Non-Calcified Coronary Artery Plaque on Coronary Computed Tomography Angiogram: Prevalence and Significance

OBJECTIVE

We aimed to assess the prevalence of non-calcified plaque (NCP) on computed tomography angiography (CCTA) in symptomatic and asymptomatic individuals. In addition, we seek to compare plaque assessment on CCTA with intravascular ultrasound-virtual histology (IVUS-VH) and to assess the prognostic value of non-calcified plaques (NCPs).

BACKGROUND

The CCTA can characterize coronary plaques and help quantify burden. Furthermore, it can provide additional prognostic information which can enable further risk stratification of patients.

METHODS

We performed a broad comprehensive review of the current literature pertaining to CCTA and primarily isolated NCP in symptomatic and asymptomatic patients. In addition, our review included studies correlating plaque on CT with IVUS-VH.

CONCLUSIONS

NCP is the initial precursor of calcified plaque and serves as a prominent marker of early coronary atherosclerosis. By detecting NCP during early stages, several measures can be implemented which can alter the evolutionary course of the underlying disease. This can potentially lead to a lower incidence of cardiovascular events.

Dual-Source Photon-Counting Computed Tomography-Part I: Clinical Overview of Cardiac CT and Coronary CT Angiography Applications

The photon-counting detector (PCD) is a new computed tomography detector technology (photon-counting computed tomography, PCCT) that provides substantial benefits for cardiac and coronary artery imaging. Compared with conventional CT, PCCT has multi-energy capability, increased spatial resolution and soft tissue contrast with near-null electronic noise, reduced radiation exposure, and optimization of the use of contrast agents. This new technology promises to overcome several limitations of traditional cardiac and coronary CT angiography (CCT/CCTA) including reduction in blooming artifacts in heavy calcified coronary plaques or beam-hardening artifacts in patients with coronary stents, and a more precise assessment of the degree of stenosis and plaque characteristic thanks to its better spatial resolution. Another potential application of PCCT is the use of a double-contrast agent to characterize myocardial tissue. In this current overview of the existing PCCT literature, we describe the strengths, limitations, recent applications, and promising developments of employing PCCT technology in CCT.

Pericoronary Adipose Tissue as a Marker of Cardiovascular Risk: JACC Review Topic of the Week

Vascular inflammation is a key driver in atherosclerotic progression and plaque rupture. Recent evidence has shown that coronary computed tomography provides a noninvasive method of quantifying coronary inflammation by mapping changes in pericoronary adipose tissue (PCAT) radiodensity, which are associated with cardiovascular diseases. However, there are significant knowledge gaps in the performance and measurement of PCAT that complicate its interpretation. In this review the authors aim to summarize the role of PCAT in cardiac imaging and explore the clinical implications and applicability as a novel biomarker of cardiovascular risk, as well as to discuss its limitations and potential pitfalls.

Atherosclerosis Imaging Quantitative Computed Tomography (AI-QCT) to guide referral to invasive coronary angiography in the randomized controlled CONSERVE trial

AIMS

We compared diagnostic performance, costs, and association with major adverse cardiovascular events (MACE) of clinical coronary computed tomography angiography (CCTA) interpretation versus semiautomated approach that use artificial intelligence and machine learning for atherosclerosis imaging-quantitative computed tomography (AI-QCT) for patients being referred for nonemergent invasive coronary angiography (ICA).

METHODS

CCTA data from individuals enrolled into the randomized controlled Computed Tomographic Angiography for Selective Cardiac Catheterization trial for an American College of Cardiology (ACC)/American Heart Association (AHA) guideline indication for ICA were analyzed. Site interpretation of CCTAs were compared to those analyzed by a cloud-based software (Cleerly, Inc.) that performs AI-QCT for stenosis determination, coronary vascular measurements and quantification and characterization of atherosclerotic plaque. CCTA interpretation and AI-QCT guided findings were related to MACE at 1-year follow-up.

RESULTS

Seven hundred forty-seven stable patients (60 ± 12.2 years, 49% women) were included. Using AI-QCT, 9% of patients had no CAD compared with 34% for clinical CCTA interpretation. Application of AI-QCT to identify obstructive coronary stenosis at the ≥50% and ≥70% threshold would have reduced ICA by 87% and 95%, respectively. Clinical outcomes for patients without AI-QCT-identified obstructive stenosis was excellent; for 78% of patients with maximum stenosis < 50%, no cardiovascular death or acute myocardial infarction occurred. When applying an AI-QCT referral management approach to avoid ICA in patients with <50% or <70% stenosis, overall costs were reduced by 26% and 34%, respectively.

CONCLUSIONS

In stable patients referred for ACC/AHA guideline-indicated nonemergent ICA, application of artificial intelligence and machine learning for AI-QCT can significantly reduce ICA rates and costs with no change in 1-year MACE.

AI Evaluation of Stenosis on Coronary CTA, Comparison With Quantitative Coronary Angiography and Fractional Flow Reserve: A CREDENCE Trial Substudy

BACKGROUND

Clinical reads of coronary computed tomography angiography (CTA), especially by less experienced readers, may result in overestimation of coronary artery disease stenosis severity compared with expert interpretation. Artificial intelligence (AI)-based solutions applied to coronary CTA may overcome these limitations.

OBJECTIVES

This study compared the performance for detection and grading of coronary stenoses using artificial intelligence-enabled quantitative coronary computed tomography (AI-QCT) angiography analyses to core lab-interpreted coronary CTA, core lab quantitative coronary angiography (QCA), and invasive fractional flow reserve (FFR).

METHODS

Coronary CTA, FFR, and QCA data from 303 stable patients (64 ± 10 years of age, 71% male) from the CREDENCE (Computed TomogRaphic Evaluation of Atherosclerotic DEtermiNants of Myocardial IsChEmia) trial were retrospectively analyzed using an Food and Drug Administration-cleared cloud-based software that performs AI-enabled coronary segmentation, lumen and vessel wall determination, plaque quantification and characterization, and stenosis determination.

RESULTS

Disease prevalence was high, with 32.0%, 35.0%, 21.0%, and 13.0% demonstrating ≥50% stenosis in 0, 1, 2, and 3 coronary vessel territories, respectively. Average AI-QCT analysis time was 10.3 ± 2.7 minutes. AI-QCT evaluation demonstrated per-patient sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 94%, 68%, 81%, 90%, and 84%, respectively, for ≥50% stenosis, and of 94%, 82%, 69%, 97%, and 86%, respectively, for detection of ≥70% stenosis. There was high correlation between stenosis detected on AI-QCT evaluation vs QCA on a per-vessel and per-patient basis (intraclass correlation coefficient = 0.73 and 0.73, respectively; P < 0.001 for both). False positive AI-QCT findings were noted in in 62 of 848 (7.3%) vessels (stenosis of ≥70% by AI-QCT and QCA of <70%); however, 41 (66.1%) of these had an FFR of <0.8.

CONCLUSIONS

A novel AI-based evaluation of coronary CTA enables rapid and accurate identification and exclusion of high-grade stenosis and with close agreement to blinded, core lab-interpreted quantitative coronary angiography. (Computed TomogRaphic Evaluation of Atherosclerotic DEtermiNants of Myocardial IsChEmia [CREDENCE]; NCT02173275).

Comparison and Optimization of Cardiovascular Risk Scores in Predicting the 4-Year Outcome of Patients with Obstructive Coronary Arteries Disease

Objective

How well cardiovascular risk models perform in selected atherosclerosis patients for predicting outcomes is unknown. We sought to compare the performance of cardiovascular risk models (Framingham, Globorisk, SCORE2 & SCORE2-OP, and an updated new model) in predicting the 4-year outcome of patients with obstructive coronary artery disease (CAD).

Methods

Patients with suspected CAD who underwent coronary computed tomography angiography (CCTA) were recruited. Obstructive CAD was defined from CCTA as ≥ 50% stenosis. Computed tomography images, the scores of the cardiovascular risk models, and 4-year composite endpoints were assessed. Whether the patients underwent revascularization within 60 days after CCTA was also recorded. Multivariate regression analysis and receiver operating characteristics (ROC) curve analysis were performed.

Results

A total of 95 patients (mean age: 69.5 ± 10.33 years; 69 males) with obstructive CAD were included in this study. After the ROC analysis, the Framingham, Globorisk, SCORE2 & SCORE2-OP risk score showed prediction values with AUC 0.628 (95% CI: 0.532-0.725), 0.647 (95% CI: 0.542-0.742), 0.684 (95% CI: 0.581-0.776), respectively. Multivariate regression analysis showed that, among the three risk models, only SCORE2 & SCORE2-OP risk score was associated with composite endpoints (hazard ratio: 1.050; 95% CI: 1.021-1.079; p = 0.001) after adjusting for confounding factors. The AUC of the new risk model by combing SCORE2 & SCORE2-OP risk score with revascularization and the number of obstructive vessels in predicting composite endpoints reached 0.898 (95% CI: 0.819-0.951).

Conclusion

The SCORE2 & SCORE2-OP risk score combined with the number of obstructive vessels and revascularization is predictive for adverse outcomes in patients with obstructive CAD.

A Noninvasive Assessment of Flow Based on Contrast Dispersion in Computed Tomography Angiography: A Computational and Experimental Phantom Study

Transluminal attenuation gradient (TAG), defined as the gradient of the contrast agent attenuation drop along the vessel, is an imaging biomarker that indicates stenosis in the coronary arteries. The transluminal attenuation flow encoding (TAFE) equation is a theoretical platform that quantifies blood flow in each coronary artery based on computed tomography angiography (CTA) imaging. This formulation couples TAG (i.e., contrast dispersion along the vessel) with fluid dynamics. However, this theoretical concept has never been validated experimentally. The aim of this proof-of-principle phantom study is to validate TAFE based on CTA imaging. Dynamic CTA images were acquired every 0.5 s. The average TAFE estimated flow rates were compared against four predefined pump values in a straight (20, 25, 30, 35, and 40 ml/min) and a tapered phantom (25, 35, 45, and 55 ml/min). Using the TAFE formulation with no correction, the flow rates were underestimated by 33% and 81% in the straight and tapered phantoms, respectively. The TAFE formulation was corrected for imaging artifacts focusing on partial volume averaging and radial variation of contrast enhancement. After corrections, the flow rates estimated in the straight and tapered phantoms had an excellent Pearson correlation of r = 0.99 and 0.87 (p < 0.001), respectively, with only a 0.6%±0.2 mL/min difference in estimation of the flow rate. In this proof-of-concept phantom study, we corrected the TAFE formulation and showed a good agreement with the actual pump values. Future clinical validations are needed for feasibility of TAFE in clinical use.

Biomarkers of Vascular Inflammation for Cardiovascular Risk Prognostication: A Meta-Analysis

OBJECTIVES

The purpose of this study was to systematically explore the added value of biomarkers of vascular inflammation for cardiovascular prognostication on top of clinical risk factors.

BACKGROUND

Measurement of biomarkers of vascular inflammation is advocated for the risk stratification for coronary heart disease (CHD).

METHODS

We systematically explored published reports in MEDLINE for cohort studies on the prognostic value of common biomarkers of vascular inflammation in stable patients without known CHD. These included common circulating inflammatory biomarkers (ie, C-reactive protein, interleukin-6 and tumor necrosis factor-a, arterial positron emission tomography/computed tomography and coronary computed tomography angiography-derived biomarkers of vascular inflammation, including anatomical high-risk plaque features and perivascular fat imaging. The main endpoint was the difference in c-index (Δ[c-index]) with the use of inflammatory biomarkers for major adverse cardiovascular events (MACEs) and mortality. We calculated I2 to test heterogeneity. This study is registered with PROSPERO (CRD42020181158).

RESULTS

A total of 104,826 relevant studies were screened and a final of 39 independent studies (175,778 individuals) were included in the quantitative synthesis. Biomarkers of vascular inflammation provided added prognostic value for the composite endpoint and for MACEs only (pooled estimate for Δ[c-index]% 2.9, 95% CI: 1.7-4.1 and 3.1, 95% CI: 1.8-4.5, respectively). Coronary computed tomography angiography-related biomarkers were associated with the highest added prognostic value for MACEs: high-risk plaques 5.8%, 95% CI: 0.6 to 11.0, and perivascular adipose tissue (on top of coronary atherosclerosis extent and high-risk plaques): 8.2%, 95% CI: 4.0 to 12.5). In meta-regression analysis, the prognostic value of inflammatory biomarkers was independent of other confounders including study size, length of follow-up, population event incidence, the performance of the baseline model, and the level of statistical adjustment. Limitations in the published literature include the lack of reporting of other metrics of improvement of risk stratification, the net clinical benefit, or the cost-effectiveness of such biomarkers in clinical practice.

CONCLUSIONS

The use of biomarkers of vascular inflammation enhances risk discrimination for cardiovascular events.

Aortic valve calcium is associated with left ventricular diastolic function in patients without evidence of ischaemic heart disease: assessment by gated single-photon emission computed tomography

BACKGROUND

Several studies have shown that aortic valve calcium (AVC) is associated with cardiovascular events. Furthermore, the extent of AVC is associated with adverse prognosis even in patients without significant aortic stenosis. We investigated the relationship between AVC and left ventricular (LV) diastolic parameters determined by gated single-photon emission computed tomography (SPECT) in patients with no evidence of ischaemic heart disease.

METHODS

This study included 157 patients with no evidence of ischaemic heart disease who underwent both coronary computed tomography and gated SPECT. The AVC scores were calculated by the Agatston method, and peak filling rate (PFR) and one-third mean filling rate (1/3 MFR) were determined as LV diastolic parameters.

RESULTS

There were 93 (59%) and 64 (41%) patients with and without AVC, respectively, and the AVC scores ranged from 0 to 1251. There was no significant difference in LV end-diastolic volume (EDV) (60 ± 18 vs 62 ± 25 mL, p = 0.52) or LV ejection fraction (67% ± 10% vs 66% ± 8%, p = 0.60) between the two groups. Patients with AVC had lower PFR (2.2 ± 0.5 vs 2.4 ± 0.5 EDV/s, p = 0.002) and 1/3 MFR (1.3 ± 0.3 vs 1.5 ± 0.4 EDV/s, p = 0.003) than those without AVC. Multivariate linear regression analysis showed that ln(AVC score + 1) was significantly associated with PFR and 1/3 MFR.

CONCLUSION

In patients without evidence of ischaemic heart disease, the extent of AVC was inversely correlated with gated SPECT-derived parameters of LV diastolic function.

Coronary Flow and Reserve by Enhanced Transthoracic Doppler Trumps Coronary Anatomy by Computed Tomography in Assessing Coronary Artery Stenosis

We report the case of a 71-year-old patient with many risk factors for coronary atherosclerosis, who underwent computed coronary angiography (CTA), in accordance with the guidelines, for recent onset atypical chest pain. CTA revealed critical (>50% lumen diameter narrowing) stenosis of the proximal anterior descending coronary, and the patient was scheduled for invasive coronary angiography (ICA). Before ICA he underwent enhanced transthoracic echo-Doppler (E-Doppler TTE) for coronary flow detection by color-guided pulsed-wave Doppler recording of the left main (LMCA) and whole left anterior descending coronary artery (LAD,) along with coronary flow reserve (CFR) in the distal LAD calculated as the ratio, of peak flow velocity during i.v. adenosine (140 mcg/Kg/m) to resting flow velocity. E-Doppler TTE mapping revealed only mild stenosis (28% area narrowing) of the mid LAD and a CFR of 3.20, in perfect agreement with the color mapping showing no flow limiting stenosis in the LMCA and LAD. ICA revealed only a very mild stenosis in the mid LAD and mild atherosclerosis in the other coronaries (intimal irregularities). Thus, coronary stenosis was better predicted by E-Doppler TTE than by CTA. Coronary flow and reserve as assessed by E-Doppler TTE trumps coronary anatomy as assessed by CTA, without exposing the patient to harmful radiation and iodinated contrast medium.

Coronary 18F-Sodium Fluoride Uptake Predicts Outcomes in Patients With Coronary Artery Disease

BACKGROUND

Reliable methods for predicting myocardial infarction in patients with established coronary artery disease are lacking. Coronary ¹⁸F-sodium fluoride (¹⁸F-NaF) positron emission tomography (PET) provides an assessment of atherosclerosis activity.

OBJECTIVES

This study assessed whether ¹⁸F-NaF PET predicts myocardial infarction and provides additional prognostic information to current methods of risk stratification.

METHODS

Patients with known coronary artery disease underwent ¹⁸F-NaF PET computed tomography and were followed up for fatal or nonfatal myocardial infarction over 42 months (interquartile range: 31 to 49 months). Total coronary ¹⁸F-NaF uptake was determined by the coronary microcalcification activity (CMA).

RESULTS

In a post hoc analysis of data collected for prospective observational studies, the authors studied 293 study participants (age: 65 ± 9 years; 84% men), of whom 203 (69%) showed increased coronary ¹⁸F-NaF activity (CMA >0). Fatal or nonfatal myocardial infarction occurred only in patients with increased coronary ¹⁸F-NaF activity (20 of 203 with a CMA >0 vs. 0 of 90 with a CMA of 0; p < 0.001). On receiver operator curve analysis, fatal or nonfatal myocardial infarction prediction was highest for ¹⁸F-NaF CMA, outperforming coronary calcium scoring, modified Duke coronary artery disease index and Reduction of Atherothrombosis for Continued Health (REACH) and Secondary Manifestations of Arterial Disease (SMART) risk scores (area under the curve: 0.76 vs. 0.54, 0.62, 0.52, and 0.54, respectively; p < 0.001 for all). Patients with CMA >1.56 had a >7-fold increase in fatal or nonfatal myocardial infarction (hazard ratio: 7.1; 95% confidence interval: 2.2 to 25.1; p = 0.003) independent of age, sex, risk factors, segment involvement and coronary calcium scores, presence of coronary stents, coronary stenosis, REACH and SMART scores, the Duke coronary artery disease index, and recent myocardial infarction.

CONCLUSIONS

In patients with established coronary artery disease, ¹⁸F-NaF PET provides powerful independent prediction of fatal or nonfatal myocardial infarction.

Estimation of endothelial shear stress in atherosclerotic lesions detected by intravascular ultrasound using computational fluid dynamics from coronary CT scans with a pulsatile blood flow and an individualized blood viscosity

INTRODUCTION

Endothelial shear stress (ESS) is a local hemodynamic factor that is dependent on vessel geometry and influences the process of atherogenesis. As in vivo measurements of ESS are not possible, it must be calculated using computational fluid dynamics (CFD). In this feasibility study we explore CFD-models generated from coronary CT-angiography (CCTA) using an individualised blood viscosity and a pulsatile flow profile derived from in vivo measurements.

MATERIALS AND METHODS

We retrospectively recruited 25 consecutive patients who received a CCTA followed by a coronary angiography including intravascular ultrasound (IVUS) and generated 3D models of the coronary arteries from the CT-datasets. We then performed CFD-simulations on these models. Hemodynamically non-relevant stenosis were identified in IVUS. They were isolated in the CFD-model and separated longitudinally into a half with atherosclerotic lesion (AL) and one without (NAL). ESS was measured and compared for both halves.

RESULTS

After excluding vessels with no IVUS data or relevant stenosis we isolated 31 hemodynamically non-relevant excentric AL from a total of 14 vessels. AL segments showed consistently significantly lower ESS when compared to their corresponding NAL segments when regarding minimum (0.9 Pa, CI [0.6, 1.2] vs. 1.3 Pa, CI [0.9, 1.8]; p = 0.004), mean (5.0 Pa, CI [3.4, 6.0] vs. 6.7 Pa, CI [5.5, 8.4]; p = 0.008) and maximum ESS values (12.4 Pa, CI [8.6, 14.6] vs. 19.6 Pa, CI [12.4, 21.0]; p = 0.005). Qualitatively ESS was lower on the inside of bifurcations and curvatures.

CONCLUSION

CFD simulations of coronary arteries from CCTA with an individualised flow profile and blood viscosity are feasible and could provide further prognostic information and a better risk stratification in coronary artery disease. Further prospective studies are needed to investigate this claim.

Association of Plasma MiRNA-204 and the Presence and Severity of Coronary Artery Calcification in Patients With Type 2 Diabetes

We investigated the association between plasma microRNA (miR)-204 and coronary artery calcification (CAC) in patients with type 2 diabetes mellitus (T2DM). We consecutively enrolled 179 individuals with T2DM who underwent coronary computed tomography at Anzhen Hospital from January 2015 to September 2016. The CAC score (CACS) was expressed in Agatston units and >10 Hounsfield units were defined as CAC-positive status. Significant CAC was observed in 98 (54.7%) patients. Plasma miR-204 levels (relative expression) were significantly lower in patients with significant CAC than controls (1.001 ± 0.100 vs 0.634 ± 0.211, P < .001). Plasma miR-204 levels were also negatively correlated with the glycosylated hemoglobin A_1c (HbA_1c) level (r = -0.702, P < .001), CACS (r = -0.710, P < .001), and the United Kingdom Prospective Diabetes Study (UKPDS) score (r = -0.355, P < .001). After multivariate logistic analyses, plasma miR-204 levels were still significantly and independently associated with the presence of CAC (odds ratio = 0.103, CI = 0.018-0.583, P < .001) after adjustment for conventional risk factors. Receiver operating characteristic curve analysis showed that plasma miR-204 levels can predict the severity and extent of CAC, and the specificity was higher than that of the traditional risk factors UKPDS score and HbA_1c. In conclusion, the downregulation of miR-204 was independently associated with CAC in patients with T2DM.

High-Risk Coronary Plaque Regression After Intensive Lifestyle Intervention in Nonobstructive Coronary Disease: A Randomized Study

OBJECTIVES

The authors sought to study the impact of diet and lifestyle intervention on changes in atherosclerotic plaque volume and composition.

BACKGROUND

Lifestyle and diet modification are the leading strategies to manage coronary artery disease; however, their direct impact on atherosclerosis remains unknown. Coronary plaque composition is related to the risk of future cardiovascular events independent of stenosis severity and can be conveniently evaluated with computed tomography angiography (CTA).

METHODS

We enrolled 92 patients (41% women; mean age 60 ± 7.7 years) with nonobstructive (<70% stenosis) coronary atherosclerosis identified by CTA. Participants were randomized (1:1) to either the DISCO (Dietary Intervention to Stop Coronary Atherosclerosis in Computed Tomography) intervention group (systematic follow-up by a dietitian to adhere to the Dietary Approaches to Stop Hypertension nutrition model together with optimal medical therapy [OMT]) or the control group (OMT alone). In all patients, CTA was repeated after 66.9 ± 13.7 weeks. The outcome was change (Δ) in atheroma volume and plaque composition. Based on atherosclerotic tissue attenuation ranges in Hounsfield units (HU), the following components of coronary plaque were distinguished: dense calcium (>351 HU), fibrous plaque (151 to 350 HU), and fibrofatty plaque combined with necrotic core (-30 to 150 HU), referred to as noncalcified plaque.

RESULTS

Percent atheroma volume increased in the control arm (Δ = +1.1 ± 3.4%; p = 0.033) versus no significant change in the experimental arm (Δ = +1.0% ± 4.2%; p = 0.127; intergroup p = 0.851). There was a reduction in noncalcified plaque in both the experimental arm (Δ = -51.3 ± 79.5 mm³ [-1.7 ± 2.7%]; p < 0.001) and the control arm (Δ = -21.3 ± 57.7 [-0.7 ± 1.9%]; p = 0.018), which was greater in the DISCO intervention group (intergroup p = 0.045). No differences in fibrous component or dense calcium changes were observed between the groups.

CONCLUSIONS

Controlled diet and lifestyle intervention together with OMT may slow the progression of atherosclerosis and reduce noncalcified plaque volume compared to OMT alone. (Dietary Intervention to Stop Coronary Atherosclerosis in Computed Tomography [DISCO-CT]; NCT02571803).

The Incremental Role of Coronary Computed Tomography in Chronic Coronary Syndromes

In the context of chronic coronary syndromes (CCS), coronary computed tomography angiography (CCTA) has gained broad acceptance as a noninvasive anatomical imaging tool with ability of excluding coronary stenosis with strong negative predictive value. Atherosclerotic plaque lesions are independent predictors of cardiovascular outcomes in high risk patients with known coronary artery disease (CAD). Calcium detection is commonly expressed through the coronary artery calcium score (CACS), but further research is warranted to confirm the powerness of a CACS-only strategy in both diagnosis and prognosis assessment. Recent studies evidence how defined plaque composition characteristics effectively relate to the risk of plaque instabilization and the overall ischemic burden. Fractional flow reserve from CCTA (FFR-CT) has been demonstrated as a reliable method for noninvasive functional evaluation of coronary lesions severity, while the assessment of perfusion imaging under stress conditions is growing as a useful tool for assessment of myocardial ischemia. Moreover, specific applications in procedural planning of transcatheter valve substitution and follow-up of heart transplantation have gained recent importance. This review illustrates the incremental role of CCTA, which can potentially revolutionize the diagnosis and management pathway within the wide clinical spectrum of CCS.

Relative clinical value of coronary computed tomography and stress echocardiography-guided management of stable chest pain patients: a propensity-matched analysis

AIMS

The European Society of Cardiology recommends coronary computed tomography (CCT) for the assessment of low-risk patients with suspected stable angina. We aimed to assess in a real-life setting the relative clinical value of stress echocardiography (SE)- and CCT-guided management in this population.

METHODS AND RESULTS

Patients with stable chest pain and no prior history of coronary artery disease (CAD) who underwent CCT or SE as the initial investigative strategy were propensity-matched (990 patients each group-age: 59 ± 13.2 years, males: 47.9%) to account for baseline differences in cardiovascular risk factors. Inconclusive tests were 6% vs. 3% (P < 0.005) in CCT vs. SE. Severe (≥70% stenosis) on CCT and inducible ischaemia on SE detected obstructive CAD by invasive coronary angiography in 63% vs. 57% patients (P = 0.33). Over the follow-up period (median 717, interquartile range 93-1069 days) more patients underwent invasive coronary angiography (21.5% vs. 7.3%, P < 0.005), revascularization (7.3% vs. 3.5%, P < 0.005), further functional testing 33.4% vs. 8.7% (P < 0.005), but more patients were prescribed statins 8.8% vs. 3.8% (P < 0.005) in the CCT vs. the SE arm, respectively. Combined all-cause mortality and acute myocardial infarction was low-CCT-2.3% and SE-3.3%-with no significant difference (P = 0.16).

CONCLUSION

Initial SE-guided management was similar for the detection of obstructive CAD, demonstrated better resource utilization, but was associated with reduced prescription of statins although with no difference in medium-term outcome compared to CCT in this very low-risk population. However, a randomized study with longer follow-up is needed to confirm the clinical value of our findings.

Impact of Slice Thickness on the Predictive Value of Lung Cancer Screening Computed Tomography in the Evaluation of Coronary Artery Calcification

Background

Image reconstruction thickness may impact quantitative coronary artery calcium scoring (CACS) from lung cancer screening computed tomography (LCSCT), limiting its application in practice.

Methods and Results

We evaluated Agatston‐based quantitative CACS from 1.25‐mm LCSCT and cardiac computed tomography for agreement in 87 patients. We then evaluated Agatston‐based quantitative CACS from 1.25‐, 2.5‐, and 5.0‐mm slice thickness LCSCT for agreement in 258 patients. Secondary analysis included the impact of slice thickness on predictive value of 4‐year outcomes. Median age of patients who underwent 1.25‐mm LCSCT and cardiac computed tomography was 63 years (interquartile interval, 57, 68). CACS from 1.25‐mm LCSCT and cardiac computed tomography demonstrated a strong Pearson correlation, R=0.9770 (0.965, 0.985), with good agreement. The receiver operating characteristic curve areas under the curve for cardiac computed tomography and LCSCT were comparable at 0.8364 (0.6628, 1.01) and 0.8208 (0.6431, 0.9985), respectively (P=0.733). Median age of patients who underwent LCSCT with 3 slice thicknesses was 66 years (interquartile interval, 63, 73). Compared with CACS from 1.25‐mm scans, CACS from 2.5‐ and 5.0‐mm scans demonstrated strong Pearson correlations, R=0.9949 (0.9935, 0.996) and R=0.9478 (0.9338, 0.959), respectively, though bias was largely negative for 5.0‐mm scans. Receiver operating characteristic curve areas under the curve for 1.25‐, 2.5‐, and 5.0‐mm scans were comparable at 0.7040 (0.6307, 0.7772), 0.7063 (0.6327, 0.7799), and 0.7194 (0.6407, 0.7887), respectively (P=0.6487). When using individualized high‐risk thresholds derived from respective receiver operating characteristic curves, all slice thicknesses demonstrated similar prognostic value.

Conclusions

Slice thickness is an important consideration when interpreting Agatston CACS from LCSCTs. Despite the absence of ECG gating, it appears reasonable to report CACS from either 1.25‐ or 2.5‐mm slice thickness LCSCT to help stratify cardiovascular risk. Conversely, 5.0‐mm scans largely underidentify calcium, limiting practical use within the established CACS values used to categorize cardiovascular risk.

The natural history of napkin-ring sign by coronary computed tomography angiography

Introduction

Despite their significance, the prevalence and the incidence of vulnerable plaques in coronary arteries, as well as their natural history, remain poorly known.

Aim

To evaluate the prevalence, incidence and evolution of napkin-ring sign (NRS), and to establish factors associated with its presence, progression, or regression, in patients with suspected coronary artery disease (CAD).

Material and methods

The study is based on a single-center prospective registry. Eighty-nine patients with suspected CAD underwent two computed tomography angiography (CTA) examinations within an interval of at least 24 months. High-risk plaque was defined by the presence of a low-attenuation area adjacent to the coronary lumen, surrounded by a ring of higher attenuation – NRS.

Results

At the baseline 53 NRS were observed in 22 (25%) patients, 7 (8%) patients had single NRS and 15 (17%) had multiple NRS. After the follow-up period, there were 68 NRS in 32 patients. In 18 patients progression was observed with 23 additional NRS. Presence of single NRS and diabetes were independent predictors of NRS progression.

Conclusions

The number of NRS plaque tends to increase over time in patients with suspected CAD. The progression may be predicted by the presence of diabetes or single NRS.

Relationship Between Sleep Apnea and Coronary Artery Calcium in Patients With Ischemic Stroke

Study Objectives: Coronary artery disease is considered to be the major cause of death amongst patients with ischemic stroke. The coronary artery calcium (CAC) score is related not only to sleep-disordered breathing, but also with future risk of cardiovascular mortality. We investigated the association between the severity of sleep-disordered breathing and CAC score in patients with ischemic stroke.

Methods: We included 32 patients who underwent coronary multichannel computed tomography and polysomnography (within 2 years of the stroke event) amongst the patients admitted to our clinic due to acute ischemic stroke. We investigated vascular risk factors, polysomnography findings, and sleep questionnaire scores, and their relationships with the CAC score.

Results: All patients were found to have sleep apnea of any degree, and 23 (72%) had severe sleep apnea. Twenty-three (72%) patients had a positive CAC score. Higher CAC scores were associated with elevated respiratory disturbance index (RDI), apnea index, oxygen desaturation index, and STOP-BANG test scores. Multivariate analysis after adjusting for potential confounding factors revealed independent relationships between the CAC score and the RDI (ß [SE] = 5.3 [2.1], p = 0.01), oxygen desaturation index (ß [SE] = 6.8 [2.8], p = 0.02), and STOP-BANG test score (ß [SE] = 90.3 [37.7], p = 0.02).

Conclusion: Our findings indicate a relationship between coronary atherosclerotic burden measured by the CAC score and the severity of sleep apnea. Performing polysomnography could be useful for investigating the severity of hidden coronary artery disease among these patients.

Impact of non-invasive anatomical testing on optimal medical prescription in patients with suspected coronary artery disease

Background

Compared to functional testing, coronary computed tomography angiography (CTA) improves clinical outcomes in patients with suspected coronary artery disease (CAD). This is thought to be the result of an increased prescription of preventive medical therapy (statins and aspirin) when relying on a CTA imaging strategy. We compared the rate of statins prescription in a patient cohort assessed either with coronary CTA or exercise testing, and evaluated the agreement on medication prescriptions.

Methods

Consecutive patients who underwent coronary CTA and exercise test for suspected CAD were included. Four clinical cardiologists independently analysed each case based on clinical information and the result of either coronary CTA or exercise test. For each case, treatment strategy and prescription were recorded while blinded to the results of the other cardiac test. Treatment strategy was reassessed using the alternative imaging modality three weeks after the first evaluation.

Results

A total of 113 patients were included. Mean age was 56.7±11.5 years, 52% were males and diabetes were present in 6%. Coronary CTA showed an obstructive epicardial stenosis in 21.4% and any type of atherosclerotic plaque in 54.2%. Functional testing identified ischemia in 9.1%. The use of coronary CTA resulted in higher number of statin (64.9% vs. 44.5%, P<0.001) and aspirin (21.4% vs. 4.3%, P<0.001) prescriptions. There was a substantial agreement on the prescription of statins (mean Cohen's κ coefficient of 0.79±0.07).

Conclusions

Epicardial atherosclerotic disease was found in half of patients with suspected CAD as assessed by coronary CTA. Compared to functional testing, coronary CTA evaluation by coronary was associated with an increase in the rate preventive therapy prescription.

Pretransplant Cardiac Evaluation Using Novel Technology

Hematopoietic stem-cell transplantation (HSCT) is a complex procedure that has been increasingly successful in treating malignant and nonmalignant conditions. Despite its effectiveness, it can be associated with potentially life-threatening adverse effects. New onset heart failure, ischemic disease, and arrhythmias are among the most notable cardiovascular complications post-HSCT. As a result, appropriate cardiac risk stratification prior to transplant could result in decreased morbidity and mortality by identifying patients with a higher probability of tolerating possible toxicities associated with HSCT. In this review, we aim to discuss the utility of cardiac screening using novel modalities of imaging technology in the pre-HSCT phase.

[A Case of Apical Hypertrophic Cardiomyopathy With Rare Anomaly of Coronary Arteries Origin]

A clinical case of apical hypertrophic cardiomyopathy (HCM) in 44‑years old man is presented. In this patient exercise ECG testing and 24‑hour ECG monitoring revealed exercise-induced ST depression in the angiographically confirmed absence of coronary atherosclerosis. The uncommonness of this observation was the combination of HCM with a rare anomaly of coronary arteries origin.

High burden of coronary atherosclerosis in patients with a new diagnosis of type 2 diabetes

PURPOSE

The purposes of this study were to compare the presence, extent and composition of coronary plaques in asymptomatic patients with newly diagnosed type 2 diabetes to age- and sex-matched controls.

METHODS

Patients with newly diagnosed (<1 year) type 2 diabetes ( n = 44) and controls ( n = 44) underwent contrast-enhanced coronary computed tomography angiography. Advanced plaque analysis including total plaque volume and volumes of plaque components (calcified plaque and non-calcified plaque, including low-attenuation [low-density non-calcified plaque]) was performed using validated semi-automated software.

RESULTS

Coronary artery calcification was more often seen in patients with type 2 diabetes (66%) versus controls (48%), p < 0.05. Both the absolute volume (median; interquartile range) of low-density non-calcified plaque (7.9 mm³; 0-50.5 mm³ vs 0; 0-34.3 mm³, p < 0.05) and the increase in low-density non-calcified plaque ratio in relation to total plaque volume ( τ = 0.5, p < 0.001) were significantly higher in patients with type 2 diabetes. More patients with type 2 diabetes had spotty calcification (31% vs 0%, p < 0.05). By multivariate analysis, the presence of any low-density non-calcified plaque was higher in males (odds ratio: 4.06, p < 0.05), who also demonstrated a larger low-density non-calcified plaque volume ( p < 0.001). The presence and extent of low-density non-calcified plaque increased with age, smoking, hypertension and hyperglycaemia, all p < 0.05.

CONCLUSION

Asymptomatic patients with newly diagnosed type 2 diabetes had plaque features associated with increased vulnerability as compared with age- and sex-matched controls.

Comparison of Anatomic and Clinical Outcomes in Patients Undergoing Alternative Initial Noninvasive Testing Strategies for the Diagnosis of Stable Coronary Artery Disease

Background

The optimal initial noninvasive diagnostic testing strategy for stable coronary artery disease (CAD) is unknown. Although American guidelines recommend an exercise stress test as the first‐line test, European guidelines suggest that stress imaging (myocardial perfusion imaging or stress echocardiography) or coronary computed tomography angiography may be preferable. Understanding the relationship between the initial strategy and downstream yield of obstructive CAD and major adverse cardiac events may provide insight as to the optimal strategy.

Methods and Results

We conducted a population‐based retrospective cohort study of adults in Ontario, Canada, using health administrative and clinical data. The relationship between the initial testing strategy and obstructive CAD on invasive angiography was examined. Patients were then followed from their angiogram onward to determine whether they developed a composite end point of major adverse cardiac events. After adjusting for covariates, patients with initial myocardial perfusion imaging (odds ratio: 0.92; 95% confidence interval, 0.85, 1.00), coronary computed tomography angiography (odds ratio: 1.51; 95% confidence interval, 0.91, 2.49), or stress echo (odds ratio: 0.95; 95% confidence interval, 0.84, 1.08) did not a have significantly different yield of obstructive CAD compared with those with an initial exercise stress test. Furthermore, there was no significant difference in downstream major adverse cardiac events after invasive angiography among the 4 initial testing strategies after adjusting for clinically relevant covariates.

Conclusions

Our study found no evidence to suggest significant differences in either yield of obstructive CAD or downstream major adverse cardiac events in patients undergoing an initial noninvasive testing strategy with stress or anatomical imaging compared with those undergoing an initial exercise stress test.

An Audit on the Appropriateness of Coronary Computed Tomography Angiography Referrals in a Tertiary Cardiac Center

BACKGROUND

In response to growing concerns regarding the overuse of coronary computed tomography angiography (CCTA) in the clinical setting, multiple societies, including the American College of Cardiology Foundation, have jointly published revised criteria regarding the appropriate use of this imaging modality. However, previous research indicates significant discrepancies in the rate of adherence to these guidelines.

AIM

To assess the appropriateness of CCTA referrals in a tertiary cardiac center in Bahrain.

METHODS

This retrospective clinical audit examined the records of patients referred to CCTA between the April 1, 2015 and December 31, 2015 in Mohammed bin Khalifa Cardiac Center. Using information from medical records, each case was meticulously audited against guidelines to categorize it as appropriate, inappropriate, or uncertain.

RESULTS

Of the 234 records examined, 176 (75.2%) were appropriate, 47 (20.1%) were uncertain, and 11 (4.7%) were inappropriate. About 74.4% of all referrals were to investigate coronary artery disease (CAD). The most common indication that was deemed appropriate was the detection of CAD in the setting of suspected ischemic equivalent in patients with an intermediate pretest probability of CAD (65.9%). Most referrals deemed inappropriate were requested to detect CAD in asymptomatic patients at low or intermediate risk of CAD (63.6%).

CONCLUSION

This audit demonstrates a relatively low rate of inappropriate CCTA referrals, indicating the appropriate and efficient use of this resource in the Mohammed bin Khalifa Cardiac Center. Agreement on and reclassification of "uncertain" cases by guideline authorities would facilitate a deeper understanding of referral appropriateness.

Use of the augmentation index from applanation tonometry of the radial artery for assessing the extent of coronary artery calcium as assessed by coronary computed tomography

BACKGROUND

The augmentation index (AI) obtained from applanation tonometry of the radial artery is technically the easiest and quickest of available methods for assessing arterial stiffness. We tested the hypothesis that the radial AI is associated with the extent of coronary artery calcium (CAC) as assessed by coronary computed tomography (CCT).

METHODS AND RESULTS

This study included 161 patients with known or suspected coronary artery disease undergoing central hemodynamic measurements and CCT. Radial AI was recorded and was corrected in accordance with heart rate (radial AI@75). Thirty-seven patients had no CAC (CAC score = 0), 85 had low-grade CAC (CAC score = 1-399), and 39 had high-grade CAC (CAC score ≥400). Coronary risk factors, except for age and serum creatinine, were similar among the three groups. There were significant differences in brachial systolic blood pressure (SBP) (p = 0.011) and radial AI@75 (%) (p = 0.006). Multivariate analysis showed that age (β = 0.27, p = 0.001), serum creatinine (β = 0.18, p = 0.03), and radial AI@75 (β = 0.24, p = 0.005) were significantly associated with ln (CAC score + 1), whereas brachial SBP was not. Additionally, serum creatinine (odds ratio: 11.91, 95% confidence interval: 1.46-112.0, p = 0.02) and radial AI@75 (per 10%) (odds ratio: 1.76, 95% confidence interval: 1.22-2.64, p = 0.002) were independent factors associated with high-grade CAC.

CONCLUSIONS

Our results suggest that the radial AI is better for estimating CAC than brachial SBP in patients with known or suspected coronary artery disease.

Fused cardiac hybrid imaging with coronary computed tomography angiography and positron emission tomography in patients with complex coronary artery anomalies

OBJECTIVE

To provide data on the value of fused cardiac hybrid imaging with coronary computed tomography angiography (CCTA) and positron emission tomography myocardial perfusion imaging (PET-MPI) in patients with complex coronary artery anomalies (CCAA).

DESIGN/SETTING

This is a retrospective, single-center study.

PATIENTS

Seven consecutive patients with CCAA (mean 57 ± 7 y, 86% were male) who underwent clinically indicated hybrid CCTA/PET-MPI between 2005 and 2015 in our clinic were included. The findings from both modalities and fused cardiac hybrid imaging were evaluated in these patients.

RESULTS

Out of the seven patients with CCAA, two patients had Bland-White-Garland anomaly, two patients showed a coronary artery fistula, two patients showed a "single right," and one patient showed a "single left" coronary artery. Semiquantitative fused hybrid CCTA/PET-MPI depicted inferolateral scar matching the territory of a nonanomalous vessel with significant concomitant coronary artery disease (CAD) in one patient only. In contrast, analysis of quantitative myocardial blood flow (MBF) as assessed by fused hybrid CCTA/PET-MPI revealed abnormally reduced flow capacities in the territories subtended by the anomalous vessels in 4 patients.

CONCLUSIONS

In this case series of middle-aged patients with CCAA, perfusion defects as assessed by semiquantitative PET-MPI were rare and attributable to concomitant CAD rather than to the anomalous vessel itself. By contrast, impaired MBF as assessed by quantitative hybrid CCTA/PET-MPI was revealed in the majority of patients in the vessel territories subtended by the anomalous coronary artery itself. Fused hybrid CCTA/PET-MPI incorporating information on morphology and on semiquantitative and quantitative myocardial perfusions may provide added value for the management of patients with CCAA.

To assess vascular calcification in the patients of hypoparathyroidism using multidetector computed tomography scan

BACKGROUND

Our pilot data showed an increased intima media thickness in the patients with sporadic idiopathic hypoparathyroidism (SIH). Alteration in homeostasis of calcium, phosphate, and parathyroid hormone (PTH) may predispose to increase the risk of cardiovascular morbidity and mortality. The data on objective assessment of this increased risk is however lacking.

OBJECTIVE

To assess the effect of altered calcium, phosphate, and PTH homeostasis in the patients with SIH on coronary calcium score (a marker of increase vascular risk) by multidetector computed tomography scan (MDCT).

METHODS

In this case-control study, we measured coronary CT calcium score in 30 patients of SIH and compared with 40 age and sex matched healthy subjects. Correlation of coronary calcium score with biochemical parameters was evaluated.

RESULTS

Three of the 30 cases (10%) with SIH were found to have coronary artery calcification (CAC) of varying degree, whereas none of the control showed CAC (P = 0.07). The patients with CAC had significantly lower serum calcium levels (albumin corrected), as compared to the patients without CAC. Inverse correlation of CAC was found with serum calcium levels. No correlation was found with other biochemical parameters.

CONCLUSION

The vascular risk is increased in the patients with SIH as assessed by coronary calcium score measured by MDCT. Low serum calcium levels might be a predisposing factor for this increased risk.

Noninvasive testing strategies in symptomatic, intermediate-risk CAD patients: a perspective on the "PROMISE" trial and its potential implementation in clinical practice

While the results of the Prospective Multicenter Imaging Study for Evaluation of Chest Pain trial (PROMISE trial) are negative for the primary outcome, the results from this large, contemporary trial of >10,000 patients provide important insights into clinical management of patients presenting with chest pain. The results reinforce that while diagnostic testing is an important component of modern management, its choice should be directed by a clinician in a clinical context and with subsequent management in mind. Based on presentation and pre-test probability, the clinician will decide if any additional testing necessary is necessary and if that is the case chose the most appropriate test according to current guidelines, applied to the individual patient and clinical scenario.

Implications of Gender Difference in Coronary Calcification as Assessed by CT Coronary Angiography

BACKGROUND

Arterial calcium as measured by 64-slice computed tomography coronary angiography (64-CT) is a reliable predictor of cardiovascular disease risk. Lipid-rich plaques with lower degrees of calcification may pose greater risk for adverse coronary events than more stabilized calcified plaques as a result of the increased risk of plaque rupture, migration, and subsequent acute coronary syndrome. We sought to examine coronary artery calcium scores as measured via 64-CT to assess the extent of calcification and plaque distribution in women compared to men.

METHODS

A total of 138 patients referred for 64-CT were evaluated. Computerized tomographic angiography was performed using the GE LightSpeed VCT. Subgroup analysis comparing male and female data (including demographic data) was performed. All major coronary arteries were analyzed for coronary stenosis/plaque characterization as well as total vessel calcium (Agatston) score quantification. Patient demographics and coronary risk factors were recorded.

RESULTS

A total of 552 coronary arteries were evaluated in 138 patients (85 men, 53 women). The average age for females was 64.4 ± 10.8 years and for males 60.0 ± 12.8 years. The only demographic/cardiovascular risk factor in which the difference between men and women was significant was smoking history, where 23.5% of men had a history of smoking while only 9.6% of females endorsed having a smoking history (P < 0.044). On comparison of all total vessel calcium scores, males had a higher total mean calcium score than females in each individual vessel. The results were as follows for males versus females, respectively: left main total vessel calcium score 46.49 versus 16.71 (P = 0.167); left anterior descending 265.21 versus 109.6 (P < 0.003); left circumflex 130.5 versus 39.7 (P < 0.004); and right coronary 213.5 versus 73.8 (P < 0.01). The odds of having a total calcium score >100 (versus not) was 3.62 times greater in males relative to females, given that all the other cardiovascular risk factors are adjusted for (95% confidence interval: 1.37-9.54). On average, men had an average of 2.1 ± 1.5 epicardial vessels with a calcium score ≥11 compared to 1.3 ± 1.4 for women (P < 0.005).

CONCLUSION

There are clear differences between males and females regarding total vessel calcium scores and therefore risk of future adverse coronary events. Males tended to have higher average calcium scores in each coronary artery than females with a greater tendency to have multiple vessel involvement. Using this information, more large-scale, randomized controlled studies should be performed to correlate differences in the extent of coronary calcification with the observed variance in clinical presentation during coronary events between males and females as a means to potentially establish gender-specific therapeutic regimens.

High-risk plaque detected on coronary CT angiography predicts acute coronary syndromes independent of significant stenosis in acute chest pain: results from the ROMICAT-II trial

BACKGROUND

It is not known whether high-risk plaque, as detected by coronary computed tomography angiography (CTA), permits improved early diagnosis of acute coronary syndromes (ACS) independently to the presence of significant coronary artery disease (CAD) in patients with acute chest pain.

OBJECTIVES

The primary aim of this study was to determine whether high-risk plaque features, as detected by CTA in the emergency department (ED), may improve diagnostic certainty of ACS independently and incrementally to the presence of significant CAD and clinical risk assessment in patients with acute chest pain but without objective evidence of myocardial ischemia or myocardial infarction (MI).

METHODS

We included patients randomized to the coronary CTA arm of the ROMICAT-II (Rule Out Myocardial Infarction/Ischemia Using Computer-Assisted Tomography II) trial. Readers assessed coronary CTA qualitatively for the presence of nonobstructive CAD (1% to 49% stenosis), significant CAD (≥50% or ≥70% stenosis), and the presence of at least 1 of the high-risk plaque features (positive remodeling, low <30 Hounsfield units plaque, napkin-ring sign, spotty calcium). In logistic regression analysis, we determined the association of high-risk plaque with ACS (MI or unstable angina pectoris) during the index hospitalization and whether this was independent of significant CAD and clinical risk assessment.

RESULTS

Overall, 37 of 472 patients who underwent coronary CTA with diagnostic image quality (mean age 53.9 ± 8.0 years; 52.8% men) had ACS (7.8%; MI n = 5; unstable angina pectoris n = 32). CAD was present in 262 patients (55.5%; nonobstructive CAD in 217 patients [46.0%] and significant CAD with ≥50% stenosis in 45 patients [9.5%]). High-risk plaques were more frequent in patients with ACS and remained a significant predictor of ACS (odds ratio [OR]: 8.9; 95% CI: 1.8 to 43.3; p = 0.006) after adjustment for ≥50% stenosis (OR: 38.6; 95% CI: 14.2 to 104.7; p < 0.001) and clinical risk assessment (age, sex, number of cardiovascular risk factors). Similar results were observed after adjustment for ≥70% stenosis.

CONCLUSIONS

In patients presenting to the ED with acute chest pain but negative initial electrocardiogram and troponin, presence of high-risk plaques on coronary CTA increased the likelihood of ACS independent of significant CAD and clinical risk assessment (age, sex, and number of cardiovascular risk factors). (Multicenter Study to Rule Out Myocardial Infarction by Cardiac Computed Tomography [ROMICAT-II]; NCT01084239).

Cardiac magnetic resonance and computed tomography angiography for clinical imaging of stable coronary artery disease. Diagnostic classification and risk stratification

Despite advances in the pharmacologic and interventional treatment of coronary artery disease (CAD), atherosclerosis remains the leading cause of death in Western societies. X-ray coronary angiography has been the modality of choice for diagnosing the presence and extent of CAD. However, this technique is invasive and provides limited information on the composition of atherosclerotic plaque. Coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR) have emerged as promising non-invasive techniques for the clinical imaging of CAD. Hereby, CCTA allows for visualization of coronary calcification, lumen narrowing and atherosclerotic plaque composition. In this regard, data from the CONFIRM Registry recently demonstrated that both atherosclerotic plaque burden and lumen narrowing exhibit incremental value for the prediction of future cardiac events. However, due to technical limitations with CCTA, resulting in false positive or negative results in the presence of severe calcification or motion artifacts, this technique cannot entirely replace invasive angiography at the present time. CMR on the other hand, provides accurate assessment of the myocardial function due to its high spatial and temporal resolution and intrinsic blood-to-tissue contrast. Hereby, regional wall motion and perfusion abnormalities, during dobutamine or vasodilator stress, precede the development of ST-segment depression and anginal symptoms enabling the detection of functionally significant CAD. While CT generally offers better spatial resolution, the versatility of CMR can provide information on myocardial function, perfusion, and viability, all without ionizing radiation for the patients. Technical developments with these 2 non-invasive imaging tools and their current implementation in the clinical imaging of CAD will be presented and discussed herein.

What is the optimal cut-off point for low coronary artery calcium score assessed by computed tomography? Multi-Detector Computed Tomography ANIN Registry

AIM

This prospective study was conducted to evaluate the incidence and predictors of coronary artery disease (CAD) in relation to the low coronary artery calcium (CAC) score among patients with intermediate probability of CAD.

MATERIAL AND METHODS

A total of 1132 consecutive patients were included in the analysis (58.7 ±10.9 years, 46.7% males). Coronary computed tomography (CCT) angiography was performed in a multi-detector computed tomography scanner. Coronary artery calcium score was calculated by the Agatston method. Obstructive CAD was defined as the presence of coronary artery stenosis ≥ 50% on CCT angiography.

RESULTS

Coronary artery disease was diagnosed in nearly one-fourth of patients (n = 272, 24%). In the receiver operating characteristics (ROC) curve analysis a CAC score of 10 was used as an optimal cut-off point for discriminating obstructive CAD (sensitivity: 0.79, specificity: 0.75, p < 0.0001) whereas for a CAC score of 100 the sensitivity and specificity were 0.48 and 0.92, respectively. On multivariate analysis after adjustment for age, gender, hypertension, hyperlipidemia, creatinine levels, only in patients with CAC score ≤ 10 age (OR = 1.05, 95% CI: 1.02-1.08, p = 0.0005, OR = 1.05, 95% CI: 1.03-1.08, p < 0.0001) and male gender (OR = 3.45, 95% CI: 1.92-6.22, p < 0.0001), likewise in group with CAC score ≤ 100 age (OR = 1.05, 95% CI: 1.03-1.08, p < 0.0001) and male gender (OR = 3.31, 95% CI: 1.88-5.81, p < 0.0001) were independent predictors of obstructive CAD.

CONCLUSIONS

The cut-off point of 10 for CAC score determined patients with CAD with the best sensitivity and specificity. Therefore, a total CAC score < 10 should be classified as "low". In patients with a low CAC score obstructive high risk plaques prone to rupture are presented and are associated with increasing age and male gender.