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Objectives This study sought to investigate the impact of low tube voltage scanning heterogeneity of coronary luminal attenuation on plaque quantification and characterization with coronary computed tomography angiography (CCTA). Background The impact of low tube voltage and coronary luminal attenuation on quantitative coronary plaque remains uncertain. Methods A total of 1,236 consecutive patients (age: 60 ± 9 years; 41% female) who underwent serial CCTA at an interval of ≥2 years were included from an international registry. Patients with prior revascularization or nonanalyzable coronary CTAs were excluded. Total coronary plaque volume was assessed and subclassified based on specific Hounsfield unit (HU) threshold: necrotic core, fibrofatty plaque, and fibrous plaque and dense calcium. Luminal attenuation was measured in the aorta. Results With increasing luminal HU ( 500 HU), percent calcified plaque was increased (16%, 27%, and 40% in the median; P Conclusions Low tube voltage usage affected plaque morphology, mainly through an increase in luminal HU with a resultant increase in calcified plaque and a reduction in fibrofatty and necrotic core. These findings should be considered as CCTA-based plaque measures are being used to guide medical management and, in particular, when being used as a measure of treatment response. (Progression of Atherosclerotic Plaque Determined by Computed Tomographic Angiography Imaging [PARADIGM]; NCT02803411 )

Objectives This study designed and evaluated an end-to-end deep learning solution for cardiac segmentation and quantification. Background Segmentation of cardiac structures from coronary computed tomography angiography (CCTA) images is laborious. We designed an end-to-end deep-learning solution. Methods Scans were obtained from multicenter registries of 166 patients who underwent clinically indicated CCTA. Left ventricular volume (LVV) and right ventricular volume (RVV), left atrial volume (LAV) and right atrial volume (RAV), and left ventricular myocardial mass (LVM) were manually annotated as ground truth. A U-Net-inspired, deep-learning model was trained, validated, and tested in a 70:20:10 split. Results Mean age was 61.1 ± 8.4 years, and 49% were women. A combined overall median Dice score of 0.9246 (interquartile range: 0.8870 to 0.9475) was achieved. The median Dice scores for LVV, RVV, LAV, RAV, and LVM were 0.938 (interquartile range: 0.887 to 0.958), 0.927 (interquartile range: 0.916 to 0.946), 0.934 (interquartile range: 0.899 to 0.950), 0.915 (interquartile range: 0.890 to 0.920), and 0.920 (interquartile range: 0.811 to 0.944), respectively. Model prediction correlated and agreed well with manual annotation for LVV (r = 0.98), RVV (r = 0.97), LAV (r = 0.78), RAV (r = 0.97), and LVM (r = 0.94) (p Conclusions A deep-learning model rapidly segmented and quantified cardiac structures. This was done with high accuracy on a pixel level, with good agreement with manual annotation, facilitating its expansion into areas of research and clinical import.

Objectives This study compared the safety and diagnostic yield of a selective referral strategy using coronary computed tomographic angiography (CCTA) compared with a direct referral strategy using invasive coronary angiography (ICA) as the index procedure. Background Among patients presenting with signs and symptoms suggestive of coronary artery disease (CAD), a sizeable proportion who are referred to ICA do not have a significant, obstructive stenosis. Methods In a multinational, randomized clinical trial of patients referred to ICA for nonemergent indications, a selective referral strategy was compared with a direct referral strategy. The primary endpoint was noninferiority with a multiplicative margin of 1.33 of composite major adverse cardiovascular events (blindly adjudicated death, myocardial infarction, unstable angina, stroke, urgent and/or emergent coronary revascularization or cardiac hospitalization) at a median follow-up of 1-year. Results At 22 sites, 823 subjects were randomized to a selective referral and 808 to a direct referral strategy. At 1 year, selective referral met the noninferiority margin of 1.33 (p = 0.026) with a similar event rate between the randomized arms of the trial (4.6% vs. 4.6%; hazard ratio: 0.99; 95% confidence interval: 0.66 to 1.47). Following CCTA, only 23% of the selective referral arm went on to ICA, which was a rate lower than that of the direct referral strategy. Coronary revascularization occurred less often in the selective referral group compared with the direct referral to ICA (13% vs. 18%; p Conclusions In stable patients with suspected CAD who are eligible for ICA, the comparable 1-year major adverse cardiovascular events rates following a selective referral and direct referral strategy suggests that both diagnostic approaches are similarly effective. In the selective referral strategy, the reduced use of ICA was associated with a greater diagnostic yield, which supported the usefulness of CCTA as an efficient and accurate method to guide decisions of ICA performance. (Coronary Computed Tomographic Angiography for Selective Cardiac Catheterization [CONSERVE]; NCT01810198)

Objectives This study sought to compare the performance of history-based risk scores in predicting obstructive coronary artery disease (CAD) among patients with stable chest pain from the SCOT-HEART study. Background Risk scores for estimating pre-test probability of CAD are derived from referral-based populations with a high prevalence of disease. The generalizability of these scores to lower prevalence populations in the initial patient encounter for chest pain is uncertain. Methods We compared 3 scores among patients with suspected CAD in the coronary computed tomographic angiography (CTA) randomized arm of the SCOT-HEART study for the outcome of obstructive CAD by coronary CTA: the updated Diamond-Forrester score (UDF), CAD Consortium clinical score (CAD2), and CONFIRM risk score (CRS). We tested calibration with goodness-of-fit, discrimination with area under the receiver-operating curve (AUC), and reclassification with net reclassification improvement (NRI) to identify low-risk patients. Results In 1,738 patients (age 58 ± 10 years and 44.0% women), overall calibration was best for UDF, with underestimation by CRS and CAD2. Discrimination by AUC was highest for CAD2 at 0.79 (95% confidence interval [CI]: 0.77 to 0.81) than for UDF (0.77 [95% CI: 0.74 to 0.79]) or CRS (0.75 [95% CI: 0.73 to 0.77]) (p Conclusions In this multicenter clinic-based cohort of patients with suspected CAD and uniform CAD evaluation by coronary CTA, CAD2 provided the best discrimination and classification, despite overestimation of obstructive CAD as evaluated by coronary CTA. CRS exhibited intermediate performance followed by UDF for discrimination and reclassification.

OBJECTIVES:This study sought to describe the impact of statins on individual coronary atherosclerotic plaques. BACKGROUND:Although statins reduce the risk of major adverse cardiovascular events, their long-term effects on coronary atherosclerosis remain unclear. METHODS:We performed a prospective, multinational study consisting of a registry of consecutive patients without history of coronary artery disease who underwent serial coronary computed tomography angiography at an interscan interval of ≥2 years. Atherosclerotic plaques were quantitatively analyzed for percent diameter stenosis (%DS), percent atheroma volume (PAV), plaque composition, and presence of high-risk plaque (HRP), defined by the presence of ≥2 features of low-attenuation plaque, positive arterial remodeling, or spotty calcifications. RESULTS:Among 1,255 patients (60 ± 9 years of age; 57% men), 1,079 coronary artery lesions were evaluated in statin-naive patients (n = 474), and 2,496 coronary artery lesions were evaluated in statin-taking patients (n = 781). Compared with lesions in statin-naive patients, those in statin-taking patients displayed a slower rate of overall PAV progression (1.76 ± 2.40% per year vs. 2.04 ± 2.37% per year, respectively; p = 0.002) but more rapid progression of calcified PAV (1.27 ± 1.54% per year vs. 0.98 ± 1.27% per year, respectively; p 50% DS were not different (1.0% vs. 1.4%, respectively; p > 0.05). Statins were associated with a 21% reduction in annualized total PAV progression above the median and 35% reduction in HRP development. CONCLUSIONS:Statins were associated with slower progression of overall coronary atherosclerosis volume, with increased plaque calcification and reduction of high-risk plaque features. Statins did not affect the progression of percentage of stenosis severity of coronary artery lesions but induced phenotypic plaque transformation. (Progression of AtheRosclerotic PlAque DetermIned by Computed TomoGraphic Angiography Imaging [PARADIGM]; NCT02803411).

Objectives The purpose of this study was to develop and validate a simple-to-use nomogram for prediction of 5-, 10-, and 15-year survival among asymptomatic adults. Background Simple-to-use prognostication tools that incorporate robust methods such as coronary artery calcium scoring (CACS) for predicting near-, intermediate- and long-term mortality are warranted. Methods In a consecutive series of 9,715 persons (mean age: 53.4 ± 10.5 years; 59.3% male) undergoing CACS, we developed a nomogram using Cox proportional hazards regression modeling that included: age, sex, smoking, hypertension, dyslipidemia, diabetes, family history of coronary artery disease, and CACS. We developed a prognostic index (PI) summing the number of risk points corresponding to weighted covariates, which was used to configure the nomogram. Validation of the nomogram was assessed by discrimination and calibration applied to a separate cohort of 7,824 adults who also underwent CACS. Results A total of 936 and 294 deaths occurred in the derivation and validation sets at a median follow-up of 14.6 years (interquartile range: 13.7 to 15.5 years) and 9.4 years (interquartile range: 6.8 to 11.5 years), respectively. The developed model effectively predicted 5-, 10-, and 15-year probability of survival. The PI displayed high discrimination in the derivation and validation sets (C-index 0.74 and 0.76, respectively), indicating suitable external performance of our nomogram model. The predicted and actual estimates of survival in each dataset according to PI quartiles were similar (though not identical), demonstrating improved model calibration. Conclusions A simple-to-use nomogram effectively predicts 5-, 10- and 15-year survival for asymptomatic adults undergoing screening for cardiac risk factors. This nomogram may be considered for use in clinical care.

Objectives This study sought to assess clinical outcomes associated with the novel Coronary Artery Disease–Reporting and Data System (CAD-RADS) scores used to standardize coronary computed tomography angiography (CTA) reporting and their potential utility in guiding post-coronary CTA care. Background Clinical decision support is a major focus of health care policies aimed at improving guideline-directed care. Recently, CAD-RADS was developed to standardize coronary CTA reporting and includes clinical recommendations to facilitate patient management after coronary CTA. Methods In the multinational CONFIRM (COronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multicenter) registry, 5,039 patients without known coronary artery disease (CAD) underwent coronary CTA and were stratified by CAD-RADS scores, which rank CAD stenosis severity as 0 (0%), 1 (1% to 24%), 2 (25% to 49%), 3 (50% to 69%), 4A (70% to 99% in 1 to 2 vessels), 4B (70% to 99% in 3 vessels or ≥50% left main), or 5 (100%). Kaplan-Meier and multivariable Cox models were used to estimate all-cause mortality or myocardial infarction (MI). Receiver-operating characteristic (ROC) curves were used to compare CAD-RADS to the Duke CAD Index and traditional CAD classification. Referrals to invasive coronary angiography (ICA) after coronary CTA were also assessed. Results Cumulative 5-year event-free survival ranged from 95.2% to 69.3% for CAD-RADS 0 to 5 (p Conclusions CAD-RADS effectively identified patients at risk for adverse events. Frequent ICA use was observed among patients without severe CAD, many of whom were asymptomatic or not taking antianginal drugs. Incorporating CAD-RADS into coronary CTA reports may provide a novel opportunity to promote evidence-based care post-coronary CTA.

Objectives The purpose of this study was to examine sex-specific associations, if any, between per-vessel coronary artery disease (CAD) extent and the risk of major adverse cardiovascular events (MACE) over a 5-year study duration. Background The presence and extent of CAD diagnosed by coronary computed tomography angiography (CTA) is associated with increased short-term mortality and MACE. Nevertheless, some uncertainty remains regarding the influence of sex on these findings. Methods 5,632 patients (mean age 60.2 ± 11.8 years, 36.5% women) from the CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter) registry were followed for 5 years. Obstructive CAD was defined as ≥50% luminal stenosis in a coronary vessel. Using Cox proportional hazards models, we calculated the hazard ratio (HR) for incident MACE among women and men, defined as death or myocardial infarction. Results Obstructive CAD was more prevalent in men (42% vs. 26%; p Conclusions In a large prospective coronary CTA cohort followed long-term, we did not observe an interaction of sex for the association between MACE risk and increased per-vessel extent of obstructive CAD. These findings highlight the persistent prognostic significance of anatomic CAD subsets as detected by coronary CTA for the risk of MACE in both women and men.

Objectives The aim of this study was to examine the long-term prognosis in asymptomatic individuals with a coronary artery calcium (CAC) score of 0 and its associated warranty period. Background Emerging evidence supports a CAC score of 0 as a favorable cardiovascular short-to intermediate-term prognostic factor. Methods A total of 9,715 individuals undergoing CAC imaging were stratified by age, Framingham risk score (FRS), and National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) categories and followed for a mean of 14.6 years (range 12.9 to 16.8 years). Cox regression, area under the receiver-operating characteristic curve, and net reclassification information were used to assess all-cause mortality, discrimination, and reclassification of a CAC score of 0 compared with the FRS and NCEP ATP III, respectively. A warranty period was pre-defined as Results In 4,864 individuals with a baseline CAC score of 0 (mean age, 52.1 ± 10.8 years; 57.9% male), 229 deaths occurred. The warranty period of a CAC score of 0 was almost 15 years for individuals at low and intermediate risk with no significant differences regarding age and sex. A CAC score of 0 was associated with a vascular age of 1, 10, 20, and 30 years less than the chronological age of individuals between 50 and 59, 60 and 69, 70 and 79, and 80 years of age and older, respectively. The CAC score was the strongest predictor of death (hazard ratio: 2.67, 95% confidence interval: 2.29 to 3.11) that enabled discrimination and consistent reclassification beyond the FRS (area under the receiver-operating characteristic curve: 0.71 vs. 0.64, p Conclusions A CAC score of 0 confers a 15-year warranty period against mortality in individuals at low to intermediate risk that is unaffected by age or sex. Furthermore, in individuals considered at high risk by clinical risk scores, a CAC score of 0 confers better survival than in individuals at low to intermediate risk but with any CAC score.

OBJECTIVES: This study sought to develop a clinical model that identifies patients with and without high-risk coronary artery disease (CAD). BACKGROUND: Although current clinical models help to estimate a patient's pre-test probability of obstructive CAD, they do not accurately identify those patients with and without high-risk coronary anatomy. METHODS: Retrospective analysis of a prospectively collected multinational coronary computed tomographic angiography (CTA) cohort was conducted. High-risk anatomy was defined as left main diameter stenosis >= 50%, 3-vessel disease with diameter stenosis >= 70%, or 2-vessel disease involving the proximal left anterior descending artery. Using a cohort of 27,125, patients with a history of CAD, cardiac transplantation, and congenital heart disease were excluded. The model was derived from 24,251 consecutive patients in the derivation cohort and an additional 7,333 nonoverlapping patients in the validation cohort. RESULTS: The risk score consisted of 9 variables: age, sex, diabetes, hypertension, current smoking, hyperlipidemia, family history of CAD, history of peripheral vascular disease, and chest pain symptoms. Patients were divided into 3 risk categories: low (= 18 points). The model was statistically robust with area under the curve of 0.76 (95% confidence interval [CI]: 0.75 to 0.78) in the derivation cohort and 0.71 (95% CI: 0.69 to 0.74) in the validation cohort. Patients who scored = 18 points had a high specificity of 99.3% and a positive likelihood ratio (8.48). In the validation group, the prevalence of high-risk CAD was 1% in patients with = 18 points. CONCLUSIONS: We propose a scoring system, based on clinical variables, that can be used to identify patients at high and low pre-test probability of having high-risk CAD. Identification of these populations may detect those who may benefit from a trial of medical therapy and those who may benefit most from an invasive strategy. (C) 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Objectives This study assessed the diagnostic performance of coronary computed tomography angiography (CTA) for the detection and exclusion of significant coronary artery stenosis as remotely interpreted on a mobile handheld device with dedicated medical imaging software. Background Recent advances in technology now permit remote interpretation of medical imaging studies on mobile handheld devices, although the diagnostic performance of this approach is unknown. Methods We evaluated 102 patients with stable chest pain and both 64-detector row coronary CTA and quantitative invasive coronary angiography. The diagnostic performance of remote coronary CTA interpretation was assessed using a mobile handheld device and employing dedicated software. The coronary CTA studies were examined in an intent-to-diagnose manner for the presence or absence of coronary artery stenosis ≥50% on a per-artery and per-patient level; results were compared with quantitative invasive coronary angiography. Two blinded imagers independently interpreted coronary CTA studies, with a third imager achieving consensus for discordance. Coronary CTAs were re-interpreted in random order to determine interobserver agreement. Finally, coronary CTAs were evaluated on a dedicated 3-dimensional imaging workstation; results were compared to mobile handheld device findings for intertechnology agreement. Results The prevalence of significant coronary artery stenosis was 25% (26 of 102) at the per-patient level and 10% (40 of 405) at the per-artery level. Per-patient and per-artery sensitivity, specificity, and positive and negative predictive values were: 100% (26 of 26), 78% (59 of 76), 60% (26 of 43), and 100% (59 of 59), respectively; and 95% (38 of 40), 85% (310 of 365), 41% (38 of 93), and 99% (310 of 312), respectively. At the per-artery level, interobserver, intraobserver, and intertechnology agreement was 0.74, 0.89, and 0.75, respectively (p Conclusions The interpretation of coronary CTA using a mobile handheld device with dedicated software for medical image evaluation possesses high diagnostic accuracy for detection and exclusion of significant coronary stenosis.

Objectives We derived mean values for cardiac dimensions, volumes, function, and mass in a normotensive nonobese population free of cardiovascular disease. Background Multidetector computed tomography (MDCT) permits study of cardiac chamber size, function, and mass. Age- and gender-specific mean values are not available. Methods A total of 103 normotensive, nonobese adults (43% women, age 51 ± 14 years) who presented consecutively to 2 medical centers for clinically indicated MDCTs with neither history of nor MDCT evidence of significant cardiovascular disease were studied for left ventricular (LV) and right ventricular (RV) end-systolic (ES) and end-diastolic (ED) linear dimensions and volumes; LV and RV ejection fraction (EF), and LV mass (LVM); and left atrial (LA) and right atrial (RA) end-systolic volumes (LAESV and RAESV, respectively) by 1-dimensional (1D), 2-dimensional (2D), and 3-dimensional (3D) measurements. Results The LV volumes using 3D techniques were lower than 2D techniques (LVEDV mean 144 ± 71 ml vs. 150 ± 70 ml), with higher LVEF (63 ± 15% vs. 57 ± 13%) (p 2.7 was 24.3 ± 11.0 g/m 2.7 and mean relative wall thickness was 0.16 to 0.44. Evaluation by 20 versus 10 cardiac phases resulted in higher LVEF (mean difference: 3.4 ± 9.0%, p 2 = 0.97, p Conclusions This study establishes age- and gender-specific values for LV, RV, LA, and RA size, function, and mass in adults free of cardiovascular disease, hypertension, and obesity using 1D, 2D, and 3D methods. These data can be used as a reference for future MDCT studies.