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Machine learning (ML) models of risk prediction with coronary artery calcium (CAC) and CAC characteristics exhibit high performance, but are not inherently interpretable.To determine the direction and magnitude of impact of CAC characteristics on 10-year all-cause mortality (ACM) with explainable ML.We analyzed asymptomatic subjects in the CAC consortium. We trained ML models on 80% and tested on 20% of the data with XGBoost, using clinical characteristics ​+ ​CAC (ML 1) and additional CAC characteristics of CAC density and number of calcified vessels (ML 2). We applied SHAP, an explainable ML tool, to explore the relationship of CAC and CAC characteristics with 10-year all-cause and CV mortality.2376 deaths occurred among 63,215 patients [68% male, median age 54 (IQR 47-61), CAC 3 (IQR 0-94.3)]. ML2 was similar to ML1 to predict all-cause mortality (Area Under the Curve (AUC) 0.819 vs 0.821, p ​= ​0.23), but superior for CV mortality (0.847 vs 0.845, p ​= ​0.03). Low CAC density increased mortality impact, particularly ≤0.75. Very low CAC density ≤0.75 was present in only 4.3% of the patients with measurable density, and 75% occurred in CAC1-100. The number of diseased vessels did not increase mortality overall when simultaneously accounting for CAC and CAC density.CAC density contributes to mortality risk primarily when it is very low ≤0.75, which is primarily observed in CAC 1-100. CAC and CAC density are more important for mortality prediction than the number of diseased vessels, and improve prediction of CV but not all-cause mortality. Explainable ML techniques are useful to describe granular relationships in otherwise opaque prediction models.

Although acute coronary syndrome culprit lesions occur more frequently in the proximal coronary artery, whether the proximal clustering of high-risk plaque is reflected in earlier-stage atherosclerosis remains unclarified. We evaluated the longitudinal distribution of stable atherosclerotic lesions on coronary computed tomography angiography (CCTA) in 1,478 patients (mean age, 61 years; men, 58%) enrolled from a prospective multinational registry of consecutive patients undergoing serial CCTA. Of 3,202 coronary artery lesions identified, 2,140 left lesions were classified (based on the minimal lumen diameter location) into left main (LM, n = 128), proximal (n = 739), and other (n = 1,273), and 1,062 right lesions were classified into proximal (n = 355) and other (n = 707). Plaque volume (PV) was the highest in proximal lesions (median, 26.1 mm3), followed by LM (20.6 mm3) and other lesions (15.0 mm3, p

BACKGROUND Among symptomatic patients, it remains unclear whether a coronary artery calcium (CAC) score alone is sufficient or misses a sizeable burden and progressive risk associated with obstructive and nonobstructive atherosclerotic plaque.OBJECTIVES Among patients with low to high CAC scores, our aims were to quantify co-occurring obstructive and nonobstructive noncalcified plaque and serial progression of atherosclerotic plaque volume.METHODS A total of 698 symptomatic patients with suspected coronary artery disease (CAD) underwent serial coronary computed tomographic angiography (CTA) performed 3.5 to 4.0 years apart. Atherosclerotic plaque was quantified, including by compositional subgroups. Obstructive CAD was defined as >= 50% stenosis. Multivariate linear regression models were used to measure atherosclerotic plaque progression by CAC scores. Cox proportional hazard models estimated CAD event risk (median of 10.7 years of follow-up).RESULTS Across baseline CAC scores from 0 to >= 400, total plaque volume ranged from 30.4 to 522.4 mm(3) (P < 0.001) and the prevalence of obstructive CAD increased from 1.4% to 49.1% (P < 0.001). Of those with a 0 CAC score, 97.9% of total plaque was noncalcified. Among patients with baseline CAC = 100. Progression varied compositionally by baseline CAC scores. Patients with no CAC had disproportionate growth in noncalcified plaque, and for every 1 mm(3) increase in calcified plaque, there was a 5.5 mm(3) increase in noncalcified plaque volume. By comparison, patients with CAC scores of >= 400 exhibited disproportionate growth in calcified plaque with a volumetric increase 15.7-fold that of noncalcified plaque. There was a graded increase in CAD event risk by the CAC with rates from 3.3% for no CAC to 21.9% for CAC >= 400 (P < 0.001).CONCLUSIONS CAC imperfectly characterizes atherosclerotic disease burden, but its subgroups exhibit pathogenic patterns of early to advanced disease progression and stratify long-term prognostic risk. (C) 2022 by the American College of Cardiology Foundation.

Atrial fibrillation (AF) remains the most common arrhythmia in clinical practice. The choice between a rate-control and rhythm-control strategy depends on various factors, including the anatomical and functional substrate. This study investigates the anatomical and functional characteristics of both atria in patients with AF and explores the potential therapeutic implications. From an ongoing registry of patients with paroxysmal or permanent AF, those who underwent cardiac computed tomography (CCT) were included. Left atrial (LA) and right atrial (RA) sizes were measured on CCT, whereas bi-atrial function was quantified with speckle tracking strain echocardiography. The mean LA volume index was 41.6 ± 5.6 ml/m

Aims The relationship between dyspnoea, coronary artery disease (CAD), and major cardiovascular events (MACE) is poorly understood. This study evaluated (i) the association of dyspnoea with the severity of anatomical CAD by coronary computed tomography angiography (CCTA) and (ii) to which extent CAD explains MACE in patients with dyspnoea. Methods and results From the international COronary CT Angiography EvaluatioN for Clinical Outcomes: An InteRnational Multicenter (CONFIRM) registry, 4425 patients (750 with dyspnoea) with suspected but without known CAD were included and prospectively followed for ≥5 years. First, the association of dyspnoea with CAD severity was assessed using logistic regression analysis. Second, the prognostic value of dyspnoea for MACE (myocardial infarction and death), and specifically, the interaction between dyspnoea and CAD severity was investigated using Cox proportional-hazard analysis. Mean patient age was 60.3 ± 11.9 years, 63% of patients were male and 592 MACE events occurred during a median follow-up duration of 5.4 (IQR 5.1–6.0) years. On uni- and multivariable analysis (adjusting for age, sex, body mass index, chest pain typicality, and risk factors), dyspnoea was associated with two- and three-vessel/left main (LM) obstructive CAD. The presence of dyspnoea increased the risk for MACE [hazard ratio (HR) 1.57, 95% confidence interval (CI): 1.29–1.90], which was modified after adjusting for clinical predictors and CAD severity (HR 1.26, 95% CI: 1.02–1.55). Conversely, when stratified by CAD severity, dyspnoea did not provide incremental prognostic value in one-, two-, or three-vessel/LM obstructive CAD, but dyspnoea did provide incremental prognostic value in non-obstructive CAD. Conclusion In patients with suspected CAD, dyspnoea was independently associated with severe obstructive CAD on CCTA. The severity of obstructive CAD explained the elevated MACE rates in patients presenting with dyspnoea, but in patients with non-obstructive CAD, dyspnoea portended additional risk.

Question Is statin therapy associated with atherosclerotic plaque progression as assessed across a range of density measurements by coronary computed tomography angiography? Findings In this cohort study assessing serial coronary computed tomography angiographic images of 2458 coronary lesions among 857 patients, untreated coronary lesions progressed in volume for all 6 compositional plaque types-low attenuation (-30 to 75 Hounsfield units [HU]), fibro-fatty (76-130 HU), fibrous (131-350 HU), low-density calcium (351-700 HU), high-density calcium (701-1000 HU), and 1K (>1000 HU) plaque-whereas statin therapy was associated with decreases in low-attenuation and fibro-fatty plaque and with greater progression of high-density calcium and 1K plaque. Statin therapy was not associated with a change in calcified plaque but with a transformation toward more dense calcium, which was associated with slower overall plaque progression. Meaning These results suggest an association of statin use with greater rates of transformation of coronary atherosclerosis toward high-density calcium, supporting the concept of reduced atherosclerotic risk with increased densification of calcium.This cohort study uses coronary computed tomography angiography to investigate whether statin therapy is associated with alterations in the volume or calcium density of 6 compositional atherosclerotic plaque types in patients with coronary artery disease.Importance The density of atherosclerotic plaque forms the basis for categorizing calcified and noncalcified morphology of plaques. Objective To assess whether alterations in plaque across a range of density measurements provide a more detailed understanding of atherosclerotic disease progression. Design, Setting, and Participants This cohort study enrolled 857 patients who underwent serial coronary computed tomography angiography 2 or more years apart and had quantitative measurements of coronary plaques throughout the entire coronary artery tree. The study was conducted from 2013 to 2016 at 13 sites in 7 countries. Main Outcomes and Measures The main outcome was progression of plaque composition of individual coronary plaques. Six plaque composition types were defined on a voxel-level basis according to the plaque attenuation (expressed in Hounsfield units [HU]): low attenuation (-30 to 75 HU), fibro-fatty (76-130 HU), fibrous (131-350 HU), low-density calcium (351-700 HU), high-density calcium (701-1000 HU), and 1K (>1000 HU). The progression rates of these 6 compositional plaque types were evaluated according to the interaction between statin use and baseline plaque volume, adjusted for risk factors and time interval between scans. Plaque progression was also examined based on baseline calcium density. Analysis was performed among lesions matched at baseline and follow-up. Data analyses were conducted from August 2019 through March 2020. Results In total, 2458 coronary lesions in 857 patients (mean [SD] age, 62.1 [8.7] years; 540 [63.0%] men; 548 [63.9%] received statin therapy) were included. Untreated coronary lesions increased in volume over time for all 6 compositional types. Statin therapy was associated with volume decreases in low-attenuation plaque (beta, -0.02; 95% CI, -0.03 to -0.01; P = .001) and fibro-fatty plaque (beta, -0.03; 95% CI, -0.04 to -0.02; P < .001) and greater progression of high-density calcium plaque (beta, 0.02; 95% CI, 0.01-0.03; P < .001) and 1K plaque (beta, 0.02; 95% CI, 0.01-0.03; P < .001). When analyses were restricted to lesions without low-attenuation plaque or fibro-fatty plaque at baseline, statin therapy was not associated with a change in overall calcified plaque volume (beta, -0.03; 95% CI, -0.08 to 0.02; P = .24) but was associated with a transformation toward more dense calcium. Interaction analysis between baseline plaque volume and calcium density showed that more dense coronary calcium was associated with less plaque progression. Conclusions and Relevance The results suggest an association of statin use with greater rates of transformation of coronary atherosclerosis toward high-density calcium. A pattern of slower overall plaque progression was observed with increasing density. All findings support the concept of reduced atherosclerotic risk with increased densification of calcium.

Aims The relationship between AtheroSclerotic CardioVascular Disease (ASCVD) risk and vessel-specific plaque evaluation using coronary computed tomography angiography (CCTA), focusing on plaque extent and composition, has not been examined. To evaluate differences in quantified plaque characteristics (using CCTA) between the three major coronary arteries [left anterior descending (LAD), right coronary (RCA), and left circumflex (LCx)] among subgroups of patients with varying ASCVD risk. Methods and results Patients were included from a prospective, international registry of consecutive patients who underwent CCTA for evaluation of coronary artery disease. ASCVD risk groups were Conclusion Among patients with varying risk of ASCVD, plaque in the LCx is decidedly less and is comprised of less non-calcified plaque supporting prior evidence of the lower rates of acute coronary events in this vessel.

Aims Anatomic series commonly report the extent and severity of coronary artery disease (CAD), regardless of location. The aim of this study was to evaluate differences in atherosclerotic plaque burden and composition across the major epicardial coronary arteries. Methods and results A total of 1271 patients (age 60 ± 9 years; 57% men) with suspected CAD prospectively underwent coronary computed tomography angiography (CCTA). Atherosclerotic plaque volume was quantified with categorization by composition (necrotic core, fibrofatty, fibrous, and calcified) based on Hounsfield Unit density. Per-vessel measures were compared using generalized estimating equation models. On CCTA, total plaque volume was lowest in the LCx (10.0 ± 29.4 mm3), followed by the RCA (32.8 ± 82.7 mm3; P Conclusion Atherosclerotic plaque, irrespective of vessel volume, varied across the epicardial coronary arteries; with a significantly lower burden and different compositions in the LCx when compared with the LAD and RCA. These volumetric and compositional findings support a diverse milieu for atherosclerotic plaque development and may contribute to a varied acute coronary risk between the major epicardial coronary arteries.

Aims In patients without obstructive coronary artery disease (CAD), we examined the prognostic value of risk factors and atherosclerotic extent. Methods and results Patients from the long-term CONFIRM registry without prior CAD and without obstructive (≥50%) stenosis were included. Within the groups of normal coronary computed tomography angiography (CCTA) (N = 1849) and non-obstructive CAD (N = 1698), the prognostic value of traditional clinical risk factors and atherosclerotic extent (segment involvement score, SIS) was assessed with Cox models. Major adverse cardiac events (MACE) were defined as all-cause mortality, non-fatal myocardial infarction, or late revascularization. In total, 3547 patients were included (age 57.9 ± 12.1 years, 57.8% male), experiencing 460 MACE during 5.4 years of follow-up. Age, body mass index, hypertension, and diabetes were the clinical variables associated with increased MACE risk, but the magnitude of risk was higher for CCTA defined atherosclerotic extent; adjusted hazard ratio (HR) for SIS >5 was 3.4 (95% confidence interval [CI] 2.3–4.9) while HR for diabetes and hypertension were 1.7 (95% CI 1.3–2.2) and 1.4 (95% CI 1.1–1.7), respectively. Exclusion of revascularization as endpoint did not modify the results. In normal CCTA, presence of ≥1 traditional risk factors did not worsen prognosis (log-rank P = 0.248), while it did in non-obstructive CAD (log-rank P = 0.025). Adjusted for SIS, hypertension and diabetes predicted MACE risk in non-obstructive CAD, while diabetes did not increase risk in absence of CAD (P-interaction = 0.004). Conclusion Among patients without obstructive CAD, the extent of CAD provides more prognostic information for MACE than traditional cardiovascular risk factors. An interaction was observed between risk factors and CAD burden, suggesting synergistic effects of both.

The purpose of this review is to summarize the work published by the Journal of Cardiovascular Computed Tomography (JCCT) for the year 2019, highlighting original research and new guidelines.

Cardiac computed tomography (CT) is an excellent technique to detect and quantify coronary atherosclerosis including coronary calcification. A coronary artery calcium score (CACS) can be derived from a simple noncontrast chest CT and has shown great value to guide clinical management. Several studies have shown the excellent long-term survival free from major cardiac events for patients without calcium, and increasing burden of calcium relates to a proportional increase in risk. This chapter will summarize the recent literature how CACS can help in managing mainly asymptomatic individuals at risk for heart attacks. Second, coronary computed tomography angiography has emerged as valuable test of choice to evaluate patients with chest pain. It helps to reassure patients in the absence of coronary artery disease and visualizes coronary stenosis that may benefit from revascularization. In addition, this chapter will highlight how detailed coronary plaque quantification, characterization, and identification of high-risk coronary plaque features improve diagnosis of ischemic vessels and score risk for future events.