Row Computed Tomography Coronary Angiography Research Articles

Extent of subclinical atherosclerosis on coronary computed tomography and impact of statins in patients with diabetes without known coronary artery disease: Results from CONFIRM registry

BackgroundAbsence of subclinical atherosclerosis is considered safe to defer statin therapy in general population. However, impact of statins on atherosclerotic cardiovascular disease in patients with diabetes stratified by coronary artery calcium (CAC) scores and extent of non-obstructive CAD on coronary computed tomography angiography (CCTA) has not been evaluated. MethodsCONFIRM (Coronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multi-center Registry) study enrolled consecutive adults 18 years of age between 2005 and 2009 who underwent 364-detector row CCTA for suspected CAD. The long-term registry includes data on 12,086 subjects who underwent CCTA at 17 centers in 9 countries. In this sub-study of CONFIRM registry, patients with diabetes mellitus (DM) and without diabetes mellitus with normal CCTA or non-obstructive plaque (<50 % diameter stenosis) for whom data on baseline statin use was available were included. CAC score was calculated using Agatston score. The magnitude of non-obstructive coronary artery disease on CCTA was quantified using segment involvement score (SIS). Primary outcome was major cardiovascular events (MACE) which included all-cause mortality, myocardial infarction, and target vessel re-vascularization. ResultsA total of 7247 patients (Mean age 56.8 years) with a median follow up of 5 years were included. For DM patients, baseline statin therapy significantly reduced MACE for patients with CAC ≥100 (HR: 0.24; 95 % CI 0.07–0.87; p = 0.03) and SIS≥3 (HR: 0.23; 95 % CI 0.06–0.83; p = 0.024) compared to those not on statin therapy. Among Diabetics with lower CAC (<100) and SIS (≤3) scores, MACE was similar in statin and non-statin groups. In contrast, among non-DM patients, MACE was similar in statin and no statin groups irrespective of baseline CAC (1–99 or ≥100) and SIS. ConclusionIn this large multicenter cohort of patients, the presence and extent of subclinical atherosclerosis as assessed by CAC and SIS identified patients most likely to derive benefit from statin therapy.

MO632: Impact of Diabetic Kidney Disease on Coronary Artery Plaque Progression

Abstract BACKGROUND AND AIMS The aim of this study was to evaluate the relationship between diabetic kidney disease (DKD) and change in coronary plaque volume in asymptomatic diabetes patients. METHOD In this prospective observational study, we analyzed 79 asymptomatic type 2 diabetes patients (age, 63.7 ± 8.1 years; male, 69.3%) without prior history of coronary artery disease who underwent serial 320-row computed tomography coronary angiography with an interscan interval of more than 24 months (median 37.7 months). Total coronary plaque volume was assessed at baseline and after 3 years, using QAngio CT (MEDIS) for vessel diameters greater than 1.5 mm in the three main branches. The primary endpoint was coronary plaque progression (PP), which was defined as the absolute change in coronary plaque volume during the 3 years. PP was compared among four groups, which were divided according to the presence or absence of DKD at baseline and after 3 years, as follows: Group 1 (no DKD at baseline, no DKD after 3 years), Group 2 (DKD at baseline, no DKD after 3 years), Group 3 (no DKD at baseline, DKD after 3 years), Group 4 (DKD at baseline, DKD after 3 years)]. DKD was defined as albuminuria &amp;gt;30 mg/g Cr or eGFR &amp;lt;60 mL/min/1.73 m2. We conducted univariate linear regression analysis to assess the association of DKD groups with PP. RESULTS Plaque volumes were significantly greater in Group 4 than in Group 1 both at baseline and after 3 years (Table 1). PP was also significantly greater in Group 4 than in Group 1 (β-coefficient: 293.6, P &amp;lt; 0.01). Group 4 had greater PP compared with Group 1 after adjustment (β-coefficient: 181.6, P &amp;lt; 0.05). CONCLUSION DKD may be an independent risk factor for coronary plaque progression in asymptomatic type 2 diabetic patients without a history of cardiovascular disease. Early therapeutic intervention in such patients may prevent the onset of coronary artery disease.

Role of Multi-detector Row (320) CT Coronary Angiography in Assessment of Coronary Stents in Comparison with Coronary Angiography

Role of Multi-detector Row (320) CT Coronary Angiography in Assessment of Coronary Stents in Comparison with Coronary Angiography

Associations between the psoas major muscle index and the presence and severity of coronary artery disease.

The associations between the presence and severity of coronary artery disease (CAD) and measurements of the psoas major muscle (PMM) as assessed by multidetector row coronary computed tomography angiography (MDCT) are not known.We enrolled 793 patients who were clinically suspected to have CAD or had at least one cardiac risk factor and had undergone MDCT. The number of significantly stenosed coronary vessels (VD) and measurements of the PMM index (PMMI) were determined using MDCT.PMMI in the CAD group was significantly lower than that in the non-CAD group in males, but not females. In addition, the levels of PMMI tended to increase as the number of VD decreased in males. When male patients were divided into 2 groups according to median value of age, that is, relatively younger (53.4 ± 9.2 years) and older (72.6 ± 5.7 years) groups, the presence of CAD was independently associated with PMMI in the younger group by a multiple logistic regression analysis. The cut-off level of PMMI that gave the greatest sensitivity and specificity for the diagnosis of CAD in younger males was 8.3 cm2/m2 (sensitivity 0.441, specificity 0.752).In conclusion, PMMI may be an imaging marker for evaluating the presence and/or severity of CAD in males, and particularly in the non-elderly.

Clinical Predictors of Coronary Artery Plaque Progression by Quantitative Serial Assessment Using 320-Row Computed Tomography Coronary Angiography in Asymptomatic Patients with Type 2 Diabetes Mellitus

BackgroundNatural history of coronary plaque progression (PP) in patients with diabetes mellitus (DM) remains unclear. This study aimed to investigate the clinical predictors of coronary PP in patients with DM. MethodsIn this prospective observational study, we analyzed 70 asymptomatic patients (age, 64.4 years; male, 67%) with type 2 DM without prior history of coronary artery disease who underwent serial 320-row computed tomography coronary angiography with an interscan interval of more than 24 months (median 37.7 months). Study endpoint was PP, which was defined if coronary plaque volumes (PVs) at follow-up minus PVs at baseline was >0. We evaluated plaque composition using the Hounsfield Unit thresholds and insulin resistance estimated by the homeostasis model assessment of insulin resistance (HOMA-IR). ResultsThirty-nine patients who showed PP had a higher increase in hemoglobin A1c (⊿HbA1c) from baseline to follow-up than those without PP (0.3% ± 0.8% vs −0.4% ± 1.1%; p = 0.01), although there was no statistical difference in HbA1c at baseline (7.1 ± 0.5% vs. 7.3 ± 1.4%; p = 0.24). In multivariable analysis, ⊿HbA1c [odds ratio (OR): 3.05; 95% confidence interval (CI): 1.39–6.67; p = 0.001] was an independent predictor for PP.Increase in low-density lipoprotein cholesterol (⊿LDL-C), not ⊿HbA1c, was significantly correlated to percent change in necrotic core (NC) volume (β-coefficients: 0.04; 95% CI: 0.004 - 0.08; p = 0.03). Among 48 patients without insulin therapy, patients with PP (n = 28) had a higher increase in HOMA-IR than those without PP (n = 20) (0.95 ± 2.00 vs. −0.63 ± 1.31; p = 0.003). ConclusionsIncrease in HbA1c and HOMA-IR was associated with PP in asymptomatic patients with type 2 DM, whereas increase in LDL-C was correlated to increase in NC.

Reduction of the Body Weight-adapted Volume of Contrast Material by Increasing the Injection Rate in 320-detector Row Coronary CT Angiography

Background: 320-detector row dynamic volume computed tomography (CT) scanner was widely applied in coronary CT angiography (CCTA)，which made it possible to reduce the volume of contrast material (CM) used. Some studies have reported the feasibility of reducing the CM in 320-detector row CCTA using a weight-adapted injection protocol. However, it hasn't been studied to investigate what was the significance of increasing the injection rate with a lower volume of CM. Objective: To investigate the feasibility of reducing the body weight-adapted volume of CM by increasing the injection rate in 320-detector row CCTA. Methods: A total of 116 patients who underwent 320-detector row CCTA were divided into three groups. Group A received 0.7 ml/kg of CM (350 mg I/ml) at an injection rate of 5.0 ml/s (<i>n</i> = 40); group B received 0.6 ml/kg of CM at 5.5 ml/s (<i>n</i> = 39); group C received 0.5 ml/kg of CM at 6.0 ml/s (<i>n</i> = 37). A 30-ml 0.9% saline chaser was administered after the CM. Enhancement values of the cardiovascular territories and coronary arteries were measured and compared. Image quality was also evaluated and compared among the three groups. Result: Enhancement values of the proximal coronary arterial segments for group C were significantly lower than those for groups A and B (all, <i>P</i> < 0.05), whereas there were no significant differences between groups A and B (all, <i>P</i> > 0.05). Similar statistical results were found in the proportion of proximal coronary arterial segments with enhancement values ≥ 300 HU, image quality ratings and the proportion of the main of coronary arterial segments with image quality scores ≥ 3 on both per-vessel and per-patient analyses. Conclusion: At least 0.6 ml/kg with 350 mg I/ml of CM at 5.5 ml/s injection rate was required to achieve sufficient and credible evaluation of the coronary artery in 320-detector row CCTA.

Machine learning of clinical variables and coronary artery calcium scoring for the prediction of obstructive coronary artery disease on coronary computed tomography angiography: analysis from the CONFIRM registry.

Symptom-based pretest probability scores that estimate the likelihood of obstructive coronary artery disease (CAD) in stable chest pain have moderate accuracy. We sought to develop a machine learning (ML) model, utilizing clinical factors and the coronary artery calcium score (CACS), to predict the presence of obstructive CAD on coronary computed tomography angiography (CCTA). The study screened 35281 participants enrolled in the CONFIRM registry, who underwent ≥64 detector row CCTA evaluation because of either suspected or previously established CAD. A boosted ensemble algorithm (XGBoost) was used, with data split into a training set (80%) on which 10-fold cross-validation was done and a test set (20%). Performance was assessed of the (1) ML model (using 25 clinical and demographic features), (2) ML + CACS, (3) CAD consortium clinical score, (4) CAD consortium clinical score + CACS, and (5) updated Diamond-Forrester (UDF) score. The study population comprised of 13054 patients, of whom 2380 (18.2%) had obstructive CAD (≥50% stenosis). Machine learning with CACS produced the best performance [area under the curve (AUC) of 0.881] compared with ML alone (AUC of 0.773), CAD consortium clinical score (AUC of 0.734), and with CACS (AUC of 0.866) and UDF (AUC of 0.682), P < 0.05 for all comparisons. CACS, age, and gender were the highest ranking features. A ML model incorporating clinical features in addition to CACS can accurately estimate the pretest likelihood of obstructive CAD on CCTA. In clinical practice, the utilization of such an approach could improve risk stratification and help guide downstream management.

Adjustment of CT-fractional flow reserve based on fluid-structure interaction underestimation to minimize 1-year cardiac events.

The purpose of the study was to evaluate the optimal cut-off value of CT-Fractional Flow Reserve (CT-FFR) using fluid-structure interaction and how to adjust the CT-FFR's underestimation from a standpoint of minimize 1-year cardiac events. Subjects were 38 cases with 44 vessels in which stenosis of 30-90% was detected using one-rotation scanning by 320-row coronary CT angiography (CCTA) and invasive FFR (i-FFR) was performed within subsequent 90days. CT-FFR was calculated using on-site from the multiple cardiac phases. A hypothetical 1-year cardiac event incidence was estimated using previous evidences when revascularization was decided based on CT-FFR. We assessed the optimal cut-off value of CT-FFR and how to correct the CT-FFR to minimize hypothetical cardiac events under four different disease prevalence (20%, 25%, 30%, 35%, and 40%). A total of 16 vessels had i-FFR ≤ 0.8. On per-patient basis, the sensitivity, specificity, positive predict value, negative predict value, and diagnostic accuracy of CT-FFR≦0.8 vs CCTA > 50% to detect functional stenosis defined as invasive FFR≦0.80 were 93.3% vs 73.3%, 73.9% vs 26.1%, 70.0% vs 39.3%, 94.4% vs 60.0%, and 81.6% vs 44.7%, respectively. For minimize 1-year cardiac events, the optimal cut-off value for more than 30% of disease prevalence was 0.80. However, the optimal cut-off value for 20, 25, and 30% was 0.54 in any cases. After the adjustment of CT-FFR using a formula of 0.3X + 0.634 for CT-FFR < 0.7 to counteract its underestimation, the % reduction of the events for 20, 25, 30, 35, and 40% at a 0.80 cut-off were 19.0%, 15.6%, 12.6%, 10.0%, and 7.7% respectively. It was reasonable to support that the optimal cut-off value was 0.80 in disease prevalence of more than 30% for minimize 1-year cardiac events. However, underestimation should be adjusted to reduce cardiac events, especially when disease prevalence is low.

Inter- and Intraoperator Variability in Measurement of On-Site CT-derived Fractional Flow Reserve Based on Structural and Fluid Analysis: A Comprehensive Analysis.

To measure the inter- and intraobserver variability among operators of varying expertise in conducting CT-derived fractional flow reserve (CT FFR) measurements on-site by using structural and fluid analysis and to evaluate differences in reproducibility between two different training methods for end users. This retrospective analysis of the prospectively enrolled cohort included 22 symptomatic patients who underwent both 320-detector row coronary CT angiography and catheter-derived fractional flow reserve (FFR) within 90 days. Thirteen operators of varying expertise were assigned to one of two training arms: arm 1, on-site training by a specialist in CT FFR technology; arm 2, self-training through use of written materials. After the training, all 13 operators reviewed the CT data and measured CT FFR in 24 vessels in 22 patients. Inter- and intraoperator variability and agreements between CT FFR and catheter-derived FFR measurements were evaluated. The overall intraclass correlation coefficient (ICC) among operators was 0.71 (95% confidence interval: 0.58, 0.83) with a mean absolute difference (± standard deviation) of 0.027 ± 0.022. The operators in arm 2 showed greater interoperator differences than those in arm 1 (0.031 ± 0.024 vs 0.023 ± 0.018; P = .024). Among operators who recalculated CT FFR, the mean CT FFR value did not significantly differ between the first and second calculations (ICC, 0.66; 95% confidence interval: 0.46, 0.87), with the medical specialists producing the lowest intraoperator variability (0.053 ± 0.060). The overall correlation coefficient between CT FFR and catheter FFR was r = 0.61, with a mean absolute difference of 0.096 ± 0.089. Good reproducibility of CT FFR values calculated on-site on the basis of structural and fluid analysis was observed among operators of varying expertise. Face-to-face training sessions may cause less variability.© RSNA, 2019Supplemental material is available for this article.

The utility of coronary computed tomography angiography in elderly patients.

BackgroundCoronary computed tomography angiography (CCTA) is often avoided in elderly patients due to a presumption that a high proportion of patients will have heavily calcified plaque limiting an accurate assessment. We sought to assess the image quality, luminal stenosis and utility of CCTA in elderly patients with suspected coronary artery disease (CAD) and stable chest pain.MethodsRetrospective analysis of elderly patients (> 75 years) who underwent 320-detector row CCTA between 2012–2017 at MonashHeart. The CCTA was analysed for degree maximal coronary stenosis by CAD-RADS classification, image quality by a 5-point Likert score (1-poor, 2-adequate, 3-good, 4-very good, 5-excellent) and presence of artefact limiting interpretability.Results1011 elderly patients (62% females, 78.8 ± 3.3 years) were studied. Cardiovascular risk factor prevalence included: hypertension (65%), hyperlipidaemia (48%), diabetes (19%) and smoking (21%). The CCTA was evaluable in 68% of patients which included 52% with non-obstructive CAD (< 50% stenosis), 48% with obstructive CAD (> 50%) stenosis. Mean Likert score was 3.1 ± 0.6 corresponding to good image quality. Of the 323 (32%) of patients with a non-interpretable CCTA, 80% were due to calcified plaque and 20% due to motion artefact. Male gender (P = 0.009), age (P = 0.02), excess motion (P < 0.01) and diabetes mellitus (P = 0.03) were associated with non-interpretable CCTA.ConclusionAlthough CCTA is a feasible non-invasive tool for assessment of elderly patients with stable chest pain, clinicians should still be cautious about referring elderly patients for CCTA. Patients who are male, diabetic and >78 years of age are significantly less likely to have interpretable scans.

Impact of abdominal fat distribution, visceral fat, and subcutaneous fat on coronary plaque scores assessed by 320-row computed tomography coronary angiography

Background and aimsObesity is a risk factor for coronary artery disease (CAD), but the association between fat distribution, i.e., visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), and coronary artery plaque morphology remains unclear. This study explored the association between abdominal fat distribution and coronary artery plaques. MethodsWe retrospectively evaluated 4327 consecutive patients without CAD history, undergoing coronary computed tomography (CT) angiography. Plaques were assessed using segment stenosis score (SSS) and segment involvement score (SIS). We evaluated abdominal VAT and SAT areas using CT images. Patients were categorized into four groups: low VAT (<median)/low SAT (<median); low VAT/high SAT (≥median); high VAT (≥median)/low SAT; and high VAT/high SAT. ResultsMean age was 65 years (men, 66.4%). VAT area correlated with SSS (β-coefficient = 0.11, p < 0.001) and SIS (β-coefficient = 0.006, p < 0.001), whereas SAT area was inversely correlated with SSS (β-coefficient = −0.007,p < 0.001) and SIS (β-coefficient = −0.004, p < 0.001). The low VAT/high SAT group had the lowest risk of higher SSS (≥5) and SIS (≥5) (odds ratio [OR] using low VAT/low SAT group as the reference category, 0.76, 95% confidence interval [CI], 0.61–0.95, p < 0.05; OR, 0.68, 95% CI, 0.53–0.88, p < 0.01, respectively) in multivariate analysis adjusted for age, sex, and traditional CAD risk factors. In the obese population (body mass index ≥25, n = 1694), the low VAT/high SAT group had the lowest risk of higher coronary plaque scores. ConclusionsHigher SAT and lower VAT were inversely correlated with the extent and severity of coronary artery plaques. Fat distribution may be useful for evaluating risk and prognosis of CAD.

The predictive factors affecting false positive in on-site operated CT-fractional flow reserve based on fluid and structural interaction

BackgroundA novel algorithm has been developed for the on-site analysis of CT-fractional flow reserve (CT-FFR) using fluid structural interactions. There have been no reports on the factors affecting the diagnostic performance of CT-FFR using this algorithm. We evaluated the factors predictive of false-positive CT-FFR findings compared to invasive FFR as a reference standard. MethodsThe subjects were 66 consecutive cases (81 vessels) who underwent invasive FFR assessment within 90 days of the detection of 30–90% stenosis of one vessel of the major coronary artery, from among patients with suspected coronary arterial disease who underwent one-rotation scanning by 320-row coronary CT angiography (CCTA). The prospective CCTA mode was used for all patients, with the X-ray exposure set in a range of 70–99% of the RR interval. The FFR was calculated on-site from multiple cardiac phases. Factors associated with a false-positive finding of functional stenosis on CT-FFR, defined as an invasive FFR of ≤0.80, were evaluated using logistic regression analysis. ResultsThirty-nine vessels (48.1%) had an invasive FFR of ≤0.80. CT-FFR and invasive FFR values disagreed in 13 vessels in 13 patients. The values were false positive in 12 of the vessels. In an analysis of patient characteristics, the body mass index (odds ratio, 1.33; 95%CI, 1.06–1.67; p = 0.01) and Image noise (odds ratio, 1.18; 95%CI, 1.01–1.40; p = 0.04) were predictive of false-positive findings. The presence of calcified plaque (odds ratio, 5.16; 95%CI, 1.06–20.85; p = 0.01) was the only significant predictive factor in a vessel-based analysis of lesion characteristics. ConclusionsThe presence of calcified plaque exerted a significant effect on the diagnostic performance of CT-FFR, and did so independently of the degree of calcification indicated by the Agatston score.

Initial evaluation of three-dimensionally printed patient-specific coronary phantoms for CT-FFR software validation.

We developed three-dimensionally (3D) printed patient-specific coronary phantoms that are capable of sustaining physiological flow and pressure conditions. We assessed the accuracy of these phantoms from coronary CT acquisition, benchtop experimentation, and CT-FFR software. Five patients with coronary artery disease underwent 320-detector row coronary CT angiography (CCTA) (Aquilion ONE, Canon Medical Systems) and a catheter lab procedure to measure fractional flow reserve (FFR). The aortic root and three main coronary arteries were segmented (Vitrea, Vital Images) and 3D printed (Eden 260V, Stratasys). Phantoms were connected into a pulsatile flow loop, which replicated physiological flow and pressure gradients. Contrast was introduced and the phantoms were scanned using the same CT scanner model and CCTA protocol as used for the patients. Image data from the phantoms were input to a CT-FFR research software (Canon Medical Systems) and compared to those derived from the clinical data, along with comparisons between image measurements and benchtop FFR results. Phantom diameter measurements were within 1mm on average compared to patient measurements. Patient and phantom CT-FFR results had an absolute mean difference of 4.34% and Pearson correlation of 0.95. We have demonstrated the capabilities of 3D printed patient-specific phantoms in a diagnostic software.

Feasible scan timing for 320-row coronary CT angiography generated by the time to peak in the ascending aorta

PurposeA 320-row CT scanner can briefly scan the entire heart. Therefore, the feasible scan timing is required. The aim of this study was to propose a refined method for feasible scan timing for coronary CT angiography (CCTA) using a time-density curve of the ascending aorta (AAo). MethodsOne-hundred and twenty-nine patients were prospectively enrolled. All patients were performed test-bolus method. For the initial 65 patients, the scan timing was determined as a 3.0 s delay at the peak time in the AAo, which was defined as the conventional protocol (COV-P). For the next 64 patients, a scan timing of 1.0, 3.0, or 5.0 s delay was determined according to the interval from the contrast media arrival to peak time in the AAo, which was defined as the arrival to peak protocol (AP-P). The optimal scan timing was identified by the measurement of CT number in the left atrium, left ventricle, AAo, and descending aorta. The coronary enhancement and heterogeneity were compared between the two protocols. ResultsThe optimal scan timing was significantly higher in the AP-P than in the COV-P (85.9% vs. 61.5%, p = 0.0017). The CT number in the left circumflex artery (LCX) was significantly higher in the AP-P than the COV-P (344.5 Hounsfield units vs. 316.3 Hounsfield units, p = 0.0484). The heterogeneous index of the LCX was significantly greater for the COV-P than the AP-P (−36.8 vs. –25.8, p = 0.0028). ConclusionsThe AP-P can be used to determine the optimal scan timing for CCTA and contributes to stable coronary enhancement.

The effect of heart rate on coronary plaque measurements in 320-row coronary CT angiography.

Repeatability of quantitative assessment of atherosclerotic plaques is important for the accurate detection of high-risk plaques in coronary CT angiography (CTA). We assessed the effect of heart rate (HR) on plaque CT number using a coronary artery model and a cardiac phantom capable of simulating cardiac motion. The coronary artery model with luminal stenosis on a cardiac phantom was imaged with a simulated HR of 0, 50, 60, and 70 beats per minute using a 320-row CT scanner. We reconstructed CT images for cardiac diastolic phases (for 75% R-R interval) using filtered back projection (FBP), hybrid iterative reconstruction (AIDR3D), and model-based iterative reconstruction (FIRST). Two observers measured plaque attenuation in the lesion with 75% stenosis. The coefficient of determination (R2) was obtained to evaluate interobserver agreement. At HR 70, FIRST improved the correlation between two observers compared with FBP and AIDR3D (FIRST: R2 = 0.68, p < 0.05; FBP: R2 = 0.29, p = 0.31; AIDR3D: R2 = 0.22, p = 0.18). These R2 at HR 70 were lower compared with at HR 50 (FIRST: R2 = 0.92, p < 0.05; FBP: R2 = 0.83, p < 0.05; AIDR3D: R2 = 0.87, p < 0.05) and HR 0 (FIRST: R2 = 0.97, p < 0.05; FBP: R2 = 0.89, p < 0.05; AIDR3D: R2 = 0.95, p < 0.05). Higher HR affected plaque measurement repeatability in coronary CTA. FIRST may improve plaque measurement repeatability at the higher HR compared with FBP and AIDR3D.

Aortic Root Calcification Score as an Independent Factor for Predicting Major Adverse Cardiac Events in Familial Hypercholesterolemia.

Aim: The aims of this study were: 1) to determine whether the accumulation of aortic root calcification (ARC) assessed using coronary computed tomography angiography (CCTA) can predict future cardiovascular events, and 2) to estimate the onset and progression of ARC in patients with familial hypercholesterolemia (FH).Methods: One hundred thirteen consecutive Japanese patients with heterozygous FH (male = 54, mean age = 52.1 ± 15.6 years, mean LDL-C = 299.0 ± 94.6 mg/dL), without known coronary artery disease, who underwent 64-detector row CCTA were retrospectively evaluated. ARC was defined as the presence of calcium at the aortic root. The extent of ARC was expressed in Agatston units as the ARC-score. Major adverse cardiac events (MACE) were defined as either cardiac death, ST elevated myocardial infarction (STEMI), non-ST elevated myocardial infarction (NSTEMI), unstable angina pectoris (UAP), planned percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), or stroke. The periods to MACE were estimated using multivariate logistic regression analysis.Results: During the follow-up period (median 1635 days), 19 instances of MACE occurred. Multivariate logistic regression analysis revealed that ARC was a significant independent predictor of MACE (OR= 1.48; 95% CI 1.11–1.87, p < 0.001, respectively). The regression equations were Y= 0.09X − 1.59 (R2 = 0.34, p < 0.001) in males and Y = 0.08X − 1.60 (R2 = 0.13, p < 0. 05) in females.Conclusions: ARC was significantly associated with future MACE in Japanese patients with heterozygous FH. ARC may start to develop, on average, at 17.4 and 19.7 years of age in males and females, respectively, with heterozygous FH.

Temporal averaging for analysis of four-dimensional whole-heart computed tomography perfusion of the myocardium: proof-of-concept study.

To assess the feasibility of four-dimensional (4D) whole-heart computed tomography perfusion (CTP) of the myocardium and the added value of temporal averaging of consecutive 3D datasets from different heartbeats for analysis. We included 30 patients with suspected or known coronary artery disease (CAD) who underwent 320-row coronary CT angiography (CTA) and myocardial CTP. Out of these, 15 patients underwent magnetic resonance myocardial perfusion imaging (MR MPI). All CTP examinations were initiated after 3min of intravenous infusion of adenosine (140µg/kg/min) and were performed dynamically covering the entire heart every heart beat over a period of 20 ± 3 heart beats. Temporal averaging for dynamic CTP visualisation was analysed for the combination of two, three, four, six, and eight consecutive 3D datasets. Input time attenuation curves (TAC) were delivered from measurement points in the centre of the left ventricle. In all 30 patients, myocardial 4D CTP was feasible and temporal averaging was successfully implemented for all planned combinations of 3D datasets. Temporal averaging of three consecutive 3D datasets showed best performance in the analysis of all CTP image quality parameters: noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), subjective image quality, and diagnostic accuracy with an improvement of SNR and CNR by a factor of 2.2 ± 1.3 and 1.3 ± 0.9. With increasing level of temporal averaging, the input TACs became smoother, but also shorter. Out of the 11 perfusion defects detected with MR MPI, 9 defects were also visible on the 4D CTP images. Whole-heart CTP of the myocardium is feasible and temporal averaging of dynamic datasets improves quantitative image quality parameters and visualization of perfusion defects while further studies are needed to assess its added value for quantification of perfusion parameters.

Abstract 16606: 30-day and 2-year Prognostic Information of Total Atheroma Volume, Segment Stenosis Score, and Traditional Coronary Artery Stenosis Assessment by CT Angiography - Results From the CORE320 International Study

Introduction: Among abundant information on coronary artery disease (CAD) features by CT angiography (CTA), total atheroma volume and segment stenosis score (SSS) have recently shown promise for clinical utility. Methods: We followed 379 patients with suspected or known CAD enrolled in the CORE320 study for 2 years after 320-detector row CT coronary angiography. CT images were analyzed for semi-automatically derived total % atheroma volume (total atherosclerotic burden/vessel volume analyzed) and SSS in addition to traditional stenosis assessment (≥50%). Outcome variables were 1) 30-day revascularization and 2) major adverse cardiac events (MACE) after 2 years follow up. Events included cardiac death, myocardial infarction, hospitalization for acute chest pain or heart failure, arrhythmia, and revascularization. Area under the curve (AUC) and Kaplan-Meyer analysis were used to compare risk prediction and survival analysis according to CT CAD characteristics. Results: Thirty-day revascularization was most accurately predicted by CT stenosis assessment (AUC 75, confidence interval [CI] 71-80) vs. % atheroma volume (70 [65-74] and CTA SSS (67 [62-72]) (p=0.007). Prediction of MACE (45 late revascularizations, 5 myocardial infarctions, 1 cardiac death, 8 hospitalizations for chest pain or congestive heart failure, and 1 arrhythmia) was similar for % atheroma volume (64 [71 for patients without history of CAD]) and CTA stenosis assessment (65 [70]) but risk discrimination using common criteria trended favorably for % atheroma volume (FIGURE). Accuracy was low for CTA SSS (58 [62]). Conclusions: Semi-automated assessment of % total atheroma volume by CTA performs similarly to standard stenosis assessment for predicting short and long term event rates, especially revascularization, in patients with suspected CAD and holds promise for more nuanced risk discrimination. In contrast, CTA segment stenosis score performed only modestly in our analysis.

Diagnostic Performance of Transluminal Attenuation Gradient and Noninvasive Fractional Flow Reserve Derived from 320-Detector Row CT Angiography to Diagnose Hemodynamically Significant Coronary Stenosis: An NXT Substudy.

To compare the diagnostic performance of 320-detector row computed tomography (CT) coronary angiography-derived computed fractional flow reserve (FFR; FFRCT), transluminal attenuation gradient (TAG; TAG320), and CT coronary angiography alone to diagnose hemodynamically significant stenosis as determined by invasive FFR. This substudy of the prospective NXT study (no. NCT01757678) was approved by each participating institution's review board, and informed consent was obtained from all participants. Fifty-one consecutive patients who underwent 320-detector row CT coronary angiographic examination and invasive coronary angiography with FFR measurement were included. Independent core laboratories determined coronary artery disease severity by using CT coronary angiography, TAG320, FFRCT, and FFR. TAG320 is defined as the linear regression coefficient between luminal attenuation and axial distance from the coronary ostium. FFRCT was computed from CT coronary angiography data by using computational fluid dynamics technology. Diagnostic performance was evaluated and compared on a per-vessel basis by the area under the receiver operating characteristic (ROC) curve (AUC). Among 82 vessels, 24 lesions (29%) had ischemia by FFR (FFR ≤ 0.80). FFRCT exhibited a stronger correlation with invasive FFR compared with TAG320 (Spearman ρ, 0.78 vs 0.47, respectively). Overall per-vessel accuracy, sensitivity, specificity, and positive and negative predictive values for TAG320 (<15.37) were 78%, 58%, 86%, 64%, and 83%, respectively; and those of FFRCT were 83%, 92%, 79%, 65%, and 96%, respectively. ROC curve analysis showed a significantly larger AUC for FFRCT (0.93) compared with that for TAG320 (0.72; P = .003) and CT coronary angiography alone (0.68; P = .008). FFRCT computed from 320-detector row CT coronary angiography provides better diagnostic performance for the diagnosis of hemodynamically significant coronary stenoses compared with CT coronary angiography and TAG320.

Is Metabolic Syndrome Predictive of Prevalence, Extent, and Risk of Coronary Artery Disease beyond Its Components? Results from the Multinational Coronary CT Angiography Evaluation for Clinical Outcome: An International Multicenter Registry (CONFIRM)

Although metabolic syndrome is associated with increased risk of cardiovascular disease and events, its added prognostic value beyond its components remains unknown. This study compared the prevalence, severity of coronary artery disease (CAD), and prognosis of patients with metabolic syndrome to those with individual metabolic syndrome components. The study cohort consisted of 27125 consecutive individuals who underwent ≥64-detector row coronary CT angiography (CCTA) at 12 centers from 2003 to 2009. Metabolic syndrome was defined as per NCEP/ATP III criteria. Metabolic syndrome patients (n=690) were matched 1:1:1 to those with 1 component (n=690) and 2 components (n=690) of metabolic syndrome for age, sex, smoking status, and family history of premature CAD using propensity scoring. Major adverse cardiac events (MACE) were defined by a composite of myocardial infarction (MI), acute coronary syndrome, mortality and late target vessel revascularization. Patients with 1 component of metabolic syndrome manifested lower rates of obstructive 1-, 2-, and 3-vessel/left main disease compared to metabolic syndrome patients (9.4% vs 13.8%, 2.6% vs 4.5%, and 1.0% vs 2.3%, respectively; p<0.05), while those with 2 components did not (10.5% vs 13.8%, 2.8% vs 4.5% and 1.3% vs 2.3%, respectively; p>0.05). At 2.5 years, metabolic syndrome patients experienced a higher rate of MACE compared to patients with 1 component (4.4% vs 1.6%; p=0.002), while no difference observed compared to individuals with 2 components (4.4% vs 3.2% p=0.25) of metabolic syndrome. In conclusion, Metabolic syndrome patients have significantly greater prevalence, severity, and prognosis of CAD compared to patients with 1 but not 2 components of metabolic syndrome.