Real-world evidence study on the impact of SPECT MPI, PET MPI, cCTA and stress echocardiography on downstream healthcare utilisation in patients with coronary artery disease in the US

BACKGROUND

Coronary artery disease (CAD) is associated with a large clinical and economic burden. However, consensus on the optimal approach to CAD diagnosis is lacking. This study sought to compare downstream healthcare resource utilisation following different cardiac imaging modalities, to inform test selection for CAD diagnosis.

METHODS

Claims and electronic health records data from the Decision Resources Group Real-World Evidence US Data Repository were analysed for 2.5 million US patients who underwent single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI), positron emission tomography myocardial perfusion imaging (PET MPI), coronary computed tomography angiography (cCTA), or stress echocardiography between January 2016 and March 2018. Patients were stratified into nine cohorts based on suspected or existing CAD diagnosis, pre-test risk, and prior events or interventions. Downstream healthcare utilisation, including additional diagnostic imaging, coronary angiography, and cardiac-related health system encounters, was compared by cohort and index imaging modality.

RESULTS

Among patients with suspected CAD diagnosed within 3 months of the index test, PET MPI was associated with lower downstream utilisation; 25-37% of patients who underwent PET MPI required additional downstream healthcare resources compared with 40-49% of patients who received SPECT MPI, 35-41% of patients who underwent cCTA, and 44-47% of patients who received stress echocardiography. Patients who underwent PET MPI experienced fewer acute cardiac events (5.3-9.4%) and generally had lower rates of healthcare encounters (0.8-4.1%) and invasive coronary angiography (ICA, 15.4-24.2%) than those who underwent other modalities. SPECT MPI was associated with more downstream ICA (31.3-38.2%) and a higher rate of cardiac events (9.5-13.2%) compared with PET MPI (5.3-9.4%) and cCTA (6.9-9.9%). Across all cohorts, additional diagnostic imaging was 1.6 to 4.7 times more frequent with cCTA compared with PET MPI.

CONCLUSION

Choice of imaging modality for CAD diagnosis impacts downstream healthcare utilisation. PET MPI was associated with lower utilisation across multiple metrics compared with other imaging modalities studied.

Diagnostic accuracy of whole heart coronary magnetic resonance angiography: a systematic review and meta-analysis

BACKGROUND

The purpose of this meta-analysis was to comprehensively investigate the diagnostic ability of 1.5 T and 3.0 T whole heart coronary angiography (WHCA) to detect significant coronary artery disease (CAD) on X-ray coronary angiography.

METHODS

A literature search of electronic databases, including PubMed, Web of Science Core Collection, Cochrane advanced search, and EMBASE, was performed to retrieve and integrate articles showing significant CAD detectability of 1.5 and 3.0 T WHCA.

RESULTS

Data from 1899 patients from 34 studies were included in the meta-analysis. 1.5 T WHCA had a summary area under ROC of 0.88 in the patient-based analysis, 0.90 in the vessel-based analysis, and 0.92 in the segment-based analysis. These values for 3.0 T WHCA were 0.94, 0.95, 0.96, respectively. Contrast-enhanced 3.0 T WHCA had significantly higher specificity than non-contrast-enhanced 1.5 T WHCA on a patient-based analysis (0.87, 95% CI 0.80-0.92 vs. 0.74, 95% CI 0.64-0.82, P = 0.02). There were no differences in diagnostic performance on a patient-based analysis by use of vasodilators, beta-blockers or between Asian and Western countries.

CONCLUSIONS

The diagnostic performance of WHCA was deemed satisfactory, with contrast-enhanced 3.0 T WHCA exhibiting higher specificity compared to non-contrast-enhanced 1.5 T WHCA in a patient-based analysis. There were no significant differences in diagnostic performance on a patient-based analysis in terms of vasodilator or beta-blocker use, nor between Asian and Western countries. However, further large-scale multicentre studies are crucial for the widespread global adoption of WHCA.

Characteristics and key differences between patient populations receiving imaging modalities for coronary artery disease diagnosis in the US

BACKGROUND

There are limited data on the impact of imaging modality selection for the assessment of coronary artery disease (CAD) risk on downstream resource utilisation. This study sought to identify differences between patient populations in the US undergoing stress echocardiography, single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI), positron emission tomography (PET) MPI, and coronary computed tomography angiography (cCTA) for the assessment of CAD risk, and associated physician referral patterns.

METHODS

Claims and electronic health records data for 2.5 million US patients who received stress echocardiography, cCTA, SPECT MPI or PET MPI between January 2016 and March 2018, from the Decision Resources Group Real-World Evidence US Data Repository, were analysed. Patients were stratified into suspected and existing CAD cohorts, and further stratified by pre-test risk and presence and recency of interventions or acute cardiac events (within 1-2 years pre-index test). Linear and logistic regression were used to compare numeric and categorical variables.

RESULTS

Physicians were more likely to refer patients to standalone SPECT MPI (77%) and stress echocardiography (18%) than PET MPI (3%) and cCTA (2%). Overall, 43% of physicians referred more than 90% of their patients to standalone SPECT MPI. Just 3%, 1% and 1% of physicians referred more than 90% of their patients to stress echocardiography, PET MPI or cCTA. At the aggregated imaging level, patients who underwent stress echocardiography or cCTA had similar comorbidity profiles. Comorbidity profiles were also similar for patients who underwent SPECT MPI and PET MPI.

CONCLUSION

Most patients underwent SPECT MPI at the index date, with very few undergoing PET MPI or cCTA. Patients who underwent cCTA at the index date were more likely to undergo additional imaging tests compared with those who underwent other imaging modalities. Further evidence is needed to understand factors influencing imaging test selection across patient populations.

Use of cardiac imaging in chronic coronary syndromes: the EURECA Imaging registry

BACKGROUND

The prospective, multicentre EURECA registry assessed the use of imaging and adoption of the European Society of Cardiology (ESC) Guidelines (GL) in patients with chronic coronary syndromes (CCS).

METHODS

Between May 2019 and March 2020, 5156 patients were recruited in 73 centres from 24 ESC member countries. The adoption of GL recommendations was evaluated according to clinical presentation and pre-test probability (PTP) of obstructive coronary artery disease (CAD).

RESULTS

The mean age of the population was 64 ± 11 years, 60% of patients were males, 42% had PTP >15%, 27% had previous CAD, and ejection fraction was <50% in 5%. Exercise ECG was performed in 32% of patients, stress imaging as the first choice in 40%, and computed tomography coronary angiography (CTCA) in 22%. Invasive coronary angiography (ICA) was the first or downstream test in 17% and 11%, respectively. Obstructive CAD was documented in 24% of patients, inducible ischaemia in 19%, and 13% of patients underwent revascularization. In 44% of patients, the overall diagnostic process did not adopt the GL. In these patients, referral to stress imaging (21% vs. 58%; P < 0.001) or CTCA (17% vs. 30%; P < 0.001) was less frequent, while exercise ECG (43% vs. 22%; P < 0.001) and ICA (48% vs. 15%; P < 0.001) were more frequently performed. The adoption of GL was associated with fewer ICA, higher proportion of diagnosis of obstructive CAD (60% vs. 39%, P < 0.001) and revascularization (54% vs. 37%, P < 0.001), higher quality of life, fewer additional testing, and longer times to late revascularization.

CONCLUSIONS

In patients with CCS, current clinical practice does not adopt GL recommendations on the use of diagnostic tests in a significant proportion of patients. When the diagnostic approach adopts GL recommendations, invasive procedures are less frequently used and the diagnostic yield and therapeutic utility are superior.

The Cost Effectiveness of Coronary CT Angiography and the Effective Utilization of CT-Fractional Flow Reserve in the Diagnosis of Coronary Artery Disease

Given the high global disease burden of coronary artery disease (CAD), a major problem facing healthcare economic policy is identifying the most cost-effective diagnostic strategy for patients with suspected CAD. The aim of this review is to assess the long-term cost-effectiveness of coronary computed tomography angiography (CCTA) when compared with other diagnostic modalities and to define the cost and effective diagnostic utilization of computed tomography-fractional flow reserve (CT-FFR). A search was conducted through the MEDLINE database using PubMed with 16 of 119 manuscripts fitting the inclusion and exclusion criteria for review. An analysis of the data included in this review suggests that CCTA is a cost-effective strategy for both low risk acute chest pain patients presenting to the emergency department (ED) and low-to-intermediate risk stable chest pain outpatients. For patients with intermediate-to-high risk, CT-FFR is superior to CCTA in identifying clinically significant stenosis. In low-to-intermediate risk patients, CCTA provides a cost-effective diagnostic strategy with the potential to reduce economic burden and improve long-term health outcomes. CT-FFR should be utilized in intermediate-to-high risk patients with stenosis of uncertain clinical significance. Long-term analysis of cost-effectiveness and diagnostic utility is needed to determine the optimal balance between the cost-effectiveness and diagnostic utility of CT-FFR.

Generating Appropriate and Reliable Evidence for Value Assessment of Medical Devices: An Ispor Medical Devices and Diagnostics Special Interest Group Report

Background: Health Technology Assessment methods have become an important health policy tool. Yet recommendations for what constitutes appropriate and reliable evidence for assessment of medical devices are still debated because methods to evaluate pharmaceuticals are often, and incorrectly, the starting point for assessments.

Objectives:

The study aims to: (i) propose recommendations on appropriate methodologies to assess the evidence on medical devices (ii) identify assessment methods that can be used to measure device value and (iii) suggest key areas for future work

Methods:

ISPOR's Medical Devices and Diagnostics Special Interest Group conducted a comprehensive search of databases and gray literature on evidence development and value assessment on medical devices. The literature search was supplemented with hand searching from high impact journals in the related field. The 10-person expert working group obtained written comments through multiple rounds of review from internal and external stakeholders. Recommendations were made to guide future research.

Results:

Multi-criteria decision analysis was identified as a useful approach to assess the value of treatment. Consideration should be given to resource use measures; valid and reliable functional status questionnaires; and general and disease-specific, health-related, quality-of-life measures in economic evaluations of device use. For future work, best practices for value framework design.

Conclusions:

Integration of value-based evidence in an evidence-generation and -synthesis process is needed to support market access and adoption. Methodological recommendations for measuring value can be challenging when the selection of domains and assessment of value are not device-specific.

Non-invasive imaging software to assess the functional significance of coronary stenoses: a systematic review and economic evaluation

BACKGROUND

QAngio^® XA 3D/QFR^® (three-dimensional/quantitative flow ratio) imaging software (Medis Medical Imaging Systems BV, Leiden, the Netherlands) and CAAS^® vFFR^® (vessel fractional flow reserve) imaging software (Pie Medical Imaging BV, Maastricht, the Netherlands) are non-invasive technologies to assess the functional significance of coronary stenoses, which can be alternatives to invasive fractional flow reserve assessment.

OBJECTIVES

The objectives were to determine the clinical effectiveness and cost-effectiveness of QAngio XA 3D/QFR and CAAS vFFR.

METHODS

We performed a systematic review of all evidence on QAngio XA 3D/QFR and CAAS vFFR, including diagnostic accuracy, clinical effectiveness, implementation and economic analyses. We searched MEDLINE and other databases to January 2020 for studies where either technology was used and compared with fractional flow reserve in patients with intermediate stenosis. The risk of bias was assessed with quality assessment of diagnostic accuracy studies. Meta-analyses of diagnostic accuracy were performed. Clinical and implementation outcomes were synthesised narratively. A simulation study investigated the clinical impact of using QAngio XA 3D/QFR. We developed a de novo decision-analytic model to estimate the cost-effectiveness of QAngio XA 3D/QFR and CAAS vFFR relative to invasive fractional flow reserve or invasive coronary angiography alone. Scenario analyses were undertaken to explore the robustness of the results to variation in the sources of data used to populate the model and alternative assumptions.

RESULTS

Thirty-nine studies (5440 patients) of QAngio XA 3D/QFR and three studies (500 patients) of CAAS vFFR were included. QAngio XA 3D/QFR had good diagnostic accuracy to predict functionally significant fractional flow reserve (≤ 0.80 cut-off point); contrast-flow quantitative flow ratio had a sensitivity of 85% (95% confidence interval 78% to 90%) and a specificity of 91% (95% confidence interval 85% to 95%). A total of 95% of quantitative flow ratio measurements were within 0.14 of the fractional flow reserve. Data on the diagnostic accuracy of CAAS vFFR were limited and a full meta-analysis was not feasible. There were very few data on clinical and implementation outcomes. The simulation found that quantitative flow ratio slightly increased the revascularisation rate when compared with fractional flow reserve, from 40.2% to 42.0%. Quantitative flow ratio and fractional flow reserve resulted in similar numbers of subsequent coronary events. The base-case cost-effectiveness results showed that the test strategy with the highest net benefit was invasive coronary angiography with confirmatory fractional flow reserve. The next best strategies were QAngio XA 3D/QFR and CAAS vFFR (without fractional flow reserve). However, the difference in net benefit between this best strategy and the next best was small, ranging from 0.007 to 0.012 quality-adjusted life-years (or equivalently £140-240) per patient diagnosed at a cost-effectiveness threshold of £20,000 per quality-adjusted life-year.

LIMITATIONS

Diagnostic accuracy evidence on CAAS vFFR, and evidence on the clinical impact of QAngio XA 3D/QFR, were limited.

CONCLUSIONS

Quantitative flow ratio as measured by QAngio XA 3D/QFR has good agreement and diagnostic accuracy compared with fractional flow reserve and is preferable to standard invasive coronary angiography alone. It appears to have very similar cost-effectiveness to fractional flow reserve and, therefore, pending further evidence on general clinical benefits and specific subgroups, could be a reasonable alternative. The clinical effectiveness and cost-effectiveness of CAAS vFFR are uncertain. Randomised controlled trial evidence evaluating the effect of quantitative flow ratio on clinical and patient-centred outcomes is needed.

FUTURE WORK

Studies are required to assess the diagnostic accuracy and clinical feasibility of CAAS vFFR. Large ongoing randomised trials will hopefully inform the clinical value of QAngio XA 3D/QFR.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019154575.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 25, No. 56. See the NIHR Journals Library website for further project information.

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.

The optimal diagnostic strategies for patient with coronary artery diseases and stable chest pain syndrome: a cost-effectiveness analysis

Background

Numerous invasive and noninvasive diagnostic tests with different cost and effectiveness exist for detection of coronary artery disease. This diversity leads to unnecessary utilization of health services. For this reason, this study focused on the cost-effectiveness analysis of diagnostic strategies for coronary artery disease from the perspective of the health care system with 1-year time horizon.

Results

Incremental cost effectiveness ratios of all strategies were less than the threshold except for the electrocardiography-computed tomography angiography-coronary angiography strategy, and cost of the cardiac magnetic resonance imaging-based strategy was higher than the cost of other strategies. Also, the number of correct diagnosis in the electrocardiography-coronary angiography strategy was higher than the other strategies, and its ICER was 15.197 dollars per additional correct diagnosis. Moreover, the sensitivity analysis found that the probability of doing MRI and sensitivity of the exercise electrocardiography had impact on the results.

Conclusion

The most cost-effective strategy for acute patient is ECG-CA strategy, and for chronic patient, the most cost-effective strategies are electrocardiography-single photon emission computed tomography-coronary angiography and electrocardiography-exercise electrocardiography-coronary angiography. Applying these strategies in the same clinical settings may lead to a better utilization of resources.

Computed tomography coronary angiography - past, present and future

Computed tomography coronary angiography (CTCA) is a robust and reliable non-invasive alternative imaging modality to invasive coronary angiography, which is the reference standard in evaluating the degree of coronary artery stenosis. CTCA has high negative predictive value and can confidently exclude significant coronary artery disease (CAD) in low to intermediate risk patients. Over the years, substantial effort has been made to reduce the radiation dose and increase the cost efficiency of CTCA. In this review, we present the evolution of computed tomography scanners in the context of coronary artery imaging as well as its clinical applications and limitations. We also highlight the future directions of CTCA as a one-stop non-invasive imaging modality for anatomic and functional assessment of CAD.

Cost-effectiveness of myocardial perfusion SPECT and stress test according to coronary revascularization therapy, cardiac events and total mortality: Register of 8,496 patients

OBJECTIVE

The aim was to analyze the cost-effectiveness ratio (CER) of stress electrocardiogram (ES) and stress myocardial perfusion imaging (SPECT-MPI) according to coronary revascularization (CR) therapy, cardiac events (CE) and total mortality (TM).

MATERIAL AND METHODS

A total of 8,496 consecutive patients who underwent SPECT-MPI were followed-up (mean 5.3±3.5years). Cost-effectiveness for coronary bypass (CABG) or percutaneous CR (PCR) (45.6%/54.4%) according to combined electrocardiographic ischemia and scintigraphic ischemia were evaluated. Effectiveness was evaluated as TM, CE, life-year saved observed (LYSO) and CE-LYSO; costs analyses were conducted from the perspective of the health care payer. A sensitivity analysis was performed considering current CABG/PCR ratios (12%/88%).

RESULTS

When electrocardiogram and SPECT approaches are combined, the cost-effectiveness values for CABG ranged between 112,589€ (electrocardiographic and scintigraphic ischemia) and 2,814,715€ (without ischemia)/event avoided, 38,664 and 2,221,559€/LYSO; for PCR ranged between 18,824€ (electrocardiographic and scintigraphic ischemia) and 46,377€ (without ischemia)/event avoided, 6,464 and 36,604€/LYSO. To CE: the cost-effectiveness values of the CABG and CPR in presence of electrocardiographic and scintigraphic ischemia were 269,904€/CE-avoided and 24,428€/CE-avoided, respectively; and the €/LYSO of the CABG and PCR were 152,488 and 13,801, respectively. The RCE was maintained for the current proportion of revascularized patients (12%/88%).

CONCLUSIONS

Combined ES and SPECT-MPI results, allows differentiation between patient groups, where the PCR and CABG are more cost-effective in different economic frameworks. The major CER in relation to CR, CE and TM occurs in patients with electrocardiographic and scintigraphic ischemia. PCR is more cost-effective than CABG.

Comparison of coronary CT angiography versus functional imaging for CABG patients: A resource utilization analysis

AIMS

The impact of anatomical versus functional testing in patients with prior coronary artery bypass surgery (CABG) is poorly defined. We therefore sought to determine the rates of downstream investigations and the attendant healthcare costs in CABG patients undergoing CCTA versus SPECT.

METHODS AND RESULTS

2754 consecutive CABG patients were imaged by SPECT (2163) or CCTA (591). 425 patients (15.4%) underwent downstream testing which was more common in those imaged with CCTA versus SPECT (23.18% vs 13.31% respectively, p < 0.01). When a propensity score adjustment was made for differences in baseline characteristics, the findings in downstream testing persisted (p < 0.01). When patients who subsequently underwent repeat revascularization (arguably the highest risk patients) were removed from the analysis, downstream testing remained more frequent in CCTA (12.7%) versus SPECT imaged patients (8.8%) (p = 0.01). Costs of downstream tests per patient were two-fold greater in the CCTA group in comparison to the SPECT group ($366.79 ± 29.59 vs $167.35 ± 10.12 respectively, p < 0.01). Conversely, total costs which included the index costs were less in the CCTA group, $764.66 ± 29.59 versus $1396.73 ± 1012 for the SPECT cohort, p < 0.0001).

CONCLUSIONS

Index imaging with SPECT versus CCTA in CABG patients was associated with fewer downstream tests, less ICA, less repeat revascularization but greater expense. Cost however is only part of the decision making process that determines an optimal index test. Until CCTA demonstrates improved risk stratification over SPECT in CABG patients it is likely SPECT will remain the preferred first imaging test.

Probabilistic Graphical Modeling for Estimating Risk of Coronary Artery Disease: Applications of a Flexible Machine-Learning Method

Objectives. Coronary artery disease (CAD) is the leading cause of death and disease burden worldwide, causing 1 in 7 deaths in the United States alone. Risk prediction models that can learn the complex causal relationships that give rise to CAD from data, instead of merely predicting the risk of disease, have the potential to improve transparency and efficacy of personalized CAD diagnosis and therapy selection for physicians, patients, and other decision makers. Methods. We use Bayesian networks (BNs) to model the risk of CAD using the Z-Alizadehsani data set-a published real-world observational data set of 303 Iranian patients at risk for CAD. We also describe how BNs can be used for incorporation of background knowledge, individual risk prediction, handling missing observations, and adaptive decision making under uncertainty. Results. BNs performed on par with machine-learning classifiers at predicting CAD and showed better probability calibration. They achieved a mean 10-fold area under the receiver-operating characteristic curve (AUC) of 0.93 ± 0.04, which was comparable with the performance of logistic regression with L1 or L2 regularization (AUC: 0.92 ± 0.06), support vector machine (AUC: 0.92 ± 0.06), and artificial neural network (AUC: 0.91 ± 0.05). We describe the use of BNs to predict with missing data and to adaptively calculate prognostic values of individual variables under uncertainty. Conclusion. BNs are powerful and versatile tools for risk prediction and health outcomes research that can complement traditional statistical techniques and are particularly useful in domains in which information is uncertain or incomplete and in which interpretability is important, such as medicine.

Coronary computed tomography angiography vs. myocardial single photon emission computed tomography in patients with intermediate risk chest pain: a randomized clinical trial for cost-effectiveness comparison based on real-world cost

AIMS

To compare the cost-effectiveness of coronary computed tomography angiography (CCTA) vs. myocardial single photon emission computed tomography (SPECT) in patients with stable intermediate risk chest pain.

METHODS AND RESULTS

Non-acute patients with 10-90% pre-test probability of coronary artery disease from three high-volume centres in Korea (n = 965) were randomized 1:1 to CCTA or myocardial SPECT as the initial non-invasive imaging test. Medical costs after randomization, the downstream outcome, including all-cause death, acute coronary syndrome, cerebrovascular accident, repeat revascularization, stent thrombosis, and significant bleeding following the initial test and the quality-adjusted life-years (QALYs) gained by the EuroQoL-5D questionnaire was compared between the two groups. In all, 903 patients underwent the initially randomized study (n = 460 for CCTA, 443 for SPECT). In all, 65 patients underwent invasive coronary angiography (ICA) in the CCTA and 85 in the SPECT group, of which 4 in the CCTA and 30 in the SPECT group demonstrated no stenosis on ICA [6.2% (4/65) vs. 35.3% (30/85), P-value < 0.001]. There was no difference in the downstream clinical events. QALYs gained was higher in the SPECT group (0.938 vs. 0.955, P-value = 0.039) but below the threshold of minimal clinically important difference of 0.08. Overall cost per patient was lower in the CCTA group (USD 4514 vs. 5208, P-value = 0.043), the tendency of which was non-significantly opposite in patients with 60-90% pre-test probability (USD 5807 vs. 5659, P-value = 0.845).

CONCLUSION

CCTA is associated with fewer subsequent ICA with no difference in downstream outcome. CCTA may be more cost-effective than SPECT in Korean patients with stable, intermediate risk chest pain.

Accuracy and clinical outcomes of coronary CT angiography for patients with suspected coronary artery disease: a single-centre study in Singapore

INTRODUCTION

This study aimed to assess the accuracy and outcomes of coronary computed tomography angiography (CCTA) performed in a regional hospital in Singapore.

METHODS

The Changi General Hospital CCTA database was retrospectively analysed over a 24-month period. Electronic hospital records, catheter coronary angiography (CCA) and CCTA electronic databases were used to gather data on major adverse cardiovascular events (MACE) and CCA results. CCTA findings were deemed positive if coronary artery stenosis ≥ 50% was reported or if the stenosis was classified as moderate or severe. CCA findings were considered positive if coronary artery stenosis ≥ 50% was reported.

RESULTS

The database query returned 679 patients who had undergone CCTA for the evaluation of suspected coronary artery disease. Of the 101 patients in the per-patient accuracy analysis group, there were six true negatives, one false negative, 81 true positives and 13 false positives, resulting in a negative predictive value of 85.7% and positive predictive value of 86.2%. The mean age of the study sample was 53 ± 13 years and 255 (37.6%) patients were female. Mean duration of patient follow-up was 360 days. Of the 513 negative CCTA patients, none developed MACE during the follow-up period, and of the 164 positive CCTA patients, 19 (11.6%) developed MACE (p < 0.001).

CONCLUSION

Analysis of CCTA studies suggested accuracy and outcomes that were consistent with published clinical data. There was a one-year MACE-free warranty period following negative CCTA findings.

Coronary calcium score improves the estimation for pretest probability of obstructive coronary artery disease and avoids unnecessary testing in individuals at low extreme of traditional risk factor burden: validation and comparison of CONFIRM score and genders extended model

BACKGROUND

Reliability of models for estimating pretest probability (PTP) of obstructive coronary artery disease (CAD) has not been investigated in individuals at low extreme of traditional risk factor (RF) burden. Thus, we sought to validate and compare CONFIRM score and Genders extended model (GEM) among these individuals.

METHODS

We identified symptomatic individuals with 0 or 1 RF who underwent coronary calcium scan and coronary computed tomographic angiography (CCTA). Follow-up clinical data were also recorded. PTP of obstructive CAD for every individual was estimated according to CONFIRM score and GEM, respectively. Area under the receiver operating characteristic curve (AUC), integrated discrimination improvement (IDI), net reclassification improvement (NRI) and Hosmer-Lemeshow (H-L) test were used to assess the performance of models.

RESULTS

There were 1201 individuals with 0 RF and 2415 with 1 RF. The AUC for GEM was significantly larger than that for CONFIRM score, no matter in individuals with 0 (0.843 v.s. 0.762, p < 0.0001) or 1 (0.823 v.s. 0.752, p < 0.0001) RF. Compared to CONFIRM score, GEM demonstrated positive IDI (5% in individuals with 0 RF and 8% in individuals with 1 RF), positive NRI (41.50% in individuals with 0 RF and 40.19% in individuals with 1 RF), better prediction of clinical events and less discrepancy between observed and predicted probabilities, resulting in a significant decrease of unnecessary testing, especially in negative individuals.

CONCLUSION

In individuals at low extreme of traditional RF burden of CAD, the addition of coronary calcium score provided a more accurate estimation for PTP and application of GEM instead of CONFIRM score could avoid unnecessary testing.

Systematic review of cost-effectiveness of myocardial perfusion scintigraphy in patients with ischaemic heart disease: A report from the cardiovascular committee of the European Association of Nuclear Medicine. Endorsed by the European Association of Cardiovascular Imaging

Coronary artery disease (CAD) is a major cause of death and disability. Several diagnostic tests, such as myocardial perfusion scintigraphy (MPS), are accurate for the detection of CAD, as well as having prognostic value for the prediction of cardiovascular events. Nevertheless, the diagnostic and prognostic value of these tests should be cost-effective and should lead to improved clinical outcome. We have reviewed the literature on the cost-effectiveness of MPS in different circumstances: (i) the diagnosis and management of CAD; (ii) comparison with exercise electrocardiography (ECG) and other imaging tests; (iii) as gatekeeper to invasive coronary angiography (ICA), (iv) the impact of appropriate use criteria; (v) acute chest pain, and (vi) screening of asymptomatic patients with type-2 diabetes. In total 57 reports were included. Although most non-invasive imaging tests are cost-effective compared with alternatives, the data conflict on which non-invasive strategy is the most cost-effective. Different definitions of cost-effectiveness further confound the subject. Computer simulations of clinical diagnosis and management are influenced by the assumptions made. For instance, diagnostic accuracy is often defined against an anatomical standard that is wrongly assumed to be perfect. Conflicting data arise most commonly from these incorrect or differing assumptions.

The External Validity of Prediction Models for the Diagnosis of Obstructive Coronary Artery Disease in Patients With Stable Chest Pain: Insights From the PROMISE Trial

OBJECTIVES

This study sought to externally validate prediction models for the presence of obstructive coronary artery disease (CAD).

BACKGROUND

A better assessment of the probability of CAD may improve the identification of patients who benefit from noninvasive testing.

METHODS

Stable chest pain patients from the PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) trial with computed tomography angiography (CTA) or invasive coronary angiography (ICA) were included. The authors assumed that patients with CTA showing 0% stenosis and a coronary artery calcium (CAC) score of 0 were free of obstructive CAD (≥50% stenosis) on ICA, and they multiply imputed missing ICA results based on clinical variables and CTA results. Predicted CAD probabilities were calculated using published coefficients for 3 models: basic model (age, sex, chest pain type), clinical model (basic model + diabetes, hypertension, dyslipidemia, and smoking), and clinical + CAC score model. The authors assessed discrimination and calibration, and compared published effects with observed predictor effects.

RESULTS

In 3,468 patients (1,805 women; mean 60 years of age; 779 [23%] with obstructive CAD on CTA), the models demonstrated moderate-good discrimination, with C-statistics of 0.69 (95% confidence interval [CI]: 0.67 to 0.72), 0.72 (95% CI: 0.69 to 0.74), and 0.86 (95% CI: 0.85 to 0.88) for the basic, clinical, and clinical + CAC score models, respectively. Calibration was satisfactory although typical chest pain and diabetes were less predictive and CAC score was more predictive than was suggested by the models. Among the 31% of patients for whom the clinical model predicted a low (≤10%) probability of CAD, actual prevalence was 7%; among the 48% for whom the clinical + CAC score model predicted a low probability the observed prevalence was 2%. In 2 sensitivity analyses excluding imputed data, similar results were obtained using CTA as the outcome, whereas in those who underwent ICA the models significantly underestimated CAD probability.

CONCLUSIONS

Existing clinical prediction models can identify patients with a low probability of obstructive CAD. Obstructive CAD on ICA was imputed for 61% of patients; hence, further validation is necessary.

Rationale and design of the Coronary Computed Tomographic Angiography for Selective Cardiac Catheterization: Relation to Cardiovascular Outcomes, Cost Effectiveness and Quality of Life (CONSERVE) trial

Although coronary computed tomography angiography (CCTA) has shown promise as a "gatekeeper" to invasive coronary angiography (ICA) in longitudinal cohort studies, it remains unknown whether the strategy of selective ICA by initial performance of CCTA is either safe or effective when compared with a direct ICA strategy in patients with an American Heart Association (AHA)/American College of Cardiology (ACC) guideline-directed indication for ICA.

OBJECTIVES

The CONSERVE trial is a prospective randomized multicenter trial to determine the clinical effectiveness of "selective catheterization" vs "direct catheterization" strategies for stable patients with suspected but without known coronary artery disease, who meet AHA/ACC guideline indication for ICA.

METHODS

Patients being referred for clinically indicated nonemergent ICA with an AHA/ACC class II guideline indication for ICA will be randomized to either direct catheterization or selective catheterization strategy. Patients in the direct catheterization arm will proceed directly to ICA as planned, whereas patients in the select catheterization arm will undergo initial CCTA, followed by ICA at the discretion of the site physician. All CCTAs and ICAs will be interpreted on site. Follow-up testing and/or therapy after CCTA or ICA will be at the discretion of the site physician.

RESULTS

This trial will report a primary clinical end point of noninferiority rates of major adverse cardiac events, as defined by the composite of death, nonfatal myocardial infarction, unstable angina, stroke, urgent or emergent coronary revascularization, or cardiac hospitalization.

CONCLUSION

The CONSERVE trial will determine whether selective catheterization strategy, based on initial CCTA in patients being referred to ICA, is safe and effective.

Impact of Clinical Guideline Recommendations on the Application of Coronary Computed Tomographic Angiography in Patients with Suspected Stable Coronary Artery Disease

Background:

Coronary computed tomographic angiography (CCTA) has been widely used in patients who are at intermediate risk for having stable coronary artery disease (SCAD), and 2013 European Society of Cardiology Guidelines on the Management of SCAD (2013G) recommended the appropriate application of CCTA. However, 2013G has not been subjected to systematic analyses for subsequent impact on clinical practice.

Methods:

A total of 5320 patients suspected with SCAD were enrolled and scheduled for CCTA from March 2013 to September 2014. For each patient, pretest probability of SCAD was calculated according to updated Diamond-Forrester model (UDFM). Appropriate CCTA or appropriate stress test was determined as described in the 2013G. A generalized estimating equation model was used to determine the trends in the half-monthly rate of appropriate CCTA.

Results:

Overall, only 61.37% of patients received appropriate CCTA, and there was insignificant change over time (P = 0.8701). The application of CCTA in patients who should have had a stress test accounted for most of the inappropriate CCTA before (22.29%) or after (19.98%) the publication of the 2013G. In all patients or any subgroup, no significant change in the adjusted half-monthly rate of appropriate CCTA was found after the publication of the 2013G (odds ratio, 1.002; 95% confidence interval, 0.982–1.021; P = 0.8678).

Conclusions:

These findings suggest that the 2013G have not, to date, been fully incorporated into clinical practice, and the clinical utilization of CCTA remains unreasonable to some extent.

Changes in Medical Therapy and Lifestyle After Anatomical or Functional Testing for Coronary Artery Disease

Background

Diagnostic testing in the care of patients newly presenting with symptoms suggestive of coronary artery disease may influence risk factor management, independent of test type or test results. However, little is known about changes in medications and lifestyle after anatomical or functional testing.

Methods and Results

We examined what factors influenced preventive medical therapy and lifestyle practices at 60 days among 10 003 symptomatic patients (53% women; mean age 61 years) randomly assigned to anatomical testing with coronary computed tomographic angiography or functional testing (NCT01174550). We also assessed the association of preventive changes with major cardiovascular events. There were no differences in medications/lifestyle at baseline. At 60 days, relative to baseline, the computed tomographic angiography strategy was associated with a higher proportion of patients newly initiating aspirin (11.8% versus 7.8%), statins (12.7% versus 6.2%), and β‐blockers (8.1% versus 5.3%), compared to functional testing (P<0.0001 for each). No significant differences between computed tomographic angiography and functional testing strategies were observed for initiation of exercise, quitting smoking, or weight loss in overweight/obese patients, though overall prevalence of healthy eating was higher after computed tomographic angiography (P=0.002) while obese/overweight status was lower (P=0.040). Positive initial test results and revascularization demonstrated stronger associations with preventive medications and lifestyle than test type. Medication initiation was not associated with fewer cardiovascular events.

Conclusions

Positive initial test results and revascularization are primary drivers of changes in preventive medical and lifestyle practices, with test type making secondary contributions. However, substantial opportunities exist to further reduce cardiovascular risk.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01174550.

Cardiovascular outcomes after pharmacologic stress myocardial perfusion imaging

BACKGROUND

While pharmacologic stress single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) is used for noninvasive evaluation of patients who are unable to perform treadmill exercise, its impact on net reclassification improvement (NRI) of prognosis is unknown.

METHODS

We evaluated the prognostic value of pharmacologic stress MPI for prediction of cardiovascular death or non-fatal myocardial infarction (MI) within 1 year at a single-center, university-based laboratory. We examined continuous and categorical NRI of pharmacologic SPECT-MPI for prediction of outcomes beyond clinical factors alone.

RESULTS

Six thousand two hundred forty patients (median age 66 years [IQR 56-74], 3466 men) were studied and followed for 5963 person-years. SPECT-MPI variables associated with increased risk of cardiovascular death or non-fatal MI included summed stress score, stress ST-shift, and post-stress resting left ventricular ejection fraction ≤50%. Compared to a clinical model which included age, sex, cardiovascular disease, risk factors, and medications, model χ(2) (210.5 vs. 281.9, P < .001) and c-statistic (0.74 vs. 0.78, P < .001) were significantly increased by addition of SPECT-MPI predictors (summed stress score, stress ST-shift and stress resting left ventricular ejection fraction). SPECT-MPI predictors increased continuous NRI by 49.4% (P < .001), reclassifying 66.5% of patients as lower risk and 32.8% as higher risk of cardiovascular death or non-fatal MI. Addition of MPI predictors to clinical factors using risk categories, defined as <1%, 1% to 3%, and >3% annualized risk of cardiovascular death or non-fatal MI, yielded a 15.0% improvement in NRI (95% CI 7.6%-27.6%, P < .001).

CONCLUSIONS

Pharmacologic stress MPI substantially improved net reclassification of cardiovascular death or MI risk beyond that afforded by clinical factors.

Recent Scientific Evidence and Technical Developments in Cardiovascular Computed Tomography

In recent years, coronary computed tomography angiography has become an increasingly safe and noninvasive modality for the evaluation of the anatomical structure of the coronary artery tree with diagnostic benefits especially in patients with a low-to-intermediate pretest probability of disease. Currently, increasing evidence from large randomized diagnostic trials is accumulating on the diagnostic impact of computed tomography angiography for the management of patients with acute and stable chest pain syndrome. At the same time, technical advances have substantially reduced adverse effects and limiting factors, such as radiation exposure, the amount of iodinated contrast agent, and scanning time, rendering the technique appropriate for broader clinical applications. In this work, we review the latest developments in computed tomography technology and describe the scientific evidence on the use of cardiac computed tomography angiography to evaluate patients with acute and stable chest pain syndrome.

Cost-effectiveness of quantitative pretest probability intended to reduce unnecessary medical radiation exposure in emergency department patients with chest pain and dyspnea

OBJECTIVES

Quantitative pretest probability (qPTP) incorporated into a decision support tool with advice can reduce unnecessary diagnostic testing among patients with symptoms suggestive of acute coronary syndrome (ACS) and pulmonary embolism (PE), reducing 30-day costs without an increase in 90-day adverse outcomes. This study estimates long-term (beyond 90-day) costs and outcomes associated with qPTP. The authors hypothesized that qPTP reduces lifetime costs and improves outcomes in low-risk patients with symptoms suggestive of ACS and PE.

METHODS

This was a cost-effectiveness analysis of a multicenter, randomized controlled trial of adult emergency patients with dyspnea and chest pain, in which a clinician encountering a low-risk patient with symptoms suggestive of ACS or PE conducted either the intervention (qPTP for ACS and PE with advice) or the sham (no qPTP and no advice). Effect of the intervention over a patient's lifetime was assessed using a Markov microsimulation model. Short-term costs and outcomes were from the trial; long-term outcomes and costs were from the literature. Outcomes included lifetime transition to PE, ACS, and intracranial hemorrhage (ICH); mortality from cancer, ICH, PE, ACS, renal failure, and ischemic stroke; quality-adjusted life-years (QALYs); and total medical costs compared between simulated intervention and sham groups.

RESULTS

Markov microsimulation for a 40-year-old patient receiving qPTP found lifetime cost savings of $497 for women and $528 for men, associated with small gains in QALYs (2 and 6 days, respectively) and lower rates of cancer mortality in both sexes, but a reduction in ICH only in males. Sensitivity analysis for patients aged 60 years predicted that qPTP would continue to save costs and also reduce mortality from both ICH and cancer. Use of qPTP significantly reduced the lifetime probability of PE diagnosis, with lower probability of death from PE in both sexes aged 40 to 60 years. However, use of qPTP reduced the rate of ACS diagnosis and death from ACS at age 40, but increased the death rate from ACS at age 60 for both sexes.

CONCLUSIONS

Widespread use of a combined qPTP for both ACS and PE has the potential to decrease costs by reducing diagnostic testing, while improving most long-term outcomes in emergency patients with chest pain and dyspnea.

The optimal imaging strategy for patients with stable chest pain: a cost-effectiveness analysis

BACKGROUND

The optimal imaging strategy for patients with stable chest pain is uncertain.

OBJECTIVE

To determine the cost-effectiveness of different imaging strategies for patients with stable chest pain.

DESIGN

Microsimulation state-transition model.

DATA SOURCES

Published literature.

TARGET POPULATION

60-year-old patients with a low to intermediate probability of coronary artery disease (CAD).

TIME HORIZON

Lifetime.

PERSPECTIVE

The United States, the United Kingdom, and the Netherlands.

INTERVENTION

Coronary computed tomography (CT) angiography, cardiac stress magnetic resonance imaging, stress single-photon emission CT, and stress echocardiography.

OUTCOME MEASURES

Lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios.

RESULTS OF BASE-CASE ANALYSIS

The strategy that maximized QALYs and was cost-effective in the United States and the Netherlands began with coronary CT angiography, continued with cardiac stress imaging if angiography found at least 50% stenosis in at least 1 coronary artery, and ended with catheter-based coronary angiography if stress imaging induced ischemia of any severity. For U.K. men, the preferred strategy was optimal medical therapy without catheter-based coronary angiography if coronary CT angiography found only moderate CAD or stress imaging induced only mild ischemia. In these strategies, stress echocardiography was consistently more effective and less expensive than other stress imaging tests. For U.K. women, the optimal strategy was stress echocardiography followed by catheter-based coronary angiography if echocardiography induced mild or moderate ischemia.

RESULTS OF SENSITIVITY ANALYSIS

Results were sensitive to changes in the probability of CAD and assumptions about false-positive results.

LIMITATIONS

All cardiac stress imaging tests were assumed to be available. Exercise electrocardiography was included only in a sensitivity analysis. Differences in QALYs among strategies were small.

CONCLUSION

Coronary CT angiography is a cost-effective triage test for 60-year-old patients who have nonacute chest pain and a low to intermediate probability of CAD.

PRIMARY FUNDING SOURCE

Erasmus University Medical Center.

Cost-effectiveness of coronary CT angiography in patients with chest pain: Comparison with myocardial single photon emission tomography

BACKGROUND

Coronary CT angiography (CCTA) has been proven accurate and is incorporated in clinical recommendations for coronary artery disease (CAD) diagnosis workup, but cost-effectiveness data, especially in comparison to other methods such as myocardial single photon emission CT (SPECT) are insufficient.

OBJECTIVE

To compare the cost-effectiveness of CCTA and myocardial SPECT in a real-world setting.

METHODS

We performed a retrospective cohort study on consecutive patients with suspected CAD and a pretest probability between 10% and 90%. Test accuracy was compared by correcting referral bias to coronary angiography depending on noninvasive test results based on the Bayes' theorem and also by incorporating 1-year follow-up results. Cost-effectiveness was analyzed using test accuracy and quality-adjusted life year (QALY). The model using diagnostic accuracy used the number of patients accurately diagnosed among 1000 persons as the effect and contained only expenses for diagnostic testing as the cost. In the model using QALY, a decision tree was developed, and the time horizon was 1 year.

RESULTS

CCTA was performed in 635 patients and SPECT in 997 patients. An accurate diagnosis per 1000 patients was achieved in 725 patients by CCTA vs 661 patients by SPECT. In the model using diagnostic accuracy, CCTA was more effective and less expensive than SPECT ($725.38 for CCTA vs $661.46 for SPECT). In the model using QALY, CCTA was generally more effective in terms of life quality (0.00221 QALY) and cost ($513) than SPECT. However, cost utility varied among subgroups, with SPECT outperforming CCTA in patients with a pretest probability of 30% to 60% (0.01890 QALY; $113).

CONCLUSION

These results suggest that CCTA may be more cost-effective than myocardial SPECT.

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.

Cost minimization analysis of beta-blocker at the time of CT imaging for suspected of coronary heart disease in Japan

OBJECTIVES

To conduct a cost-minimization analysis of landiolol for CT diagnosis of coronary heart diseases in patients with tachycardia in Japan.

METHODS

A decision-tree model was constructed to analyze costs from the healthcare payer's perspective. Drug costs and diagnosis costs, computer tomography coronary angiography (CTCA), and coronary angiography (CAG), are adopted to the model. Landiolol is administered only to slow the heart rate to take CT images appropriately. Since some trials proved that there was no difference between landiolol and placebo in terms of efficacy and safety, this study conducted cost-minimization analysis. Of those suspected of coronary heart diseases, 22.5% are thought to be taking beta-blockers. The success rates for CT scanning for landiolol and placebo, derived from domestic trial data, were 81.4% (96/118, 77.8-84.9%) and 54.2% (64/118, 49.7-58.8%). Patients who failed to take a CT image were thought to take CAG. The healthcare cost was derived from a Japanese fee schedule. Costs of landiolol, CT imaging, and CAG are JPY2634 (USD1 = JPY100, as of November 20, 2013), JPY38,116, and JPY101,322, respectively. The positive rate for CAG, derived from domestic trial data, was 37.1% (33/89, 32.0-42.2%). Various sensitivity analyses, both univariate and probabilistic ones, were conducted.

RESULTS

In the base case analysis, expected costs per patient for landiolol and placebo were JPY78,956 and JPY82,232, respectively. In budget impact analysis, 81,062 patients are eligible for landiolol and it can save JPY266million for whole patients. Sensitivity analyses suggested the robustness of the results.

LIMITATIONS

This study did not consider any adverse effects in the decision-tree model. This model was developed especially for measuring the cost-saving effect of landiolol, through decreasing the number of patients who require CAG, due to imaging failure.

CONCLUSIONS

Landiolol for CTCA diagnosis in patients suspected of coronary heart disease with tachycardia is thought to be cost saving.