Fractional flow reserve derived from computed tomography coronary angiography in the assessment and management of stable chest pain: the FORECAST randomized trial

Real world impact of added FFR-CT to coronary CT angiography on clinical decision-making and patient prognosis - IMPACT FFR study

OBJECTIVES

The addition of CT-derived fractional flow reserve (FFR-CT) increases the diagnostic accuracy of coronary CT angiography (CCTA). We assessed the impact of FFR-CT in routine clinical practice on clinical decision-making and patient prognosis in patients suspected of stable coronary artery disease (CAD).

METHODS

This retrospective, single-center study compared a cohort that received CCTA with FFR-CT to a historical cohort that received CCTA before FFR-CT was available. We assessed the clinical management decisions after FFR-CT and CCTA and the rate of major adverse cardiac events (MACEs) during the 1-year follow-up using chi-square tests for independence. Kaplan-Meier curves were used to visualize the occurrence of safety outcomes over time.

RESULTS

A total of 360 patients at low to intermediate risk of CAD were included, 224 in the CCTA only group, and 136 in the FFR-CT group. During follow-up, 13 MACE occurred in 12 patients, 9 (4.0%) in the CCTA group, and three (2.2%) in the FFR-CT group. Clinical management decisions differed significantly between both groups. After CCTA, 60 patients (26.5%) received optimal medical therapy (OMT) only, 115 (51.3%) invasive coronary angiography (ICA), and 49 (21.9%) single positron emission CT (SPECT). After FFR-CT, 106 patients (77.9%) received OMT only, 27 (19.9%) ICA, and three (2.2%) SPECT (p < 0.001 for all three options). The revascularization rate after ICA was similar between groups (p = 0.15). However, patients in the CCTA group more often underwent revascularization (p = 0.007).

CONCLUSION

Addition of FFR-CT to CCTA led to a reduction in (invasive) diagnostic testing and less revascularizations without observed difference in outcomes after 1 year.

KEY POINTS

• Previous studies have shown that computed tomography-derived fractional flow reserve improves the accuracy of coronary computed tomography angiography without changes in acquisition protocols. • This study shows that use of computed tomography-derived fractional flow reserve as gatekeeper to invasive coronary angiography in patients suspected of stable coronary artery disease leads to less invasive testing and revascularization without observed difference in outcomes after 1 year. • This could lead to a significant reduction in costs, complications and (retrospectively unnecessary) usage of diagnostic testing capacity, and a significant increase in patient satisfaction.

Functional coronary angiography for the assessment of the epicardial vessels and the microcirculation

Over the last decade, steady progress has been made in the ability to assess coronary stenosis relevance by merging computerised analyses of angiograms with fluid dynamic modelling. The new field of functional coronary angiography (FCA) has attracted the attention of both clinical and interventional cardiologists as it anticipates a new era of facilitated physiological assessment of coronary artery disease, without the need for intracoronary instrumentation or vasodilator drug administration, and an increased adoption of ischaemia-driven revascularisation. This state-of-the-art review performs a deep dive into the foundations and rationale behind FCA indices derived from either invasive or computed angiograms. We discuss the currently available FCA systems, the evidence supporting their use, and the specific clinical scenarios in which FCA might facilitate patient management. Finally, the rapidly growing application of FCA to the diagnosis of coronary microvascular dysfunction is discussed. Overall, we aim to provide a state-of-the-art review not only to digest the achievements made so far in FCA, but also to enable the reader to follow the many publications and developments in this field that will likely take place in years to come.

Diagnostic Strategies for the Assessment of Suspected Stable Coronary Artery Disease : A Systematic Review and Meta-analysis

BACKGROUND

There is uncertainty about which diagnostic strategy for detecting coronary artery disease (CAD) provides better outcomes.

PURPOSE

To compare the effect on clinical management and subsequent health effects of alternative diagnostic strategies for the initial assessment of suspected stable CAD.

DATA SOURCES

PubMed, Embase, and Cochrane Central Register of Controlled Trials.

STUDY SELECTION

Randomized clinical trials comparing diagnostic strategies for CAD detection among patients with symptoms suggestive of stable CAD.

DATA EXTRACTION

Three investigators independently extracted study data.

DATA SYNTHESIS

The strongest available evidence was for 3 of the 6 comparisons: coronary computed tomography angiography (CCTA) versus invasive coronary angiography (ICA) (4 trials), CCTA versus exercise electrocardiography (ECG) (2 trials), and CCTA versus stress single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) (5 trials). Compared with direct ICA referral, CCTA was associated with no difference in cardiovascular death and myocardial infarction (relative risk [RR], 0.84 [95% CI, 0.52 to 1.35]; low certainty) but less index ICA (RR, 0.23 [CI, 0.22 to 0.25]; high certainty) and index revascularization (RR, 0.71 [CI, 0.63 to 0.80]; moderate certainty). Moreover, CCTA was associated with a reduction in cardiovascular death and myocardial infarction compared with exercise ECG (RR, 0.66 [CI, 0.44 to 0.99]; moderate certainty) and SPECT-MPI (RR, 0.64 [CI, 0.45 to 0.90]; high certainty). However, CCTA was associated with more index revascularization (RR, 1.78 [CI, 1.33 to 2.38]; moderate certainty) but less downstream testing (RR, 0.56 [CI, 0.45 to 0.71]; very low certainty) than exercise ECG. Low-certainty evidence compared SPECT-MPI versus exercise ECG (2 trials), SPECT-MPI versus stress cardiovascular magnetic resonance imaging (1 trial), and stress echocardiography versus exercise ECG (1 trial).

LIMITATION

Most comparisons primarily rely on a single study, many studies were underpowered to detect potential differences in direct health outcomes, and individual patient data were lacking.

CONCLUSION

For the initial assessment of patients with suspected stable CAD, CCTA was associated with similar health effects to direct ICA referral, and with a health benefit compared with exercise ECG and SPECT-MPI. Further research is needed to better assess the relative performance of each diagnostic strategy.

PRIMARY FUNDING SOURCE

None. (PROSPERO: CRD42022329635).

Optimal Measurement Sites of Coronary-Computed Tomography Angiography-derived Fractional Flow Reserve: The Insight From China CT-FFR Study

OBJECTIVES

To investigate the optimal measurement site of coronary-computed tomography angiography-derived fractional flow reserve (FFR CT ) for the assessment of coronary artery disease (CAD) in the whole clinical routine practice.

MATERIALS AND METHODS

This retrospective multicenter study included 396 CAD patients who underwent coronary-computed tomography angiography, FFR CT , and invasive FFR. FFR CT was measured at 1 cm (FFR CT -1 cm), 2 cm (FFR CT -2 cm), 3 cm (FFR CT -3 cm), and 4 cm (FFR CT -4 cm) distal to coronary stenosis, respectively. FFR CT and invasive FFR ≤0.80 were defined as lesion-specific ischemia. The diagnostic performance of FFR CT to detect ischemia was obtained using invasive FFR as the reference standard. Reduced invasive coronary angiography rate and revascularization efficiency were calculated. After a median follow-up of 35 months in 267 patients for major adverse cardiovascular events (MACE), Cox hazard proportional models were performed with FFR CT values at each measurement site.

RESULTS

For discriminating lesion-specific ischemia, the areas under the curve of FFR CT -1 cm (0.91) as well as FFR CT -2 cm (0.91) were higher than those of FFR CT -3 cm (0.89) and FFR CT -4 cm (0.88), respectively (all P <0.05). The higher reduced invasive coronary angiography rate (81.6%) was found at FFR CT -1 cm than FFR CT -2 cm (81.6% vs. 62.6%, P <0.05). Revascularization efficiency did not differ between FFR CT -1 cm and FFR CT -2 cm (80.8% vs. 65.5%, P =0.019). In 12.4% (33/267) MACE occurred and only values of FFR CT -2 cm were independently predictive of MACE (hazard ratio: 0.957 [95% CI: 0.925-0.989]; P =0.010).

CONCLUSIONS

This study indicates FFR CT -2 cm is the optimal measurement site with superior diagnostic performance and independent prognostic role.

Systematic coronary physiology improves level of agreement in diagnostic coronary angiography

OBJECTIVE

The training of interventional cardiologists (ICs), non-interventional cardiologists (NICs) and cardiac surgeons (CSs) differs, and this may be reflected in their interpretation of invasive coronary angiography (ICA) and management plan. Availability of systematic coronary physiology might result in more homogeneous interpretation and management strategy compared with ICA alone.

METHODS

150 coronary angiograms from patients with stable chest pain were presented independently to three NICs, three ICs and three CSs. By consensus, each group graded (1) coronary disease severity and (2) management plan, using options: (a) optimal medical therapy alone, (b) percutaneous coronary intervention, (c) coronary artery bypass graft or (d) more investigation required. Each group was then provided with fractional flow reserve (FFR) from all major vessels and asked to repeat the analysis.

RESULTS

There was only 'fair' level of agreement of management plan among ICs, NICs and CSs (kappa 0.351, 95% CI 0.295-0.408, p<0.001) based on ICA alone (complete agreement in 35% of cases), which almost doubled to 'good' level (kappa 0.635, 95% CI 0.572-0.697, p<0.001) when comprehensive FFR was available (complete agreement in 66% of cases). Overall, the consensus management plan changed in 36.7%, 52% and 37.3% of cases for ICs, NICs and CSs, respectively, when FFR data were available.

CONCLUSIONS

Compared with ICA alone, the availability of systematic FFR of all major coronary arteries produced a significantly more concordant interpretation and more homogeneous management plan among IC, NIC and CS specialists. Comprehensive physiological assessment may be of value in routine care for Heart Team decision-making.

TRIAL REGISTRATION NUMBER

NCT01070771.

Evolving Diagnostic and Management Advances in Coronary Heart Disease

Despite considerable improvement in diagnostic modalities and therapeutic options over the last few decades, the global burden of ischemic heart disease is steadily rising, remaining a major cause of death worldwide. Thus, new strategies are needed to lessen cardiovascular events. Researchers in different areas such as biotechnology and tissue engineering have developed novel therapeutic strategies such as stem cells, nanotechnology, and robotic surgery, among others (3D printing and drugs). In addition, advances in bioengineering have led to the emergence of new diagnostic and prognostic techniques, such as quantitative flow ratio (QFR), and biomarkers for atherosclerosis. In this review, we explore novel diagnostic invasive and noninvasive modalities that allow a more detailed characterization of coronary disease. We delve into new technological revascularization procedures and pharmacological agents that target several residual cardiovascular risks, including inflammatory, thrombotic, and metabolic pathways.

Computed tomographic angiography in coronary artery disease

Coronary computed tomographic angiography (CCTA) is becoming the first-line investigation for establishing the presence of coronary artery disease and, with fractional flow reserve (FFRCT), its haemodynamic significance. In patients without significant epicardial obstruction, its role is either to rule out atherosclerosis or to detect subclinical plaque that should be monitored for plaque progression/regression following prevention therapy and provide risk classification. Ischaemic non-obstructive coronary arteries are also expected to be assessed by non-invasive imaging, including CCTA. In patients with significant epicardial obstruction, CCTA can assist in planning revascularisation by determining the disease complexity, vessel size, lesion length and tissue composition of the atherosclerotic plaque, as well as the best fluoroscopic viewing angle; it may also help in selecting adjunctive percutaneous devices (e.g., rotational atherectomy) and in determining the best landing zone for stents or bypass grafts.

2022 use of coronary computed tomographic angiography for patients presenting with acute chest pain to the emergency department: An expert consensus document of the Society of cardiovascular computed tomography (SCCT): Endorsed by the American College of Radiology (ACR) and North American Society for cardiovascular Imaging (NASCI)

Coronary computed tomography angiography (CTA) improves the quality of care for patients presenting with acute chest pain (ACP) to the emergency department (ED), particularly in patients with low to intermediate likelihood of acute coronary syndrome (ACS). The Society of Cardiovascular Computed Tomography Guidelines Committee was formed to develop recommendations for acquiring, interpreting, and reporting of coronary CTA to ensure appropriate, safe, and efficient use of this modality. Because of the increasing use of coronary CTA testing for the evaluation of ACP patients, the Committee has been charged with the development of the present document to assist physicians and technologists. These recommendations were produced as an educational tool for practitioners evaluating acute chest pain patients in the ED, in the interest of developing systematic standards of practice for coronary CTA based on the best available data or broad expert consensus. Due to the highly variable nature of medical care, approaches to patient selection, preparation, protocol selection, interpretation or reporting that differs from these guidelines may represent an appropriate variation based on a legitimate assessment of an individual patient's needs.

Addition of FFRct in the diagnostic pathway of patients with stable chest pain to reduce unnecessary invasive coronary angiography (FUSION) : Rationale and design for the multicentre, randomised, controlled FUSION trial

BACKGROUND

Coronary computed tomography angiography (CCTA) is widely used in the diagnostic work-up of patients with stable chest pain. CCTA has an excellent negative predictive value, but a moderate positive predictive value for detecting coronary stenosis. Computed tomography-derived fractional flow reserve (FFRct) is a non-invasive, well-validated technique that provides functional assessment of coronary stenosis, improving the positive predictive value of CCTA. However, to determine the value of FFRct in routine clinical practice, a pragmatic randomised, controlled trial (RCT) is required. We will conduct an RCT to investigate the impact of adding FFRct analysis in the diagnostic pathway of patients with a coronary stenosis on CCTA on the rate of unnecessary invasive coronary angiography, cost-effectiveness, quality of life and clinical outcome.

METHODS

The FUSION trial is a prospective, multicentre RCT that will randomise 528 patients with stable chest pain and anatomical stenosis of ≥ 50% but < 90% in at least one coronary artery of ≥ 2 mm on CCTA, to FFRct-guided care or usual care in a 1:1 ratio. Follow-up will be 1 year. The primary endpoint is the rate of unnecessary invasive coronary angiography within 90 days.

CONCLUSION

The FUSION trial will evaluate the use of FFRct in stable chest pain patients from the Dutch perspective. The trial is funded by the Dutch National Health Care Institute as part of the research programme 'Potentially Promising Care' and the results will be used to assess if FFRct reimbursement should be included in the standard health care package.

To Explore the Influencing Factors of Pericoronary Adipose Tissue and Noninvasive Fractional Flow Reserve on the Progression of Coronary Heart Disease Based on 320-Slice Coronary CTA

BACKGROUND

The objective of the study was to measure pericoronal adipose tissue parameters, fractional flow reserve with coronary artery computed tomographic angiography (CTA), and difference of fractional flow reserve with coronary artery CTA, by using high-performance 320-slice coronary CTA combined with semiautomatic quantitative software and explore the relationship between them and progression of coronary artery disease.

METHODS

According to the inclusion criteria, 118 patients with complete data were selected. According to the results of coronary angiography during follow-up review, the patients were divided into coronary artery disease progression group (n = 43) and coronary artery disease stable group (n = 75), and the clinical baseline data, pericoronal adipose tissue volume, pericoronal adipose tissue fat attenuation index, fractional flow reserve with coronary artery CTA, and difference of fractional flow reserve with coronary artery CTA were compared between the 2 groups. According to univariate and multivariate logistic regression analyses, the risk factors related to coronary artery disease progression were screened out from pericoronal adipose tissue parameters and noninvasive hemodynamic characteristics (fractional flow reserve with coronary artery CTA and difference of fractional flow reserve with coronary artery CTA).

RESULTS

There was no significant difference in baseline clinical data between the progression group and the stable group (P >.05). The left anterior descending artery-fat attenuation index-40 mm, left anterior descending artery-fat attenuation index-70 mm, left circumflex artery-fat attenuation index-70 mm, right coronary artery-fat attenuation index-70 mm, and difference of fractional flow reserve with coronary artery CTA in the progression group were higher than those in the stable group, while fractional flow reserve with coronary artery CTA was lower than that in the stable group, and the differences were statistically significant (P <.05). After adjusting for several factors, the results showed that left anterior descending artery-fat attenuation index-40 mm (P =.002; odds ratio = 1.237; 95% CI: 1.081-1.415), right coronary artery-fat attenuation index-70 mm (P =.039; odds ratio = 1.119; 95% CI: 1.006-1.246), fractional flow reserve with coronary artery CTA (P =.001; odds ratio = 0.708; 95% CI: 0.581-0.846), and difference of fractional flow reserve with coronary artery CTA (P <.001; odds ratio = 1.846; 95% CI: 1.394-2.445) were related to the progression of coronary artery disease. Compared with the above 5 indicators, the area under curve (AUC) of the above indicators combined is larger (0.897).

CONCLUSIONS

Quantitative pericoronal adipose tissue parameters and noninvasive hemodynamic characteristics based on 320-slice coronary CTA can be used as the basis for predicting the progression of coronary artery disease.

National Institute for Health and Care Excellence guidelines on myocardial revascularisation

Cardiologists in the UK predominantly use the National Institute for Health and Care Excellence (NICE) and European Society of Cardiology guidelines to help guide decision-making. This article will appraise the current recommendations from NICE regarding myocardial revascularisation and compare them with other major international guidelines. While there are many similarities, subtle differences exist. These differences arise in part due to the evidence base at time of publication, as well as from the different healthcare systems that they are designed for, and from the cost-effectiveness models that dominate the methodology used by NICE. The clinical implications of the differences between the international guidelines will be analysed.

Randomized comparison of chest pain evaluation with FFRCT or standard care: Factors determining US costs

BACKGROUND

FFR_CT assesses the functional significance of lesions seen on CTCA, and may be a more efficient approach to chest pain evaluation. The FORECAST randomized trial found no significant difference in costs within the UK National Health Service, but implications for US costs are unknown. The purpose of this study was to compare costs in the FORECAST trial based on US healthcare cost weights, and to evaluate factors affecting costs.

METHODS

Patients with stable chest pain were randomized either to the experimental strategy (CTCA with selective FFR_CT), or to standard clinical pathways. Pre-randomization, the treating clinician declared the planned initial test. The primary outcome was nine-month cardiovascular care costs.

RESULTS

Planned initial tests were CTCA in 912 patients (65%), stress testing in 393 (28%), and invasive angiography in 94 (7%). Mean US costs did not differ overall between the experimental strategy and standard care (cost difference +7% (+$324), CI -12% to +26%, p ​= ​0.49). Costs were 4% lower with the experimental strategy in the planned invasive angiography stratum (p for interaction ​= ​0.66). Baseline factors independently associated with costs were older age (+43%), male sex (+55%), diabetes (+37%), hypertension (+61%), hyperlipidemia (+94%), prior angina (+24%), and planned invasive angiography (+160%). Post-randomization cost drivers were coronary revascularization (+348%), invasive angiography (267%), and number of tests (+35%).

CONCLUSIONS

Initial evaluation of chest pain using CTCA with FFR_CT had similar US costs as standard care pathways. Costs were increased by baseline coronary risk factors and planned invasive angiography, and post-randomization invasive procedures and the number of tests. Registration at ClinicalTrials.gov (NCT03187639).

2023 Guidelines of the Taiwan Society of Cardiology on the Diagnosis and Management of Chronic Coronary Syndrome

Coronary artery disease (CAD) covers a wide spectrum from persons who are asymptomatic to those presenting with acute coronary syndromes (ACS) and sudden cardiac death. Coronary atherosclerotic disease is a chronic, progressive process that leads to atherosclerotic plaque development and progression within the epicardial coronary arteries. Being a dynamic process, CAD generally presents with a prolonged stable phase, which may then suddenly become unstable and lead to an acute coronary event. Thus, the concept of "stable CAD" may be misleading, as the risk for acute events continues to exist, despite the use of pharmacological therapies and revascularization. Many advances in coronary care have been made, and guidelines from other international societies have been updated. The 2023 guidelines of the Taiwan Society of Cardiology for CAD introduce a new concept that categorizes the disease entity according to its clinical presentation into acute or chronic coronary syndromes (ACS and CCS, respectively). Previously defined as stable CAD, CCS include a heterogeneous population with or without chest pain, with or without prior ACS, and with or without previous coronary revascularization procedures. As cardiologists, we now face the complexity of CAD, which involves not only the epicardial but also the microcirculatory domains of the coronary circulation and the myocardium. New findings about the development and progression of coronary atherosclerosis have changed the clinical landscape. After a nearly 50-year ischemia-centric paradigm of coronary stenosis, growing evidence indicates that coronary atherosclerosis and its features are both diagnostic and therapeutic targets beyond obstructive CAD. Taken together, these factors have shifted the clinicians' focus from the functional evaluation of coronary ischemia to the anatomic burden of disease. Research over the past decades has strengthened the case for prevention and optimal medical therapy as central interventions in patients with CCS. Even though functional capacity has clear prognostic implications, it does not include the evaluation of non-obstructive lesions, plaque burden or additional risk-modifying factors beyond epicardial coronary stenosis-driven ischemia. The recommended first-line diagnostic tests for CCS now include coronary computed tomographic angiography, an increasingly used anatomic imaging modality capable of detecting not only obstructive but also non-obstructive coronary plaques that may be missed with stress testing. This non-invasive anatomical modality improves risk assessment and potentially allows for the appropriate allocation of preventive therapies. Initial invasive strategies cannot improve mortality or the risk of myocardial infarction. Emphasis should be placed on optimizing the control of risk factors through preventive measures, and invasive strategies should be reserved for highly selected patients with refractory symptoms, high ischemic burden, high-risk anatomies, and hemodynamically significant lesions. These guidelines provide current evidence-based diagnosis and treatment recommendations. However, the guidelines are not mandatory, and members of the Task Force fully realize that the treatment of CCS should be individualized to address each patient's circumstances. Ultimately, the decision of healthcare professionals is most important in clinical practice.

Is it the Time to Move Towards Coronary Computed Tomography Angiography-Derived Fractional Flow Reserve Guided Percutaneous Coronary Intervention? The Pros and Cons

Coronary artery disease is the leading cause of mortality worldwide. Diagnosis is conventionally performed by direct visualization of the arteries by invasive coronary angiography (ICA), which has inherent limitations and risks. Measurement of fractional flow reserve (FFR) has been suggested for a more accurate assessment of ischemia in the coronary artery with high accuracy for determining the severity and decision on the necessity of intervention. Nevertheless, invasive coronary angiography-derived fractional flow reserve (ICA-FFR) is currently used in less than one-third of clinical practices because of the invasive nature of ICA and the need for additional equipment and experience, as well as the cost and extra time needed for the procedure. Recent technical advances have moved towards non-invasive high-quality imaging modalities, such as magnetic resonance, single-photon emission computed tomography, and coronary computed tomography (CT) scan; however, none had a definitive modality to confirm hemodynamically significant coronary artery stenosis. Coronary computed tomography angiography (CCTA) can provide accurate anatomic and hemodynamic data about the coronary lesion, especially calculating fractional flow reserve derived from CCTA (CCTA-FFR). Although growing evidence has been published regarding CCTA-FFR results being comparable to ICA-FFR, CCTA-FFR has not yet replaced the invasive conventional angiography, pending additional studies to validate the advantages and disadvantages of each diagnostic method. Furthermore, it has to be identified whether revascularization of a stenotic lesion is plausible based on CCTA-FFR and if the therapeutic plan can be determined safely and accurately without confirmation from invasive methods. Therefore, in the present review, we will outline the pros and cons of using CCTA-FFR vs. ICA-FFR regarding diagnostic accuracy and treatment decision-making.

Computed tomography coronary angiography in non-ST-segment elevation myocardial infarction

Electrocardiography and high-sensitivity cardiac troponin testing are routinely applied as the initial step for clinical evaluation of patients with suspected non-ST-segment elevation myocardial infarction. Once diagnosed, patients with non-ST-segment elevation myocardial infarction are commenced on antithrombotic and secondary preventative therapies before undergoing invasive coronary angiography to determine the strategy of coronary revascularisation. However, this clinical pathway is imperfect and can lead to challenges in the diagnosis, management, and clinical outcomes of these patients. Computed tomography coronary angiography (CTCA) has increasingly been utilised in the setting of patients with suspected non-ST-segment elevation myocardial infarction, where it has an important role in avoiding unnecessary invasive coronary angiography and reducing downstream non-invasive functional testing for myocardial ischaemia. CTCA is an excellent gatekeeper for the cardiac catheterisation laboratory. In addition, CTCA provides complementary information for patients with myocardial infarction in the absence of obstructive coronary artery disease and highlights alternative or incidental diagnoses for those with cardiac troponin elevation. However, the routine application of CTCA has yet to demonstrate an impact on subsequent major adverse cardiovascular events. There are several ongoing studies evaluating CTCA and its associated technologies that will define and potentially expand its application in patients with suspected or diagnosed non-ST-segment elevation myocardial infarction. We here review the current evidence relating to the clinical application of CTCA in patients with non-ST-segment elevation myocardial infarction and highlight the areas where CTCA is likely to have an increasing important role and impact for our patients.

Coronary Computed Tomography Angiography-derived Fractional Flow Reserve: An Expert Consensus Document of Chinese Society of Radiology

Invasive fractional flow reserve (FFR) measured by a pressure wire is a reference standard for evaluating functional stenosis in coronary artery disease. Coronary computed tomography angiography-derived fractional flow reserve (CT-FFR) uses advanced computational analysis methods to noninvasively obtain FFR results from a single conventional coronary computed tomography angiography data to evaluate the hemodynamic significance of coronary artery disease. More and more evidence has found good correlation between the results of noninvasive CT-FFR and invasive FFR. CT-FFR has proven its potential in optimizing patient management, improving risk stratification and prognosis, and reducing total health care costs. However, there is still a lack of standardized interpretation of CT-FFR technology in real-world clinical settings. This expert consensus introduces the principle, workflow, and interpretation of CT-FFR; summarizes the state-of-the-art application of CT-FFR; and provides suggestions and recommendations for the application of CT-FFR with the aim of promoting the standardized application of CT-FFR in clinical practice.

Noninvasive diagnostic modalities for the diagnosis of coronary artery disease: A guide for acute care NPs

ABSTRACT

Selecting noninvasive diagnostic tests for coronary artery disease can be a daunting task to acute care NPs. This article provides an overview of the pathophysiology of coronary artery disease, relevant noninvasive diagnostic imaging modalities, and an evidence-based approach to guide subsequent diagnostic and therapeutic interventions.

Left ventricular assessment with artificial intelligence increases the diagnostic accuracy of stress echocardiography

AIMS

To evaluate whether left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS), automatically calculated by artificial intelligence (AI), increases the diagnostic performance of stress echocardiography (SE) for coronary artery disease (CAD) detection.

METHODS AND RESULTS

SEs from 512 participants who underwent a clinically indicated SE (with or without contrast) for the evaluation of CAD from seven hospitals in the UK and US were studied. Visual wall motion scoring (WMS) was performed to identify inducible ischaemia. In addition, SE images at rest and stress underwent AI contouring for automated calculation of AI-LVEF and AI-GLS (apical two and four chamber images only) with Ultromics EchoGo Core 1.0. Receiver operator characteristic curves and multivariable risk models were used to assess accuracy for identification of participants subsequently found to have CAD on angiography. Participants with significant CAD were more likely to have abnormal WMS, AI-LVEF, and AI-GLS values at rest and stress (all P < 0.001). The areas under the receiver operating characteristics for WMS index, AI-LVEF, and AI-GLS at peak stress were 0.92, 0.86, and 0.82, respectively, with cut-offs of 1.12, 64%, and -17.2%, respectively. Multivariable analysis demonstrated that addition of peak AI-LVEF or peak AI-GLS to WMS significantly improved model discrimination of CAD [C-statistic (bootstrapping 2.5th, 97.5th percentile)] from 0.78 (0.69-0.87) to 0.83 (0.74-0.91) or 0.84 (0.75-0.92), respectively.

CONCLUSION

AI calculation of LVEF and GLS by contouring of contrast-enhanced and unenhanced SEs at rest and stress is feasible and independently improves the identification of obstructive CAD beyond conventional WMSI.

Routine Pressure Wire Assessment Versus Conventional Angiography in the Management of Patients With Coronary Artery Disease: The RIPCORD 2 Trial

BACKGROUND

Measurement of fractional flow reserve (FFR) has an established role in guiding percutaneous coronary intervention. We tested the hypothesis that, at the stage of diagnostic invasive coronary angiography, systematic FFR-guided assessment of coronary artery disease would be superior, in terms of resource use and quality of life, to assessment by angiography alone.

METHODS

We performed an open-label, randomized, controlled trial in 17 UK centers, recruiting 1100 patients undergoing invasive coronary angiography for the investigation of stable angina or non-ST-segment-elevation myocardial infarction. Patients were randomized to either angiography alone (angiography) or angiography with systematic pressure wire assessment of all epicardial vessels >2.25 mm in diameter (angiography+FFR). The coprimary outcomes assessed at 1 year were National Health Service hospital costs and quality of life. Prespecified secondary outcomes included clinical events.

RESULTS

In the angiography+FFR arm, the median number of vessels examined was 4 (interquartile range, 3-5). The median hospital costs were similar: angiography, £4136 (interquartile range, £2613-£7015); and angiography+FFR, £4510 (£2721-£7415; P=0.137). There was no difference in median quality of life using the visual analog scale of the EuroQol EQ-5D-5L: angiography, 75 (interquartile range, 60-87); and angiography+FFR, 75 (interquartile range, 60-90; P=0.88). The number of clinical events was as follows: deaths, 5 versus 8; strokes, 3 versus 4; myocardial infarctions, 23 versus 22; and unplanned revascularizations, 26 versus 33, with a composite hierarchical event rate of 8.7% (48 of 552) for angiography versus 9.5% (52 of 548) for angiography+FFR (P=0.64).

CONCLUSIONS

A strategy of systematic FFR assessment compared with angiography alone did not result in a significant reduction in cost or improvement in quality of life.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01070771.

Real-world validation of fractional flow reserve computed tomography in patients with stable angina: Results from the prospective AFFECTS trial

BACKGROUND

Fractional flow reserve computed tomography (FFRct) allows for non-invasive assessment of hemodynamically significant coronary artery disease (CAD). Real-world data regarding the diagnostic performance of FFRct is scarce. We aim to validate the diagnostic performance of FFRct against invasive coronary angiography (ICA) in patients with stable angina and an abnormal single photon emission computed tomography (SPECT) study.

METHODS

This prospective, single-cohort, real-world study enrolled consecutive adult patients with stable angina and an abnormal SPECT study who were referred for ICA. Prior to ICA, FFRct analysis was performed. Sensitivity and specificity of FFRct were evaluated at the patient and vessel level against ICA. Physician intuition-based diagnosis of hemodynamically significant CAD was also documented prior to ICA.

RESULTS

A total of 66 patients were enrolled; 10 were excluded due to protocol deviation or missing studies. FFRct achieved 95% sensitivity and 83% specificity at the patient level, and 78% sensitivity and 88% specificity at the vessel level. FFRct was most accurate in the left circumflex artery (sensitivity 83%, specificity 92%) and the least in the left anterior descending artery (80% sensitivity, 78% specificity). FFRct identified hemodynamically significant CAD more accurately than physician intuition (sensitivity 95% vs 84%; specificity 83% vs 46%). If physicians had been unblinded to FFRct, ICA may have been avoided in up to 53% of patients.

CONCLUSION

We performed a real-world study to validate the diagnostic performance of FFRct against gold-standard invasive imaging. FFRct has high sensitivity and specificity for the diagnosis of hemodynamically significant CAD in intermediate-to-high risk patients.

Perspectives in noninvasive imaging for chronic coronary syndromes

Both the latest European guidelines on chronic coronary syndromes and the American guidelines on chest pain have underlined the importance of noninvasive imaging to select patients to be referred to invasive angiography. Nevertheless, although coronary stenosis has long been considered the main determinant of inducible ischemia and symptoms, growing evidence has demonstrated the importance of other underlying mechanisms (e.g., vasospasm, microvascular disease, energetic inefficiency). The search for a pathophysiology-driven treatment of these patients has therefore emerged as an important objective of multimodality imaging, integrating "anatomical" and "functional" information. We here provide an up-to-date guide for the choice and the interpretation of the currently available noninvasive anatomical and/or functional tests, focusing on emerging techniques (e.g., coronary flow velocity reserve, stress-cardiac magnetic resonance, hybrid imaging, functional-coronary computed tomography angiography, etc.), which could provide deeper pathophysiological insights to refine diagnostic and therapeutic pathways in the next future.

Appropriateness criteria for the use of cardiac computed tomography, SIC-SIRM part 2: acute chest pain evaluation; stent and coronary artery bypass graft patency evaluation; planning of coronary revascularization and transcatheter valve procedures; cardiomyopathies, electrophysiological applications, cardiac masses, cardio-oncology and pericardial diseases evaluation

In the past 20 years, cardiac computed tomography (CCT) has become a pivotal technique for the noninvasive diagnostic workup of coronary and cardiac diseases. Continuous technical and methodological improvements, combined with fast growing scientific evidence, have progressively expanded the clinical role of CCT. Randomized clinical trials documented the value of CCT in increasing the cost-effectiveness of the management of patients with acute chest pain presenting in the emergency department, also during the pandemic. Beyond the evaluation of stents and surgical graft patency, the anatomical and functional coronary imaging have the potential to guide treatment decision-making and planning for complex left main and three-vessel coronary disease. Furthermore, there has been an increasing demand to use CCT for preinterventional planning in minimally invasive procedures, such as transcatheter valve implantation and mitral valve repair. Yet, the use of CCT as a roadmap for tailored electrophysiological procedures has gained increasing importance to assure maximum success. In the meantime, innovations and advanced postprocessing tools have generated new potential applications of CCT from the simple coronary anatomy to the complete assessment of structural, functional and pathophysiological biomarkers of cardiac disease. In this complex and revolutionary scenario, it is urgently needed to provide an updated guide for the appropriate use of CCT in different clinical settings. This manuscript, endorsed by the Italian Society of Cardiology (SIC) and the Italian Society of Medical and Interventional Radiology (SIRM), represents the second of two consensus documents collecting the expert opinion of cardiologists and radiologists about current appropriate use of CCT.

Coronary Physiology: Delivering Precision Medicine?

Coronary physiological assessment is now widely used to assess epicardial coronary lesions in cath lab. Based on clinical evidence, fractional flow reserve (FFR) is the gold standard method to select whether epicardial coronary lesions need revascularization. While additional epicardial indexes, such as instantaneous wave-free ratio (iFR), are also used for revascularization decision-making, several indexes are now also available to explore the coronary microcirculation. Therefore, coronary physiological assessment now allows to explore the entire coronary tree and offer the potential of precision medicine for patients affected by coronary artery disease (CAD). This paper will provide review of the epicardial and microvascular indexes available for the assessment of coronary physiology. More specifically, the already demonstrated contributions of these indexes in the management of CAD and the role they could play in precision medicine will be reviewed with special emphasis on chronic coronary syndrome.

Atheroma or ischemia: which is more important for managing patients with stable chest pain?

In the evaluation and management of patients with stable chest pain/chronic coronary syndrome, cardiologists need to be able to weigh up the relative merits of managing these patients using either optimal therapy alone or optimal therapy plus revascularization. These decisions rely on an understanding of both the presence and the degree of coronary atheroma and myocardial ischemia, and the impact that these have on patients' symptoms and their prognosis. In this review the authors examine the relative impact of the anatomical and physiological assessment of patients with chronic coronary syndrome and how it can be used to achieve optimal and tailored therapy.

What is the Role of Coronary Physiology in the Management of Patients with Chronic Coronary Syndromes?

The use of coronary physiology in patients with chronic coronary syndromes is highly variable, and the evidence base complex. Tests of coronary physiology have traditionally been invasive (e.g., fractional flow reserve), but novel non-invasive methods are now available which provide additional anatomical information (e.g., computed tomography-based fractional flow reserve and angiogram-derived physiology). This review summarises the evidence for and against the relative value of these tests for patients being investigated for chest pain that may represent chronic coronary syndromes, and for those triaged to percutaneous coronary intervention.

Is CT-derived fractional flow reserve superior to ischaemia testing?

NA.

Clinical applications of cardiac computed tomography: a consensus paper of the European Association of Cardiovascular Imaging-part II

Cardiac computed tomography (CT) was initially developed as a non-invasive diagnostic tool to detect and quantify coronary stenosis. Thanks to the rapid technological development, cardiac CT has become a comprehensive imaging modality which offers anatomical and functional information to guide patient management. This is the second of two complementary documents endorsed by the European Association of Cardiovascular Imaging aiming to give updated indications on the appropriate use of cardiac CT in different clinical scenarios. In this article, emerging CT technologies and biomarkers, such as CT-derived fractional flow reserve, perfusion imaging, and pericoronary adipose tissue attenuation, are described. In addition, the role of cardiac CT in the evaluation of atherosclerotic plaque, cardiomyopathies, structural heart disease, and congenital heart disease is revised.

The prospective randomized trial of the optimal evaluation of cardiac symptoms and revascularization: Rationale and design of the PRECISE trial

BACKGROUND

Clinicians vary widely in their preferred diagnostic approach to patients with non-acute chest pain. Such variation exposes patients to potentially avoidable risks, as well as inefficient care with increased costs and unresolved patient concerns.

METHODS

The Prospective Randomized Trial of the Optimal Evaluation of Cardiac Symptoms and Revascularization (PRECISE) trial (NCT03702244) compares an investigational "precision" diagnostic strategy to a usual care diagnostic strategy in participants with stable chest pain and suspected coronary artery disease (CAD).

RESULTS

PRECISE randomized 2103 participants with stable chest pain and a clinical recommendation for testing for suspected CAD at 68 outpatient international sites. The investigational precision evaluation strategy started with a pre-test risk assessment using the PROMISE Minimal Risk Tool. Those at lowest risk were assigned to deferred testing (no immediate testing), and the remainder received coronary computed tomographic angiography (cCTA) with selective fractional flow reserve (FFR_CT) for any stenosis meeting a threshold of ≥30% and <90%. For participants randomized to usual care, the clinical care team selected the initial noninvasive or invasive test (diagnostic angiography) according to customary practice. The use of cCTA as the initial diagnostic strategy was proscribed by protocol for the usual care strategy. The primary endpoint is time to a composite of major adverse cardiac events (MACE: all-cause death or non-fatal myocardial infarction) or invasive cardiac catheterization without obstructive CAD at 1 year. Secondary endpoints include health care costs and quality of life.

CONCLUSIONS

PRECISE will determine whether a precision approach comprising a strategically deployed combination of risk-based deferred testing and cCTA with selective FFR_CT improves the clinical outcomes and efficiency of the diagnostic evaluation of stable chest pain over usual care.

Detection of Vulnerable Coronary Plaques Using Invasive and Non-Invasive Imaging Modalities

Acute coronary syndrome (ACS) mostly arises from so-called vulnerable coronary plaques, particularly prone for rupture. Vulnerable plaques comprise a specific type of plaque, called the thin-cap fibroatheroma (TFCA). A TCFA is characterized by a large lipid-rich necrotic core, a thin fibrous cap, inflammation, neovascularization, intraplaque hemorrhage, microcalcifications or spotty calcifications, and positive remodeling. Vulnerable plaques are often not visible during coronary angiography. However, different plaque features can be visualized with the use of intracoronary imaging techniques, such as intravascular ultrasound (IVUS), potentially with the addition of near-infrared spectroscopy (NIRS), or optical coherence tomography (OCT). Non-invasive imaging techniques, such as computed tomography coronary angiography (CTCA), cardiovascular magnetic resonance (CMR) imaging, and nuclear imaging, can be used as an alternative for these invasive imaging techniques. These invasive and non-invasive imaging modalities can be implemented for screening to guide primary or secondary prevention therapies, leading to a more patient-tailored diagnostic and treatment strategy. Systemic pharmaceutical treatment with lipid-lowering or anti-inflammatory medication leads to plaque stabilization and reduction of cardiovascular events. Additionally, ongoing studies are investigating whether modification of vulnerable plaque features with local invasive treatment options leads to plaque stabilization and subsequent cardiovascular risk reduction.

Computed tomography coronary angiography as the noninvasive in stable coronary artery disease? Long-term outcomes meta-analysis

Aim: To compare outcomes of coronary computed tomography angiography (CCTA) with that of functional testing (FT) in stable coronary artery disease. Methods: We searched PubMed, Embase, and Cochrane for randomized controlled trials (RCTs). A random-effects meta-analysis targeting all-cause death and nonfatal acute coronary syndromes was performed. Results: Eight RCTs enrolling 29,579 patients were included. Pooled relative risk (RR) for the primary end point was similar between CCTA and FT (RR = 0.97; 95% CI: 0.76-1.22). CCTA outperformed FT in nonfatal myocardial infarction (MI) (RR = 0.59; 95% CI: 0.41-0.83) and in downstream testing (OR: 0.47; 95% CI: 0.21-1.01). Conclusion: Updated data of stable coronary artery disease suggests that CCTA improved nonfatal MI and downstream testing.

Prognostic Value of Coronary CT Angiography-Derived Fractional Flow Reserve in Non-obstructive Coronary Artery Disease: A Prospective Multicenter Observational Study

Coronary artery disease (CAD) is a major contributor to morbidity and mortality worldwide. Myocardial ischemia may occur in patients with normal or non-obstructive CAD on invasive coronary angiography (ICA). The comprehensive evaluation of coronary CT angiography (CCTA) integrated with fractional flow reserve derived from CCTA (CT-FFR) to CAD may be essential to improve the outcomes of patients with non-obstructive CAD. China CT-FFR Study-2 (ChiCTR2000031410) is a large-scale prospective, observational study in 29 medical centers in China. The primary purpose is to uncover the relationship between the CCTA findings (including CT-FFR) and the outcome of patients with non-obstructive CAD. At least 10,000 patients with non-obstructive CAD but without previous revascularization will be enrolled. A 5-year follow-up will be performed. The primary endpoint is the occurrence of major adverse cardiovascular events (MACE), including all-cause mortality, non-fatal myocardial infarct, unplanned revascularization, and hospitalization for unstable angina. Clinical characteristics, laboratory and imaging examination results will be collected to analyze their prognostic value.

Cardiovascular computed tomography imaging for coronary artery disease risk: plaque, flow and fat

Cardiac imaging is central to the diagnosis and risk stratification of coronary artery disease, beyond symptoms and clinical risk factors, by providing objective evidence of myocardial ischaemia and characterisation of coronary artery plaque. CT coronary angiography can detect coronary plaque with high resolution, estimate the degree of functional stenosis and characterise plaque features. However, coronary artery disease risk is also driven by biological processes, such as inflammation, that are not fully reflected by severity of stenosis, myocardial ischaemia or by coronary plaque features. New cardiac CT techniques can assess coronary artery inflammation by imaging perivascular fat, and this may represent an important step forward in identifying the ‘residual risk’ that is not detected by plaque or ischaemia imaging. Coronary artery disease risk assessment that incorporates clinical factors, plaque characteristics and perivascular inflammation offers a more comprehensive individualised approach to quantify and stratify coronary artery disease risk, with potential healthcare benefits for prevention, diagnosis and treatment recommendations. Furthermore, identifying new biomarkers of cardiovascular risk has the potential to refine early-life prevention strategies, before atherosclerosis becomes established.

OUP accepted manuscript

This article reviews the most relevant literature published in 2021 on the role of cardiovascular imaging in cardiovascular medicine. Coronavirus disease 2019 (COVID-19) continued to impact the healthcare landscape, resulting in reduced access to hospital-based cardiovascular care including reduced routine diagnostic cardiovascular testing. However, imaging has also facilitated the understanding of the presence and extent of myocardial damage caused by the coronavirus infection. What has dominated the imaging literature beyond the pandemic are novel data on valvular heart disease, the increasing use of artificial intelligence (AI) applied to imaging, and the use of advanced imaging modalities in both ischaemic heart disease and cardiac amyloidosis.

Automated Echocardiographic Detection of Severe Coronary Artery Disease Using Artificial Intelligence

OBJECTIVES

The purpose of this study was to establish whether an artificially intelligent (AI) system can be developed to automate stress echocardiography analysis and support clinician interpretation.

BACKGROUND

Coronary artery disease is the leading global cause of mortality and morbidity and stress echocardiography remains one of the most commonly used diagnostic imaging tests.

METHODS

An automated image processing pipeline was developed to extract novel geometric and kinematic features from stress echocardiograms collected as part of a large, United Kingdom-based prospective, multicenter, multivendor study. An ensemble machine learning classifier was trained, using the extracted features, to identify patients with severe coronary artery disease on invasive coronary angiography. The model was tested in an independent U.S.

STUDY

How availability of an AI classification might impact clinical interpretation of stress echocardiograms was evaluated in a randomized crossover reader study.

RESULTS

Acceptable classification accuracy for identification of patients with severe coronary artery disease in the training data set was achieved on cross-fold validation based on 31 unique geometric and kinematic features, with a specificity of 92.7% and a sensitivity of 84.4%. This accuracy was maintained in the independent validation data set. The use of the AI classification tool by clinicians increased inter-reader agreement and confidence as well as sensitivity for detection of disease by 10% to achieve an area under the receiver-operating characteristic curve of 0.93.

CONCLUSION

Automated analysis of stress echocardiograms is possible using AI and provision of automated classifications to clinicians when reading stress echocardiograms could improve accuracy, inter-reader agreement, and reader confidence.