Should NICE guidelines be universally accepted for the evaluation of stable coronary disease? A debate.

The 2016 National Institute of Health and Care Excellence clinical guideline for the assessment and diagnosis of chest pain positions coronary computed tomography angiography as the first test for all stable chest pain patients without confirmed coronary artery disease and discards the previous emphasis on calculation of pre-test likelihood recommended in their 2012 edition of the guidelines. On the other hand, the American College of Cardiology Foundation/American Heart Association and the European Society of Cardiology guidelines continue to present the stress testing functional modalities as the tests of choice. The aim of this review is to present, in the form of a debate, the pros and cons of these paradigm changing recommendations, with an emphasis on literature review and projection of future needs, with conclusions to be drawn by the reader.

Fractional Flow Reserve and Coronary Computed Tomographic Angiography: A Review and Critical Analysis.

Invasive fractional flow reserve (FFR) is now the gold standard for intervention. Noninvasive functional imaging analyses derived from coronary computed tomographic angiography (CTA) offer alternatives for evaluating lesion-specific ischemia. CT-FFR, CT myocardial perfusion imaging, and transluminal attenuation gradient/corrected contrast opacification have been studied using invasive FFR as the gold standard. CT-FFR has demonstrated significant improvement in specificity and positive predictive value compared with CTA alone for predicting FFR of ≤0.80, as well as decreasing the frequency of nonobstructive invasive coronary angiography. High-risk plaque characteristics have also been strongly implicated in abnormal FFR. Myocardial computed tomographic perfusion is an alternative method with promising results; it involves more radiation and contrast. Transluminal attenuation gradient/corrected contrast opacification is more controversial and may be more related to vessel diameter than stenosis. Important considerations remain: (1) improvement of CTA quality to decrease unevaluable studies, (2) is the diagnostic accuracy of CT-FFR sufficient? (3) can CT-FFR guide intervention without invasive FFR confirmation? (4) what are the long-term outcomes of CT-FFR-guided treatment and how do they compare with other functional imaging-guided paradigms? (5) what degree of stenosis on CTA warrants CT-FFR? (6) how should high-risk plaque be incorporated into treatment decisions? (7) how will CT-FFR influence other functional imaging test utilization, and what will be the effect on the practice of cardiology? (8) will a workstation-based CT-FFR be mandatory? Rapid progress to date suggests that CTA-based lesion-specific ischemia will be the gatekeeper to the cardiac catheterization laboratory and will transform the world of intervention.

Subclinical atherosclerosis imaging comes of age: coronary artery calcium in primary prevention.

PURPOSE OF REVIEW: The goal of this review is to update the contributions of subclinical atherosclerosis imaging of coronary artery calcified plaque (CAC) to the primary prevention of coronary artery disease. RECENT FINDINGS: Recent articles have increased support for the following: superiority of CAC determined risk to conventional risk factor-based paradigms, reclassification of risk by CAC, serial CAC scanning to assess the efficacy of therapy, CAC evaluation of high-risk groups (diabetes and other disease states characterized by inflammation), and redefinition of normal and abnormal lipids, ideal treatment goals and residual risk, as well as statin potency. SUMMARY: The paradigm shifts implicit in the supremacy of CAC herald a transformation in primary prevention from conventional risk factor paradigms to the evaluation of the disease itself by subclinical atherosclerosis imaging.

Cardiac CT angiography in current practice: An American society for preventive cardiology clinical practice statement✰.

In this clinical practice statement, we represent a summary of the current evidence and clinical applications of cardiac computed tomography (CT) in evaluation of coronary artery disease (CAD), from an expert panel organized by the American Society for Preventive Cardiology (ASPC), and appraises the current use and indications of cardiac CT in clinical practice. Cardiac CT is emerging as a front line non-invasive diagnostic test for CAD, with evidence supporting the clinical utility of cardiac CT in diagnosis and prevention. CCTA offers several advantages beyond other testing modalities, due to its ability to identify and characterize coronary stenosis severity and pathophysiological changes in coronary atherosclerosis and stenosis, aiding in early diagnosis, prognosis and management of CAD. This document further explores the emerging applications of CCTA based on functional assessment using CT derived fractional flow reserve, peri­coronary inflammation and artificial intelligence (AI) that can provide personalized risk assessment and guide targeted treatment. We sought to provide an expert consensus based on the latest evidence and best available clinical practice guidelines regarding the role of CCTA as an essential tool in cardiovascular prevention - applicable to risk assessment and early diagnosis and management, noting potential areas for future investigation.

The role of atherosclerosis imaging in redefining normal and abnormal cholesterol values, and risk reduction in primary prevention statin trials.

The emergence of atherosclerosis imaging, using coronary calcium scanning (CAC) and carotid intima media thickness (CIMT) and plaque as stronger predictors of cardiovascular events than risk factors of atherosclerosis, has created a paradigm shift in the primary prevention of cardiovascular disease. Rather than population-derived indices to define normal or abnormal low-density lipoprotein (or other lipid values) in the untreated individual patient, it is more appropriate to define "normal" as "cholesterol values at which level there is no subclinical atherosclerosis" and "abnormal" as "cholesterol values at which level there is subclinical atherosclerosis," with the severity of "abnormal" depending on the degree of subclinical atherosclerosis. Similarly, the low-density lipoprotein treatment goal is the level at which atherosclerosis progression is halted. Extension of the subclinical atherosclerosis risk-based paradigms to primary prevention trials dramatically changes the manner in which trials should be conducted in the future, as well as the results of trials already performed. For example, asymptomatic patients with a CAC score of 0 have an extraordinarily low event rate but have been included in primary prevention statin trials even though their risk without treatment is very small. Reanalysis of the statin primary prevention trials after excluding the percentage (40%) of patients who would be expected to have a CAC score of 0 yields an absolute risk increase of 60% in both the placebo group (from 5.4% to 8.5%), and the statin group (from 3.0% to 4.8%). Absolute risk reduction increased by 58% (from 2.4% to 3.8%). Relative risk reduction of 44% was unchanged. In conclusion, 1) the presence or absence of atherosclerosis as measured by CAC redefines normal or abnormal lipid levels in an individual patient; 2) statin absolute risk reduction is significantly greater than previously appreciated; and 3) patients with a CAC score of 0 should be excluded from primary prevention randomized controlled trials.

Current and evolving stent evaluation by coronary computed tomographic angiography.

OBJECTIVES: To demonstrate the variety of stent abnormalities that may be evaluated by coronary computed tomographic angiography (CTA). BACKGROUND: The application of CTA to the evaluation of coronary stents has focused almost entirely on the detection of in-stent restenosis. METHODS: All CTA performed for stent evaluation at a single institution were reviewed. RESULTS: In addition to in-stent restenosis, stent fracture, and overlap failure, a multiplicity of stent-related problems not previously addressed by CTA was categorized and illustrated: late stent thrombosis, jailed branches, edge stenosis, bifurcation stents, inadequate stent expansion, stent aneurysms, peri-stent plaque, and stenting into bridged myocardium. CONCLUSIONS: CTA may be used to evaluate the full range of stent-related problems. This work provides the framework for future studies validating these applications.

Stent sizing by coronary computed tomographic angiography: comparison with conventional coronary angiography in an experienced setting.

OBJECTIVES: The goal was to compare stent sizing by coronary computed tomographic angiography (CCTA) with that deployed in an experienced setting based upon conventional coronary angiography (CA). BACKGROUND: Stent sizing is currently performed by visual estimation, with infrequent guidance by intravascular ultrasound. CCTA permits quantitative determination of stent length (Stent L) and diameter (Stent D). METHODS: Projected L (CTA-Stent L) and D (CTA-Stent D) were determined from CCTA obtained in 248 patients with 352 lesions undergoing percutaneous coronary intervention within 4 months of the CCTA, and were compared to the Stent-L and Stent-D of the actually deployed stents. The effects of lesion modification and calcified plaque were also evaluated. RESULTS: There were significant correlations between CTA-Stent L and Stent L (r = 0.656, P < 0.0001) and between CTA-Stent D and Stent D (r = 0.40, P < 0.001). Median predicted CTA-Stent L was slightly longer (20 mm vs. 18 mm, P < 0.0001) and predicted CTA-Stent D was slightly smaller (3.0 mm vs. 3.2 mm, P < 0.0001) than Stent-L and Stent-D, respectively. The differences were unchanged in stents with lesion modification by pre-dilation or intracoronary nitroglycerin. CTA Stent-L and CTA Stent-D increased significantly with increasing calcium (P < 0.0001 and P = 0.019, respectively). CONCLUSIONS: (1) There are significant correlations between CCTA and CA based stent sizing in an experienced setting. (2) CCTA projects slightly longer and slightly smaller diameter stents than those deployed during PCI irrespective of lesion modification; the small differences are unlikely to have clinical significance. (3) CCTA may offer a noninvasive alternative to intravascular ultrasound for stent planning.

Coronary artery calcium: utilization for primary prevention of CHD.

The rapidly accumulating data supporting coronary artery calcium (CAC) has necessitated multiple paradigm shifts in primary prevention: 1) CAC is the most powerful predictor of cardiac risk in the asymptomatic primary prevention population. 2) The most important role of risk factors may be to identify the modifiable targets of risk reduction in patients with risk already established by CAC. 3) "Normal cholesterol" values derived from population-based studies are not relevant for individual patients. 4) Measures of subclinical atherosclerosis (ie, serial CAC), rather than lipid values, define residual risk just as they define pretreatment risk. 5) Randomized controlled trials are not a prerequisite for implementation of CAC screening. 6) Trials evaluating lipid-treating drugs should exclude patients with 0 CAC. 7) CAC is the most cost-effective primary prevention approach.

Usefulness of 64-detector computed tomographic angiography for diagnosing in-stent restenosis in native coronary arteries.

The purpose of this study was to evaluate the accuracy of detector computed tomographic angiographic qualitative and quantitative analyses for the detection of in-stent restenosis (ISR) Previous studies have used qualitative analyses exclusively and have excluded "unevaluable" stents. Multidetector computed tomographic angiography (MDCT) was performed before quantitative coronary angiography in 67 patients with 132 stents that were evaluated by 2 techniques: (1) qualitative, on the basis of degree of visual hypodensity, and (2) quantitative, comparing in-stent with prestent Hounsfield units. All stents were evaluated, irrespective of image quality. The incidence of ISR was 12.5%. The sensitivity (94%), specificity (74%), and positive predictive value (39%) of the qualitative evaluation were superior to the quantitative technique (82%, 54%, and 21%, respectively); negative predictive values were similar (99% vs 95%). Accuracies were equal in stents located in proximal and distal vessels. In conclusion, ISR can be evaluated qualitatively by 64-slice MDCT with excellent sensitivity and negative predictive accuracy without exclusion of unevaluable stents and with reasonable specificity but low positive predictive value. Quantitative analysis was less accurate.

Applications of multislice coronary computed tomographic angiography to percutaneous coronary intervention: how did we ever do without it?

By providing data previously available only by intravascular ultrasound, 64-slice multidetector computed tomographic angiography (CTA) will impact percutaneous coronary intervention (PCI) in multiple areas: (1) pre-PCI patient selection; (2) identification of significant lesions; (3) in-stent restenosis; (4) procedure planning: stent sizing, choice of intervention, and equipment, chronic total occlusions, 3D-CTA in the catheterization laboratory; (5) plaque evaluation and identification of high-risk lesions; (6) postcatheterization decisions, and (7) structural heart disease. The likely outcome is transformation of the catheterization laboratory into a streamlined interventional suite, utilizing on-line CTA data in an interactive format.

CAC-DRS: Coronary Artery Calcium Data and Reporting System. An expert consensus document of the Society of Cardiovascular Computed Tomography (SCCT).

The goal of CAC-DRS: Coronary Artery Calcium Data and Reporting System is to create a standardized method to communicate findings of CAC scanning on all noncontrast CT scans, irrespective of the indication, in order to facilitate clinical decision-making, with recommendations for subsequent patient management. The CAC-DRS classification is applied on a per-patient basis and represents the total calcium score and the number of involved arteries. General recommendations are provided for further management of patients with different degrees of calcified plaque burden based on CAC-DRS classification. In addition, CAC-DRS will provide a framework of standardization that may benefit quality assurance and tracking patient outcomes with the potential to ultimately result in improved quality of care.

Usefulness of computed tomographic angiography guided percutaneous coronary intervention.

The intravascular ultrasound qualities of coronary computed tomographic angiography provide the rationale for a new approach to the selection of patients for percutaneous coronary intervention and to guide the performance of the procedure. Minimum luminal diameter and minimum luminal area derived from computed tomographic angiography are readily measured and are used to triage patients to medical therapy or angiographic evaluation, with subsequent decisions based on the severity of disease and intravascular ultrasound findings. Technical decisions related to percutaneous coronary intervention are guided by lesion length and plaque characteristics. In conclusion, computed tomographic angiography has the requisite intravascular ultrasound characteristics to greatly impact percutaneous coronary intervention.

Evaluation of myocardial bridging of the left anterior descending coronary artery by 64-slice multidetector computed tomographic angiography.

The purpose of this study was to use the unique characteristics of multidetector computed tomographic coronary angiography to evaluate the prevalence and characteristics of myocardial bridging (MB) in a large series of patients and to assess the relation between atherosclerosis and MB. Three hundred consecutive coronary angiograms obtained by 64-slice multidetector computed tomography were evaluated retrospectively. For comparison of symptoms and concomitant atherosclerosis, 245 patients were included in the study and categorized into group 1 (n = 108) with MB and group 2 (n = 137) with no MB in the left anterior descending coronary artery (LAD). Axial and multiplanar reformatted images of all arteries were analyzed for the presence of measurable obstructive coronary disease (>25% stenosis) and minor luminal (<25% stenosis) calcified and noncalcified plaque and for MB in the LAD. Longitudinal and cross-sectional views were used for MB measurements. MB was found in 44% of patients (108 of 245) and was present equally in men and women (45% and 41%, p = NS). The mid LAD was the most common location (66%, p <0.001). There were no atherosclerotic lesions within the MB segments. The presence of MB did not influence the presence or severity of atherosclerotic lesions in the nonbridged segments of the LAD. In conclusion, MB as demonstrated by 64-slice multidetector computed tomographic coronary angiography is more common than previously reported by coronary angiography. The bridged segment appears to be free of atherosclerosis.

2016 SCCT/STR guidelines for coronary artery calcium scoring of noncontrast noncardiac chest CT scans: A report of the Society of Cardiovascular Computed Tomography and Society of Thoracic Radiology.

The Society of Cardiovascular Computed Tomography (SCCT) and the Society of Thoracic Radiology (STR) have jointly produced this document. Experts in this subject have been selected from both organizations to examine subject-specific data and write this guideline in partnership. A formal literature review, weighing the strength of evidence has been performed. When available, information from studies on cost was considered. Computed tomography (CT) acquisition, CAC scoring methodologies and clinical outcomes are the primary basis for the recommendations in this guideline. This guideline is intended to assist healthcare providers in clinical decision making. The recommendations reflect a consensus after a thorough review of the best available current scientific evidence and practice patterns of experts in the field and are intended to improve patient care while acknowledging that situations arise where additional information may be needed to better inform patient care.

2016 SCCT/STR guidelines for coronary artery calcium scoring of noncontrast noncardiac chest CT scans: A report of the Society of Cardiovascular Computed Tomography and Society of Thoracic Radiology.

The Society of Cardiovascular Computed Tomography (SCCT) and the Society of Thoracic Radiology (STR) have jointly produced this document. Experts in this subject have been selected from both organizations to examine subject-specific data and write this guideline in partnership. A formal literature review, weighing the strength of evidence has been performed. When available, information from studies on cost was considered. Computed tomography (CT) acquisition, CAC scoring methodologies and clinical outcomes are the primary basis for the recommendations in this guideline. This guideline is intended to assist healthcare providers in clinical decision making. The recommendations reflect a consensus after a thorough review of the best available current scientific evidence and practice patterns of experts in the field and are intended to improve patient care while acknowledging that situations arise where additional information may be needed to better inform patient care.