Clinical contributions of 64-slice computed tomography in the evaluation of cardiomyopathy of unknown origin

The Role of Cardiac Computed Tomography in Heart Failure

PURPOSE OF REVIEW

Cardiac computed tomography (CT) is becoming a more widely applied tool in the diagnosis and management of a variety of cardiovascular conditions, including heart failure. The aim of this narrative review is to examine the role of cardiac CT in patients with heart failure.

RECENT FINDINGS

Coronary computed tomographic angiography has robust diagnostic accuracy for ruling out coronary artery disease. These data are reflected in updated guidelines from major cardiology organizations. New roles for cardiac CT in myocardial imaging, perfusion scanning, and periprocedural planning, execution, and monitoring are being implemented. Cardiac CT is useful in ruling out coronary artery disease its diagnostic accuracy, accessibility, and safety. It is also intricately linked to invasive cardiac procedures that patients with heart failure routinely undergo.

Diagnostic accuracy of coronary computed tomography angiography in ischemic workup of heart failure: a meta-analysis

Aim: The role of coronary computed tomography angiography (CCTA) in evaluating the etiology of heart failure with reduced ejection fraction (HFrEF) is unclear. This is a meta-analysis assessing the pooled diagnostic accuracy of CCTA in diagnosing significant coronary artery disease in HFrEF. Materials & methods: Electronic databases were searched for studies comparing CCTA with invasive coronary angiography in HFrEF. A random-effects model meta-analysis was conducted. Results: Five studies comprising 269 patients were included. On patient-based analysis, pooled sensitivity and specificity of CCTA were 0.99 (95% CI: 0.94-1.00) and 0.94 (95% CI: 0.90-0.97), respectively. On segment-based analysis, pooled sensitivity and specificity were 0.74 (95% CI: 0.67-0.80) and 0.99 (95% CI: 0.98-0.99), respectively. Conclusion: CCTA has excellent diagnostic accuracy in diagnosing significant coronary artery disease in newly diagnosed HFrEF.

Multimodality imaging in the diagnosis, risk stratification, and management of patients with dilated cardiomyopathies: an expert consensus document from the European Association of Cardiovascular Imaging

Dilated cardiomyopathy (DCM) is defined by the presence of left ventricular or biventricular dilatation and systolic dysfunction in the absence of abnormal loading conditions or coronary artery disease sufficient to explain these changes. This is a heterogeneous disease frequently having a genetic background. Imaging is important for the diagnosis, the prognostic assessment and for guiding therapy. A multimodality imaging approach provides a comprehensive evaluation of all the issues related to this disease. The present document aims to provide recommendations for the use of multimodality imaging according to the clinical question. Selection of one or another imaging technique should be based on the clinical condition and context. Techniques are presented with the aim to underscore what is 'clinically relevant' and what are the tools that 'can be used'. There remain some gaps in evidence on the impact of multimodality imaging on the management and the treatment of DCM patients where ongoing research is important.

Methodological quality of diagnostic accuracy studies on non-invasive coronary CT angiography: influence of QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) items on sensitivity and specificity

OBJECTIVES

To evaluate the methodological quality of diagnostic accuracy studies on coronary computed tomography (CT) angiography using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) tool.

METHODS

Each QUADAS item was individually defined to adapt it to the special requirements of studies on coronary CT angiography. Two independent investigators analysed 118 studies using 12 QUADAS items. Meta-regression and pooled analyses were performed to identify possible effects of methodological quality items on estimates of diagnostic accuracy.

RESULTS

The overall methodological quality of coronary CT studies was merely moderate. They fulfilled a median of 7.5 out of 12 items. Only 9 of the 118 studies fulfilled more than 75 % of possible QUADAS items. One QUADAS item ("Uninterpretable Results") showed a significant influence (P = 0.02) on estimates of diagnostic accuracy with "no fulfilment" increasing specificity from 86 to 90 %. Furthermore, pooled analysis revealed that each QUADAS item that is not fulfilled has the potential to change estimates of diagnostic accuracy.

CONCLUSIONS

The methodological quality of studies investigating the diagnostic accuracy of non-invasive coronary CT is only moderate and was found to affect the sensitivity and specificity. An improvement is highly desirable because good methodology is crucial for adequately assessing imaging technologies.

KEY POINTS

• Good methodological quality is a basic requirement in diagnostic accuracy studies. • Most coronary CT angiography studies have only been of moderate design quality. • Weak methodological quality will affect the sensitivity and specificity. • No improvement in methodological quality was observed over time. • Authors should consider the QUADAS checklist when undertaking accuracy studies.

Use of 3x2 tables with an intention to diagnose approach to assess clinical performance of diagnostic tests: meta-analytical evaluation of coronary CT angiography studies

OBJECTIVE

To determine whether a 3 × 2 table, using an intention to diagnose approach, is better than the "classic" 2 × 2 table at handling transparent reporting and non-evaluable results, when assessing the accuracy of a diagnostic test.

DESIGN

Based on a systematic search for diagnostic accuracy studies of coronary computed tomography (CT) angiography, full texts of relevant studies were evaluated to determine whether they could calculate an alternative 3 × 2 table. To quantify an overall effect, we pooled diagnostic accuracy values according to a meta-analytical approach.

DATA SOURCES

Medline (via PubMed), Embase (via Ovid), and ISI Web of Science electronic databases.

ELIGIBILITY CRITERIA

Prospective English or German language studies comparing coronary CT with conventional coronary angiography in all patients and providing sufficient data for a patient level analysis.

RESULTS

120 studies (10,287 patients) were eligible. Studies varied greatly in their approaches to handling non-evaluable findings. We found 26 studies (including 2298 patients) that allowed us to calculate both 2 × 2 tables and 3 × 2 tables. Using a bivariate random effects model, we compared the 2 × 2 table with the 3 × 2 table, and found significant differences for pooled sensitivity (98.2 (95% confidence interval 96.7 to 99.1) v 92.7 (88.5 to 95.3)), area under the curve (0.99 (0.98 to 1.00) v 0.93 (0.91 to 0.95)), positive likelihood ratio (9.1 (6.2 to 13.3) v 4.4 (3.3 to 6.0)), and negative likelihood ratio (0.02 (0.01 to 0.04) v 0.09 (0.06 to 0.15); (P<0.05)).

CONCLUSION

Parameters for diagnostic performance significantly decrease if non-evaluable results are included by a 3 × 2 table for analysis (intention to diagnose approach). This approach provides a more realistic picture of the clinical potential of diagnostic tests.

Accuracy of multi-slice computed tomography for measurement of left ventricular ejection fraction compared with cardiac magnetic resonance imaging and two-dimensional transthoracic echocardiography: a systematic review and meta-analysis

BACKGROUND

Multi-slice computed tomography (MSCT) allows non-invasive assessment of the coronary arteries and simultaneously can provide measurement of left ventricular ejection fraction (LVEF). The accuracy of newer MSCT generations (64-slice or more) for assessment of LVEF compared with magnetic resonance imaging (MRI) and two-dimensional transthoracic echocardiography (TTE) has not been evaluated in a meta-analysis.

PURPOSE

To evaluate, via a systematic literature review and meta-analysis, whether MSCT can assess LVEF with high accuracy compared with MRI and TTE.

METHODS

Electronic databases and reference lists for relevant published studies were searched. Twenty-seven eligible studies provided mean LVEF% with its standard deviation (SD) measured by MSCT versus MRI and TTE. Meta-analysis of weighted mean difference (WMD) and Bland-Altman method were used to quantify the mean difference and agreement between MSCT compared with MRI and TTE.

RESULTS

The results of combining 12 studies showed no significant difference in LVEF% between MSCT and MRI with a WMD of -0.11 (-1.48, 1.26, 95% CI), p=0.88. Bland-Altman analysis showed excellent agreement between MSCT and MRI with a bias of 0.0 (-3.7, 3.7 ± 1.96SD) with 95% CI. The results of combining 15 studies showed no significant difference in LVEF between MSCT versus TTE measurements with a WMD of 0.19 (-1.13 to 1.50; 95% CI), p=0.87. Bland-Altman analysis showed excellent agreement between MSCT and TTE with a bias of 0.3 (-4.7, 5.7 ± 1.96SD) with 95% CI.

CONCLUSION

The newer MSCT generations can provide accurate LVEF measurement compared to MRI and TTE. MSCT represents a valid technique for the combined evaluation of LVEF and coronary artery disease.

Diagnostic performance of computed tomography angiography for differentiating ischemic vs nonischemic cardiomyopathy

BACKGROUND

Although the use of computed tomography angiography (CTA) is considered "appropriate" to distinguish ischemic vs nonischemic etiology in patients with cardiomyopathy under the current clinical practice guideline, the evidence to support this has not been evaluated in larger scale studies. Thus, we conducted a meta-analysis of available studies published by October 2010 to address this question.

METHODS

Studies evaluating the diagnostic accuracy of CTA versus invasive coronary angiography (as the gold standard) for significant coronary artery disease (CAD) detection (ischemic cardiomyopathy) in patients with no known history of CAD with significantly depressed left ventricular function (ejection fraction; EF < 35%) were selected for the meta-analysis. Sensitivity, specificity, positive, and negative likelihood ratios were calculated on per patient and per segment basis using random effects model (DerSimonian-Laird Method) for computing summary estimates and receiver operator curve (ROC) analysis for evaluating overall diagnostic accuracy.

RESULTS

Six studies comprising 452 patients met the selection criteria for the meta-analysis. The pooled patient population was 62 ± 3 years old, with 29% females, 16% diabetics, and 43% with a history of hypertension. Mean EF was 32% ± 1%. The pooled summary estimate of sensitivity of CTA for diagnosis of ischemic cardiomyopathy was 98% [95% confidence interval (CI); 94% to 99%] and specificity was 97% (CI 94% to 98%), yielding a negative likelihood ratio of 0.06 (CI 0.02 to 0.13) and positive likelihood ratio of 20.85 (CI 12 to 36). There was no significant heterogeneity between studies for these estimates. The receiver operator curve analysis showed a robust discriminate diagnostic accuracy of ischemic etiology with an area under curve of 0.99 (P < .00001).

CONCLUSION

CTA appears as a clinically applicable accurate diagnostic modality to exclude ischemic etiology in patients with cardiomyopathy of undetermined cause and this further supports the appropriateness of the use of CTA to determine the cause of new onset cardiomyopathy of unknown etiology.