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Background: The association of atherosclerotic features with first acute coronary syndromes (ACS) has not accounted for plaque burden., Objectives: The purpose of this study was to identify atherosclerotic features associated with precursors of ACS., Methods: We performed a nested case-control study within a cohort of 25,251 patients undergoing coronary computed tomographic angiography (CTA) with follow-up over 3.4 ± 2.1 years. Patients with ACS and nonevent patients with no prior coronary artery disease (CAD) were propensity matched 1:1 for risk factors and coronary CTA-evaluated obstructive (≥50%) CAD. Separate core laboratories performed blinded adjudication of ACS and culprit lesions and quantification of baseline coronary CTA for percent diameter stenosis (%DS), percent cross-sectional plaque burden (PB), plaque volumes (PVs) by composition (calcified, fibrous, fibrofatty, and necrotic core), and presence of high-risk plaques (HRPs)., Results: We identified 234 ACS and control pairs (age 62 years, 63% male). More than 65% of patients with ACS had nonobstructive CAD at baseline, and 52% had HRP. The %DS, cross-sectional PB, fibrofatty and necrotic core volume, and HRP increased the adjusted hazard ratio (HR) of ACS (1.010 per %DS, 95% confidence interval [CI]: 1.005 to 1.015; 1.008 per percent cross-sectional PB, 95% CI: 1.003 to 1.013; 1.002 per mm 3 fibrofatty plaque, 95% CI: 1.000 to 1.003; 1.593 per mm 3 necrotic core, 95% CI: 1.219 to 2.082; all p < 0.05). Of the 129 culprit lesion precursors identified by coronary CTA, three-fourths exhibited <50% stenosis and 31.0% exhibited HRP., Conclusions: Although ACS increases with %DS, most precursors of ACS cases and culprit lesions are nonobstructive. Plaque evaluation, including HRP, PB, and plaque composition, identifies high-risk patients above and beyond stenosis severity and aggregate plaque burden., (Published by Elsevier Inc.)

The current paper details the recommendations arising from an NIH-NHLBI/NCI-sponsored symposium held in November 2012, aiming to identify key components of a radiation accountability framework fostering patient-centered imaging and shared decision-making in cardiac imaging. Symposium participants, working in 3 tracks, identified key components of a framework to target critical radiation safety issues for the patient, the laboratory, and the larger population of patients with known or suspected cardiovascular disease. The use of ionizing radiation during an imaging procedure should be disclosed to all patients by the ordering provider at the time of ordering, and reinforced by the performing provider team. An imaging protocol with effective dose ≤3 mSv is considered very low risk, not warranting extensive discussion or written informed consent. However, a protocol effective dose >20 mSv was proposed as a level requiring particular attention in terms of shared decision-making and either formal discussion or written informed consent. Laboratory reporting of radiation dosimetry is a critical component of creating a quality laboratory fostering a patient-centered environment with transparent procedural methodology. Efforts should be directed to avoiding testing involving radiation, in patients with inappropriate indications. Standardized reporting and diagnostic reference levels for computed tomography and nuclear cardiology are important for the goal of public reporting of laboratory radiation dose levels in conjunction with diagnostic performance. The development of cardiac imaging technologies revolutionized cardiology practice by allowing routine, noninvasive assessment of myocardial perfusion and anatomy. It is now incumbent upon the imaging community to create an accountability framework to safely drive appropriate imaging utilization., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study was designed to assess the effects on resource utilization of routine coronary computed tomographic angiography (CCTA) in triaging chest pain patients in the emergency department (ED)., Background: The routine use of CCTA for ED evaluation of chest pain is feasible and safe., Methods: We conducted a retrospective multivariate analysis of data from two risk-matched cohorts of 894 ED patients presenting with chest pain to assess the impact of CCTA versus standard evaluation on admissions rate, length of stay, major adverse cardiovascular event rates, recidivism rates, and downstream resource utilization., Results: The overall admission rate was lower with CCTA (14% vs. 40%; p < 0.001). Standard evaluation was associated with a 5.5-fold greater risk for admission (odds ratio [OR]: 5.53; p < 0.001). Expected ED length of stay with standard evaluation was about 1.6 times longer (OR: 1.55; p < 0.001). There were no differences in the rates of death and acute myocardial infarction within 30 days of the index visit between the two groups. The likelihood of returning to the ED within 30 days for recurrent chest pain was 5 times greater with standard evaluation (OR: 5.06; p = 0.022). Standard evaluation was associated with a 7-fold greater likelihood of invasive coronary angiography without revascularization (OR: 7.17; p < 0.001), while neither group was significantly more likely to receive revascularization (OR: 2.06; p = 0.193). The median radiation dose with CCTA was 5.88 mSv (n = 1039; confidence interval: 5.2 to 6.4)., Conclusions: The routine use of CCTA in ED evaluation of chest pain reduces healthcare resource utilization., (Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to examine patterns of follow-up invasive coronary angiography (ICA) and revascularization (REV) after coronary computed tomography angiography (CCTA)., Background: CCTA is a noninvasive test that permits direct visualization of the extent and severity of coronary artery disease (CAD). Post-CCTA patterns of follow-up ICA and REV are incompletely defined., Methods: We examined 15,207 intermediate likelihood patients from 8 sites in 6 countries; these patients were without known CAD, underwent CCTA, and were followed up for 2.3 ± 1.2 years for all-cause mortality. Coronary artery stenosis was judged as obstructive when ≥50% stenosis was present. A multivariable logistic regression was used to estimate ICA use. A Cox proportional hazards model was used to estimate all-cause mortality., Results: During follow-up, ICA rates for patients with no CAD to mild CAD according to CCTA were low (2.5% and 8.3%), with similarly low rates of REV (0.3% and 2.5%). Most ICA procedures (79%) occurred ≤3 months of CCTA. Obstructive CAD was associated with higher rates of ICA and REV for 1-vessel (44.3% and 28.0%), 2-vessel (53.3% and 43.6%), and 3-vessel (69.4% and 66.8%) CAD, respectively. For patients with <50% stenosis, early ICA rates were elevated; over the entirety of follow-up, predictors of ICA were mild left main, mild proximal CAD, respectively, or higher coronary calcium scores. In patients with <50% stenosis, the relative hazard for death was 2.2 (p = 0.011) for ICA versus no ICA. Conversely, for patients with CAD, the relative hazard for death was 0.61 for ICA versus no ICA (p = 0.047)., Conclusions: These findings support the concept that CCTA may be used effectively as a gatekeeper to ICA., (Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study was conducted to evaluate the correlation between stress test results and coronary computed tomography angiography (CCTA) findings and comparative diagnostic performance of the 2 modalities in patients undergoing invasive coronary angiography (ICA)., Background: Recent data suggest that only a third of patients undergoing ICA have obstructive coronary artery disease (CAD); accurate pre-ICA risk stratification is needed., Methods: At 47 centers participating in the ACIC (Advanced Cardiovascular Imaging Consortium) in Michigan, patients without known CAD who were undergoing CCTA within 3 months of a stress test were studied. Demographics, risk factors, symptoms, and stress test results were correlated with obstructive CAD (>50% stenosis) on CCTA and ICA., Results: Among 6,198 patients (age 56 ± 12 years, 48% men), >50% stenosis was seen in 1,158 (18.7%) on CCTA. Independent predictors included male sex (odds ratio [OR]: 2.37, 95% confidence interval [CI]: 1.83 to 3.06), current smoking (OR: 2.23, 95% CI: 1.57 to 3.17), older age (OR per 10-year increment: 2.14, 95% CI: 1.89 to 2.41), hypertension (OR: 1.8, 95% CI: 1.37 to 2.34), and typical angina (OR: 1.48, 95% CI: 1.03 to 2.12). Stress test results were not predictive. Among patients undergoing ICA (n = 621), there was a strong correlation of ICA with CCTA findings (OR: 9.09, 95% CI: 5.57 to 14.8, p < 0.001), but not stress results (OR: 0.79, 95% CI: 0.56 to 1.11, p = 0.17)., Conclusions: Stress test findings did not predict obstructive CAD on CCTA, observed in <20% of patients in this large study group. The strong association of CCTA with ICA suggests that it may serve as an effective "gatekeeper" to invasive testing in patients needing adjudication of stress test results. (Advanced Cardiovascular Imaging Consortium: A Collaborative Quality Improvement Project [ACIC]; NCT00640068)., (Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The purpose of this study was to describe the prevalence and severity of coronary artery disease (CAD) in relation to prognosis in symptomatic patients without coronary artery calcification (CAC) undergoing coronary computed tomography angiography (CCTA)., Background: The frequency and clinical relevance of CAD in patients without CAC are unclear., Methods: We identified 10,037 symptomatic patients without CAD who underwent concomitant CCTA and CAC scoring. CAD was assessed as <50%, ≥50%, and ≥70% stenosis. All-cause mortality and the composite endpoint of mortality, myocardial infarction, or late coronary revascularization (≥90 days after CCTA) were assessed., Results: Mean age was 57 years, 56% were men, and 51% had a CAC score of 0. Among patients with a CAC score of 0, 84% had no CAD, 13% had nonobstructive stenosis, and 3.5% had ≥50% stenosis (1.4% had ≥70% stenosis) on CCTA. A CAC score >0 had a sensitivity, specificity, and negative and positive predictive values for stenosis ≥50% of 89%, 59%, 96%, and 29%, respectively. During a median of 2.1 years, there was no difference in mortality among patients with a CAC score of 0 irrespective of obstructive CAD. Among 8,907 patients with follow-up for the composite endpoint, 3.9% with a CAC score of 0 and ≥50% stenosis experienced an event (hazard ratio: 5.7; 95% confidence interval: 2.5 to 13.1; p < 0.001) compared with 0.8% of patients with a CAC score of 0 and no obstructive CAD. Receiver-operator characteristic curve analysis demonstrated that the CAC score did not add incremental prognostic information compared with CAD extent on CCTA for the composite endpoint (CCTA area under the curve = 0.825; CAC + CCTA area under the curve = 0.826; p = 0.84)., Conclusions: In symptomatic patients with a CAC score of 0, obstructive CAD is possible and is associated with increased cardiovascular events. CAC scoring did not add incremental prognostic information to CCTA., (Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The purpose of this study was to compare the efficiency, cost, and safety of a diagnostic strategy employing early coronary computed tomographic angiography (CCTA) to a strategy employing rest-stress myocardial perfusion imaging (MPI) in the evaluation of acute low-risk chest pain., Background: In the United States, >8 million patients require emergency department evaluation for acute chest pain annually at an estimated diagnostic cost of >$10 billion., Methods: This multicenter, randomized clinical trial in 16 emergency departments ran between June 2007 and November 2008. Patients were randomly allocated to CCTA (n = 361) or MPI (n = 338) as the index noninvasive test. The primary outcome was time to diagnosis; the secondary outcomes were emergency department costs of care and safety, defined as freedom from major adverse cardiac events in patients with normal index tests, including 6-month follow-up., Results: The CCTA resulted in a 54% reduction in time to diagnosis compared with MPI (median 2.9 h [25th to 75th percentile: 2.1 to 4.0 h] vs. 6.3 h [25th to 75th percentile: 4.2 to 19.0 h], p < 0.0001). Costs of care were 38% lower compared with standard (median $2,137 [25th to 75th percentile: $1,660 to $3,077] vs. $3,458 [25th to 75th percentile: $2,900 to $4,297], p < 0.0001). The diagnostic strategies had no difference in major adverse cardiac events after normal index testing (0.8% in the CCTA arm vs. 0.4% in the MPI arm, p = 0.29)., Conclusions: In emergency department acute, low-risk chest pain patients, the use of CCTA results in more rapid and cost-efficient safe diagnosis than rest-stress MPI. Further studies comparing CCTA to other diagnostic strategies are needed to optimize evaluation of specific patient subsets. (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment [CT-STAT]; NCT00468325)., (Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Rapid technological advances have facilitated high-resolution noninvasive coronary angiography using multislice computed tomography. Appropriateness guidelines recently have been published in the Journal of the American College of Cardiology and endorsed by several imaging specialty societies. Clinical studies are now available supporting the use of this method in selected diagnostic situations, particularly when the exclusion of coronary artery disease is of paramount clinical concern.

Objectives: This study sought to compare the safety, diagnostic efficacy, and efficiency of multi-slice computed tomography (MSCT) with standard diagnostic evaluation of low-risk acute chest pain patients., Background: Over 1 million patients have emergency center evaluations for acute chest pain annually, at an estimated diagnostic cost of over $10 billion. Multi-slice computed tomography has a high negative predictive value for exclusion of coronary artery stenoses., Methods: We randomized patients to MSCT (n = 99) versus SOC (n = 98) protocols. The MSCT patients with minimal disease were discharged; those with stenosis >70% underwent catheterization, whereas cases with intermediate lesions or non-diagnostic scans underwent stress testing. Outcomes included: safety (freedom from major adverse events over 6 months), diagnostic efficacy (clinically correct and definitive diagnosis), as well as time and cost of care., Results: Both approaches were completely (100%) safe. The MSCT alone immediately excluded or identified coronary disease as the source of chest pain in 75% of patients, including 67 with normal coronary arteries and 8 with severe disease referred for invasive evaluation. The remaining 25% of patients required stress testing, owing to intermediate severity lesions or non-diagnostic scans. During the index visit, MSCT evaluation reduced diagnostic time compared with SOC (3.4 h vs. 15.0 h, p < 0.001) and lowered costs (1,586 dollars vs. 1,872 dollars, p < 0.001). Importantly, MSCT patients required fewer repeat evaluations for recurrent chest pain (MSCT, 2 of 99 (2.0%) patients vs. SOC, 7 of 99 (7%) patients; p = 0.10)., Conclusions: Multi-slice computed tomographic coronary angiography can definitively establish or exclude coronary disease as the cause of chest pain. However, inability to determine the physiological significance of intermediate severity coronary lesions and cases with inadequate image quality are present limitations. (Study of Coronary Artery Computed Tomography to Diagnose Emergency Chest Pain CR; http://clinicaltrials.gov/ct/show/NCT00273832?order=1; NCT00273832).

Objectives: The aim of our study was to evaluate the diagnostic accuracy of multislice computed tomography (MSCT) coronary angiography using a new 64-slice scanner., Background: The new 64-slice MSCT scanner has improved spatial resolution of 0.4 mm and a faster rotation time (330 ms) compared to prior MSCT scanners., Methods: We studied 70 consecutive patients undergoing elective invasive coronary angiography. Patients were excluded for atrial fibrillation, but not for high heart rate, coronary calcification, or obesity. All vessels were analyzed, including those <1.5 mm in diameter; MSCT lesions were analyzed quantitatively as well as by a qualitative scale and compared to quantitative coronary angiography (QCA). Results were also analyzed for significant coronary stenoses (over 50% luminal narrowing) by segment, by artery, and by patient., Results: All scans showed diagnostic image quality. Of 1,065 segments, 935 (88%) could be evaluated, and 773 of 935 (83%) could be assessed quantitatively by both MSCT and QCA. The Spearman correlation coefficient between MSCT and QCA was 0.76 (p < 0.0001). Bland-Altman analysis demonstrated a mean difference in percent stenosis of 1.3 +/- 14.2%. A total of 26% of patients had calcium scores above 400 Agatston U, 25% had heart rates >70 beats/min, and 50% were obese. Specificity, sensitivity, and positive and negative predictive values for the presence of significant stenoses were: by segment (n = 935), 86%, 95%, 66%, and 98%, respectively; by artery (n = 279), 91%, 92%, 80%, and 97%, respectively; by patient (n = 70), 95%, 90%, 93%, and 93%, respectively., Conclusions: Our results indicate high quantitative and qualitative diagnostic accuracy of 64-slice MSCT in comparison to QCA in a broad spectrum of patients.