstruction technique (Smart Phase, GE Healthcare—SP) for selection of the best cardiac phase with least coronary motion when compared with expert manual selection (MS) of best phase in patients with high heart rate. A total of 46 patients with heart rates above 75 bpm who underwent single beat coronary computed tomography angiography (CCTA) were enrolled in this study. CCTA of all subjects were performed on a 256-detector row CT scanner (Revolution CT, GE Healthcare, Waukesha, Wisconsin, US). With the SP technique, the acquired phase range was automatically searched in 2% phase intervals during the reconstruction process to determine the optimal phase for coronary assessment, while for routine expert MS, reconstructions were performed at 5% intervals and a best phase was manually determined. The reconstruction and review times were recorded to measure the workflow efficiency for each method. Two reviewers subjectively assessed image quality for each coronary artery in the MS and SP reconstruction volumes using a 4-point grading scale. The average HR of the enrolled patients was 91.1±19.0bpm. A total of 204 vessels were assessed. The subjective image quality using SP was comparable to that of the MS, 1.45±0.85 vs 1.43±0.81 respectively (p = 0.88). The average time was 246 seconds for the manual best phase selection, and 98 seconds for the SP selection, resulting in average time saving of 148 seconds (60%) with use of the SP algorithm. The coronary specific automatic cardiac best phase selection technique (Smart Phase) improves clinical workflow in high heart rate patients and provides image quality comparable with manual cardiac best phase selection. Reconstruction of single-beat CCTA exams with SP can benefit the users with less experienced in CCTA image interpretation.

Peripheral blood circular RNA hsa_circ_0124644 can be used as a diagnostic biomarker of coronary artery disease

The aim of the present study was to investigate the expression of circular RNAs (circRNAs) in the peripheral blood of coronary artery disease (CAD) patients and the potential use of circRNAs as diagnostic biomarkers of CAD. We first analysed peripheral blood circRNAs of 12 CAD patients and 12 control individuals by RNA microarray and found that 22 circRNAs were differentially expressed between these two groups: 12 were upregulated, and 10 were downregulated. Then, we selected 5 circRNAs as candidate biomarkers under stricter screening criteria and verified them in another group of subjects consisting of 30 control individuals and 30 CAD patients with different SYNTAX scores. These 5 circRNAs were all remarkably increased in the CAD group. Hsa_circ_0124644 had the largest area under the curve (AUC). We tested hsa_circ_0124644 in an independent cohort consisting of 115 control individuals and 137 CAD patients. After we included the risk factors for CAD, the AUC slightly increased from 0.769 (95% confidence interval = [0.710–0.827], P < 0.001) to 0.804 ([0.751–0.857], P < 0.001), and when combined with hsa_circ_0098964, the diagnostic value slightly increased. Taken together, our results suggest that hsa_circ_0124644 can be used as a diagnostic biomarker of CAD.

Imaging Atherosclerosis

Advances in atherosclerosis imaging technology and research have provided a range of diagnostic tools to characterize high-risk plaque in vivo; however, these important vascular imaging methods additionally promise great scientific and translational applications beyond this quest. When combined with conventional anatomic- and hemodynamic-based assessments of disease severity, cross-sectional multimodal imaging incorporating molecular probes and other novel noninvasive techniques can add detailed interrogation of plaque composition, activity, and overall disease burden. In the catheterization laboratory, intravascular imaging provides unparalleled access to the world beneath the plaque surface, allowing tissue characterization and measurement of cap thickness with micrometer spatial resolution. Atherosclerosis imaging captures key data that reveal snapshots into underlying biology, which can test our understanding of fundamental research questions and shape our approach toward patient management. Imaging can also be used to quantify response to therapeutic interventions and ultimately help predict cardiovascular risk. Although there are undeniable barriers to clinical translation, many of these hold-ups might soon be surpassed by rapidly evolving innovations to improve image acquisition, coregistration, motion correction, and reduce radiation exposure. This article provides a comprehensive review of current and experimental atherosclerosis imaging methods and their uses in research and potential for translation to the clinic.

[Ischemic burden vs. coronary artery morphology : What is crucial for the indication of revascularization?]

Ischemic heart disease still represents the leading cause of death in the western world despite a decrease of mortality in the last decade. For the diagnostics of coronary artery morphology, invasive coronary angiography represents the gold standard. Nevertheless, in recent years the importance of functional diagnostics of the coronary arteries has increased and various imaging procedures for the measurement of fractional flow reserve (FFR) during coronary angiography were established and recommended for ischemia testing in the actual guidelines on myocardial revascularization.Imaging modalities for diagnostics of the functional relevance of coronary artery disease include stress echocardiography, magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and positron emission tomography (PET). These procedures enable advanced risk stratification and therapy guiding in patients with suspected or known coronary artery disease. In future algorithms, hybrid imaging may facilitate the determination of anatomical and functional aspects after only one investigation.In the present article, the role of ischemia testing is compared with morphological methods for the diagnosis of coronary artery disease, individual risk stratification, and therapy guiding.

Recent developments in the use of computed tomography scanners in coronary artery imaging

INTRODUCTION

Within the past decade, substantial evolution of Coronary CT Angiography (CCTA) has affected evaluation and management of coronary artery disease. In particular, technical advancement of hardware technology and image reconstruction of CT scanners have played an important role in this context making it possible to acquire abundant data with excellent temporal and spatial resolution within a shorter scan time. In addition, a concern related to the high radiation exposure in the initial noninvasive coronary artery imaging has triggered improvement in dose reduction techniques.

AREAS COVERED

In this review article, we have focused on recent technological developments in CT scanners and the impact of these developments on CCTA parameters. Expert Commentary: CCTA plays an important role in coronary artery disease management, and technical development of the CT scanners can be expected to address and remedy technical limitations.