Coronary computed tomographic angiography and risk of all-cause mortality and nonfatal myocardial infarction in subjects without chest pain syndrome from the CONFIRM Registry (coronary CT angiography evaluation for clinical outcomes: an international multicenter registry)

Coronary Microvascular Function and Cardiovascular Risk Factors in Women With Angina Pectoris and No Obstructive Coronary Artery Disease: The iPOWER Study

BACKGROUND

The majority of women with angina-like chest pain have no obstructive coronary artery disease when evaluated with coronary angiography. Coronary microvascular dysfunction is a possible explanation and associated with a poor prognosis. This study evaluated the prevalence of coronary microvascular dysfunction and the association with symptoms, cardiovascular risk factors, psychosocial factors, and results from diagnostic stress testing.

METHODS AND RESULTS

After screening 3568 women, 963 women with angina-like chest pain and a diagnostic coronary angiogram without significant coronary artery stenosis (<50%) were consecutively included. Mean age (SD) was 62.1 (9.7). Assessment included demographic and clinical data, blood samples, questionnaires, and transthoracic echocardiography during rest and high-dose dipyridamole (0.84 mg/kg) with measurement of coronary flow velocity reserve (CFVR) by Doppler examination of the left anterior descending coronary artery. CFVR was successfully measured in 919 (95%) women. Median (IQR) CFVR was 2.33 (1.98-2.76), and 241 (26%) had markedly impaired CFVR (<2). In multivariable regression analysis, predictors of impaired CFVR were age (P<0.01), hypertension (P=0.02), current smoking (P<0.01), elevated heart rate (P<0.01), and low high-density lipoprotein cholesterol (P=0.02), but these variables explained only a little of the CFVR variation (r(2)=0.09). CFVR was not associated with chest pain characteristics or results from diagnostic stress testing.

CONCLUSION

Impaired CFVR was detected in a substantial proportion, which suggests that coronary microvascular dysfunction plays a role in the development of angina pectoris. CFVR was associated with few cardiovascular risk factors, suggesting that CFVR is an independent parameter in the risk evaluation of these women. Symptom characteristics and results from stress testing did not identify individuals with impaired CFVR.

The Emerging Roles of Coronary Computed Tomographic Angiography: Acute Chest Pain Evaluation and Screening for Asymptomatic Individuals

Coronary computed tomographic angiography (CCTA) has been widely available since 2004. After that, the diagnostic accuracy of CCTA has been extensively validated with invasive coronary angiography for detection of coronary arterial stenosis. In this paper, we reviewed the updated evidence of the role of CCTA in both scenarios including acute chest pain and screening in asymptomatic adults. Several large-scale studies have been conducted to evaluate the diagnostic value of CCTA in the context of acute chest pain patients. CCTA could play a role in delivering more efficient care. For risk stratification of asymptomatic patients using CCTA, latest studies have revealed incremental benefits. Future studies evaluating the totality of plaque characteristics may be useful for determining the role of noncalcified plaque for risk stratification in asymptomatic individuals.

KEY WORDS

Acute chest pain • Computed tomography • Coronary artery disease • Health screening • Stable angina.

Prognostic Value of Coronary Computed Tomography Imaging in Patients at High Risk Without Symptoms of Coronary Artery Disease

At present, traditional risk factors are used to guide cardiovascular management of asymptomatic subjects. Intensified surveillance may be warranted in those identified as high risk of developing cardiovascular disease (CVD). This study aims to determine the prognostic value of coronary computed tomography (CT) angiography (CCTA) next to the coronary artery calcium score (CACS) in patients at high CVD risk without symptoms suspect for coronary artery disease (CAD). A total of 665 patients at high risk (mean age 56 ± 9 years, 417 men), having at least one important CVD risk factor (diabetes mellitus, familial hypercholesterolemia, peripheral artery disease, or severe hypertension) or a calculated European systematic coronary risk evaluation of >10% were included from outpatient clinics at 2 academic centers. Follow-up was performed for the occurrence of adverse events including all-cause mortality, nonfatal myocardial infarction, unstable angina, or coronary revascularization. During a median follow-up of 3.0 (interquartile range 1.3 to 4.1) years, adverse events occurred in 40 subjects (6.0%). By multivariate analysis, adjusted for age, gender, and CACS, obstructive CAD on CCTA (≥50% luminal stenosis) was a significant predictor of adverse events (hazard ratio 5.9 [CI 1.3 to 26.1]). Addition of CCTA to age, gender, plus CACS, increased the C statistic from 0.81 to 0.84 and resulted in a total net reclassification index of 0.19 (p <0.01). In conclusion, CCTA has incremental prognostic value and risk reclassification benefit beyond CACS in patients without CAD symptoms but with high risk of developing CVD.

Differential Prognostic Value of Coronary Computed Tomography Angiography in Relation to Exercise Electrocardiography in Asymptomatic Subjects

BACKGROUND

To explore the prognostic performance of coronary computed tomography angiography (CCTA) and exercise electrocardiography (XECG) in asymptomatic subjects.

METHODS

We retrospectively enrolled 812 (59 ± 9 years, 60.8% male) asymptomatic subjects who underwent CCTA and XECG concurrently from 2003 through 2009. Subjects were followed-up for major adverse cardiac events (MACE) including cardiac death, nonfatal myocardial infarction, unstable angina, and revascularization after 90 days from index CCTA.

RESULTS

The prevalence of occult coronary artery disease (CAD) detected by CCTA was 17.5% and 120 subjects (14.8%) had positive XECG. During a mean follow-up of 37 ± 16 months, nine subjects experienced MACE. In multivariable Cox-regression analysis, only the presence of CAD by CCTA independently predicted future MACE (p = 0.002). Moreover, CAD by CCTA improved the predictive value when added to a clinical risk factor model using the likelihood ratio test (p < 0.001). Notably, the prognostic value of CCTA persisted in the moderate-to-high-risk group as classified by the Duke treadmill score (p = 0.040), but not in the low-risk group (p = 0.991).

CONCLUSION

CCTA provides incremental prognostic benefit over and above XECG in an asymptomatic population, especially for those in a moderate-to-high-risk group as classified by the Duke treadmill score. Risk stratification using XECG may prove valuable for identifying asymptomatic subjects who can benefit from CCTA.

CT coronary angiographic evaluation of suspected anginal chest pain

Non-invasive imaging plays a critical role in the assessment of patients presenting with suspected angina chest pain. However, wide variations in practice across Europe and North America highlight the lack of consensus in selecting the appropriate first-line test for the investigation of coronary artery disease (CAD). CT coronary angiography (CTCA) has a high negative predictive value for excluding the presence of CAD. As such, it serves as a potential 'gatekeeper' to downstream testing by reducing the rate of inappropriate invasive coronary angiography. Two recent large multicentre randomised control trials have provided insights into whether CTCA can be incorporated into chest pain care pathways to improve risk stratification of CAD. They demonstrate that using CTCA enhances diagnostic certainty and improves the targeting of appropriate invasive investigations and therapeutic interventions. Importantly, reductions in cardiac death and non-fatal myocardial infarction appear to be attained through the more appropriate use of preventative therapy and coronary revascularisation when guided by CTCA. With this increasing portfolio of evidence, CTCA should be considered the non-invasive investigation of choice in the evaluation of patients with suspected angina pectoris due to coronary heart disease.

CLINICAL TRIAL NUMBER

NCT01149590, post-results.

Quantifying the impact of using Coronary Artery Calcium Score for risk categorization instead of Framingham Score or European Heart SCORE in lipid lowering algorithms in a Middle Eastern population

Background

The use of the Coronary Artery Calcium Score (CACS) for risk categorization instead of the Framingham Risk Score (FRS) or European Heart SCORE (EHS) to improve classification of individuals is well documented. However, the impact of reclassifying individuals using CACS on initiating lipid lowering therapy is not well understood. We aimed to determine the percentage of individuals not requiring lipid lowering therapy as per the FRS and EHS models but are found to require it using CACS and vice versa; and to determine the level of agreement between CACS, FRS and EHS based models.

Methods

Data was collected for 500 consecutive patients who had already undergone CACS. However, only 242 patients met the inclusion criteria and were included in the analysis. Risk stratification comparisons were conducted according to CACS, FRS, and EHS, and the agreement (Kappa) between them was calculated.

Results

In accordance with the models, 79.7% to 81.5% of high-risk individuals were down-classified by CACS, while 6.8% to 7.6% of individuals at intermediate risk were up-classified to high risk by CACS, with slight to moderate agreement. Moreover, CACS recommended treatment to 5.7% and 5.8% of subjects untreated according to European and Canadian guidelines, respectively; whereas 75.2% to 81.2% of those treated in line with the guidelines would not be treated based on CACS.

Conclusion

In this simulation, using CACS for risk categorization warrants lipid lowering treatment for 5–6% and spares 70–80% from treatment in accordance with the guidelines. Current strong evidence from double randomized clinical trials is in support of guideline recommendations. Our results call for a prospective trial to explore the benefits/risks of a CACS-based approach before any recommendations can be made.

Visualization of Coronary Artery Calcification: Influence on Risk Modification

OBJECTIVES

Direct health provider to patient presentation of coronary computed tomography angiography findings may increase adherence to preventive therapy and risk modification. The purpose of this study was to assess the influence of visualization of coronary artery calcification and lifestyle recommendations on cholesterol concentrations and other risk variables in symptomatic patients with nonobstructive coronary artery disease and hyperlipidemia.

METHODS

We performed a prospective 2-center randomized controlled trial. Patients were randomized 1:1 to intervention or standard follow-up in general practice. The primary end point was change in plasma total cholesterol concentration at 6 months follow-up.

RESULTS

We included 189 patients (mean [± standard deviation] age 61 [12] years, 57% were male). Median (range) Agatston score was 166 (70-2054). The reduction in plasma total cholesterol concentrations tended to be higher in the intervention group than in the control group, 51.04 mg/dL versus 45.63 mg/dL (P = .181). In a subgroup including patients continuing statin therapy during follow-up (n = 147), the reduction in plasma total cholesterol concentrations was more pronounced in the intervention group than in the control group, 66.13 mg/dL versus 55.68 mg/dL (P = .027). In the intervention group, there was a higher degree of statin adherence and a higher proportion of patients who stopped smoking and commenced healthier dietary behavior than in the control group.

CONCLUSIONS

Visualization of coronary artery calcification and brief recommendations about risk modification after coronary computed tomography angiography in symptomatic patients with nonobstructive coronary artery disease and hyperlipidemia may have a favorable influence on plasma total cholesterol concentration, adherence to statin therapy, and risk behavior. Further investigations are needed.

Neither endothelial function nor carotid artery intima-media thickness predicts coronary computed tomography angiography plaque burden in clinically healthy subjects: a cross-sectional study

Background

Cardiovascular risk assessment is usually based on traditional risk factors and risk assessment algorithms. However, a number of risk markers that might provide additional predictive power have been identified. Endothelial function determined by digital reactive hyperemia peripheral arterial tonometry (RH-PAT) and carotid artery intima-media thickness (IMT) have both been proposed as surrogate markers for coronary artery disease (CAD). We aimed to examine the ability of RH-PAT and IMT to predict coronary computed tomography angiography (CTA) plaque burden in clinically healthy subjects.

Methods

Fifty-eight clinically healthy volunteers (50–73 years old) underwent testing for RH-PAT and IMT as well as coronary CTA, including coronary artery calcium (CAC) scoring. Coronary CTA was analyzed with respect to any atheromatous plaques, stenotic as well as non-stenotic. The Mann–Whitney U-test was used to compare the groups with and without CAD and the Spearman test was used to test for correlation between variables.

Results

Twenty-five (43 %) subjects had normal coronary arteries, without any signs of atherosclerosis. The median (range) number of diseased segments was 1 (0–10), RH-PAT index 2.2 (1.4-4.9), IMT 0.70 (0.49-0.99) mm and CAC 4 (0–1882). There was no association between presence or extent of CAD and RH-PAT index (Spearman correlation coefficient r_s = 0.13) or IMT (r_s = 0.098). As expected, CAC was strongly correlated to presence and extent of CAD by coronary CTA (r_s =0.86; p < 0.0001).

Conclusions

Neither evaluation of endothelial function by RH-PAT nor assessment of carotid artery IMT can reliably be used to predict coronary CTA plaque burden in clinically healthy subjects.

State-of-the-Art Updates on Cardiac Computed Tomographic Angiography for Assessing Coronary Artery Disease

OPINION STATEMENT

Cardiac computed tomographic angiography (CCTA) is a noninvasive imaging modality that is increasingly useful for the evaluation of coronary artery disease (CAD). Over the past decade, CCTA has consistently demonstrated an excellent sensitivity for the detection and exclusion of coronary atherosclerosis in patients with stable or acute chest pain symptoms. Large prospective registries have repeatedly demonstrated the prognostic significance of the presence, extent, or absence of CAD by CCTA. In response to initial concerns, technical advances have permitted a dramatic reduction in patient radiation exposure with preserved image quality. For many patients, the radiation dose of CCTA is less than half of that with conventional myocardial perfusion imaging while providing significantly more anatomic information. Furthermore, CCTA's excellent spatial resolution is increasingly being used for noninvasive assessment of coronary plaque, including the detection of higher-risk vulnerable plaque and association between plaque characteristics and ischemia. Finally, new promising techniques that incorporate physiology with anatomy, such as CT-based fractional flow reserve (FFR-CT) and CT perfusion (CTP), are allowing for the noninvasive hemodynamic assessment of coronary stenoses and improvements in the specificity of CCTA findings. Such advances augur a coming transition when CCTA will be a first-line test for the detection, exclusion, and even management of CAD in many patients.

Management of Coronary Artery Calcium and Coronary CTA Findings

Coronary artery calcium (CAC) testing and coronary computed tomography angiography (CTA) have significant data supporting their ability to identify coronary artery disease (CAD) and classify patient risk for atherosclerotic cardiovascular disease (ASCVD). Evidence regarding CAC use for screening has established an excellent prognosis in patients with no detectable CAC, and the ability to risk re-classify the majority of asymptomatic patients considered intermediate risk by traditional risk scores. While data regarding the ideal management of CAC findings are limited, evidence supports statin consideration in patients with CAC > 0 and individualized aspirin therapy accounting for CAD risk factors, CAC severity, and factors which increase a patient's risk of bleeding. In patients with stable or acute symptoms undergoing coronary CTA, a normal CTA predicts excellent prognosis, allowing reassurance and disposition without further testing. When CTA identifies nonobstructive CAD (<50 % stenosis), observational data support consideration of statin use/intensification in patients with extensive plaque (at least four coronary segments involved) and patients with high-risk plaque features. In patients with both nonobstructive and obstructive CAD, multiple studies have now demonstrated an ability of CTA to guide management and improve CAD risk factor control. Still, significant under-treatment of cardiovascular risk factors and high-risk image findings remain, among concerns that CTA may increase invasive angiography and revascularization. To fully realize the impact of atherosclerosis imaging for ASCVD prevention, patient engagement in lifestyle changes and the modification of ASCVD risk factors remain the foundation of care. This review provides an overview of available data and recommendations in the management of CAC and CTA findings.

Role of cardiac multidetector computed tomography beyond coronary angiography

Cardiac multidetector computed tomography (MDCT) has become a useful noninvasive modality for anatomical imaging of coronary artery disease (CAD). Currently, the main clinical advantage of coronary computed tomography angiography (CCTA) appears to be related to its high negative predictive value at low or intermediate pretest probability for CAD. With the development of technical aspects of MDCT, clinical practice and research are increasingly shifting toward defining the clinical implication of plaque morphology, myocardial perfusion, and patient outcomes. The presence of positive vessel remodeling, low-attenuation plaques, napkin-ring sign, or spotty calcification on CCTA could be useful information on high-risk vulnerable plaques. The napkin-ring sign, especially, showed higher accuracy for the detection of thin-cap fibroatheroma. Recently, it was reported that cardiac 3D single-photon emission tomography/CT fusion imaging, noninvasive fractional flow reserve computed from CT, and integrated CCTA and CT myocardial perfusion were associated with improved diagnostic accuracy for the detection of hemodynamically significant CAD. Furthermore, several randomized, large clinical trials have evaluated the clinical value of CCTA for chest pain triage in the emergency department or long-term reduction in death, myocardial infarction, or hospitalization for unstable angina. In this review we discuss the role of cardiac MDCT beyond coronary angiography, including a comparison with other currently available imaging modalities used to examine atherosclerotic plaque and myocardial perfusion.

New insights from major prospective cohort studies with cardiac CT

Each year, 11 million patients present in the USA with new symptoms suggestive of obstructive coronary artery disease (CAD). Most undergo stress testing but <10% demonstrate myocardial ischemia. Moreover, up to 60% will have CAD which adversely affects outcomes. Cardiac computed tomography (CCT) is being used increasingly as an alternative to stress testing to rule out obstructive CAD in symptomatic patients, and large cohort studies in asymptomatic patients have identified burden of coronary atherosclerosis as a predictor of major adverse cardiovascular events (MACE). This review article will critically evaluate major clinical studies on the use of CCT in both symptomatic and asymptomatic patients and discuss the lessons for the clinical use of CCT.

Korean guidelines for the appropriate use of cardiac CT

The development of cardiac CT has provided a non-invasive alternative to echocardiography, exercise electrocardiogram, and invasive angiography and cardiac CT continues to develop at an exponential speed even now. The appropriate use of cardiac CT may lead to improvements in the medical performances of physicians and can reduce medical costs which eventually contribute to better public health. However, until now, there has been no guideline regarding the appropriate use of cardiac CT in Korea. We intend to provide guidelines for the appropriate use of cardiac CT in heart diseases based on scientific data. The purpose of this guideline is to assist clinicians and other health professionals in the use of cardiac CT for diagnosis and treatment of heart diseases, especially in patients at high risk or suspected of heart disease.

Increase in ultrasonic intensity of blood speckle across moderate coronary artery stenosis is an independent predictor of functional coronary artery stenosis measured by fractional flow reserve: pilot study

Background and Aims

The degree of coronary artery stenosis should be assessed both anatomically and functionally. We observed that the intensity of blood speckle (IBS) on intravascular ultrasound (IVUS) is low proximal to a coronary artery stenosis, and high distal to the stenosis. We defined step-up IBS as the distal minus the proximal IBS, and speculated that this new parameter could be used for the functional evaluation of stenosis on IVUS. The aims of this study were to assess the relationships between step-up IBS and factors that affect coronary blood flow, and between step-up IBS and fractional flow reserve (FFR).

Methods and Results

This study enrolled 36 consecutive patients with angina who had a single moderate stenosis in the left anterior descending artery. All patients were evaluated by integrated backscatter IVUS and intracoronary pressure measurements. FFR was calculated from measurements using a coronary pressure wire during hyperemia. Conventional gray-scale IVUS images were recorded, and integrated backscatter was measured in three cross-sectional slices proximal and distal to the stenosis. Step-up IBS was calculated as (mean distal integrated backscatter value) − (mean proximal integrated backscatter value). Stepwise multiple linear regression analysis showed that the heart rate (r = 0.45, P = 0.005), ejection fraction (r = −0.39, P = 0.01), and hemoglobin level (r = −0.32, P = 0.04) were independently correlated with step-up IBS, whereas proximal and distal IBS were not associated with these factors. There was a strong inverse correlation between step-up IBS and FFR (r = −0.84, P < 0.001), which remained significant on stepwise multiple linear regression analysis.

Conclusions

The newly defined parameter of step-up IBS is potentially useful for the functional assessment of coronary artery stenosis.

The myth of the "vulnerable plaque": transitioning from a focus on individual lesions to atherosclerotic disease burden for coronary artery disease risk assessment

The cardiovascular science community has pursued the quest to identify vulnerable atherosclerotic plaque in patients for decades, hoping to prevent acute coronary events. However, despite major advancements in imaging technology that allow visualization of rupture-prone plaques, clinical studies have not demonstrated improved risk prediction compared with traditional approaches. Considering the complex relationship between plaque rupture and acute coronary event risk suggested by pathology studies and confirmed by clinical investigations, these results are not surprising. This review summarizes the evidence supporting a multifaceted hypothesis of the natural history of atherosclerotic plaque rupture. Managing patients at risk of acute coronary events mandates a greater focus on the atherosclerotic disease burden rather than on features of individual plaques.

Scoring of coronary artery calcium scans: history, assumptions, current limitations, and future directions

Coronary artery calcium (CAC) scanning is a reliable, noninvasive technique for estimating overall coronary plaque burden and for identifying risk for future cardiac events. Arthur Agatston and Warren Janowitz published the first technique for scoring CAC scans in 1990. Given the lack of available data correlating CAC with burden of coronary atherosclerosis at that time, their scoring algorithm was remarkable, but somewhat arbitrary. Since then, a few other scoring techniques have been proposed for the measurement of CAC including the Volume score and Mass score. Yet despite new data, little in this field has changed in the last 15 years. The main focus of our paper is to review the implications of the current approach to scoring CAC scans in terms of correlation with the central disease - coronary atherosclerosis. We first discuss the methodology of each available scoring system, describing how each of these scores make important indirect assumptions in the way they account (or do not account) for calcium density, location of calcium, spatial distribution of calcium, and microcalcification/emerging calcium that might limit their predictive power. These assumptions require further study in well-designed, large event-driven studies. In general, all of these scores are adequate and are highly correlated with each other. Despite its age, the Agatston score remains the most extensively studied and widely accepted technique in both the clinical and research settings. After discussing CAC scoring in the era of contrast enhanced coronary CT angiography, we discuss suggested potential modifications to current CAC scanning protocols with respect to tube voltage, tube current, and slice thickness which may further improve the value of CAC scoring. We close with a focused discussion of the most important future directions in the field of CAC scoring.

Effects of cardiac medications for patients with obstructive coronary artery disease by coronary computed tomographic angiography: results from the multicenter CONFIRM registry

OBJECTIVE

This study sought to determine the correlation between baseline cardiac medications and cardiovascular outcomes in patients with obstructive coronary artery disease (CAD) diagnosed by coronary computed tomographic angiography (CCTA).

METHODS

1637 patients (mean age 64.8 ± 10.2 years, 69.6% male) with obstructive CAD from the CONFIRM (COronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multicenter) registry were followed over the course of three years. Obstructive CAD was defined as a ≥50% stenosis in an epicardial vessel. Medications analyzed included statins, aspirin, beta-blockers, angiotensin converting enzyme (ACE) inhibitors, and angiotensin receptor blockers (ARBs). Using Cox proportional-hazards models, we calculated the hazard ratio (HR) with 95% confidence intervals (95% CIs) for incident major adverse cardiovascular events (MACE), defined as death, acute coronary syndrome, or myocardial infarction.

RESULTS

At the time of CCTA, 59%, 54%, 40%, and 46% of patients were using statins, aspirin, beta-blockers, and ACE inhibitors or ARBs, respectively. Statins were associated with a 43% (95% CI = 0.38-0.87, p = 0.008) lower adjusted risk of MACE. Following adjustment, aspirin, beta-blockers, ACE inhibitors and ARBs did not attenuate the risk of MACE. When restricted to patients with multivessel obstructive CAD, only statins were associated with lower risk of MACE.

CONCLUSION

In patients with obstructive CAD by CCTA, the baseline use of statins was associated with improved clinical outcomes. Other cardiac medications-including aspirin, beta-blockers, ACE inhibitors, and ARBs-were not associated with reduced risk of MACE.

The Western Denmark Cardiac Computed Tomography Registry: a review and validation study

BACKGROUND

As a subregistry to the Western Denmark Heart Registry (WDHR), the Western Denmark Cardiac Computed Tomography Registry (WDHR-CCTR) is a clinical database established in 2008 to monitor and improve the quality of cardiac computed tomography (CT) in Western Denmark.

OBJECTIVE

We examined the content, data quality, and research potential of the WDHR-CCTR.

METHODS

We retrieved 2008-2012 data to examine the 1) content; 2) completeness of procedure registration using the Danish National Patient Registry as reference; 3) completeness of variable registration comparing observed vs expected numbers; and 4) positive predictive values as well as negative predictive values of 19 main patient and procedure variables.

RESULTS

By December 31, 2012, almost 22,000 cardiac CTs with up to 40 variables for each procedure have been registered. Of these, 87% were coronary CT angiography performed in patients with symptoms indicative of coronary artery disease. Compared with the Danish National Patient Registry, the overall procedure completeness was 72%. However, an additional medical record review of 282 patients registered in the Danish National Patient Registry, but not in the WDHR-CCTR, showed that coronary CT angiographies accounted for only 23% of all nonregistered cardiac CTs, indicating >90% completeness of coronary CT angiographies in the WDHR-CCTR. The completeness of individual variables varied substantially (range: 0%-100%), but was >85% for more than 70% of all variables. Using medical record review of 250 randomly selected patients as reference standard, the positive predictive value for the 19 variables ranged from 89% to 100% (overall 97%), whereas the negative predictive value ranged from 97% to 100% (overall 99%). Stratification by center status showed consistently high positive and negative predictive values for both university (96%/99%) and nonuniversity centers (97%/99%).

CONCLUSION

WDHR-CCTR provides ongoing prospective registration of all cardiac CTs performed in Western Denmark since 2008. Overall, the registry data have a high degree of completeness and validity, making it a valuable tool for clinical epidemiological research.

Significance of a positive family history for coronary heart disease in patients with a zero coronary artery calcium score (from the Multi-Ethnic Study of Atherosclerosis)

Although a coronary artery calcium (CAC) score of 0 is associated with a very low 10-year risk for cardiac events, this risk is nonzero. Subjects with a family history of coronary heart disease (CHD) has been associated with more subclinical atherosclerosis than subjects without a family history of CHD. The purpose of this study was to assess the significance of a family history for CHD in subjects with a CAC score of 0. The Multi-Ethnic Study of Atherosclerosis cohort includes 6,814 participants free of clinical cardiovascular disease (CVD) at baseline. Positive family history was defined as reporting a parent, sibling, or child who had a heart attack. Time to incident CHD or CVD event was modeled using the multivariable Cox regression; 3,185 subjects were identified from the original Multi-Ethnic Study of Atherosclerosis cohort as having a baseline CAC score of 0 (mean age 58 years, 37% men). Over a median follow-up of 10 years, 101 participants (3.2%) had CVD events and 56 (1.8%) had CHD events. In age- and gender-adjusted analyses, a family history of CHD was associated with an ∼70% increase in CVD (hazard ratio 1.73, 95% confidence interval 1.17 to 2.56) and CHD (hazard ratio 1.72, 95% confidence interval 1.01 to 2.91) events. CVD events remained significant after further adjustment for ethnicity, risk factors, and baseline medication use. In conclusion, asymptomatic subjects with a 0 CAC score and a positive family history of CHD are at increased risk for CVD and CHD events compared with those without a family history of CHD, although absolute event rates remain low.

Incremental prognostic utility of coronary CT angiography for asymptomatic patients based upon extent and severity of coronary artery calcium: results from the COronary CT Angiography EvaluatioN For Clinical Outcomes InteRnational Multicenter (CONFIRM) study

AIM

Prior evidence observed no predictive utility of coronary CT angiography (CCTA) over the coronary artery calcium score (CACS) and the Framingham risk score (FRS), among asymptomatic individuals. Whether the prognostic value of CCTA differs for asymptomatic patients, when stratified by CACS severity, remains unknown.

METHODS AND RESULTS

From a 12-centre, 6-country observational registry, 3217 asymptomatic individuals without known coronary artery disease (CAD) underwent CACS and CCTA. Individuals were categorized by CACS as: 0-10, 11-100, 101-400, 401-1000, >1000. For CCTA analysis, the number of obstructive vessels-as defined by the per-patient presence of a ≥50% luminal stenosis-was used to grade the extent and severity of CAD. The incremental prognostic value of CCTA over and above FRS was measured by the likelihood ratio (LR) χ(2), C-statistic, and continuous net reclassification improvement (NRI) for prediction, discrimination, and reclassification of all-cause mortality and non-fatal myocardial infarction. During a median follow-up of 24 months (25th-75th percentile, 17-30 months), there were 58 composite end-points. The incremental value of CCTA over FRS was demonstrated in individuals with CACS >100 (LRχ(2), 25.34; increment in C-statistic, 0.24; NRI, 0.62, all P < 0.001), but not among those with CACS ≤100 (all P > 0.05). For subgroups with CACS >100, the utility of CCTA for predicting the study end-point was evident among individuals whose CACS ranged from 101 to 400; the observed predictive benefit attenuated with increasing CACS.

CONCLUSION

Coronary CT angiography provides incremental prognostic utility for prediction of mortality and non-fatal myocardial infarction for asymptomatic individuals with moderately high CACS, but not for lower or higher CACS.

A New Approach in Risk Stratification by Coronary CT Angiography

For a decade, coronary computed tomographic angiography (CCTA) has been used as a promising noninvasive modality for the assessment of coronary artery disease (CAD) as well as cardiovascular risks. CCTA can provide more information incorporating the presence, extent, and severity of CAD; coronary plaque burden; and characteristics that highly correlate with those on invasive coronary angiography. Moreover, recent techniques of CCTA allow assessing hemodynamic significance of CAD. CCTA may be potentially used as a substitute for other invasive or noninvasive modalities. This review summarizes risk stratification by anatomical and hemodynamic information of CAD, coronary plaque characteristics, and burden observed on CCTA.

Differential association between metabolic syndrome and coronary artery disease evaluated with cardiac computed tomography according to the presence of diabetes in a symptomatic Korean population

BACKGROUND

Metabolic syndrome (MetS) is associated with increased risks of diabetes and coronary artery disease (CAD). Despite the controversial inclusion of established diabetes in MetS, the association between MetS and CAD according to diabetes status has not been elucidated in the Asian population.

METHODS

We evaluated the association between MetS and CAD using the parameters including any plaque, obstructive plaque, and coronary artery calcium score (CACS) >100 according to diabetes status in 2,869 symptomatic Korean subjects who underwent cardiac computed tomographic angiography.

RESULTS

The prevalence of MetS was significantly higher in the diabetic subjects than in the non-diabetic subjects (69% vs. 34%, P <0.001). The incidence of any plaque (64% vs. 43%, P <0.001), obstructive plaque (26% vs. 13%, P = 0.006), and CACS >100 (23% vs. 12%, P = 0.012) was significantly higher in diabetic subjects than in non-diabetic subjects. Among the MetS components, decreased high-density lipoprotein level was significantly associated with any plaque (odds ratio [OR] 1.35), obstructive plaque (OR 1.55), and CACS >100 (OR 1.57) in the non-diabetic subjects (P <0.01, respectively). However, none of the MetS components were associated with all the parameters in the diabetic subjects. Multivariate regression analysis revealed that MetS and the number of MetS components (MetSN) were independently associated with any plaque (MetS: OR 1.55, P <0.001; MetSN: OR 1.22, P <0.001), obstructive plaque (MetS: OR 1.52, P = 0.003; MetSN: OR 1.25, P <0.001), and CACS >100 (MetS: OR 1.46, P = 0.015; MetSN: OR 1.21, P = 0.004) only in the non-diabetic subjects, respectively.

CONCLUSIONS

MetS was independently associated with the presence and severity of CAD only in the non-diabetic subjects among the symptomatic Korean population.

Coronary plaque imaging by coronary computed tomography angiography

Coronary computed tomography angiography (CTA) has become the useful noninvasive imaging modality alternative to the invasive coronary angiography for detecting coronary artery stenoses in patients with suspected coronary artery disease (CAD). With the development of technical aspects of coronary CTA, clinical practice and research are increasingly shifting toward defining the clinical implication of plaque morphology and patients outcomes by coronary CTA. In this review we discuss the coronary plaque morphology estimated by CTA beyond coronary angiography including the comparison to the currently available other imaging modalities used to examine morphological characteristics of the atherosclerotic plaque. Furthermore, this review underlies the value of a combined assessment of coronary anatomy and myocardial perfusion in patients with CAD, and adds to an increasing body of evidence suggesting an added diagnostic value when combining both modalities. We hope that an integrated, multi-modality imaging approach will become the gold standard for noninvasive evaluation of coronary plaque morphology and outcome data in clinical practice.

Status of hypertension and coronary stenosis in asymptomatic type 2 diabetic patients: analysis from Coronary Computed Tomographic Angiography Registry

BACKGROUND

Limited data exist regarding the prevalence of coronary artery disease (CAD) as well as clinical outcomes in asymptomatic diabetic patients with normotension, controlled hypertension, and uncontrolled hypertension.

METHODS

We enrolled 935 consecutive asymptomatic type 2 diabetic patients without known CAD. Coronary computed tomography angiography was used to evaluate the prevalence and severity of CAD. Blood pressure was measured at baseline. Patients were assigned to one of the three groups: normotension (n=314), controlled hypertension (systolic blood pressure (SBP)< 140 mm Hg with treatment, n=458), or uncontrolled hypertension (SBP ≥ 140 mm Hg with or without treatment, n=163).

RESULTS

Obstructive CAD (≥ 50% stenosis) increased from the prevalence in normotensive patients (33%) to that in patients with controlled (40%) or uncontrolled hypertension (52%) (p=0.003). The incidence of obstructive CAD in multivessel or left main CAD also increased across the three groups (13%, 21%, 32%, respectively, p<0.001). A multivariate logistic regression analysis showed that uncontrolled hypertension was an independent predictor of obstructive CAD (adjusted odds ratio, 2.13; 95% confidence interval (CI), 1.42 to 3.21, p<0.001). During a median follow-up of 3.1 years, uncontrolled hypertension was associated with increased risk of cardiac death or myocardial infarction compared to the risk in normotensive patients (hazard ratio, 6.11; 95% CI, 1.65 to 22.6, p=0.007).

CONCLUSION

In asymptomatic type 2 diabetic patients, uncontrolled hypertension was associated with increased risk of CAD and poor clinical outcomes.

Histogram analysis of lipid-core plaques in coronary computed tomographic angiography: ex vivo validation against histology

PURPOSE

In coronary computed tomographic angiography (CTA), low attenuation of coronary atherosclerotic plaque is associated with lipid-rich plaques. However, an overlap in Hounsfield units (HU) between fibrous and lipid-rich plaque as well as an influence of luminal enhancement on plaque attenuation was observed and may limit accurate detection of lipid-rich plaques by CTA. We sought to determine whether the quantitative histogram analysis improves accuracy of the detection of lipid-core plaque (LCP) in ex vivo hearts by validation against histological analysis.

MATERIALS AND METHODS

Human donor hearts were imaged with a 64-slice computed tomographic scanner using a standard coronary CTA protocol, optical coherence tomography (OCT), a histological analysis. Lipid-core plaque was defined in the histological analysis as any fibroatheroma with a lipid/necrotic core diameter of greater than 200 μm and a circumference greater than 60 degrees as well as a cap thickness of less than 450 μm. In OCT, lipid-rich plaque was determined as a signal-poor region with diffuse borders in 2 quadrants or more. In CTA, the boundaries of the noncalcified plaque were manually traced. The absolute and relative areas of low attenuation plaque based on pixels with less than 30, less than 60, and less than 90 HU were calculated using quantitative histogram analysis.

RESULTS

From 5 hearts, a total of 446 cross sections were coregistered between CTA and the histological analysis. Overall, 55 LCPs (12%) were identified by the histological analysis. In CTA, the absolute and relative areas of low attenuation plaque less than 30, less than 60, and less than 90 HU were 0.14 (0.31) mm2 (4.22% [9.02%]), 0.69 (0.95) mm2 (18.28% [21.22%]), and 1.35 (1.54) mm2 (35.65% [32.07%]), respectively. The low attenuation plaque area correlated significantly with histological lipid content (lipid/necrotic core size [in square millimeter] and a portion of lipid/necrotic core on the entire plaque) at all thresholds but was the strongest at less than 60 HU (r = 0.53 and r = 0.48 for the absolute and relative areas, respectively). Using a threshold of 1.0 mm2 or greater, the absolute plaque area of less than 60 HU in CTA yielded 69% sensitivity and 80% specificity to detect LCP, whereas sensitivity and specificity were 73% and 71% for using 25.0% or higher relative area less than 60 HU. The discriminatory ability of CTA for LCP was similar between the absolute and relative areas (the area under the curve, 0.744 versus 0.722; P = 0.37). Notably, the association of the low attenuation plaque area in CTA with LCP was not altered by the luminal enhancement for the relative (P = 0.48) but for the absolute measurement (P = 0.03). Similar results were achieved when validated against lipid-rich plaque by OCT in a subset of 285 cross sections.

CONCLUSIONS

In ex vivo conditions, the relative area of coronary atherosclerotic plaque less than 60 HU in CTA as derived from quantitative histogram analysis has good accuracy to detect LCP as compared with a histological analysis independent of differences in luminal contrast enhancement.

Usefulness of coronary artery calcium for detecting significant coronary artery disease in asymptomatic individuals

OBJECTIVES

To confirm the value of the coronary artery calcium (CAC) score as an indicator of significant coronary artery disease (CAD) in the asymptomatic Spanish population, using noninvasive coronary angiography by multidetector computed tomography (MDCT).

METHODS

This was a retrospective study of 232 asymptomatic individuals, referred for a cardiovascular health checkup that included CAC and MDCT.

RESULTS

Participants' mean age was 54.6 years (SD ± 12.8); 73.3% of them were men. The mean CAC value was 117.8 (SD ± 277). The individuals with arterial hypertension, diabetes mellitus, smoking and 3 or more risk factors had significantly greater CAC scores. Some 16.4% of the participants were in the ≥75 percentile population for CAC. The MDCT identified 148 individuals (63.8%) with CAD; the coronary lesions were not significant in 116 individuals (50%) and were significant (>50% stenosis) in 32 (13.8%). The participants with diabetes, smoking and ≥3 risk vascular factors had a greater prevalence of significant stenosis. The individuals with >50% stenosis had higher CAC values (352.5 vs. 1; P<.0001), and those in the ≥75 percentile had a high percentage of significant lesions (57.9% vs. 5.2%; P<.0001). The predictors of significant CAD were a CAC score >300 (OR=10.9; 95% CI 3.35-35.8; P=.0001), belonging to the ≥75 percentile (OR=5.65; 95% CI 1.78-17.93; P=.03) and having 3 or more vascular risk factors (OR=4.19; 95% CI 1.44-12.14; P=.008).

CONCLUSION

CAC quantification is an effective method for determining the extent and magnitude of CAD and delimiting the predictive capacity of traditional risk factors.

CV imaging: what was new in 2012?

Echocardiography, single-photon emission computed tomography (SPECT), positron emission tomography (PET), cardiac magnetic resonance, and cardiac computed tomography can be used for anatomic and functional imaging of the heart. All 4 methods are subject to continuous improvement. Echocardiography benefits from the more widespread availability of 3-dimensional imaging, strain and strain rate analysis, and contrast applications. SPECT imaging continues to provide very valuable prognostic data, and PET imaging, on the one hand, permits quantification of coronary flow reserve, a strong prognostic predictor, and, on the other hand, can be used for molecular imaging, allowing the analysis of extremely small-scale functional alterations in the heart. Magnetic resonance is gaining increasing importance as a stress test, mainly through perfusion imaging, and continues to provide very valuable prognostic information based on late gadolinium enhancement. Magnetic resonance coronary angiography does not substantially contribute to clinical cardiology at this point in time. Computed tomography imaging of the heart mainly concentrates on the imaging of coronary artery lumen and plaque and has made substantial progress regarding outcome data. In this review, the current status of the 5 imaging techniques is illustrated by reviewing pertinent publications of the year 2012.

Association between postprandial triglycerides and coronary artery disease detected by coronary computed tomography angiography

BACKGROUND

Studies have demonstrated the association of severe anatomical coronary artery disease (CAD) with postprandial triglycerides (TG) concentrations. Nevertheless the relationship between less severe atherosclerosis plaque burden and postprandial TG is less established.

OBJECTIVE

to study the relationship between postprandial TG and CAD detected by coronary computed tomographic angiography (CTA).

MATERIAL AND METHODS

130 patients who underwent an oral fat tolerance test were enrolled (85 with CAD detected by CTA and 45 without). Postprandial lipemia was studied by measuring TG from T0h to T6h with 2-h intervals, and analyzed the TG change over time using a longitudinal multivariable linear mixed effects model with the log normal of the TG as the primary outcome.

RESULTS

The majority of individuals with CAD had non-obstructive disease (63.3%) Patients with CAD had a slower clearance of postprandial TG change from 4 h to 6 h (p<0.05) compared to patients without CAD. These results remained significant after adjustment for fasting TG and glucose, age, gender, body mass index, and waist circumference. However, those differences did not reach statistical significance after adjustment for fasting HDL-C.

CONCLUSION

Patients with mild (<25% lumen obstruction) and moderate CAD (25-50% lumen obstruction) detected by coronary CTA had an impaired postprandial metabolism, with a delayed TG clearance, when compared to individuals with no CAD. This difference was partially explained by the lower HDL-C. Thus, though postprandial TG may contribute to the development of CAD, this association is partially related to low HDL-C.

Update on cardiac imaging techniques 2013

Cardiac imaging is a cornerstone of diagnosis in heart conditions, and an essential tool for assessing prognosis and establishing treatment decisions. This year, echocardiography stands out as a guide in interventional procedures and in choosing the size of the prosthesis. It is also proving to be a valuable technique in low-flow, low-gradient aortic stenosis. Three-dimensional echocardiography is advancing our knowledge of cardiac anatomy and valvular measurements. The parameters indicating tissue deformation have predictive power in valve disease and in the follow-up of drug-induced cardiotoxicity. Single-photon emission computed tomography and positron emission tomography are proving useful in ischemic heart disease and in the diagnosis of cardiac inflammation and infections. The role of computed tomography has been strengthened in noninvasive coronary angiography, the emergency room management of chest pain, assessment of chronic occlusions, and morphologic study of coronary plaque. Cardiac magnetic resonance imaging remains the gold standard for tissue characterization in ischemic heart disease and cardiomyopathies, and is assuming a greater role in stress studies and in the assessment of myocardial viability.