Usefulness of the Agatston score = 0 to exclude ischemic cardiomyopathy in patients with heart failure

Prevention of Coronary Artery Disease-Related Heart Failure: The Role of Computed Tomography Scan

During the past decade, coronary computed tomography angiography has emerged as the primary modality to noninvasively detect and rule out coronary artery disease. Therefore, this technique could play an important role in identifying patients at high risk of heart failure, considering the high prevalence of coronary artery disease in these patients. The latest technologies have also increased diagnostic accuracy, helping to close the gap with the other functional imaging modalities.

Best practice for the nuclear medicine technologist in CT-based attenuation correction and calcium score for nuclear cardiology

The use of hybrid systems is increasingly growing in Europe and this is progressively important for the final result of diagnostic tests. As an integral part of the hybrid imaging system, computed tomography (CT) plays a crucial role in myocardial perfusion imaging diagnostics. Throughout Europe, a variety of equipment is available and also different university curricula of the nuclear medicine technologist are observed. Hence, the Technologist Committee of the European Association of Nuclear Medicine proposes to identify, through a bibliographic review, the recommendations for best practice in computed tomography applied to attenuation correction and calcium score in myocardial perfusion imaging, which courses in the set of knowledge, skills, and competencies for nuclear medicine technologists. This document aims at providing recommendations for CT acquisition protocols and CT image optimization in nuclear cardiology.

Computed tomography coronary angiography for patients with heart failure (CTA-HF): a randomized controlled trial (IMAGE-HF 1C)

AIMS

This randomized controlled trial sought to determine the financial impact of an initial diagnostic strategy of coronary computed tomography angiography (CCTA) in patients with heart failure (HF) of unknown aetiology. Invasive coronary angiography (ICA) is used to investigate HF patients. CCTA may be a non-invasive cost-effective alternative to ICA. This randomized controlled trial sought to determine the financial impact of an initial diagnostic strategy of coronary computed tomography angiography (CCTA) in patients with heart failure (HF) of unknown aetiology.

METHODS AND RESULTS

This multicentre, international trial enrolled patients with HF of unknown aetiology. The primary outcome was the cost of CCTA vs. ICA strategies at 12 months. Clinical outcomes were also collected. An 'intention-to-diagnose' analysis was performed and a secondary 'as-tested' analysis was based on the modality received. Two hundred and forty-six patients were randomized (age = 57.8 ± 11.0 years, ejection fraction = 30.1 ± 10.1%). The severity of coronary artery disease was similar in both groups. In the 121 CCTA patients, 93 avoided ICA. Rates of downstream ischaemia and viability testing were similar for both arms. There were no significant differences in the composite clinical outcomes or quality of life measures. The cost of CCTA trended lower than ICA [CDN -$871 (confidence interval, CI -$4116 to $3028)]. Using an 'as-tested' analysis, CCTA was associated with a decrease in healthcare costs (CDN -$2932, 95% CI -$6248 to $746).

CONCLUSION

In patients with HF of unknown aetiology, costs were not statistically different between the CCTA and ICA strategies.

CLINICAL TRIALS.GOV

NCT01283659.

Coronary risk stratification of patients with newly diagnosed heart failure

Objective

Coronary artery disease (CAD) is frequent in patients with newly diagnosed heart failure (HF). Multislice CT (MSCT) is a non-invasive alternative to coronary angiography (CAG) suggested for patients with a low-to-intermediate risk of CAD. No established definition of such patients exists. Our purpose was to develop a simple score to identify as large a group as possible with a suitable pretest risk of CAD.

Methods

Retrospective study of patients in Denmark undergoing CAG due to newly diagnosed HF from 2010 to 2014. All Danish patients were registered in two databases according to geographical location. We used data from one registry and multiple logistic regression with backwards elimination to find predictors of CAD and used the derived OR to develop a clinical risk score called the CT-HF score, which was subsequently validated in the other database.

Results

The main cohort consisted of 2171 patients and the validation cohort consisted of 2795 patients with 24% and 27% of patients having significant CAD, respectively. Among significant predictor, the strongest was extracardiac arteriopathy (OR 2.84). Other significant factors were male sex, smoking, hyperlipidaemia, diabetes mellitus, angina and age. A proposed cut-off of 9 points identified 61% of patients with a 15% risk of having CAD, resulting in an estimated savings of 15% of the cost and 21% of the radiation.

Conclusions

A simple score based on clinical risk factors could identify HF patients with a low risk of CAD; these patients may have benefitted from MSCT as a gatekeeper for CAG.

Diagnostic Accuracy of Computed Tomography Coronary Angiography in Patients Presenting with Heart Failure of Unknown Etiology in the Middle East

Objectives:

The purpose of this study is to assess the diagnostic performance of coronary artery calcium score (CACS), computed tomography coronary angiography (CTCA), and the prevalence of coronary artery disease (CAD) as etiology of heart failure (HF) in the Middle Eastern population.

Background:

CTCA has several advantages compared to invasive coronary angiography (ICA). However, studies on the diagnostic accuracy of CTCA and CACS in detecting the prevalence of CAD in patients with newly diagnosed HF are lacking in the Middle East.

Methods:

This study included 204 patients with symptoms of HF and ejection fraction (EF) of <50% by echocardiography who underwent CTCA for diagnosis of CAD within 3 months. The exclusion criteria were defined as patients with a history of CAD, percutaneous coronary intervention, or coronary artery bypass grafting. All patients with obstructive CAD based on CTCA were referred for ICA. In addition, 30 patients with normal CTCA also underwent ICA for verification.

Results:

The mean age was 48 ± 13 years, 69% (n = 141) were male and 31% (n = 73) were female, mean left ventricular EF was 31% ± 9%, and mean CACS was 58 ± 120. Based on the CTCA results, 169 patients had normal or nonobstructive CAD, whereas 35 patients had obstructive CAD. ICA was performed in all 35 patients with obstructive CAD; 30 of them were confirmed as having abnormal ICA, and only 5 had nonobstructive CAD. In addition, 30 patients with normal CTCA underwent ICA testing and were confirmed as having normal ICA. The CTCA had 100% sensitivity, 84% specificity, 86% positive predictive value, and 100% negative predictive value. Of the total population, 30 (15%) who were documented as having obstructive CAD were classified as CAD HF based on ICA. The remaining 174 (85%) patients were classified as having no CAD HF based on normal CTCA and/or ICA. The prevalence of CAD HF based on ICA was 15%. There was a strong correlation between CACS and both CTCA and ICA, with P = 0.001 and 0.0048, respectively.

Conclusion:

In patients with newly diagnosed HF, CACS and CTCA had a 100% sensitivity and negative value as well as overall excellent diagnostic accuracy. CACS = 0 excluded CAD as the etiology of HF with correlation between CACS groups and both CTCA and ICA. The prevalence of CAD as etiology of HF in the study population was 15%.

Single low-dose CT scan optimized for rest-stress PET attenuation correction and quantification of coronary artery calcium

BACKGROUND

Coronary artery calcium is an important marker of coronary artery disease. Myocardial perfusion imaging (MPI) using PET-CT technology requires a CT scan for attenuation correction (CTAC) but is not used routinely to measure coronary calcium burden. This study aimed to determine if a low-dose CTAC scan can also accurately quantify coronary artery calcium.

METHODS

Twenty-three patients underwent both a traditional coronary artery calcium scan on a dedicated cardiac CT scanner (CAC-CT) and a myocardial perfusion scan on a hybrid PET-CT scanner. The standard MPI protocol includes rest and stress-matched PET and CTAC scans. The post-stress CTAC scan was modified to approximate the CAC-CT scan protocol while maintaining ~0.5 mSv dose. Coronary artery calcium scores were compared between the Ca-CTAC and CAC-CT scans.

RESULTS

The modified Ca-CTAC scan showed a trend toward slight decreases in segmental stress perfusion of 2-3.5% in the anterior wall segments (P < 0.05). Correlation and agreement between the proposed Ca-CTAC and standard CAC-CT calcium scores at the optimal threshold of 110 HU were also excellent (r (2) = 0.99, κ = 1.0). There was a small difference in the regression slope vs unity: Ca-CTAC = 0.96 × CAC (P < 0.05), but the categorical classification of calcium was accurate in all twenty-three patients (κ = 1.0).

CONCLUSION

A single low-dose rest CTAC scan can be used for accurate attenuation correction of rest and stress PET perfusion images, thus allowing a post-stress CTAC scan to be optimized for improved quantification of coronary artery calcium without increasing radiation dose vs standard protocols.

Coronary artery calcification on low-dose computed tomography: comparison of Agatston and Ordinal Scores

OBJECTIVE

To compare Agatston with Ordinal Scores for the extent of coronary artery calcification (coronary artery calcium) using nongated low-dose computed tomography (CT) scans.

MATERIALS AND METHODS

A total of 631 asymptomatic participants had CT scans from 2010 to 2013. Their Ordinal and Agatston Score were classified into categories.

RESULTS

The Ordinal Score Categories showed excellent agreement (weighted kappa of 0.83; 95% confidence interval: 0.79-0.88) with the Agatston Score Categories.

CONCLUSIONS

The use of the Ordinal Score is readily obtained on low-dose CT scans that are used for CT screening for lung cancer and these scores are useful for risk stratification of coronary artery disease.

Computed tomographic coronary angiography for patients with heart failure (CTA-HF): a randomized controlled trial (IMAGE HF Project 1-C)

BACKGROUND

The prevalence of heart failure (HF) is rising in industrialized and developing countries. Though invasive coronary angiography (ICA) remains the gold standard for anatomical assessment of coronary artery disease in HF patients, alternatives are being sought. Computed tomographic coronary angiography (CTA) has emerged as an accurate non-invasive diagnostic tool for coronary artery disease (CAD) and has been demonstrated to have prognostic value. Whether or not CTA can be used in HF patients is unknown. Acknowledging the aging population, the growing prevalence of HF and the increasing financial burden of healthcare, we need to identify non-invasive diagnostic tests that are available, safe, accurate and cost-effective.

METHODS/DESIGN

The proposed study aims to provide insight into the efficacy of CTA in HF patients. A multicenter randomized controlled trial will enroll 250 HF patients requiring coronary anatomical definition. Enrolled patients will be randomized to either CTA or ICA (n = 125 per group) as the first test to define coronary anatomy. The primary outcomes will be collected to determine downstream resource utilization. Secondary outcomes will include the composite clinical events and major adverse cardiac events. In addition, the accuracy of CTA for detecting coronary anatomy and obstruction will be assessed in patients who subsequently undergo both CTA and ICA. It is expected that CTA will be a more cost-effective strategy for diagnosis: yielding similar outcomes with fewer procedural risks and improved resource utilization.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01283659. Team grant #CIF 99470.

Epicardial adipose tissue thickness as a predictor of impaired microvascular function in patients with non-obstructive coronary artery disease

OBJECTIVE

To determine if increased epicardial adipose tissue (EAT) measured by cardiac CT could be associated with impaired myocardial flow reserve (MFR) in patients with non-obstructive coronary artery disease (CAD).

BACKGROUND

Studies have shown that EAT volume is related to epicardial obstructive CAD, myocardial ischemia and major adverse cardiac events. However, the association between EAT with coronary microvascular dysfunction and impaired MFR has not been well clarified.

METHODS

Consecutive patients who underwent Rb-82 positron emission tomography (PET), coronary artery calcium (CAC) scoring and non-invasive coronary computed tomography angiography (CCTA) were screened. PET scans were analysed for standard myocardial perfusion (MPI) and MFR. CCTA results were analysed and only patients with non-obstructive CAD (<50% luminal diameter stenosis) were included. EAT thickness and volumes were measured from CT scans.

RESULTS

Of 137 patients without obstructive CAD by CCTA and with normal Rb-82 PET relative MPI, 26 (19.0%) patients had impaired MFR < 2 and 87 (64%) patients had CAC. EAT(thickness), EAT(volume) and CAC values were higher in patients with impaired MFR < 2 than those with normal MFR ≥ 2 (6.7 ± 1.6 mm vs 4.4 ± 1.0 mm, P < .0001; 119.0 ± 25.3 cm(3) vs 105.8 ± 30.5 cm(3), P < .04 and 508.9 ± 554.3 vs 167.8 ± 253.9, P < .0001, respectively). However, EAT(thickness) had a stronger negative correlation with MFR than EAT(volume) and CAC (r = -0.78 vs r = -0.25 and ρ = -0.32, P < .0001). With multivariable logistic regression analysis, only EAT(thickness) was independently associated with impaired MFR (OR 20.7, 95% CI 4.9-87.9, P < .0001). Importantly, the receiver-operator characteristic (ROC) curves demonstrated a superior performance of EAT(thickness) vs EAT(volume) and EAT(thickness) vs CAC in detecting impaired MFR (AUC: 0.945 vs 0.625, difference between AUC: 0.319, P < .0001; AUC: 0.945 vs 0.710, difference between AUC: 0.235, P < .0006, respectively). On ROC curve analysis, an EAT(thickness) cut-off value > 5.6 mm was optimal in detecting impaired MFR with a sensitivity and specificity of 81% and 92%, respectively.

CONCLUSIONS

Increased EAT appears to be associated with impaired MFR. This parameter may help improve detection of patients at risk of microvascular dysfunction.