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

Favorable impact of FFRCT on myocardial revascularization outcomes: Results from an observational real-world registry

BACKGROUND

Coronary computed tomography angiography (CCTA)-derived fractional flow reserve (FFRCT) strategy significantly decreases unnecessary invasive coronary angiography and refines the appropriateness of revascularization decision. The present study aimed to evaluate how FFRCT guided - strategy impacts outcomes postrevascularization.

METHODS

We included patients with suspected obstructive coronary artery disease (OCAD in a registry from 2013 to 2021. FFRCT entered Heart-Team decision from 2017. Propensity score adjusted Cox - and logistic - regression analyzed FFRCT's impact on post- revascularization major adverse cardiovascular events (MACE) and myocardial injury (PMI).

RESULTS

Among 7541 patients, 1601 had suspected OCAD. 559 patients underwent revascularization: 69.0 % PCI, 29.7 % CABG and 1.2 % both. 252(45.1 %) patients underwent FFRCT. Over 4.4 ± 2.2 years, 137(24.5 %) patients experienced MACE. FFRCT was associated with a trend toward reduced MACE (HR 0.736, 95 % CI 0.513-1.055, p = 0.095) and significantly reduced all-cause mortality (HR 0.476, 95 % CI 0.230-0.985, p = 0.046). In the post-2017 cohort (413 patients, follow-up 3.7 ± 1.5 years), FFRCT significantly reduced MACE (HR 0.610, 95 % CI 0.390-0.954, P = 0.030) and all-cause mortality (HR 0.285, 95 % CI 0.104-0.779, P = 0.014). In CABG patients, FFRCT was associated with lower PMI incidence (5.3 % vs. 15.6 %, p = 0.044). Multivariable analysis revealed no significant association between FFRCT use and PMI.

CONCLUSIONS

Revascularization decision-making with FFRCT translates into better post-revascularization outcomes, primarily by reducing MACE through lower mortality. There was no clear impact on PMI. These findings suggests that FFRCT's value lies indeed in improving patient selection for revascularization, but warrants further confirmation in randomized clinical trials.

Application and Performance of CT-Fractional Flow Reserve in Non-ST-Segment Elevation Myocardial Infarction

Only half of patients with non-ST-segment elevation myocardial infarction (NSTEMI) have obstructive coronary artery disease (CAD) on invasive coronary angiography (ICA). A non-invasive test that can safely rule out obstructive CAD therefore warrants investigation. Computed tomography fractional flow reserve (CT-FFR) enables hemodynamic interrogation of lesions identified on coronary computed tomography angiography (CCTA) but it has not been evaluated in NSTEMI. Inpatients with NSTEMI were recruited to undergo CCTA with CT-FFR prior to ICA. Blinded CT-FFR was performed using Siemens Frontiers cFFR, version 1.4. Invasive FFR was performed on all intermediate lesions with stenoses measuring >30% to <90%. The performance of CT-FFR and CTCA was compared to the gold-standard of ICA plus FFR. Forty patients (131 vessels) were included. The mean age was 61 ± 11 years and 75% were male. CT-FFR showed good correlation with invasive FFR (r = 0.78) and exhibited excellent diagnostic accuracy for obstructive CAD (defined as FFR<0.80 or angiographic stenosis >90%) on a per-vessel analysis, with a sensitivity of 87%, specificity 99%, positive predictive value (PPV) 97%, negative predictive value (NPV) 95% and area under the receiver operating curve (AUC) 0.93, which was superior to CCTA alone (sensitivity 82%, specificity 92%, PPV 82%, NPV 92%, AUC 0.87, p-value for AUC comparison = 0.04). On a per-patient analysis, CT-FFR had a diagnostic accuracy of 100%. In conclusion, CT-FFR provides additive diagnostic accuracy to CCTA in evaluating patients with NSTEMI and exhibits good correlation with invasive FFR.

CT-derived fractional flow reserve on therapeutic management and outcomes compared with coronary CT angiography in coronary artery disease

OBJECTIVES

To determine the value of on-site deep learning-based CT-derived fractional flow reserve (CT-FFR) for therapeutic management and adverse clinical outcomes in patients suspected of coronary artery disease (CAD) compared with coronary CT angiography (CCTA) alone.

METHODS

This single-centre prospective study included consecutive patients suspected of CAD between June 2021 and September 2021 at our hospital. Four hundred and sixty-one patients were randomized into either CT-FFR+CCTA or CCTA-alone group. The first endpoint was the invasive coronary angiography (ICA) efficiency, defined as the ICA with nonobstructive disease (stenosis <50%) and the ratio of revascularization to ICA (REV-to-ICA ratio) within 90 days. The second endpoint was the incidence of major adverse cardiaovascular events (MACE) at 2 years.

RESULTS

A total of 461 patients (267 [57.9%] men; median age, 64 [55-69]) were included. At 90 days, the rate of ICA with nonobstructive disease in the CT-FFR+CCTA group was lower than in the CCTA group (14.7% vs 34.0%, P=.047). The REV-to-ICA ratio in the CT-FFR+CCTA group was significantly higher than in the CCTA group (73.5% vs. 50.9%, P=.036). No significant difference in ICA efficiency was found in intermediate stenosis (25%-69%) between the 2 groups (all P>.05). After a median follow-up of 23 (22-24) months, MACE were observed in 11 patients in the CT-FFR+CCTA group and 24 in the CCTA group (5.9% vs 10.0%, P=.095).

CONCLUSIONS

The on-site deep learning-based CT-FFR improved the efficiency of ICA utilization with a similarly low rate of MACE compared with CCTA alone.

ADVANCES IN KNOWLEDGE

The on-site deep learning-based CT-FFR was superior to CCTA for therapeutic management.

Design and Rationale of 'A pragmatic approach to the investigation of stable chest pain: a UK, multi-centre, randomised trial to assess patient outcomes, quality of life and cost effectiveness (CE-MARC 3)'

RATIONALE

The optimal non-invasive diagnostic imaging strategy for patients with suspected coronary artery disease (CAD) is widely debated. Computed Tomography Coronary Angiography (CTCA) and functional imaging are both guideline-recommended, although comparative effectiveness in patients with intermediate-high pre-test likelihood (PTL) is limited. Primary Hypothesis: We aim to establish if a personalised investigation strategy compared to CTCA first-line for allcomers, leads to improved patient outcomes.

DESIGN

In a multi-centre, randomised trial, 4,000 patients newly referred for the investigation of suspected cardiac chest pain will be recruited and randomised (1:1) to either personalised care (first-line CTCA or functional imaging based on PTL) or CTCA first-line for allcomers. The primary endpoint is time to a composite of cardiovascular death, myocardial infarction, or unobstructed coronary arteries on invasive angiography. Follow up will occur at 6 and 12 months and then annually for up to four years for symptoms, quality of life, and guideline directed medical therapy usage. A cost-effectiveness analysis will be performed capturing impacts on health, measured in quality adjusted life years (QALYs) using the EQ-5D-5L, and costs (including investigations, procedures, procedural complications, medical treatment costs and any future hospital admissions) calculated. It will be possible for the whole trial pathway to be conducted remotely with the option to perform non-face-to-face consent, randomisation, and follow-up data collection including health-related quality of life.

SITES

20 UK sites ENROLMENT: First site opened April 2022 and recruitment is due to complete by July 2025, with an average recruitment of 135 patients a month to date.

CURRENT STATUS

3,407 patients recruited and randomised by the end of February 2025 CONCLUSION: This trial will address whether, in patients with suspected cardiac chest pain, a strategy of personalised investigation according to pre-test likelihood (PTL), compared to CTCA for allcomers, leads to improved patient outcomes, quality of life and cost-effectiveness.

[Diagnostic of the chronic coronary syndrome]

The chronic coronary syndrome can be attributed to different pathophysiological epicardial or microvascular mechanisms. In the current ESC guideline from 2024, a diagnostic algorithm was developed based on a risk-factor-weighted individual pre-test probability. The baseline diagnostic includes anamnesis, electrocardiogram, and a laboratory chemical analysis, especially to exclude an acute coronary syndrome. The early and direct assessments for risk-factor-weighted individual pre-test probability are calculated by taking into account clinical symptoms, individual cardiovascular risk factors, age, and gender. Resting ECG, echocardiography and the evaluation of the peripheral arteries and data on possible known vascular calcifications in previous imaging examinations can further adjust and modify the pre-test probability. Non-invasive imaging methods (computed tomography angiography, magnetic resonance imaging, stress echocardiography, SPECT, PET) or invasive coronary angiography can be used to confirm or exclude the diagnosis of chronic coronary syndrome.

Reliability of characterising coronary artery flow with the flow-split outflow strategy: Comparison against the multiscale approach

BACKGROUND

In computational modelling of coronary haemodynamics, imposing patient-specific flow conditions is paramount, yet often impractical due to resource and time constraints, limiting the ability to perform a large number of simulations particularly for diseased cases.

OBJECTIVE

To compare coronary haemodynamics quantified using a simplified flow-split strategy with varying exponents against the clinically verified but computationally intensive multiscale simulations under both resting and hyperaemic conditions in arteries with varying degrees of stenosis.

METHODS

Six patient-specific left coronary artery trees were segmented and reconstructed, including three with severe (>70 %) and three with mild (<50 %) focal stenoses. Simulations were performed for the entire coronary tree to account for the flow-limiting effects from epicardial artery stenoses. Both a 0D-3D coupled multiscale model and a flow-split approach with four different exponents (2.0, 2.27, 2.33, and 3.0) were used. The resulting prominent haemodynamic metrics were statistically compared between the two methods.

RESULTS

Flow-split and multiscale simulations did not significantly differ under resting conditions regardless of the stenosis severity. However, under hyperaemic conditions, the flow-split method significantly overestimated the time-averaged wall shear stress by up to 16.8 Pa (p = 0.031) and underestimate the fractional flow reserve by 0.327 (p = 0.043), with larger discrepancies observed in severe stenoses than in mild ones. Varying the exponent from 2.0 to 3.0 within the flow-split methods did not significantly affect the haemodynamic results (p > 0.141).

CONCLUSIONS

Flow-split strategies with exponents between 2.0 and 3.0 are appropriate for modelling stenosed coronaries under resting conditions. Multiscale simulations are recommended for accurate modelling of hyperaemic conditions, especially in severely stenosed arteries.(247/250 words).

Data-driven analysis of technological biomarkers and functional myocardial ischemia in stable coronary artery disease using advanced statistical modeling

BackgroundFunctional myocardial ischemia (FMI) in stable coronary artery disease (SCAD) remains a critical challenge in cardiovascular care. While fractional flow reserve (FFR) is a gold-standard diagnostic technology, its clinical adoption is limited by cost and complexity. Integrating technological biomarkers and advanced analytics could enhance risk stratification and guide precision interventions.ObjectiveThis study leverages data-driven methodologies to identify and validate technological biomarkers associated with FMI in SCAD, aiming to optimize clinical decision-making through predictive modeling.MethodsA systematic search across PubMed, Embase, and Web of Science (inception-October 2023) identified studies evaluating SCAD and FMI. Inclusion criteria: cohort/case-control studies (n ≥ 100) using FFR or angiographic technologies. Meta-analyses were conducted via RevMan 5.4 and Stata 16.0, employing fixed/random-effects models. Heterogeneity was assessed using I² statistics.ResultsAnalysis of 15 studies (n = 4854) revealed that anatomical biomarkers-stenosis severity (DS%: SMD = 0.95, p < 0.0001), minimal lumen diameter (SMD = -1.33, p < 0.0001), and lesion length (SMD = 0.72, p < 0.0001)-were strongly linked to FMI. Diabetes (OR = 1.31, p = 0.003) and smoking (OR = 1.47, p < 0.0001) emerged as significant modifiable risks, while hypertension showed no association (p = 0.14). Age and gender disparities highlighted the need for personalized risk algorithms.ConclusionTechnological biomarkers and data-driven modeling provide actionable insights into FMI risk in SCAD, bridging gaps between anatomical assessments and functional outcomes. Future integration of machine learning and predictive analytics could refine risk stratification, enabling tailored therapeutic strategies.

Representation of Older Adults and Women in Randomized Trials of Non-Invasive Imaging for Chest Pain

Background

Non-invasive imaging is widely used both for initial diagnosis and to guide management of ischemic heart disease (IHD). Older adults and women with IHD may have different responses to imaging as well as to treatments and outcomes that follow compared with younger adults and men. We aimed to study the representation of older adults and women in randomized controlled trials (RCT) of non-invasive imaging among patients with acute and stable chest pain.

Methods

We conducted a systematic search to identify RCTs evaluating non-invasive, imaging-guided diagnosis and management for IHD that were published before September 1, 2023. Participation-to-Prevalence Ratio (PPR) was estimated for women and age subgroups of <65, 65-74, ≥75 years. PPR of <0.8, 0.8-1.2, and >1.2 indicated underrepresentation, appropriate representation, and overrepresentation, respectively.

Results

Among 53 RCTs, sex and age breakdown were available in 53 (n=55,893) and 21 trials (n=35,503), respectively. The median age across all trials was 57.4 years [IQR: 55.0- 60.2]. Participants aged <65 years were overrepresented with a median PPR 2.13 [IQR: 1.73- 2.43], while those aged 65-74 years and ≥75 years were underrepresented with median PPRs of 0.74 [IQR: 0.56-0.83] and 0.21 [IQR: 0.11-0.33], respectively. Women were adequately represented with a median PPR of 1.2 [1.06-1.32].

Conclusion

While women were appropriately represented, adults 65 years or older, especially those ≥75 years, were under-represented in these trials. Future RCTs on non-invasive imaging should target enrollment of older adults to ensure generalizability of results to this growing population.

CLINICAL PERSPECTIVE

In a systematic review of 53 randomized controlled trials of non-invasive imaging for chest pain published before September 1, 2023 (n=55,893 participants), adults aged 65 years and older, especially those aged 75 years and above, were significantly underrepresented, whereas women had representation proportional to prevalence estimates. These findings highlight an urgent need to increase enrollment of older adults in future imaging trials to ensure broader applicability and relevance of study results.

Abstract Figure

Implementation of a national AI technology program on cardiovascular outcomes and the health system

Coronary artery disease (CAD) is a major cause of ill health and death worldwide. Coronary computed tomographic angiography (CCTA) is the first-line investigation to detect CAD in symptomatic patients. This diagnostic approach risks greater second-line heart tests and treatments at a cost to the patient and health system. The National Health Service funded use of an artificial intelligence (AI) diagnostic tool, computed tomography (CT)-derived fractional flow reserve (FFR-CT), in patients with chest pain to improve physician decision-making and reduce downstream tests. This observational cohort study assessed the impact of FFR-CT on cardiovascular outcomes by including all patients investigated with CCTA during the national AI implementation program at 27 hospitals (CCTA n = 90,553 and FFR-CT n = 7,863). FFR-CT was safe, with no difference in all-cause (n = 1,134 (3.2%) versus 1,612 (2.9%), adjusted-hazard ratio (aHR) 1.00 (0.93-1.08), P = 0.97) or cardiovascular mortality (n = 465 (1.3%) versus 617 (1.1%), aHR 0.96 (0.85-1.08), P = 0.48), while reducing invasive coronary angiograms (n = 5,720 (16%) versus 8,183 (14.9%), aHR 0.93 (0.90-0.97), P < 0.001) and noninvasive cardiac tests (189/1,000 patients versus 167/1,000), P < 0.001). Implementation of an AI-diagnostic tool as part of a health intervention program was safe and beneficial to the patient pathway and health system with fewer cardiac tests at 2 years.

Clinical impact of CCT-FFR as first-strategy in patients with symptomatic stable coronary artery disease: A systematic review and meta-analysis

AIMS

Despite the promising results, the clinical implications of the CCT-FFR is already debated. This metanalysis aimed to determine the potential benefits of incorporating FFRCT into stable CAD management.

METHODS

After searching for studies comparing outcomes of patients with suspected stable CAD who underwent CCT-FFR as a first strategy versus non-urgent cardiovascular testing after a clinical judgment, we calculated odds ratios (ORs) and 95 ​% confidence intervals (CIs) using a random-effects or fixed-effects meta-analysis model depending on heterogeneity significance.

RESULTS

5 studies (3 RCTs and 2 observational studies) globally encompassing 5282 patients (CCT-FFR ​= ​2604 patients, Control Group ​= ​2678 patients) were included in the quantitative analysis. The rates of ICA overall (OR 1.57, 95%CI 1.36-1.81, p value ​< ​0.001) and those without obstructive CAD (OR 6.63, 95%CI 4.79-9.16, p value ​< ​0.001) were reduced in the CCTAFFR group, as compared to the control group. Moreover, CCT-FFR patients underwent coronary revascularization more frequently than patients in the control arm (OR 0.48,CI 0.38-0.62, p value ​< ​0.001). There was no significance difference between the two strategies in terms of 1 year MACE (OR 1.11,CI 0.86-1.44, p value 0.42), nonfatal MI (OR 0.73, CI 0.41-1.33, p value 0.31), all-cause mortality (OR 1.29,CI 0.47-3.54, p value 0.63) and unplanned revascularization for angina (OR 0.99, 95%CI 0.65-1.49, p value 0.95).

CONCLUSIONS

In conclusion, in the management of stable CAD, the use of CCT-FFR was associated with lower overall rates of ICA but higher rates of coronary revascularization with comparable 1-year clinical impact.

Clinical Applications of Fractional Flow Reserve Derived from Computed Tomography in Coronary Artery Disease

Computer tomography-derived fractional flow reserve (CT-FFR) represents a significant advancement in noninvasive cardiac functional assessment. This technology uses computer simulation and anatomical information from computer tomography of coronary angiogram to calculate the CT-FFR value at each point within the coronary vasculature. These values serve as a critical reference for cardiologists in making informed treatment decisions and planning. Emerging evidence suggests that CT-FFR has the potential to enhance the specificity of computer tomography of coronary angiogram, thereby reducing the need for additional diagnostic examinations such as invasive coronary angiography and cardiac magnetic resonance imaging. This could result in savings in financial cost, time, and resources for both patients and health care providers. However, it is important to note that although CT-FFR holds great promise, there are limitations to this technology. Users should be cautious of common pitfalls associated with its use. A comprehensive understanding of these limitations is essential for effectively applying CT-FFR in clinical practice.

Sex Differences in Computed Tomography Coronary Stenosis Severity Versus Flow Impairment and Impact on Revascularization, Clinical Events and Health Care Costs: A FORECAST Substudy

BACKGROUND

The impact of sex-related differences in coronary atheroma and flow impairment severity on clinical events and costs remains unclear.

METHODS AND RESULTS

This is a secondary analysis of patients with stable coronary artery disease who underwent both coronary computed tomography angiography  and fractional flow reserve derived from computed tomography as part of the FORECAST (Fractional Flow Reserve Derived From Computed Tomography Coronary Angiography in the Assessment and Management of Stable Chest Pain) trial, investigating (1) the relationship between coronary stenosis severity on coronary computed tomography angiography and fractional flow reserve derived from computed tomography FFRCT by sex and (2) the association with revascularization, resource usage, and adverse clinical events. A total of 212 patients (64 female participants [32.1%]) and 1245 vessels were included. There was no significant sex difference in the frequencies of significant coronary artery disease (38.2% of women versus 51.3% of men; P=0.073), but female participants had significantly less coronary flow impairment, according to the presence of at least 1 fractional flow reserve derived from computed tomography≤0.8 (47.0% versus 71.5%; P=0.008). Female subjects underwent fewer revascularization procedures (23.5% versus 42.3%; P=0.014), less coronary artery bypass graft surgery (2.9% versus 13.1%; P=0.025) and were less likely to be on statin treatment (72.0% versus 84.7%; P=0.022) by 9-month follow-up. This resulted in lower overall health care costs for female participants compared with male counterparts (median total cost, £1276 versus £2051; P=0.014). In multivariable Cox analysis the presence of significant coronary artery disease (hazard ratio [HR], 2.91; 95% CI, 1.30-6.51) and having a positive fractional flow reserve derived from computed tomography (HR, 4.11; 95% CI, 1.15-14.69) were independent predictors of major adverse cardiovascular events at 9 months, whereas sex was not statistically significant (p=0.13).

CONCLUSIONS

There are significant sex differences in the anatomico-functional assessment of coronary artery disease leading to differences in clinical management, costs, and adverse events.

Economic Outcomes With Precision Diagnostic Testing Versus Usual Testing in Stable Chest Pain: Results From the PRECISE Randomized Trial

BACKGROUND

The PRECISE (Prospective Randomized Trial of the Optimal Evaluation of Cardiac Symptoms and Revascularization) demonstrated that a precision diagnostic strategy reduced the primary composite of death, nonfatal myocardial infarction, or catheterization without obstructive coronary artery disease by 65% in patients with nonacute chest pain compared with usual testing. Medical cost was a prespecified secondary end point.

METHODS

PRECISE randomized 2103 patients between December 2018 and May 2021 to usual testing or a precision strategy that used deferred testing for the lowest risk patients (20%) and coronary computed tomographic angiography with selective computed tomography-derived fractional flow reserve for the remainder. Resource use consumption data were collected from all study participants and hospital cost data from US participants (n=1125) to estimate total medical costs. The primary and secondary economic outcomes were total costs at 12 months and at 45 days, respectively, from the US health care system perspective. The mean cost differences between the 2 strategies were reported by intention-to-treat.

RESULTS

At 45 days, total costs were similar between the precision strategy and usual testing (mean difference, $182 [95% CI, -$555 to $661]). By 12 months, percutaneous coronary intervention and coronary artery bypass surgery had been performed in 7.2% and 2.0% of precision strategy patients and 3.5% and 1.7% of usual testing patients, respectively. At 1 year, precision strategy costs were $5299 versus $4821 for usual testing (mean difference, $478 [95% CI, -$889 to $1437]; P=0.43). Precision care decreased mean per-patient diagnostic cost by 27% and increased mean per-patient revascularization costs by 67%.

CONCLUSIONS

In the PRECISE trial, the precision strategy, a risk-based approach endorsed by current clinical practice guidelines, improved the clinical efficiency of testing and had similar costs to usual testing at 45 days and a nonsignificant $478 cost difference at 1 year.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03702244.

Acoustic-based rule-out of stable coronary artery disease: the FILTER-SCAD trial

BACKGROUND AND AIMS

Overtesting of low-risk patients with suspect chronic coronary syndrome (CCS) is widespread. The acoustic-based coronary artery disease (CAD)-score has superior rule-out capabilities when added to pre-test probability (PTP). FILTER-SCAD tested whether providing a CAD-score and PTP to cardiologists was superior to PTP alone in limiting testing.

METHODS

At six Danish and Swedish outpatient clinics, patients with suspected new-onset CCS were randomized to either standard diagnostic examination (SDE) with PTP, or SDE plus CAD-score, and cardiologists provided with corresponding recommended diagnostic flowcharts. The primary endpoint was cumulative number of diagnostic tests at one year and key safety endpoint major adverse cardiac events (MACE).

RESULTS

In total, 2008 patients (46% male, median age 63 years) were randomized from October 2019 to September 2022. When randomized to CAD-score (n = 1002), it was successfully measured in 94.5%. Overall, 13.5% had PTP ≤ 5%, and 39.5% had CAD-score ≤ 20. Testing was deferred in 22% with no differences in diagnostic tests between groups (P for superiority = .56). In the PTP ≤ 5% subgroup, the proportion with deferred testing increased from 28% to 52% (P < .001). Overall MACE was 2.4 per 100 person-years. Non-inferiority regarding safety was established, absolute risk difference 0.49% (95% confidence interval -1.96-0.97) (P for non-inferiority = .003). No differences were seen in angina-related health status or quality of life.

CONCLUSIONS

The implementation strategy of providing cardiologists with a CAD-score alongside SDE did not reduce testing overall but indicated a possible role in patients with low CCS likelihood. Further strategies are warranted to address resistance to modifying diagnostic pathways in this patient population.

Dynamic CT myocardial perfusion combined with coronary CT angiography for detecting hemodynamical significance of coronary artery stenosis: a comparative study

This study aimed to evaluate the diagnostic performance of combined dynamic stress CT myocardial perfusion imaging (CTP) and coronary CT angiography (CTA) alongside CT-derived fractional flow reserve (CT-FFR) in detecting hemodynamically significant coronary artery disease (CAD). A total of 33 patients (86 vessels) who underwent coronary CTA, dynamic stress CTP, and coronary angiography were included. Vessels exhibiting 30-90% stenosis were subjected to FFR analysis based on coronary angiography (Angio-FFR). Hemodynamic significance, determined by Angio-FFR ≤ 0.80, and imaging findings were evaluated. The evaluation involved a comparison between the combined use of coronary CTA, CTP and CT-FFR, versus the sole use of coronary CTA. Out of 86 coronary vessels, 17 (19.8%) exhibited hemodynamically significant stenosis. The sensitivity, specificity, and accuracy of coronary CTA for detecting ischemia were 94.12%, 34.78%, and 46.51%, respectively. Adding CTP to CTA improved specificity to 88.41%, and accuracy to 87.21%, respectively. The area under the curve (AUC) for the discrimination of functional significant stenosis was 0.798 when using CTA alone, and for CTA plus CTP, it reached 0.910. Furthermore, the combination of CTA, CTP and CT-FFR, showed accuracy of 88.37%, sensitivity of 88.24% and specificity of 88.41% with the AUC of 0.946. The integration of dynamic CTP with CTA significantly enhances the diagnostic accuracy for identifying patients with hemodynamically significant CAD, compared to the use of CTA alone. This study underscores the value of combining CTP, CT-FFR, and CTA in improving diagnostic precision for CAD. The combination of CTP, CT-FFR and CTA offers a multifaceted assessment for patients with CAD by simultaneously providing anatomical detail, functional analysis, and physiological quantification, which facilitating rapid, accurate, and optimal clinical decision-making and significantly enhances patient management.

Non-invasive physiological assessment of coronary artery obstruction on coronary computed tomography angiography

Computed tomography-derived fractional flow reserve (CT-FFR) enhances the specificity of coronary computed tomography angiography (CCTA) to that of the most specific non-invasive imaging techniques, while maintaining high sensitivity in stable coronary artery disease (CAD). As gatekeeper for invasive coronary angiography (ICA), use of CT-FFR results in a significant reduction of negative ICA procedures and associated costs and complications, without increasing cardiovascular events. It is expected that CT-FFR algorithms will continue to improve, regarding accuracy and generalisability, and that introduction of new features will allow further treatment guidance and reduced invasive diagnostic testing. Advancements in CCTA quality and artificial intelligence (AI) are starting to unfold the incremental diagnostic and prognostic capabilities of CCTA's attenuation-based images in CAD, with future perspectives promising additional CCTA parameters which will enable non-invasive assessment of myocardial ischaemia as well as CAD activity and future cardiovascular risk. This review discusses practical application, interpretation and impact of CT-FFR on patient care, and how this ties into the CCTA 'one stop shop' for coronary assessment and patient prognosis. In this light, selective adoption of the most promising, objective and reproducible techniques and algorithms will yield maximal diagnostic value of CCTA without overcomplicating patient management and guideline recommendations.

The Role of Cardiac Computed Tomography Angiography in Risk Stratification for Coronary Artery Disease

Coronary computed tomography angiography (CCTA) allows the assessment of the presence and severity of obstructive and nonobstructive atherosclerotic coronary artery disease. With software developments incorporating artificial intelligence-based automated image analysis along with improved spatial resolution of CT scanners, volumetric measurements of atherosclerotic plaque, detection of high-risk plaque features, and delineation of pericoronary adipose tissue density can now be readily and accurately evaluated for a given at-risk patient. Many of these expanded diagnostic measures have been shown to be prognostically useful for prediction of major adverse cardiac events. The incremental value of plaque quantification over diameter stenosis has yet to be thoroughly discovered in current studies. Furthermore, the physiological significance of lesions can also be assessed with CT-derived fractional flow reserve, myocardial CT perfusion, and more recently shear stress, potentially leading to selective invasive coronary angiography and revascularization. Along with these technological advancements, there has been additional high-quality evidence for CCTA including large randomized clinical trials supporting high-level recommendations from many international clinical practice guidelines. Current trials largely compare a CCTA vs functional testing strategy, yet there is minimal evidence on CCTA plaque-guided therapeutic trials to measure regression of atherosclerosis and prevention of major coronary artery disease events. In this review, we summarize current evidence on comprehensive risk assessment with CCTA and future directions.

Impact of hypertension on coronary artery plaques and FFR-CT in type 2 diabetes mellitus patients: evaluation utilizing artificial intelligence processed coronary computed tomography angiography

Objective

This study utilized artificial intelligence (AI) to quantify coronary computed tomography angiography (CCTA) images, aiming to compare plaque characteristics and CT-derived fractional flow reserve (FFR-CT) in type 2 diabetes mellitus (T2DM) patients with or without hypertension (HTN).

Methods

A retrospective analysis was conducted on 1,151 patients with suspected coronary artery disease who underwent CCTA at a single center. Patients were grouped into T2DM (n = 133), HTN (n = 442), T2DM (HTN+) (n = 256), and control (n = 320). AI assessed various CCTA parameters, including plaque components, high-risk plaques (HRPs), FFR-CT, severity of coronary stenosis using Coronary Artery Disease Reporting and Data System 2.0 (CAD-RADS 2.0), segment involvement score (SIS), and segment stenosis score (SSS). Statistical analysis compared these parameters among groups.

Results

The T2DM (HTN+) group had the highest plaque volume and length, SIS, SSS, and CAD-RADS 2.0 classification. In the T2DM group, 54.0% of the plaque volume was noncalcified and 46.0% was calcified, while in the HTN group, these values were 24.0 and 76.0%, respectively. The T2DM (HTN+) group had more calcified plaques (35.7% noncalcified, 64.3% calcified) than the T2DM group. The average necrotic core volume was 4.25 mm3 in the T2DM group and 5.23 mm3 in the T2DM (HTN+) group, with no significant difference (p > 0.05). HRPs were more prevalent in both T2DM and T2DM (HTN+) compared to HTN and control groups (p < 0.05). The T2DM (HTN+) group had a higher likelihood (26.1%) of FFR-CT ≤0.75 compared to the T2DM group (13.8%). FFR-CT ≤0.75 correlated with CAD-RADS 2.0 (OR = 7.986, 95% CI = 5.466-11.667, cutoff = 3, p < 0.001) and noncalcified plaque volume (OR = 1.006, 95% CI = 1.003-1.009, cutoff = 29.65 mm3, p < 0.001). HRPs were associated with HbA1c levels (OR = 1.631, 95% CI = 1.387-1.918).

Conclusion

AI analysis of CCTA identifies patterns in quantitative plaque characteristics and FFR-CT values. Comorbid HTN exacerbates partially calcified plaques, leading to more severe coronary artery stenosis in patients with T2DM. T2DM is associated with partially noncalcified plaques, whereas HTN is linked to partially calcified plaques.

Selective FFRCT testing in suspected stable angina in clinical practice - initial experiences

Coronary CT angiography (CTA) derived fractional flow reserve (FFRCT) is recommended for physiological assessment in intermediate coronary stenosis for guiding referral to invasive coronary angiography (ICA). In this study, we report real-world data on the feasibility of implementing a CTA/FFRCT test algorithm as a gatekeeper to ICA at referral hospitals. Retrospective all-comer study of patients with new onset stable symptoms and suspected coronary stenosis (30-89%) by CTA. Evaluation of CTA datasets, interpretation of FFRCT analysis, and decisions on downstream testing were performed by skilled CT-cardiologists. CTA was performed in 3974 patients, of whom 381 (10%) were referred directly to ICA, whereas 463 (12%) to non-invasive functional testing: FFRCT 375 (81%) and perfusion imaging 88 (19%). FFRCT analysis was rejected in 8 (2%) due to inadequate CTA image quality. Number of patients deferred from ICA after FFRCT was 267 (71%), while 100 (27%) were referred to ICA. Obstructive coronary artery disease (CAD) was confirmed in 62 (62%) patients and revascularization performed in 53 (53%). Revascularization rates, n (%), were higher in patients undergoing FFRCT-guided versus CTA-guided referral to ICA: 30-69% stenosis, 28 (44%) versus 8 (21%); 70-89% stenosis, 39 (69%) versus 25 (46%), respectively, both p < 0.05. Implementation of FFRCT at referral hospitals was feasible, reduced the number of invasive procedures, and increased the revascularization rate.

Clinical Advances in Cardiovascular Computed Tomography: From Present Applications to Promising Developments

PURPOSE OF THE REVIEW

This review aims to provide a profound overview on most recent studies on the clinical significance of Cardiovascular Computed Tomography (CCT) in diagnostic and therapeutic pathways. Herby, this review helps to pave the way for a more extended but yet purposefully use in modern day cardiovascular medicine.

RECENT FINDINGS

In recent years, new clinical applications of CCT have emerged. Major applications include the assessment of coronary artery disease and structural heart disease, with corresponding recommendations by major guidelines of international societies. While CCT already allows for a rapid and non-invasive diagnosis, technical improvements enable further in-depth assessments using novel imaging parameters with high temporal and spatial resolution. Those developments facilitate diagnostic and therapeutic decision-making as well as improved prognostication. This review determined that recent advancements in both hardware and software components of CCT allow for highly advanced examinations with little radiation exposure. This particularly strengthens its role in preventive care and coronary artery disease. The addition of functional analyses within and beyond coronary artery disease offers solutions in wide-ranging patient populations. Many techniques still require improvement and validation, however, CCT possesses potential to become a "one-stop-shop" examination.

Clinical Effectiveness of Automated Coronary CT-derived Fractional Flow Reserve: A Chinese Randomized Controlled Trial

Background Coronary CT-derived fractional flow reserve (CT-FFR) has been used in patients with suspected coronary artery disease (CAD); however, whether it decreases invasive coronary angiography (ICA) use and affects prognosis remains insufficiently evidenced. Purpose To explore the effectiveness of adding CT-FFR to routine coronary CT angiography (CCTA) on short-term ICA rate and major adverse cardiovascular events (MACE) in a Chinese setting. Materials and Methods A multicenter randomized controlled trial was conducted in 17 Chinese centers, with patient inclusion from May 2021 to September 2021. Eligible individuals with 25%-99% stenosis at CCTA were randomly assigned 1:1 to a strategy of CCTA plus automated CT-FFR or CCTA alone for guiding downstream care. The primary end point was the ICA rate 90 days after enrollment. Secondary end points included 90-day and 1-year MACE rates (comprised of all-cause mortality, nonfatal myocardial infarction, and urgent revascularization) and 1-year cardiac events (comprised of cardiac death, nonfatal myocardial infarction, and urgent revascularization). The Cox proportional hazards model with center effect adjustment was used for survival comparisons. Results A total of 5297 participants (mean age, 63.5 years ± 10.8 [SD]; 3178 male) were included. During the 90-day follow-up, ICA was performed in 263 of 2633 participants (10.0%) in the CCTA plus CT-FFR group and 327 of 2640 participants (12.4%) in the CCTA-alone group (absolute rate difference: -2.40%; 95% CI: -4.10, -0.70; P = .006). The MACE rates at 90 days (0.5% [12 of 2633 participants] vs 0.8% [21 of 2640 participants]; P = .12) and 1 year (2.9% [74 of 2546 participants] vs 2.8% [72 of 2531 participants]; P = .90) were similar for both groups. At 1-year follow-up, fewer cardiac events were observed in the CCTA plus CT-FFR group compared with the CCTA-alone group (0.5% vs 1.1%; adjusted hazard ratio: 0.52; 95% CI: 0.27, 0.99; P = .047). Conclusion CT-FFR added to CCTA led to a lower 90-day ICA rate and similar 1-year MACE rate in a Chinese real-world setting. Further follow-up is warranted to demonstrate the long-term prognostic value of this management approach. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Pundziute-do Prado in this issue.

Clinical Updates in Coronary Artery Disease: A Comprehensive Review

Despite significant goals achieved in diagnosis and treatment in recent decades, coronary artery disease (CAD) remains a high mortality entity and continues to pose substantial challenges to healthcare systems globally. After the latest guidelines, novel data have emerged and have not been yet considered for routine practice. The scope of this review is to go beyond the guidelines, providing insights into the most recent clinical updates in CAD, focusing on non-invasive diagnostic techniques, risk stratification, medical management and interventional therapies in the acute and stable scenarios. Highlighting and synthesizing the latest developments in these areas, this review aims to contribute to the understanding and management of CAD helping healthcare providers worldwide.

Computed Tomography Angiography Identified High-Risk Coronary Plaques: From Diagnosis to Prognosis and Future Management

CT angiography has become, in recent years, a main evaluating modality for patients with coronary artery disease (CAD). Recent advancements in the field have allowed us to identity not only the presence of obstructive disease but also the characteristics of identified lesions. High-risk coronary atherosclerotic plaques are identified in CT angiographies via a number of specific characteristics and may provide prognostic and therapeutic implications, aiming to prevent future ischemic events via optimizing medical treatment or providing coronary interventions. In light of new evidence evaluating the safety and efficacy of intervening in high-risk plaques, even in non-flow-limiting disease, we aim to provide a comprehensive review of the diagnostic algorithms and implications of plaque vulnerability in CT angiography, identify any differences with invasive imaging, analyze prognostic factors and potential future therapeutic options in such patients, as well as discuss new frontiers, including intervening in non-flow-limiting stenoses and the role of CT angiography in patient stratification.

Chinese herbal compound preparation Qing-Xin-Jie-Yu granules for intermediate coronary lesions in patients with stable coronary artery disease: Study protocol for a multicenter, randomized, double-blind, placebo-controlled trial

INTRODUCTION

Despite the available secondary preventive treatments, the management of stable coronary artery disease (SCAD) remains challenging. Intermediate coronary lesion (ICL), defined as luminal stenosis between 50% and 70%, is a key stage of SCAD. However, existing therapeutic strategies are limitated in delaying plaque progression and associated with various adverse effects and economic burdens. Qing-Xin-Jie-Yu Granules (QXJYG) with proven anti-platelet, anti-inflammatory, and lipid-lowering effects may compensate for the drawbacks of current treatments and can be tested as a complementary therapy. Therefore, this study aims to investigate the efficacy and safety of QXJYG in treating ICL, with a particular focus on its impact on myocardial ischemia and plaque progression.

MATERIALS AND METHODS

This is a multicenter, randomized, double-blind, placebo-controlled trial. A total of 120 participants with ICL will be randomly assigned to two groups in a 1:1 ratio. In addition to basic medications, the intervention group will receive QXJYG, while the control group will receive a placebo for over 6 months, followed by a 12-month follow-up. The primary efficacy outcome is computed tomography-derived fractional flow reserve. The secondary outcomes include the degree of coronary stenosis, coronary artery calcification score, Gensini score, Seattle Angina Questionnaire score, high-sensitivity C-reactive protein, matrix metalloproteinase-9, blood lipids, and carotid artery ultrasound parameters. Major adverse cardiovascular events are recorded as endpoints. The safety outcomes include composite events of bleeding, laboratory test results, and adverse events. Clinical visits are scheduled at baseline, every 2 months during the treatment, and after a 12-month follow-up.

DISCUSSION

This trial is anticipated to yield reliable results to verify the efficacy and safety of QXJYG in the treatment of ICL, which will provide novel insights to help address the prevailing therapeutic dilemma of ICL, thereby facilitating for the management of SCAD.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2200059262. Registered on April 27, 2022.

Early-stage health technology assessment of fractional flow reserve coronary computed tomography versus standard diagnostics in patients with stable chest pain in The Netherlands

OBJECTIVES

The aim of this early-stage Health Technology Assessment (HTA) was to assess the difference in healthcare costs and effects of fractional flow reserve derived from coronary computed tomography (FFRct) compared to standard diagnostics in patients with stable chest pain in The Netherlands.

METHODS

A decision-tree model was developed to assess the difference in total costs from the hospital perspective, probability of correct diagnoses, and risk of major adverse cardiovascular events at one year follow-up. One-way sensitivity analyses were conducted to determine the main drivers of the cost difference between the strategies. A threshold analysis on the added price of FFRct analysis (computational analysis only) was conducted.

RESULTS

The mean one-year costs were €2,680 per patient for FFRct and €2,915 per patient for standard diagnostics. The one-year probability of correct diagnoses was 0.78 and 0.61, and the probability of major adverse cardiovascular events was 1.92x10-5 and 0.01, respectively. The probability and costs of revascularization and the specificity of coronary computed tomography angiography had the greatest effect on the difference in costs between the strategies. The added price of FFRct analysis should be below €935 per patient to be considered the least costly option.

CONCLUSIONS

The early-stage HTA findings suggest that FFRct may reduce total healthcare spending, probability of incorrect diagnoses, and major adverse cardiovascular events compared to current diagnostics for patients with stable chest pain in the Dutch healthcare setting over one year. Future cost-effectiveness studies should determine a value-based pricing for FFRct and quantify the economic value of the anticipated therapeutic impact.

Cardiovascular computed tomography in cardiovascular disease: An overview of its applications from diagnosis to prediction

Cardiovascular computed tomography angiography (CTA) is a widely used imaging modality in the diagnosis of cardiovascular disease. Advancements in CT imaging technology have further advanced its applications from high diagnostic value to minimising radiation exposure to patients. In addition to the standard application of assessing vascular lumen changes, CTA-derived applications including 3D printed personalised models, 3D visualisations such as virtual endoscopy, virtual reality, augmented reality and mixed reality, as well as CT-derived hemodynamic flow analysis and fractional flow reserve (FFRCT) greatly enhance the diagnostic performance of CTA in cardiovascular disease. The widespread application of artificial intelligence in medicine also significantly contributes to the clinical value of CTA in cardiovascular disease. Clinical value of CTA has extended from the initial diagnosis to identification of vulnerable lesions, and prediction of disease extent, hence improving patient care and management. In this review article, as an active researcher in cardiovascular imaging for more than 20 years, I will provide an overview of cardiovascular CTA in cardiovascular disease. It is expected that this review will provide readers with an update of CTA applications, from the initial lumen assessment to recent developments utilising latest novel imaging and visualisation technologies. It will serve as a useful resource for researchers and clinicians to judiciously use the cardiovascular CT in clinical practice.

Coronary Artery Disease: Role of Computed Tomography and Recent Advances

In this review, the authors summarize the role of coronary computed tomography angiography and coronary artery calcium scoring in different clinical presentations of chest pain and preventative care and discuss future directions and new technologies such as pericoronary fat inflammation and the growing footprint of artificial intelligence in cardiovascular medicine.

Role of non-invasive coronary imaging in stable angina

Chest pain represents a symptom of significant clinical concern due to the potential for lethal etiologies. Accordingly, it is critical to ascertain the presence of stable angina through various diagnostic tests to inform subsequent therapeutic strategies. Stable angina, while potentially progressing to more severe conditions if left untreated, suffers from a paucity of research regarding its management compared to other more fatal causes of chest pain. Recent advancements in radiological imaging necessitate a re-evaluation of the array and functionality of diagnostic tests, with particular emphasis on prioritizing non-invasive methods such as electrocardiography and echocardiography. This study undertakes a comprehensive review of the literature pertaining to various diagnostic tests for stable angina. We conclude that the management of a patient presenting with chest pain encompasses a continuum of care, beginning with a detailed patient history to estimate pre-test probability and culminating in computed tomography coronary angiography. This continuum is highly individualized, taking into account patient-specific variables, disease burden, and test indications. In an era of rapid research advancement, our findings delineate the optimal sequence of initial diagnostic tests, emphasizing the role of current non-invasive imaging modalities as outlined in standard clinical guidelines.

The Role of Coronary Physiology Assessment in the Diagnosis and Treatment of Stable Angina. Dive Inside Recent Findings of Diffuse Coronary Disease Treatment

Coronary physiology is widely used to assess epicardial coronary lesions in patients with stable angina. Based on the available evidence, physiology plays a crucial role in diagnosing and treating patients. There have been invasive methods for determining cardiac physiology, such as fractional flow reserve and instantaneous wave-free ratio. Still, new non-invasive approaches provide extra anatomical information, such as fractional flow reserve computed tomography (FFR-CT) based on computed tomography and physiology based on angiography. Even though FFR-guided percutaneous coronary intervention (PCI) is clinically beneficial, one-third of patients retain suboptimal FFR after the procedure, associated with severe adverse events, rendering PCI in diffuse coronary artery disease questionable. Using the pullback pressure gradient (PPG), we can analyze the magnitude and extent of pressure losses; a lower value may indicate diffuse disease, while a high value with an abrupt curve may indicate focal disease. Since PCI is not the best option for treating diffuse coronary disease, current strategies focus on conservatively using medical therapy or bypass surgery. It has been demonstrated that patients with diffuse disease of the left anterior descending (LAD) are at a greater risk of developing occlusion of the left internal mammary artery graft than those with focal disease and that maximal medical therapy may be the most effective treatment for these patients.

Clinical Outcomes Based on Coronary Computed Tomography-Derived Fractional Flow Reserve and Plaque Characterization

BACKGROUND

Coronary computed tomography angiography (CTA) followed by computed tomography angiography-derived fractional flow reserve (FFRCT) is now commonly used for the management of chronic coronary syndrome (CCS). CTA-verified high-risk plaque (HRP) characteristics have also been reported to be associated with a greater likelihood of adverse cardiac events but have not been used for management decisions.

OBJECTIVES

The aim of this study was to evaluate clinical outcomes based on a combination of point-of-care computed tomography angiography-derived fractional flow reserve (POC-FFRCT) and the presence of HRP in CCS patients initially treated medically or with revascularization based on invasive coronary angiography findings.

METHODS

CTA was performed as the initial test in 5,483 patients presenting with CCS between September 2015 and December 2020 followed by invasive coronary angiography and revascularization as necessary. POC-FFRCT assessment and HRP characterization were obtained subsequently in 745 consecutive patients. We investigated how HRP and POC-FFRCT, which were not available during the original clinical decision making, correlated with the endpoint defined as a composite of cardiac death, acute coronary syndrome, and a need for unplanned revascularization.

RESULTS

Cardiac events occurred in 20 patients (2.7%) during a median follow-up of 744 days. The event rate was significantly higher in patients with POC-FFRCT <0.80 compared with POC-FFRCT ≥0.8 (5.4 vs 0.5 per 100 vessel years; log-rank P < 0.0001) and in patients with HRP compared to those without HRP (3.6 vs 0.8 per 100 vessel years; log-rank P = 0.0001). POC-FFRCT <0.80 and the presence of HRP were the independent predictors of cardiac events (HR: 16.67; 95% CI: 2.63-105.39; P = 0.002) compared with POC-FFRCT ≥0.8 and absent HRP. For the vessels with POC-FFRCT <0.80 and HRP, a significantly higher rate of adverse events was observed in patients who did not undergo revascularization compared with those revascularized (16.4 vs 1.4 per 100 vessel years; log-rank P = 0.006).

CONCLUSIONS

POC-FFRCT <0.80 and the presence of HRP were the independent predictors of cardiac events, and revascularization of HRP lesions with abnormal POC-FFRCT was associated with a lower event rate.

Coronary computed tomography angiography vs functional stress imaging to triage chest pain in the emergency room?

In patients with a suspected acute coronary syndrome, non-elevated (or uncertain) (NSTE-ACS) high sensitivity cardiac troponin, no ECG changes and no recurrence of chest pain, incorporating a coronary computed tomography angiogram (CCTA) or a non-invasive functional stress imaging test as part of the initial workup should be considered (Class IIA, Level of Evidence A). There are pros and cons with each diagnostic approach. CCTA imaging has high sensitivity for detecting coronary atherosclerosis but may not provide a diagnosis since most patients do not have obstructive coronary disease. Functional imaging is useful to explain symptoms and detect obstructive coronary artery disease, but is not useful to diagnose atherosclerosis.

Cardiovascular Computed Tomography in the Diagnosis of Cardiovascular Disease: Beyond Lumen Assessment

Cardiovascular CT is being widely used in the diagnosis of cardiovascular disease due to the rapid technological advancements in CT scanning techniques. These advancements include the development of multi-slice CT, from early generation to the latest models, which has the capability of acquiring images with high spatial and temporal resolution. The recent emergence of photon-counting CT has further enhanced CT performance in clinical applications, providing improved spatial and contrast resolution. CT-derived fractional flow reserve is superior to standard CT-based anatomical assessment for the detection of lesion-specific myocardial ischemia. CT-derived 3D-printed patient-specific models are also superior to standard CT, offering advantages in terms of educational value, surgical planning, and the simulation of cardiovascular disease treatment, as well as enhancing doctor-patient communication. Three-dimensional visualization tools including virtual reality, augmented reality, and mixed reality are further advancing the clinical value of cardiovascular CT in cardiovascular disease. With the widespread use of artificial intelligence, machine learning, and deep learning in cardiovascular disease, the diagnostic performance of cardiovascular CT has significantly improved, with promising results being presented in terms of both disease diagnosis and prediction. This review article provides an overview of the applications of cardiovascular CT, covering its performance from the perspective of its diagnostic value based on traditional lumen assessment to the identification of vulnerable lesions for the prediction of disease outcomes with the use of these advanced technologies. The limitations and future prospects of these technologies are also discussed.

Derivation and validation of a novel functional FFRCT score incorporating the burden of coronary stenosis severity and flow impairment to predict clinical events

BACKGROUND

A score combining the burden of stenosis severity on coronary computed tomography angiography (CCTA) and flow impairment by fractional flow reserve derived from computed tomography (FFRCT) may be a better predictor of clinical events than either parameter alone.

METHODS

The Functional FFRCT Score (FFS) combines CCTA and FFRCT parameters in an allocated point-based system. The feasibility of the FFS was assessed in cohort of 72 stable chest pain patients with matched CCTA and FFRCT datasets. Validation was performed using 2 cohorts: (a) 4468 patients from the ADVANCE Registry to define its association with revascularization and major adverse cardiovascular events (MACE); (b) 212 patients from the FORECAST trial to determine predictors of MACE.

RESULTS

The median calculation time for the FFS was 10 (interquartile range 6-17) seconds, with strong intra-operator and inter-operator agreement (Cohen's Kappa 0.89 (±0.37, p ​< ​0.001) and 0.83 (±0.04, p ​< ​0.001, respectively). The FFS correlated strongly with both the CT-SYNTAX and the Functional CT-SYNTAX scores (rS ​= ​0.808 for both, p ​< ​0.001). In the ADVANCE cohort the FFS had good discriminatory abilities for revascularization with an area under the curve of 0.82, 95 ​% confidence interval (CI) 0.81-0.84, p ​< ​0.001. Patients in the highest FFS tertile had significantly higher rates of revascularization (61 ​% vs 5 ​%, p ​< ​0.001) and MACE (1.9 ​% vs 0.5 ​%, p ​= ​0.001) compared with the lowest FFS tertile. In the FORECAST cohort the FFS was an independent predictor of MACE at 9-month follow-up (hazard ratio 1.04, 95 ​% CI 1.01-1.08, p ​< ​0.01).

CONCLUSION

The FFS is a quick-to-calculate and reproducible score, associated with revascularization and MACE in two distinct populations of stable symptomatic patients.

CT-derived Fractional Flow Reserve: How, When, and Where to use this Novel Cardiac Imaging Tool

Fractional flow reserve computed tomography (FFRCT) is a novel imaging modality. It utilizes computational fluid dynamics analysis of coronary blood flow obtained from CCTA images to estimate the decrease in pressure across coronary stenosis during the maximum hyperemia. The FFRCT can serve as a valuable tool in the assessment of coronary artery disease (CAD). This non-invasive option can be used as an alternative to the invasive fractional Flow Reserve (FFR) evaluation, which is presently considered the gold standard for evaluating the physiological significance of coronary stenoses. It can help in several clinical situations, including Assessment of Acute and stable chest pain, virtual planning for coronary stenting, and treatment decision-making. Although FFRCT has demonstrated potential clinical applications as a non-invasive imaging technique, it is also crucial to acknowledge its limitations in clinical practice. As a result, it is imperative to meticulously evaluate the advantages and drawbacks of FFRCT individually and contemplate its application in combination with other diagnostic examinations and clinical data.

Clinical and prognostic incremental value of FFRCT in screening of patients with obstructive coronary artery disease

BACKGROUND

Coronary computed tomography angiography (CCTA) -derived fractional flow reserve (FFRCT) is recommended to evaluate the functional consequences of obstructive coronary artery disease (OCAD). Real-world incremental impacts of FFRCT use still remains under debate.

METHODS

1601 patients with suspected OCAD on CCTA (>50 ​% stenosis), including 808 (50.5 ​%) patients evaluated by FFRCT, were included from a 2013-2021 registry. Propensity adjusted impacts of FFRCT use on rates of invasive coronary angiography (ICA), myocardial revascularization (MR) and post MR major adverse cardiac events (MACE) were reported, including a sensitivity analysis in severe OCAD (>70 ​% stenosis) (n ​= ​450). Accuracy of numerical and comprehensive FFRCT interpretations in selection of patients requiring a MR were also compared.

RESULTS

1160 (72,5 ​%) ICA, 559 (34.9 ​%) MR and 137 (24.5 ​%) post MR MACE occurred at 4.7 ​± ​1.9 years. FFRCT use was independently associated with decreased rate of ICA and MR (OR: 0.66; 95 ​% CI 0.53-0.83, p ​< ​0.001 and OR: 0.71; 95 ​% CI 0.58-0.88, p ​< ​0.01, respectively). Compared to the numerical interpretation, the FFRCT comprehensive assessment increased the ratio of MR per ICA (61.7 ​% vs 50.1 ​%, p ​< ​0.01) and was more accurate in selection of patients requiring MR. FFRCT reduced post MR MACE (OR: 0.64; 95 ​% CI 0.43-0.96, p ​< ​0.05). All these associations were no longer observed in severe OCAD.

CONCLUSION

Implementing FFRCT in OCAD patients reduces ICA use, improves selection of patients requiring MR and reduces post MR MACE. However, these incremental values of FFRCT were no longer observed in severe OCAD.

Chest Pain Evaluation: Diagnostic Testing

Chest pain/discomfort (CP) is a common symptom and can be a diagnostic dilemma for many clinicians. The misdiagnosis of an acute or progressive chronic cardiac etiology may carry a significant risk of morbidity and mortality. This review summarizes the different options and modalities for establishing the diagnosis and severity of coronary artery disease. An effective test selection algorithm should be individually tailored to each patient to maximize diagnostic accuracy in a timely fashion, determine short- and long-term prognosis, and permit implementation of evidence-based treatments in a cost-effective manner. Through collaboration, a decision algorithm was developed (www.chowmd.ca/cadtesting) that could be adopted widely into clinical practice.

Financial and clinical outcomes of CT myocardial perfusion imaging and coronary CT angiography-guided versus coronary CT angiography-guided strategy

OBJECTIVES

To compare the financial and clinical outcomes of CT myocardial perfusion imaging (CT-MPI) + coronary CT angiography (CCTA)-guided versus CCTA-guided strategy in patients suspected of chronic coronary syndrome (CCS).

MATERIALS AND METHODS

This study retrospectively included consecutive patients suspected of CCS and referred for CT-MPI+CCTA-guided and CCTA-guided treatment. The details of medical costs within 3 months after index imaging, including downstream invasive procedures, hospitalization, and medications, were recorded. All patients were followed up for major adverse cardiac events (MACE) at a median time of 22 months.

RESULTS

A total of 1335 patients (559 in the CT-MPI+CCTA group and 776 in the CCTA group) were finally included. In the CT-MPI+CCTA group, 129 patients (23.1%) underwent ICA and 95 patients (17.0%) received revascularization. In the CCTA group, 325 patients (41.9%) underwent ICA whereas 194 patients (25.0%) received revascularization. An addition of CT-MPI in the evaluation strategy remarkably reduced the healthcare expenditure, compared with CCTA-guided strategy (USD 1441.36 vs. USD 232.91, p < 0.001). After adjustment for potential cofounders after inverse probability weighting, the CT-MPI+CCTA strategy was significantly associated with lower medical expenditure [adjusted cost ratio (95% CI) for total costs: 0.77 (0.65-0.91), p < 0.001]. In addition, there was no significant difference regarding the clinical outcome between the two groups (adjusted HR= 0.97; p = 0.878).

CONCLUSIONS

CT-MPI+CCTA considerably reduced medical expenditures in patients suspected of CCS, compared to the CCTA strategy alone. Moreover, CT-MPI+CCTA led to a lower rate of invasive procedures with a similar long-term prognosis.

CLINICAL RELEVANCE STATEMENT

CT myocardial perfusion imaging + coronary CT angiography-guided strategy reduced medical expenditure and invasive procedure rate.

KEY POINTS

• CT-MPI+CCTA strategy yielded significantly lower medical expenditure than did the CCTA strategy alone in patients with suspected CCS. • After adjustment for potential confounders, the CT-MPI+CCTA strategy was significantly associated with lower medical expenditure. • No significant difference was observed regarding the long-term clinical outcome between the two groups.

Comparison of an Initial Risk-Based Testing Strategy vs Usual Testing in Stable Symptomatic Patients With Suspected Coronary Artery Disease: The PRECISE Randomized Clinical Trial

Importance

Trials showing equivalent or better outcomes with initial evaluation using coronary computed tomography angiography (cCTA) compared with stress testing in patients with stable chest pain have informed guidelines but raise questions about overtesting and excess catheterization.

Objective

To test a modified initial cCTA strategy designed to improve clinical efficiency vs usual testing (UT).

Design, Setting, and Participants

This was a pragmatic randomized clinical trial enrolling participants from December 3, 2018, to May 18, 2021, with a median of 11.8 months of follow-up. Patients from 65 North American and European sites with stable symptoms of suspected coronary artery disease (CAD) and no prior testing were randomly assigned 1:1 to precision strategy (PS) or UT.

Interventions

PS incorporated the Prospective Multicenter Imaging Study for the Evaluation of Chest Pain (PROMISE) minimal risk score to quantitatively select minimal-risk participants for deferred testing, assigning all others to cCTA with selective CT-derived fractional flow reserve (FFR-CT). UT included site-selected stress testing or catheterization. Site clinicians determined subsequent care.

Main Outcomes and Measures

Outcomes were clinical efficiency (invasive catheterization without obstructive CAD) and safety (death or nonfatal myocardial infarction [MI]) combined into a composite primary end point. Secondary end points included safety components of the primary outcome and medication use.

Results

A total of 2103 participants (mean [SD] age, 58.4 [11.5] years; 1056 male [50.2%]) were included in the study, and 422 [20.1%] were classified as minimal risk. The primary end point occurred in 44 of 1057 participants (4.2%) in the PS group and in 118 of 1046 participants (11.3%) in the UT group (hazard ratio [HR], 0.35; 95% CI, 0.25-0.50). Clinical efficiency was higher with PS, with lower rates of catheterization without obstructive disease (27 [2.6%]) vs UT participants (107 [10.2%]; HR, 0.24; 95% CI, 0.16-0.36). The safety composite of death/MI was similar (HR, 1.52; 95% CI, 0.73-3.15). Death occurred in 5 individuals (0.5%) in the PS group vs 7 (0.7%) in the UT group (HR, 0.71; 95% CI, 0.23-2.23), and nonfatal MI occurred in 13 individuals (1.2%) in the PS group vs 5 (0.5%) in the UT group (HR, 2.65; 95% CI, 0.96-7.36). Use of lipid-lowering (450 of 900 [50.0%] vs 365 of 873 [41.8%]) and antiplatelet (321 of 900 [35.7%] vs 237 of 873 [27.1%]) medications at 1 year was higher in the PS group compared with the UT group (both P < .001).

Conclusions and Relevance

An initial diagnostic approach to stable chest pain starting with quantitative risk stratification and deferred testing for minimal-risk patients and cCTA with selective FFR-CT in all others increased clinical efficiency relative to UT at 1 year. Additional randomized clinical trials are needed to verify these findings, including safety.

Trial Registration

ClinicalTrials.gov Identifier: NCT03702244.

Science mapping analysis of computed tomography-derived fractional flow reverse: a bibliometric review from 2012 to 2022

Background

Computed tomography-derived fractional flow reserve (CT-FFR) is a non-invasive imagological examination used for diagnosing suspected coronary atherosclerotic heart disease, providing the morphological and functional value on a three-dimensional (3D) coronary artery model. This article aimed to collate the existing knowledge and predict this novel technology's future research hotspots.

Methods

To collect data, 1,712 articles were retrieved from the Web of Science Core Collection (WoSCC) database from 2012-2022. CiteSpace5.8.R3 was used to visually analyze the research status and predict future research hotspots.

Results

Firstly, the United States, China, and the Netherlands were identified as the countries having published the most articles about CT-FFR. Jonathan Leipsic's group ranked first for the highest number of published articles. Secondly, the visualized analysis indicated that the exploration of CT-FFR is multi-disciplinary and involves cardiology, radiology, engineering, and computer science. Thirdly, the hotspots in this field, which were inferred from the keyword distribution and clustering, included the following: "diagnostic performance", "accuracy", and the "prognostic value" of CT-FFR, and comparison of CT-FFR and other imaging methods sharing similarities. The research frontiers included technologies utilized to obtain more accurate CT-FFR values, such as artificial intelligence (AI) and deep learning.

Conclusions

As the first visualized bibliometric analysis on CT-FFR, this study captured the current accumulated information in this field and offer more insight and guidance for future research.

Impact on stable chest pain pathways of CT fractional flow reserve

OBJECTIVES

To evaluate the impact of introducing CT fractional flow reserve (FFRCT) on stable chest pain pathways, concordance with National Institute for Health and Care Excellence (NICE) chest pain guidelines, resource usage and revascularisation of patients from a tertiary UK cardiac centre rapid access chest pain clinic (RACPC).

METHODS

Single-centre before and after study comparing data from electronic records and Strategic Tracing Service of all RACPC patients attending between 1 July 2017 and 31 December 2017, and 1 August 2018 and 31 January 2019.

RESULTS

Two hundred and sixty-eight and 287 patients (overall mean age 62 years, range 26-89 years, 48.3% male), were eligible for first-line CT coronary angiography (CTCA) pre-FFRCT and post-FFRCT, respectively. First-line CTCA use per NICE Guideline CG95 increased (50.6% pre-FFRCT vs 75.7% post-FFRCT, p<0.001). More patients reached pathway endpoint (revascularisation or assumed medical management) after one investigation (74.9% pre-FFRCT vs 84.9% post-FFRCT, p=0.005). There were fewer stress (22.8% pre-FFRCT vs 7.7% post-FFRCT, p<0.001) and rest (10.4% pre-FFRCT vs 4.2% post-FFRCT, p=0.007) myocardial perfusion scans and diagnostic-only angiograms (25.5% vs 13.7%, p<0.001). Despite fewer invasive procedures (29.3% pre-FFRCT vs 17.6% post-FFRCT, p=0.002), revascularisation rates remained similar (10.4% pre-FFRCT vs 8.8% post-FFRCT, p=0.561). Avoiding invasive investigations reduced inpatient admissions (39.0% pre-FFRCT vs 24.3% post-FFRCT, p<0.001). Time to revascularisation was unchanged (153.5 days pre-FFRCT vs 142.0 post-FFRCT, p=0.925). Unplanned hospital attendances, emergency admissions and adverse events were similar.

CONCLUSIONS

FFRCT adoption was associated with greater compliance with NICE guidelines, reduced invasive diagnostic angiography, planned admissions and needing more than one test to reach a pathway endpoint.

Clinical outcomes and health care costs of transferring rural Western Australians for invasive coronary angiography, and a cost-effective alternative care model: a retrospective cross-sectional study

OBJECTIVES

To examine the severity of coronary artery disease (CAD) in people from rural or remote Western Australia referred for invasive coronary angiography (ICA) in Perth and their subsequent management; to estimate the cost savings were computed tomography coronary angiography (CTCA) offered in rural centres as a first line investigation for people with suspected CAD.

DESIGN

Retrospective cohort study.

SETTING, PARTICIPANTS

Adults with stable symptoms in rural and remote WA referred to Perth public tertiary hospitals for ICA evaluation during the 2019 calendar year.

MAIN OUTCOME MEASURES

Severity and management of CAD (medical management or revascularisation); health care costs by care model (standard care or a proposed alternative model with local CTCA assessment).

RESULTS

The mean age of the 1017 people from rural and remote WA who underwent ICA in Perth was 62 years (standard deviation, 13 years); 680 were men (66.9%), 245 were Indigenous people (24.1%). Indications for referral were non-ST elevation myocardial infarction (438, 43.1%), chest pain with normal troponin level (394, 38.7%), and other (185, 18.2%). After ICA assessment, 619 people were medically managed (60.9%) and 398 underwent revascularisation (39.1%). None of the 365 patients (35.9%) without obstructed coronaries (< 50% stenosis) underwent revascularisation; nine patients with moderate CAD (50-69% stenosis; 7%) and 389 with severe CAD (≥ 70% stenosis or occluded vessel; 75.5%) underwent revascularisation. Were CTCA used locally to determine the need for referral, 527 referrals could have been averted (53%), the ICA:revascularisation ratio would have improved from 2.6 to 1.6, and 1757 metropolitan hospital bed-days (43% reduction) and $7.3 million in health care costs (36% reduction) would have been saved.

CONCLUSION

Many rural and remote Western Australians transferred for ICA in Perth have non-obstructive CAD and are medically managed. Providing CTCA as a first line investigation in rural centres could avert half of these transfers and be a cost-effective strategy for risk stratification of people with suspected CAD.

Utility of FFRCT in Patients with Chest Pain

PURPOSE OF REVIEW

The goal of this article is to review the data supporting the use of fractional flow reserve derived from coronary computed tomography angiography (FFRCT) in patients with chest pain.

REVIEW FINDINGS

Numerous clinical trials have demonstrated that the diagnostic accuracy of coronary computed tomography angiography (CCTA) can be improved with the use of FFRCT, primarily due to its superior specificity when compared to CCTA alone. This promising development may help reduce the need for invasive angiography in patients presenting with chest pain. Furthermore, some studies have indicated that incorporating FFRCT into decision-making is safe, with an FFRCT value of ≥ 0.8 being associated with favorable outcomes. While FFRCT has been shown to be feasible in patients with acute chest pain, further large-scale studies are warranted to confirm its utility. The emergence of FFRCT as a tool for the management of patients with chest pain is promising. However, potential limitations require the interpretation of FFRCT in conjunction with clinical context.

The Use and Efficacy of FFR-CT: Real-World Multicenter Audit of Clinical Data With Cost Analysis

BACKGROUND

Fractional flow reserve-computed tomography (FFR-CT) is endorsed by UK and U.S. chest pain guidelines, but its clinical effectiveness and cost benefit in real-world practice are unknown.

OBJECTIVES

The purpose of this study was to audit the use of FFR-CT in clinical practice against England's National Institute for Health and Care Excellence guidance and assess its diagnostic accuracy and cost.

METHODS

A multicenter audit was undertaken covering the 3 years when FFR-CT was centrally funded in England. For coronary computed tomographic angiograms (CCTAs) submitted for FFR-CT analysis, centers provided data on symptoms, CCTA and FFR-CT findings, and subsequent management. Audit standards included using FFR-CT only in patients with stable chest pain and equivocal stenosis (50%-69%). Diagnostic accuracy was evaluated against invasive FFR, when performed. Follow-up for nonfatal myocardial infarction and all-cause mortality was undertaken. The cost of an FFR-CT strategy was compared to alternative stress imaging pathways using cost analysis modeling.

RESULTS

A total of 2,298 CCTAs from 12 centers underwent FFR-CT analysis. Stable chest pain was the main symptom in 77%, and 40% had equivocal stenosis. Positive and negative predictive values of FFR-CT were 49% and 76%, respectively. A total of 46 events (2%) occurred over a mean follow-up period of 17 months; FFR-CT (cutoff: 0.80) was not predictive. The FFR-CT strategy costs £2,102 per patient compared with an average of £1,411 for stress imaging.

CONCLUSIONS

In clinical practice, the National Institute for Health and Care Excellence criteria for using FFR-CT were met in three-fourths of patients for symptoms and 40% for stenosis. FFR-CT had a low positive predictive value, making its use potentially more expensive than conventional stress imaging strategies.