The diagnostic performance of multi-slice coronary computed tomographic angiography: a systematic review

An exemplary reanalysis of coronary computed tomography angiography diagnostic meta-analyses shows insufficient data sharing and incorrect sensitivity and specificity estimates

OBJECTIVES

To systematically evaluate the reproducibility of primary data and, the reproducibility and correctness of pooled sensitivity and specificity estimates reported in a sample of diagnostic meta-analyses.

STUDY DESIGN AND SETTING

We conducted an exemplary systematic review of diagnostic meta-analyses comparing coronary computed tomography angiography to invasive coronary angiography in patients with suspected coronary artery disease. The objectives were to assess 1) the reproducibility of contingency tables, 2) the reproducibility of pooled sensitivity and specificity, and 3) differences to reported results when applying a recommended bivariate binomial model for pooling sensitivity and specificity. Therefore, we reproduced the contingency tables and recalculated sensitivity and specificity by utilizing both the pooling method of each meta-analysis and a bivariate binomial model. We used linear trends to assess the improvement of these objectives over time.

RESULTS

We identified 38 diagnostic meta-analyses, each including on average 19 primary studies (range: 3 to 89 studies; total: 715-including duplicates) with an average of approximately 1800 patients per meta-analysis (range: 118 to 7516 patients). For 31 meta-analyses (82%, 95% CI: 65%, 91%), the contingency tables were reproducible; however, only 15 published them. Using the pooling method of each meta-analysis, we obtained comparable recalculated sensitivities/specificities for 28 meta-analyses (74% [57%, 86%]). Only 11 meta-analyses pooled sensitivity/specificity using a bivariate binomial model (29% [16%, 46%]). When all meta-analyses were pooled with this model, published sensitivities/specificities were confirmed for 19 of 38 meta-analyses (50% [34%, 66%]). There was only marginal improvement in data availability and application of recommended pooling methods over time.

CONCLUSION

Data sharing should become standard practice along with the use of appropriate pooling methods. Journal publication requirements may play a key role in enhancing the quality of scientific reporting and methodological standards which may lead to more reliable and consistent outcomes. The ability to reproduce sensitivity and specificity estimates in diagnostic imaging meta-analyses is dependent on the availability of contingency tables and the explicit reporting of pooling methods and software used.

Diagnostic accuracy of prospectively gated, 128-slice or greater CTCA at high heart rates: a systematic review and meta-analysis

INTRODUCTION

Prospectively gated 64-slice CT coronary angiography (CTCA) may be contraindicated for heart rates (HRs) over 65 beats per minute (bpm) due to reduced diagnostic sensitivity. Newer CT scanners typically provide 128 or more slices and superior temporal resolution compared with older models; consequently, diagnostic accuracy for current technology prospectively gated CTCA may be adequate at HRs above 65 bpm. The aim of this systematic review was to investigate the diagnostic accuracy of CTCA using 128-slice or greater CT technology when compared with conventional coronary angiography for patients with HRs >65 bpm.

METHODS

A systematic search of PubMed, CINAHL, EMBASE and Scopus was performed as well as unpublished databases, sources and reference lists. Titles and abstracts were screened by two independent reviewers. Full-text screening was then performed. Studies that determined diagnostic accuracy of coronary artery stenosis in adult patients with high heart rates utilising prospectively gated 128 detector or greater scanners were included. Studies that were included in the review underwent critical appraisal using the QUADAS-2 tool.

RESULTS

Ten studies were included in the systematic review, with nine of these included in a diagnostic test accuracy meta-analysis, including six of which reported data at the patient level. Meta-analysis indicated very high pooled sensitivity 100% (95% CI 0.99, 1.00); however, pooled specificity was less at 79% (95% CI 0.69, 0.88).

CONCLUSIONS

Prospectively gated CT coronary angiography may be justifiable at heart rates above 65 bpm if performed on a 128-slice or greater CT unit. Caution regarding the implication of a positive result is recommended due to reduced specificity. Further evidence is required before consideration of a new higher heart threshold.

Coronary Computed Tomography Angiography for Assesment of Stable Coronary Artery Disease – a Cost-effectiveness Perspective

Patients with chest pain presenting to the emergency room are currently investigated using either invasive coronary angiography (ICA) or noninvasive coronary computed tomography angiography (CCTA). ICA remains an expensive diagnostic tool and exposes patients to a high risk of periprocedural complication. Besides the currently available expansive economic evidence, there is still an important lingering issue: to establish, from the healthcare provider’s point of view, which is the most cost-effective investigation tool for the detection of significant coronary artery disease. The aim of this article is to present the latest developments in the field of imaging tools for the detection of coronary atherosclerosis in patients with chest pain, from the perspective of a cost-effectiveness analysis.

CT Angiography Followed by Invasive Angiography in Patients With Moderate or Severe Ischemia-Insights From the ISCHEMIA Trial

OBJECTIVES

This study aimed to examine the concordance of coronary computed tomographic angiography (CCTA) assessment of coronary anatomy and invasive coronary angiography (ICA) as the reference standard in patients enrolled in the ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches).

BACKGROUND

Performance of CCTA compared with ICA has not been assessed in patients with very high burdens of stress-induced ischemia and a high likelihood of anatomically significant coronary artery disease (CAD). A blinded CCTA was performed after enrollment to exclude patients with left main (LM) disease or no obstructive CAD before randomization to an initial conservative or invasive strategy, the latter guided by ICA and optimal revascularization.

METHODS

Rates of concordance were calculated on a per-patient basis in patients randomized to the invasive strategy. Anatomic significance was defined as ≥50% diameter stenosis (DS) for both modalities. Sensitivity analyses using a threshold of ≥70% DS for CCTA or considering only CCTA images of good-to-excellent quality were performed.

RESULTS

In 1,728 patients identified by CCTA as having no LM disease ≥50% and at least single-vessel CAD, ICA confirmed 97.1% without LM disease ≥50%, 92.2% with at least single-vessel CAD and no LM disease ≥50%, and only 4.9% without anatomically significant CAD. Results using a ≥70% DS threshold or only CCTA of good-to-excellent quality showed similar overall performance.

CONCLUSIONS

CCTA before randomization in ISCHEMIA demonstrated high concordance with subsequent ICA for identification of patients with angiographically significant disease without LM disease.

Radiological outpatient' visits to avoid inappropriate cardiac CT examinations: an 8-year experience report

PURPOSE

The aim of this study was to evaluate the appropriateness of the cardiac computed tomography angiography (CCTA) prescriptions according to the "2010-Appropriate-Use-Criteria-for-Cardiac-Computed-Tomography-Angiography" (AUCCTA) and "Clinical-indication-for-CCTA" (CICCTA) among different specialities (Cardiologist [CA], General Practitioner [GP], Other Specialists [OS]) and prescribers' age.

MATERIALS AND METHODS

This is a single-centre, single-arm, cohort study. We prospectively enrolled 815 patients (October 2012-May 2019) who underwent a radiological outpatient visit, before CCTA examination. Prescriptions to the examination were categorized as follows: Appropriate (A), Uncertain (U) and Inappropriate (Ina), according to AUCCTA and I, II, III and Inv for CICCTA. This categorization was stratified according to CA, GP and OS and prescribers' age. CCTA was performed in patients whom indications belong to A/U categories.

RESULTS

Eight hundred and fifteen CCTA prescriptions were analysed. An yearly increase in prescriptions was found in the eight-year observational period (2012/2019 projection: 72 vs 223). Considering AUCCTA, indication A was 540/815 (66.3%), indication U was 113/815 (13.9%) and Ina accounted for 162/815 (19.9%; 128/162 [79.0%] indications with stress test listed as criterium of inappropriateness). Only U indications decreased over years (p = 0.003). Regarding CICCTA, 501/815 (61.5%) patients were categorized as I, 144/815 (17.7%) as II, 102/815 (12.5%) as III, 67/815 (8.2%) were INV and 1/815 (0.1%) were non-classified. Clinical referrals were CA in 495/786 (63.0%), GPs in 57/786 (7.3%) GP and OS in 234/786 (29.8%) [p < 0.01]. No statistically significant differences were observed in the appropriateness among different specialty physicians. Younger doctors have a lower chance to not meet A indication (OR 0.98 [CI 95% 0.96-0.99]; p = 0.003).

CONCLUSION

Our study highlights the importance of a pre-radiological visit prior to CCTA, which prevented execution of 19.9% of inappropriate examinations. Age of prescribers had an impact on appropriateness, with younger doctors having a lower chance to not meet A indication.

Synthesis and Antiplatelet Potential Evaluation of 1,3,4-Oxadiazoles Derivatives

A novel series of 2-(3-methyl-1,6-diphenyl-1H-pyrazolo[3,4-b]pyridin-4-yl)-5-aryl-1,3,4-oxadiazoles (4a–4h) has been synthesized from corresponding hydrazones (3a–3h) and evaluated their antiplatelet aggregation effect induced by arachidonic acid and collagen. Spectral data and elemental evaluation were used to confirm the structure of the compounds while molecular docking against cyclooxygenase 1 and 2 (COX1 & COX2) and quantitative structure-activity relationship (QSAR) were performed in describing their antiplatelet potential. All synthesized compound exhibited more than 50% platelet aggregation inhibition against both arachidonic acid and collagen. Antiplatelet activities results showed that 4b and 4f compounds have highest % inhibition against arachidonic acid. High Egap and ionization potential values showed that the compound 4d, 4e and 4f were supposed to be more active and good electron donor while 4b, 4c, 4d, 4e, 4g and 4h might be more active due to more electrophilic sites. Interaction with more than one residues in the binding pocket of COX-1 in comparison with aspirin and ligand efficacy (LE) consequences showed that compounds have excellent action potential for COX-1. Computational evaluations are in good agreement with antiplatelet activities of the compounds. All compounds might be promising antiplatelet agents especially 4b, 4f and helpful in the synthesis of new drugs for the treatment of cardiovascular diseases (CVDs).

Risk factors and utility of maximum carotid intima-media thickness as a surrogate marker for coronary artery stenosis

Background

This study investigated the factors associated with coronary artery stenosis in outpatients. Furthermore, the usefulness of maximum carotid intima–media thickness (maximum-IMT) as a surrogate marker of coronary artery stenosis was evaluated.

Methods

We conducted a single-center retrospective study. A total of 601 outpatients (338 males; 263 females; mean age, 69.8±10.0 years) who underwent coronary computed tomography angiography between April 2006 and March 2012 were analyzed. The associations between coronary artery stenosis (≥75%) as determined by coronary computed tomography angiography and clinical and laboratory parameters were evaluated by multivariate logistic regression. Validation of maximum-IMT as measured by ultrasonography as a surrogate marker of coronary artery stenosis was analyzed by receiver operating characteristic (ROC) curve analysis.

Results

The estimated glomerular filtration rate (eGFR: mL/min/1.73 m²) (odds ratio [OR] 0.985, p<0.01), diabetes mellitus (OR 1.98, p<0.05), and maximum-IMT (mm) (OR 1.76, p<0.01) were significantly associated with coronary artery stenosis (≥75%). In analysis of each group categorized by identified factors, such as renal impairment (eGFR <60 mL/min/1.73 m²) and diabetes mellitus, the ROC curve of maximum-IMT was significant in the group of patients with diabetes mellitus without renal impairment (p<0.01) (cutoff value of maximum-IMT, 2.0 mm; sensitivity, 0.74; and specificity, 0.54) but not in other groups.

Conclusion

Renal impairment, diabetes mellitus, and increased maximum-IMT may be significant risk factors of coronary artery stenosis. Maximum-IMT as measured by ultrasonography may be a useful surrogate marker for coronary artery stenosis in patients with diabetes mellitus without renal impairment but not in other patients.

Incidental extra-cardiac findings on 13N-ammonia myocardial perfusion PET/CT

BACKGROUND

The objective of this study was to describe the prevalence of incidental extra-cardiac findings (IECFs) on myocardial perfusion PET/CTs and the prevalence of potentially clinically relevant and clinically irrelevant IECFs, as well as detection rate of previously unknown malignancies.

METHODS AND RESULTS

From September 2013 until February 2016, a total of 1397 consecutive patients referred for the evaluation of possible ischemia by 13NH3 PET/CT were prospectively included in a database. IECFs were categorized into three groups: potentially clinically relevant IECFs, IECFs that could potentially cause chest pain, and clinically irrelevant IECFs. Additionally, the prevalence of previously unknown malignancies was determined. In 717 (51%) of these patients, 775 IECFs were reported and 115 IECFs were categorized as potentially clinically relevant in 109 (8%) patients. A total of 145 IECFs that could potentially cause chest pain were detected in 139 (10%) patients and 515 clinically irrelevant IECFs were detected in 469 (34%) of the patients. An unknown primary malignancy was histologically proven in 19 patients (1.4%).

CONCLUSIONS

IECFs are detected on myocardial perfusion PET/CT in approximately half of the patients. In the present study, IECFs were potentially clinically relevant in 8% of the patients and in 1.4% an unknown malignancy was found, most of which were lung cancers.

Static and dynamic assessment of myocardial perfusion by computed tomography

Recent developments in computed tomography (CT) technology have fulfilled the prerequisites for the clinical application of myocardial CT perfusion (CTP) imaging. The evaluation of myocardial perfusion by CT can be achieved by static or dynamic scan acquisitions. Although both approaches have proved clinically feasible, substantial barriers need to be overcome before its routine clinical application. The current review provides an outline of the current status of CTP imaging and also focuses on disparities between static and dynamic CTPs for the evaluation of myocardial blood flow.

Superior CT coronary angiography image quality at lower radiation exposure with second generation 320-detector row CT in patients with elevated heart rate: a comparison with first generation 320-detector row CT

BACKGROUND

This study aims to compare the image quality of second generation versus first generation 320-computed tomography coronary angiography (CTCA) in patients with heart rate ≥65 bpm as it has not been specifically reported.

METHODS

Consecutive patients who underwent CTCA using second-generation-320-detector-row-CT were prospectively enrolled. A total of 50 patients with elevated (≥65 bpm) heart rate and 50 patients with controlled (<65 bpm) heart rate were included. Age and gender matched patients who were scanned with the first-generation-320-detector-row-CT were retrospectively identified. Image quality in each coronary artery segment was assessed by two blinded CT angiographers using the five-point Likert scale.

RESULTS

In the elevated heart rate cohorts, while there was no significant difference in heart rate during scan-acquisition (66 vs. 69 bpm, P=0.308), or body mass index (28.5 vs. 29.6, P=0.464), the second generation scanner was associated with better image quality (3.94±0.6 vs. 3.45±0.8, P=0.001), and with lower radiation (2.8 vs. 4.3 mSv, P=0.009). There was no difference in scan image quality for the controlled heart rate cohorts.

CONCLUSIONS

The second generation CT scanner provides better image quality at lower radiation dose in patients with elevated heart rate (≥65 bpm) compared to first generation CT scanner.

Cost-effectiveness of different diagnostic strategies in suspected stable coronary artery disease in Portugal

Background

Cost-effectiveness is an increasingly important factor in the choice of a test or therapy.

Objective

To assess the cost-effectiveness of various methods routinely used for the diagnosis of stable coronary disease in Portugal.

Methods

Seven diagnostic strategies were assessed. The cost-effectiveness of each strategy was defined as the cost per correct diagnosis (inclusion or exclusion of obstructive coronary artery disease) in a symptomatic patient. The cost and effectiveness of each method were assessed using Bayesian inference and decision-making tree analyses, with the pretest likelihood of disease ranging from 10% to 90%.

Results

The cost-effectiveness of diagnostic strategies was strongly dependent on the pretest likelihood of disease. In patients with a pretest likelihood of disease of ≤50%, the diagnostic algorithms, which include cardiac computed tomography angiography, were the most cost-effective. In these patients, depending on the pretest likelihood of disease and the willingness to pay for an additional correct diagnosis, computed tomography angiography may be used as a frontline test or reserved for patients with positive/inconclusive ergometric test results or a calcium score of >0. In patients with a pretest likelihood of disease of ≥ 60%, up-front invasive coronary angiography appears to be the most cost-effective strategy.

Conclusions

Diagnostic algorithms that include cardiac computed tomography angiography are the most cost-effective in symptomatic patients with suspected stable coronary artery disease and a pretest likelihood of disease of ≤50%. In high-risk patients (pretest likelihood of disease ≥ 60%), up-front invasive coronary angiography appears to be the most cost-effective strategy. In all pretest likelihoods of disease, strategies based on ischemia appear to be more expensive and less effective compared with those based on anatomical tests.

[Pre- and post-test probability of obstructive coronary artery disease in two diagnostic strategies: relative contributions of exercise ECG and coronary CT angiography]

INTRODUCTION

The purpose of this study was to assess the change in theoretical probability of coronary artery disease (CAD) in patients with suspected CAD undergoing coronary CT angiography (CCTA) as first line test vs. patients who underwent CCTA after an exercise ECG.

METHODS

Pre- and post-test probabilities of CAD were assessed in 158 patients with suspected CAD undergoing dual-source CCTA as the first-line test (Group A) and in 134 in whom CCTA was performed after an exercise ECG (Group B). Pre-test probabilities were calculated based on age, gender and type of chest pain. Post-test probabilities were calculated according to Bayes' theorem.

RESULTS

There were no significant differences between the groups regarding pre-test probability (median 23.5% [13.3-37.8] in group A vs. 20.5% [13.4-34.5] in group B; p=0,479). In group A, the percentage of patients with intermediate likelihood of disease (10-90%) was 90% before testing and 15% after CCTA (p<0,001), while in group B, it was 95% before testing, 87% after exercise ECG (p=NS), and 17% after CCTA (p<0,001).

CONCLUSION

Unlike exercise testing, CCTA is able to reclassify the risk in the majority of patients with an intermediate probability of obstructive CAD. The use of CCTA as a first-line diagnostic test for CAD may be beneficial in this setting.

IMPACT OF COMPUTED TOMOGRAPHY CORONARY ANGIOGRAPHY ON OTHER DIAGNOSTIC TESTS

Objectives: Information on the impact of computed tomography coronary angiography (CTCA) on patterns of care is scarce. In particular, it is not clear if, and to what extent, its adoption actually leads to a reduction in the use of other diagnostics tools. The aim of this study was to evaluate whether the adoption of CTCA in Emilia-Romagna (an Italian region with a population of 4.4 million) had any effect on utilization rates of myocardial perfusion scintigraphy (MPS) and coronary angiography (CA).

Methods: Interrupted time series (ITS) were applied to monthly volumes of MPS and CA tests performed from 2003 to 2010, to assess trends in usage rates for those procedures before and after CTCA was adopted by all the healthcare organizations operating in the region.

Results: After an increase in the first year of CTCA introduction, its use remained stable over the study period. After September 2006, a significant decrease in MPS volumes (31 percent; p < .0001) and a much less tangible decrease in CA volumes (5 percent; p < .0001), were detected by ITS analyses.

Conclusions: This study demonstrates that the use of CTCA had a greater impact on MPS usage rates than on CA.

Downstream testing and subsequent procedures after coronary computed tomographic angiography following coronary stenting in patients ≥65 years of age

Limited data are available on the use of coronary computed tomographic angiography (CCTA) in patients who have received percutaneous coronary intervention (PCI). To evaluate patterns of cardiac testing including CCTA after PCI, we created a retrospective observational dataset linking National Cardiovascular Data Registry CathPCI Registry baseline data with longitudinal inpatient and outpatient Medicare claims data for patients who received coronary stenting from November 1, 2005 through December 31, 2007. In 192,009 patients with PCI (median age 74 years), the first test after coronary stenting was CCTA for 553 (0.3%), stress testing for 89,900 (46.8%), and coronary angiography for 22,308 (11.6%); 79,248 (41.3%) had no further testing. Patients referred to CCTA first generally had similar or lower baseline risk than those referred for stress testing or catheterization first. Compared to patients with stress testing first after PCI, patients who underwent CCTA first had higher unadjusted rates of subsequent noninvasive testing (10% vs 3%), catheterization (26% vs 15%), and revascularization (13% vs 8%) within 90 days of initial testing after PCI (p <0.0001 for all comparisons). In conclusion, despite similar or lesser-risk profiles, patients initially evaluated with CCTA after PCI had more downstream testing and revascularization than patients initially evaluated with stress testing. It is unclear whether these differences derive from patient selection, performance of CCTA compared to other testing strategies, or the association of early adoption of CCTA with distinct patterns of care.

Toward evidence-based decisions in diagnostic radiology: a research and rating process for multiple decision-makers

The use of diagnostic imaging tests and the development of evidence-based guidelines, reviews, and other materials have both undergone substantial growth in recent years. However, the proliferation of evidence-based information has not translated into the universal deployment of medical and coverage policy for diagnostic imaging that is similarly evidence-based. One possible reason is the failure of those institutions generating evidence-based information to format findings in an accessible manner for all relevant stakeholders. The Institute for Clinical and Economic Review has developed a simple and transparent method for rating evidence that is accessible to clinicians, patients, payers, and other policy makers. The authors describe this process in relation to three imaging-based examples (computed tomographic colonography, coronary computed tomographic angiography, and positron emission tomography for dementia neuropathology). The issues raised, controversies considered, and use of the ratings in setting policy are discussed in relation to each example.

The role of coronary CT in the assessment and diagnosis of patients with chest pain

The role of cardiac computed tomography (CT) in the assessment and management of patients with suspected cardiac chest pain has been formally recognised in NICE guidance 95. When the technique and patient selection are appropriate, cardiac CT is a valuable diagnostic tool, particularly for patients with a low to intermediate pre-test probability of coronary artery disease. The physician must be aware of the implications of the recent guidelines; hence, we present an illustrated synopsis on the current technique and the indications for the use of calcium scoring and cardiac CT in the assessment and management of patients with suspected cardiac chest pain.