Prevalence, extent and composition of coronary plaque in patients with rheumatoid arthritis without symptoms or prior diagnosis of coronary artery disease.

OBJECTIVES: Accelerated cardiovascular morbidity and mortality occur in patients with rheumatoid arthritis (RA). We evaluated the presence, burden and compositional differences of coronary plaque in patients with RA without symptoms or diagnosis of coronary artery disease (CAD) compared against controls. METHODS: One hundred and fifty patients with RA and 150 matched controls underwent 64-slice CT angiography (CTA) for evaluation of coronary plaque. Numbers of segments with plaque per patient (Segment involvement score (SIS)), degree of segment stenosis (stenosis severity score (SSS)), plaque size (plaque burden score (PBS)), and composition were assessed using a standardised American Heart Association 15-segment model. Lesions were classified as non-calcified plaque (NCP), mixed (MP), and fully calcified plaque (CP). RESULTS:  Higher proportion of patients with RA had plaque when compared with controls (71% vs 45%, p<0.0001); 13.5% of total RA segments harboured plaque compared with 6% in controls (p<0.0001), and all plaque types were higher (p<0.001). Multivessel disease, both non-obstructive and obstructive, was more prevalent, and quantitative measures of stenotic plaque severity (SSS) and extent (PBS) were higher in RA, even after adjustments for cardiac risk factors (p<0.01 for all). A steeper progression of plaque with age was seen in RA. Disease activity associated only with presence of NCP and MP, whereas patient age was the only predictor of fully CP. CONCLUSIONS: RA patients without CAD have higher prevalence, extent, and severity of all types of coronary plaque. Residual disease activity associates with presence of higher risk NCP and MP potentially contributing to future adverse cardiac events.

Effect of statin treatment on coronary plaque progression - a serial coronary CT angiography study.

OBJECTIVES: Statins have been shown to reduce plaque progression using data on intravascular ultrasound, carotid intima-media thickness and coronary artery calcium scans. However, there is little data on effects of statins on plaque progression using Coronary CTA. The objective is to evaluate the effect of statin therapy on plaque progression using serial Coronary CTA (CCTA). METHODS: The study included 100 consecutive patients who underwent serial Coronary CTA (mean follow up: 406 ± 92 days) for evaluation of CAD without known prior heart disease or revascularization. We performed volumetric assessment of low attenuation plaque (LAP < 30 Hounsfield units), non-calcified (NCP) and calcified plaque volumes at baseline and follow up scans for vessels >2 mm in diameter. Patients who received statins were compared to those that did not. RESULTS: Total plaque progression was significantly reduced among statin user compared to non-statin users (-33.3 mm(3) ± 90.5 vs. 31.0 mm(3) ± 84.5, p = 0.0006). Statin users had significantly reduced progression of NCP volume (-47.7 mm(3) ± 71.9 vs. 13.8 mm(3) ± 76.6, p < 0.001) and significantly reduced progression of LAP volume (-12.2 mm(3) ± 19.2 vs. 5.9 mm(3) ± 23.1, p < 0.0001). When we compared for remodeling index, no statistical difference was found between the two groups (p = 0.25) and a non-significant trend toward calcium progression (29.3 mm(3) ± 67.9 vs. 10.0 mm(3) ± 53.2, p = 0.133). After adjustment for cardiovascular risk factors, mean plaque volume difference between statin and non-statin users was statistically significant for both LAP and NCP volumes (-18.1, 95% CI: -26.4, -9.8 for LAP; -101.7, 95% CI: -162.1, -41.4 for NCP; p < 0.001) respectively. CONCLUSION: Statin therapy resulted in significantly lower progression of LAP and NCP plaques compared to non-statin users.

Noninvasive fractional flow reserve derived from computed tomography angiography for coronary lesions of intermediate stenosis severity: results from the DeFACTO study.

BACKGROUND: Fractional flow reserve derived from computed tomography angiography (FFRCT) is a noninvasive method for diagnosis of ischemic coronary lesions. To date, the diagnostic performance of FFRCT for lesions of intermediate stenosis severity remains unexamined. METHODS AND RESULTS: Among 407 vessels from 252 patients at 17 centers who underwent CT, FFRCT, invasive coronary angiography, and invasive FFR, we identified 150 vessels of intermediate stenosis by CT, defined as 30% to 69% stenosis. FFRCT, FFR, and CT were interpreted in blinded fashion by independent core laboratories. FFRCT and FFR ≤0.80 were considered hemodynamically significant, whereas CT stenosis ≥50% was considered obstructive. Diagnostic performance of FFRCT versus CT was assessed for accuracy, sensitivity, specificity, positive predictive values, and negative predictive values. Area under the receiver operating characteristic curve and net reclassification improvement were evaluated. For lesions of intermediate stenosis severity, accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of FFRCT were 71%, 74%, 67%, 41%, and 90%, whereas accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of CT stenosis were 63%, 34%, 72%, 27%, and 78%. FFRCT demonstrated superior discrimination compared with CT stenosis on per-patient (area under the receiver operating characteristic curve, 0.81 versus 0.50; P=0.0001) and per-vessel basis (area under the receiver operating characteristic curve, 0.79 versus 0.53; P<0.0001). FFRCT demonstrated significant reclassification of CT stenosis for lesion-specific ischemia (net reclassification improvement, 0.45; 95% confidence interval, 0.25-0.65; P=0.01). CONCLUSIONS: FFRCT possesses high diagnostic performance for diagnosis of ischemic for lesions of intermediate stenosis severity. Notably, the high sensitivity and negative predictive value suggest the ability of FFRCT to effectively rule out intermediate lesions that cause ischemia.

Measurement of phantomless thoracic bone mineral density on coronary artery calcium CT scans acquired with various CT scanner models.

PURPOSE: To determine the accuracy and precision of thoracic phantomless bone mineral density (BMD) measurements obtained on coronary artery calcium (CAC) computed tomography (CT) scans by using a variety of commercially available CT scanners. MATERIALS AND METHODS: The institutional review board approved this Health Insurance Portability and Accountability Act-compliant study. A total of 4126 asymptomatic subjects (2022 [49%] men, 2104 [51%] women; mean age, 63.7 years ± 11.8 [standard deviation]) underwent CAC CT with the use of a quantitative CT calibration phantom for evaluation of subclinical atherosclerosis. Two hundred eighty subjects also underwent CT of the chest, abdomen, and pelvis (C7 through L5). Mean BMD of three consecutive thoracic vertebrae (in the T7-T10 range) was measured in all 4126 subjects. Individual calibration factors for each phantom insert and a general calibration factor for the spine were determined for each CT scanner model. The study population was then divided into three subgroups: All calibration factors were generated from group 1 (n = 1536) and were applied and tested in group 2 (n = 1587), and effects of various image acquisition parameters were assessed in group 3 (n = 1003). Accuracy (bias) and precision of thoracic phantomless BMD measurements across 14 CT scanner models from five manufacturers were determined. RESULTS: Phantomless BMD values correlated highly with standard phantom-based quantitative CT BMD values (r = 0.987, P < .001). Bias was 3.9% ± 1.4 for phantomless BMD measurements, and the mean coefficient of variation for the general calibration factor was 4.9% ± 2.4. CONCLUSION: Phantomless BMD can be measured accurately on CAC CT scans acquired with a variety of CT scanners without additional radiation exposure.

Diagnostic accuracy of fractional flow reserve from anatomic CT angiography.

CONTEXT: Coronary computed tomographic (CT) angiography is a noninvasive anatomic test for diagnosis of coronary stenosis that does not determine whether a stenosis causes ischemia. In contrast, fractional flow reserve (FFR) is a physiologic measure of coronary stenosis expressing the amount of coronary flow still attainable despite the presence of a stenosis, but it requires an invasive procedure. Noninvasive FFR computed from CT (FFR(CT)) is a novel method for determining the physiologic significance of coronary artery disease (CAD), but its ability to identify ischemia has not been adequately examined to date. OBJECTIVE: To assess the diagnostic performance of FFR(CT) plus CT for diagnosis of hemodynamically significant coronary stenosis. DESIGN, SETTING, AND PATIENTS: Multicenter diagnostic performance study involving 252 stable patients with suspected or known CAD from 17 centers in 5 countries who underwent CT, invasive coronary angiography (ICA), FFR, and FFR(CT) between October 2010 and October 2011. Computed tomography, ICA, FFR, and FFR(CT) were interpreted in blinded fashion by independent core laboratories. Accuracy of FFR(CT) plus CT for diagnosis of ischemia was compared with an invasive FFR reference standard. Ischemia was defined by an FFR or FFR(CT) of 0.80 or less, while anatomically obstructive CAD was defined by a stenosis of 50% or larger on CT and ICA. MAIN OUTCOME MEASURES: The primary study outcome assessed whether FFR(CT) plus CT could improve the per-patient diagnostic accuracy such that the lower boundary of the 1-sided 95% confidence interval of this estimate exceeded 70%. RESULTS: Among study participants, 137 (54.4%) had an abnormal FFR determined by ICA. On a per-patient basis, diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of FFR(CT) plus CT were 73% (95% CI, 67%-78%), 90% (95% CI, 84%-95%), 54% (95% CI, 46%-83%), 67% (95% CI, 60%-74%), and 84% (95% CI, 74%-90%), respectively. Compared with obstructive CAD diagnosed by CT alone (area under the receiver operating characteristic curve [AUC], 0.68; 95% CI, 0.62-0.74), FFR(CT) was associated with improved discrimination (AUC, 0.81; 95% CI, 0.75-0.86; P < .001). CONCLUSION: Although the study did not achieve its prespecified primary outcome goal for the level of per-patient diagnostic accuracy, use of noninvasive FFR(CT) plus CT among stable patients with suspected or known CAD was associated with improved diagnostic accuracy and discrimination vs CT alone for the diagnosis of hemodynamically significant CAD when FFR determined at the time of ICA was the reference standard.

Triaging patients with acute chest pain in the emergency department: implications of the CT-STAT trial.

Rapid advancements in multidetector-row computed tomography scanner technology over the last decade have significantly improved the diagnostic performance of coronary computed tomography angiography (CTA), enabling it to potentially become the preferred imaging modality used in the rapid assessment of chest pain patients in the emergency department. There is a growing body of evidence suggesting coronary CTA can rule out coronary artery stenosis quickly and accurately, thereby reducing the number of hospitalizations and healthcare costs, without compromising quality of care. CT-STAT is the first multicenter trial to demonstrate the power of coronary CTA to streamline patient care in the acute setting and radically transform current treatment algorithms.

Radiation dose reduction with increasing utilization of prospective gating in 64-multidetector cardiac computed tomography angiography.

BACKGROUND: Medical radiation exposure is a major concern, and several methods have been proposed to reduce radiation doses in multidetector cardiac computed tomography (CT). OBJECTIVE: The purpose of this study was to review radiation doses of clinical cardiac CT performed at our center and to evaluate the effect of radiation dose reduction strategies on the median dose delivered to patients over time. METHODS: This study included 623 consecutive clinical patients (male, 58%) who were referred for imaging. The effective dose (mSv) was derived from the product of the dose-length-product (DLP) and a conversion coefficient for the chest (0.014). RESULTS: The median radiation dose of all patients was 3.0 mSv (interquartile range [IQR], 1.9-8.1 mSv). A significant difference was observed in radiation dose between the prospective (n = 384) and retrospective (n = 239) gating groups (2.0 vs 9.6 mSv; P < 0.0001). Compared with patients with coronary artery bypass grafting (CABG; n = 52), patients without CABG had significantly lower median radiation dose (prospective gating: 2.0 vs 3.4 mSv, P < 0.0001; retrospective gating: 9.3 vs 10.3 mSv, P < 0.0001). In patients with CABG, a significant difference was observed in radiation dose between prospective and retrospective gating (3.4 vs 10.3; P < 0.0001). The median radiation doses per month at our center decreased from 6.2 to 2.1 mSv over time with increasing use of prospective gating (≤91%). CONCLUSION: Radiation reduction techniques have led to progressive decreases in radiation exposure over time, primarily because of prospective gating.

Is coronary artery calcium the key to assessment of cardiovascular risk in asymptomatic adults?

New recommendations put forth in the American College of Cardiology Foundation/American Heart Association (ACC/AHA) Guidelines for Assessment of Cardiovascular Risk in Asymptomatic Adults and the updated 2010 Appropriate Use Criteria for Cardiac Computed Tomography both reflect the unparalleled prognostic power of CAC scoring and it's unique ability to further refine current risk prediction models. The ACCF/AHA guidelines maintain the measurement of CAC is reasonable for cardiovascular risk assessment in asymptomatic adults at intermediate risk (10%-20% 10-year-risk) (IIa, Level of Evidence: B), low-to-intermediate risk (6%-10% 10-year-risk) (IIb, Level of Evidence: B), and in diabetics over age 40 (IIa, Level of Evidence: B). There now exists a large body of published evidence depicting the independent and incremental prognostic value of CAC scoring over Framingham risk score-based strategy alone, a feature unmatched by any other biomarker under investigation. Early detection of subclinical atherosclerosis through noninvasive assessment of CAC leads to more accurate risk stratification and a substantially higher net reclassification improvement (NRI) among intermediate-risk groups, deeming many patients newly eligible for lipid-lowering therapy and other preventative measures.