Diagnostic Performance of CCTA and CT-FFR for the Detection of CAD in TAVR Work-Up

Optimal timing for percutaneous coronary intervention in patients undergoing transcatheter aortic valve replacement: A network meta-analysis

BACKGROUND

The optimal timing for percutaneous coronary intervention (PCI) in patients undergoing transcatheter aortic valve replacement (TAVR) is uncertain.

OBJECTIVES

To compare different PCI timings in patients with CAD undergoing TAVR.

METHODS

MEDLINE, Embase, and Cochrane were systematically searched for studies comparing different timings of PCI in patients with aortic stenosis and coronary artery disease (CAD) undergoing TAVR. PCI in a staged procedure to TAVR and PCI concomitantly to TAVR were compared with TAVR alone without PCI. A frequentist random-effects network meta-analysis calculates the odds ratio (OR) with a 95 % confidence interval (CI). Treatments were ranked using P-score analysis.

RESULTS

Two randomized controlled trials and 24 observational studies comprising 10,901 patients with aortic stenosis and CAD were included. Compared with PCI and concomitant TAVR, staged PCI was associated with lower rates of stroke (OR 0.54; 95 % CI 0.37-0.78), myocardial infarction (OR 0.54; 95 % CI 0.31-0.91), and all-cause mortality at 30 days (OR 0.62; 95 % CI 0.41-0.95). In addition, a subgroup analysis showed that staged PCI performed after TAVR is associated with the lowest rates of all-cause mortality of all strategies. In P-score analysis, staged PCI presented the highest likelihood of preventing stroke and myocardial infarction.

CONCLUSION

In patients with aortic stenosis and CAD undergoing TAVR, staged PCI is associated with lower rates of stroke, myocardial infarction, and short-term mortality compared with other timings.

Real-world application of CCTA with CT-FFR for coronary assessment pre-TAVI: the CT2TAVI study

This study aims to evaluate the implementation of concomitant CAD assessment on pre-TAVI (transcatheter aortic valve implantation) planning CTA (CT angiography) aided by CT-FFR (CT-fractional flow reserve) [The CT2TAVI protocol] and investigates the incremental value of CT-FFR to coronary CT angiography (CCTA) alone in the evaluation of patients undergoing CT2TAVI. This is a prospective observational real-world cohort study at an academic health system on consecutive patients who underwent CTA for TAVI planning from 1/2021 to 6/2022. This represented a transition period in our health system, from not formally reporting CAD on pre-TAVI planning CTA (Group A) to routinely reporting CAD on pre-TAVI CTA (Group B; CT2TAVI protocol). All CTAs were retrospective ECG-gated using a dual source 192 slice CT scanner without nitrate or intravenous beta blocker premedication. We assessed downstream ICA and revascularization pre-TAVI and clinical outcomes 30 days and 1 year post-TAVI in both groups. 307 patients were included with 199 patients in Group A and 108 patients in Group B. In Group B, ICA was performed pre-TAVI in only 40.7% of patients. The use of CT-FFR, which was primarily aimed at identifying hemodynamically significant proximal vessel disease, helped avoid downstream invasive testing for 60.5% (23/38) of patients who were deemed to have obstructive proximal vessel disease using CCTA alone or had one or more uninterpretable proximal segments using CCTA. All-cause mortality, cardiovascular mortality, myocardial infarction and need for revascularization at 1-year post-TAVI were comparable between groups with a higher trend toward heart failure hospitalizations in Group A. Routine ICA can safely be deferred pre-TAVI, with the CT2TAVI strategy using modern CT scanners aided by CT-FFR analysis.

Coronary CTA and CT-FFR in trans-catheter aortic valve implantation candidates: a systematic review and meta-analysis

OBJECTIVES

Screening for obstructive coronary artery disease (CAD) with coronary computed tomography angiography (CCTA) could prevent unnecessary invasive coronary angiography (ICA) procedures during work-up for trans-catheter aortic valve implantation (TAVI). CT-derived fractional flow reserve (CT-FFR) improves CCTA accuracy in chest pain patients. However, its reliability in the TAVI population is unknown. This systematic review and meta-analysis assesses CCTA and CT-FFR in TAVI candidates.

METHODS

PubMed, Embase and Web of Science were searched for studies regarding CCTA and/or CT-FFR in TAVI candidates. Primary endpoint was correct identification and rule-out of obstructive CAD. Results were pooled in a meta-analysis.

RESULTS

Thirty-four articles were part of the meta-analysis, reporting results for CCTA and CT-FFR in 7235 and 1269 patients, respectively. Reference standard was mostly anatomical severity of CAD. At patient level, pooled CCTA sensitivity was 94.0% and specificity 72.4%. CT-FFR sensitivity was 93.2% and specificity 70.3% with substantial variation between studies. However, in studies that compared both, CT-FFR performed better than CCTA. Sensitivity of CCTA versus CT-FFR was 74.9% versus 83.9%, and specificity was 65.5% versus 89.8%.

CONCLUSIONS

Negative CCTA accurately rules out CAD in the TAVI population. CCTA could lead to significant reduction in pre-TAVI ICA, but false positives remain high. Diagnostic accuracy of CT-FFR was comparable to that of CCTA in our meta-analyses, but in studies performing a direct comparison, CT-FFR performed better than CCTA. However, as most studies were small and used CT-FFR software exclusively available for research, a large study on CT-FFR in TAVI work-up using commercially available CT-FFR software would be appropriate before considering routine implementation.

KEY POINTS

Question Coronary artery disease (CAD) screening with invasive coronary angiography before trans-catheter aortic valve implantation (TAVI) is often retrospectively unnecessary, revealing no obstructive CAD. Findings Coronary CTA ruled out CAD in approximately half of TAVI candidates. CT-derived fractional flow reserve (CT-FFR) performed similarly overall but better than coronary CTA in direct comparison. Clinical relevance Addition of coronary CTA to TAVI planning-CT to screen for obstructive CAD could reduce negative invasive coronary angiographies in TAVI work-up. CT-FFR could reduce false-positive coronary CTA results, improving its gatekeeper function in this population, but more data is necessary.

Correlation between hemodynamics assessed by FAI combined with CT-FFR and plaque characteristics in coronary artery stenosis

BACKGROUND

While both CT-FFR and FAI are found to be associated with the development of CAD, their relationship with hemodynamics and plaque characteristics remains unclear. The present study aims to investigate the relationship between hemodynamics assessed by FAI combined with CT-FFR and plaque characteristics in functionally significant coronary artery stenosis.

METHODS

This retrospective study included 130 patients with suspected coronary heart disease, who were admitted to the Department of Cardiology of our hospital and underwent coronary computed tomography angiography (CCTA) from January 2022 to December 2023. Clinical baseline data and relevant auxiliary examination results were collected, and CCTA, FAI, and CT-FFR data were analyzed to investigate the relationship between these imaging parameters and both the hemodynamics and plaque characteristics of coronary artery lesions.

RESULTS

From 130 patients, a total of 207 diseased vessels were analyzed and classified based on CAD-RADS grading: 128 vessels exhibited stenosis of less than 50%, and 79 exhibited stenosis exceeding 50%. Patients with more than one lesion of > 50% stenosis were classified into the myocardial ischemia group (44 cases), and the rest were categorized as the non-myocardial ischemia group (86 cases). Compared to the non-myocardial ischemia group, patients in the myocardial ischemia group were significantly older (p < 0.001). No significant difference was found between the two groups in sex, cardiovascular risk factors, or the indicator of stenotic vessel distribution. The minimum CT-FFR in vessels with < 50% stenosis was higher than in vessels with > 50% stenosis, ΔCT-FFR was lower in vessels with < 50% stenosis than in vessels with > 50% stenosis, and the median CT-FFR was significantly lower in vessels with > 50% stenosis than in vessels with < 50% stenosis (p < 0.001). Additionally, FAI-LAD, FAI-LCX, FAI-RCA, and FAI-Mean were found to be significantly higher in vessels with > 50% stenosis compared to vessels with < 50% stenosis (p < 0.05). A negative correlation was observed between the minimum CT-FFR among three main coronary arteries (LAD, LCX, RCA) and CAD-RADS classification, while both ΔCT-FFR and FAI were positively correlated with CAD-RADS classification (p < 0.05). Non-calcified plaques were more prevalent in the vessels with > 50% stenosis, primarily located in the LAD, while calcified plaques were predominantly observed in vessels with < 50% stenosis (p < 0.001). In addition, in vessels with > 50% stenosis, plaques were longer, the degree of luminal stenosis was greater, and both the total volume and burden of plaques were significantly greater than in vessels with < 50% stenosis (p < 0.001). Lastly, the FAIlesion value in the vessels with > 50% stenosis was higher than in vessels with < 50% stenosis (p < 0.001).

CONCLUSION

FAI is associated with coronary artery stenosis and myocardial ischemia, and may serve as a novel indicator for identifying myocardial ischemia. Both FAI and CT-FFR demonstrated strong predictive abilities in significant coronary stenosis.

Prognostic Significance of Computed Tomography-Derived Fractional Flow Reserve for Long-Term Outcomes in Individuals With Coronary Artery Disease

BACKGROUND

Data on the predictive value of coronary computed tomography angiography-derived fractional flow reserve (CT-FFR) for long-term outcomes are limited.

METHODS AND RESULTS

A retrospective pooled analysis of individual patient data was performed. Deep-learning-based CT-FFR was calculated. All patients enrolled were followed-up for at least 5 years. The primary outcome was major adverse cardiovascular events. The secondary outcome was death or nonfatal myocardial infarction. Predictive abilities for outcomes were compared among 3 models (model 1, constructed using clinical variables; model 2, model 1+coronary computed tomography angiography-derived anatomical parameters; and model 3, model 2+CT-FFR). A total of 2566 patients (median age, 60 [53-65] years; 56.0% men) with coronary artery disease were included. During a median follow-up time of 2197 (2127-2386) days, 237 patients (9.2%) experienced major adverse cardiovascular events. In multivariable-adjusted Cox models, CT-FFR≤0.80 (hazard ratio [HR], 5.05 [95% CI, 3.64-7.01]; P<0.001) exhibited robust predictive value. The discriminant ability was higher in model 2 than in model 1 (Harrell's C-statistics, 0.79 versus 0.64; P<0.001) and was further promoted by adding CT-FFR to model 3 (Harrell's C-statistics, 0.83 versus 0.79; P<0.001). Net reclassification improvement was 0.264 (P<0.001) for model 2 beyond model 1. Of note, compared with model 2, model 3 also exhibited improvement (net reclassification improvement=0.085; P=0.001). As for predicting death or nonfatal myocardial infarction, only incorporating CT-FFR into model 3 showed improved reclassification (net reclassification improvement=0.131; P=0.021).

CONCLUSIONS

CT-FFR provides strong and incremental prognostic information for predicting long-term outcomes. The combined models incorporating CT-FFR exhibit modest improvement of prediction abilities, which may aid in risk stratification and decision-making.

The impact of transcatheter aortic valve replacement on changes of coronary computed tomography-derived fractional flow reserve

BACKGROUND

The effect of transcatheter aortic valve replacement (TAVR) on changes of computed tomography-derived fractional flow reserve (CT-FFR) values was controversial. Thus, we aimed to identify the impact of TAVR on changes of CT-FFR values, plaque characteristics, and the associated clinical impact.

METHODS

This single-center observational study included 39 consecutive patients with severe aortic valve disease undergone TAVR between August 2019 and April 2023, whom were performed with preoperative and postoperative coronary CT angiography (CCTA). The computation of CT-FFR and plaque characteristics was performed by an independent central core laboratory.

RESULTS

Each patient underwent CCTA and CT-FFR assessment without encountering any complications. Notably, both at discharge and six months post-TAVR, there was a significant improvement observed in the New York Heart Association (NYHA) functional classification, left ventricular fractional shortening, and ejection fraction compared to pre-operative levels. The CT-FFR for left anterior descending artery (LAD), left anterior descending artery (LCX), and right coronary artery (RCA) had no obvious change at discharge compared to pre-operation (0.92 ± 0.05 vs. 0.93 ± 0.05, p = 0.109; 0.96 ± 0.03 vs. 0.95 ± 0.03, p = 0.523; 0.97 ± 0.04 vs. 0.97 ± 0.03, p = 0.533; respectively). Furthermore, TAVR did not exert a significant impact on plaque burden during the perioperative period.

Our report suggested that TAVR did not significantly affect coronary CT-FFR measurements and plaque characteristics in the perioperative period, and furthermore, the patients' cardiac function showed gradual improvement in the short-term following discharge.

Computed Tomography-Derived Fractional Flow Reserve: Developing A Gold Standard for Coronary Artery Disease Diagnostics

In recent years, a new technique called computed tomography-derived fractional flow reserve (CT-FFR) has been developed. CT-FFR overcomes many limitations in the current gold-standard fractional flow reserve (FFR) techniques while maintaining a better concordance with FFR. This technique integrates static coronary CT angiography data with hydrodynamic models, employing algorithms rather than guidewire interventions to compute the FFR. In addition to diagnosing coronary heart disease, CT-FFR has been applied in the preoperative risk assessment of major adverse cardiovascular events (MACEs) in organ transplantation and transcatheter aortic valve replacement (TAVR). Continuous advancements in CT-FFR techniques and algorithms are expanding their applicability to other methodologies. Subsequently, with robust clinical trial validation, CT-FFR can potentially supersede FFR as the primary "gatekeeper" for interventions.

Interrater Variability of ML-Based CT-FFR in Patients without Obstructive CAD before TAVR: Influence of Image Quality, Coronary Artery Calcifications, and Location of Measurement

Objectives: CT-derived fractional flow reserve (CT-FFR) can improve the specificity of coronary CT-angiography (cCTA) for ruling out relevant coronary artery disease (CAD) prior to transcatheter aortic valve replacement (TAVR). However, little is known about the reproducibility of CT-FFR and the influence of diffuse coronary artery calcifications or segment location. The objective was to assess the reliability of machine-learning (ML)-based CT-FFR prior to TAVR in patients without obstructive CAD and to assess the influence of image quality, coronary artery calcium score (CAC), and the location of measurement within the coronary tree. Methods: Patients assessed for TAVR, without obstructive CAD on cCTA were evaluated with ML-based CT-FFR by two observers with differing experience. Differences in absolute values and categorization into hemodynamically relevant CAD (CT-FFR ≤ 0.80) were compared. Results in regard to CAD were also compared against invasive coronary angiography. The influence of segment location, image quality, and CAC was evaluated. Results: Of the screened patients, 109/388 patients did not have obstructive CAD on cCTA and were included. The median (interquartile range) difference of CT-FFR values was -0.005 (-0.09 to 0.04) (p = 0.47). Differences were smaller with high values. Recategorizations were more frequent in distal segments. Diagnostic accuracy of CT-FFR between both observers was comparable (proximal: Δ0.2%; distal: Δ0.5%) but was lower in distal segments (proximal: 98.9%/99.1%; distal: 81.1%/81.6%). Image quality and CAC had no clinically relevant influence on CT-FFR. Conclusions: ML-based CT-FFR evaluation of proximal segments was more reliable. Distal segments with CT-FFR values close to the given threshold were prone to recategorization, even if absolute differences between observers were minimal and independent of image quality or CAC.

Prognostic implications of pre-transcatheter aortic valve replacement computed tomography-derived coronary plaque characteristics and stenosis severity

OBJECTIVES

The study aimed to investigate the prognostic value of pre-transcatheter aortic valve replacement (TAVR) computed tomography angiography (CTA) in assessing physiological stenosis severity (CTA-derived fractional flow reserve (CT-FFR)) and high-risk plaque characteristics (HRPC).

MATERIALS AND METHODS

Among TAVR patients who underwent pre-procedure CTA, the presence and number of HRPCs (minimum lumen area of < 4 mm2, plaque burden ≥ 70%, low-attenuating plaques, positive remodeling, napkin-ring sign, or spotty calcification) as well as CT-FFR were assessed. The risk of vessel-oriented composite outcome (VOCO, a composite of vessel-related ischemia-driven revascularization, vessel-related myocardial infarction, or cardiac death) was compared according to the number of HRPC and CT-FFR categories.

RESULTS

Four hundred and twenty-seven patients (68.4% were male) with 1072 vessels were included. Their mean age was 70.6 ± 10.6 years. Vessels with low CT-FFR (≤ 0.80) (41.7% vs. 15.8%, adjusted hazard ratio (HRadj) 1.96; 95% confidence interval (CI): 1.28-2.96; p = 0.001) or lesions with ≥ 3 HRPC (38.7% vs. 16.0%, HRadj 1.81; 95%CI 1.20-2.71; p = 0.005) demonstrated higher VOCO risk. In the CT-FFR (> 0.80) group, lesions with ≥ 3 HRPC showed a significantly higher risk of VOCO than those with < 3 HRPC (34.7% vs. 13.0%; HRadj 2.04; 95%CI 1.18-3.52; p = 0.011). However, this relative increase in risk was not observed in vessels with positive CT-FFR (≤ 0.80).

CONCLUSIONS

In TAVR candidates, both CT-FFR and the presence of ≥ 3 HRPC were associated with an increased risk of adverse clinical events. However, the value of HRPC differed with the CT-FFR category, with more incremental predictability among vessels with negative CT-FFR but not among vessels with positive CT-FFR.

CLINICAL RELEVANCE STATEMENT

In transcatheter aortic valve replacement (TAVR) candidates, pre-TAVR CTA provided the opportunity to assess coronary physiological stenosis severity and high-risk plaque characteristics, both of which are associated with worse clinical outcomes.

KEY POINTS

• The current study investigated the prognostic value of coronary physiology significance and plaque characteristics in transcatheter aortic valve replacement patients. • The combination of coronary plaque vulnerability and physiological significance showed improved accuracy in predicting clinical outcomes in transcatheter aortic valve replacement patients. • Pre-transcatheter aortic valve replacement CT can be a one-stop-shop tool for coronary assessments in clinical practice.

Combined Computed Coronary Tomography Angiography and Transcatheter Aortic Valve Implantation (TAVI) Planning Computed Tomography Reliably Detects Relevant Coronary Artery Disease Pre-TAVI

Background: Before surgical or transcatheter aortic valve implantation (TAVI), coronary status evaluation is required. The role of combined computed coronary tomography angiography (cCTA) and TAVI planning CT in this context is not yet well elucidated. This study assessed whether relevant proximal coronary disease requiring coronary revascularization can be safely detected by combined cCTA and TAVI planning CT, including CT-derived fractional flow reserve (FFR) calculation in patients with severe aortic stenosis. Methods: This study analyzed patients with successful cCTA combined with TAVI planning CT using a 128-slice dual-source scanner. The detection via cCTA of relevant left main stem stenosis (>50%) or proximal coronary artery stenosis (>70%) was compared to invasive coronary angiography (ICA). Results: This study comprised 101 consecutive TAVI patients with a median age of 83 [77-86] years, a median STS score of 3.7 [2.4-6.1] and 54% of whom had known coronary artery disease. Of 15 patients with relevant coronary stenoses, 14 (93.3%) were detected with cCTA, while false positive results were found in 25 patients. Only in patients with previous percutaneous coronary stent implantation (PCI) were false positive rates (11/29) increased. In the subgroup without previous PCI, an improved classification performance of 87.5%, being mainly due to 11.1% false positive classifications, led to a negative predictive value of 98.5%. Conclusions: Combined cCTA and CT-FFR with TAVI planning CT via state-of-the-art scanners and protocols as a one-stop shop can replace routine ICA in patients prior to TAVI due to its safe detection of relevant coronary artery stenosis, although diagnostic performance of cCTA is only reduced in patients with coronary stents.

Advanced CT measures of coronary artery disease with intermediate stenosis in patients with severe aortic valve stenosis

BACKGROUND

Coronary artery disease (CAD) and severe aortic valve stenosis (AS) frequently coexist. While pre-transcatheter aortic valve replacement (TAVR) computed tomography angiography (CTA) allows to rule out obstructive CAD, interpreting hemodynamic significance of intermediate stenoses is challenging. This study investigates the incremental value of CT-derived fractional flow reserve (CT-FFR), quantitative coronary plaque characteristics (e.g., stenosis degree, plaque volume, and composition), and peri-coronary adipose tissue (PCAT) density to detect hemodynamically significant lesions among those with AS and CAD.

MATERIALS AND METHODS

We included patients with severe AS and intermediate coronary lesions (20-80% diameter stenosis) who underwent pre-TAVR CTA and invasive coronary angiogram (ICA) with resting full-cycle ratio (RFR) assessment between 08/16 and 04/22. CTA image analysis included assessment of CT-FFR, quantitative coronary plaque analysis, and PCAT density. Coronary lesions with RFR ≤ 0.89 indicated hemodynamic significance as reference standard.

RESULTS

Overall, 87 patients (age 77.9 ± 7.4 years, 38% female) with 95 intermediate coronary artery lesions were included. CT-FFR showed good discriminatory capacity (area under receiver operator curve (AUC) = 0.89, 95% confidence interval (CI) 0.81-0.96, p < 0.001) to identify hemodynamically significant lesions, superior to anatomical assessment, plaque morphology, and PCAT density. Plaque composition and PCAT density did not differ between lesions with and without hemodynamic significance. Univariable and multivariable analyses revealed CT-FFR as the only predictor for functionally significant lesions (odds ratio 1.28 (95% CI 1.17-1.43), p < 0.001). Overall, CT-FFR ≤ 0.80 showed diagnostic accuracy, sensitivity, and specificity of 88.4% (95%CI 80.2-94.1), 78.5% (95%CI 63.2-89.7), and 96.2% (95%CI 87.0-99.5), respectively.

CONCLUSION

CT-FFR was superior to CT anatomical, plaque morphology, and PCAT assessment to detect functionally significant stenoses in patients with severe AS.

CLINICAL RELEVANCE STATEMENT

CT-derived fractional flow reserve in patients with severe aortic valve stenosis may be a useful tool for non-invasive hemodynamic assessment of intermediate coronary lesions, while CT anatomical, plaque morphology, and peri-coronary adipose tissue assessment have no incremental or additional benefit. These findings might help to reduce pre-transcatheter aortic valve replacement invasive coronary angiogram.

KEY POINTS

• Interpreting the hemodynamic significance of intermediate coronary stenoses is challenging in pre-transcatheter aortic valve replacement CT. • CT-derived fractional flow reserve (CT-FFR) has a good discriminatory capacity in the identification of hemodynamically significant coronary lesions. • CT-derived anatomical, plaque morphology, and peri-coronary adipose tissue assessment did not improve the diagnostic capability of CT-FFR in the hemodynamic assessment of intermediate coronary stenoses.

Coronary Artery Revascularization in Patients Undergoing Transcatheter Aortic Valve Replacement

Patients with concomitant severe aortic stenosis and significant coronary artery disease present a diagnostic and therapeutic challenge in clinical practice. There are no clear-cut guidelines as to the timing of revascularization in these patients who are referred for transcatheter aortic valve replacement (TAVR). This article aims to show that in patients without high-grade proximal coronary artery disease, revascularization after TAVR is safe, feasible, and practical. Additionally, the use of preoperative TAVR computed tomographic angiography might be used in both intermediate and high-risk patients rather than invasive coronary angiography to assess for significant proximal coronary artery disease to help guide the timing of revascularization.

The Role of Multimodality Imaging in Cardiomyopathy

PURPOSE OF REVIEW

There has been increasing use of multimodality imaging in the evaluation of cardiomyopathies.

RECENT FINDINGS

Echocardiography, cardiac magnetic resonance (CMR), cardiac nuclear imaging, and cardiac computed tomography (CCT) play an important role in the diagnosis, risk stratification, and management of patients with cardiomyopathies. Echocardiography is essential in the initial assessment of suspected cardiomyopathy, but a multimodality approach can improve diagnostics and management. CMR allows for accurate measurement of volumes and function, and can easily detect unique pathologic structures. In addition, contrast imaging and parametric mapping enable the characterization of tissue features such as scar, edema, infiltration, and deposition. In non-ischemic cardiomyopathies, metabolic and molecular nuclear imaging is used to diagnose rare but life-threatening conditions such amyloidosis and sarcoidosis. There is an expanding use of CCT for planning electrophysiology procedures such as cardioversion, ablations, and device placement. Furthermore, CCT can evaluate for complications associated with advanced heart failure therapies such as cardiac transplant and mechanical support devices. Innovations in multimodality cardiac imaging should lead to increased volumes and better outcomes.

Coronary Artery Disease Assessment via On-Site CT Fractional Flow Reserve in Patients Undergoing Transcatheter Aortic Valve Replacement

Purpose To examine the clinical feasibility of workstation-based CT fractional flow reserve (CT-FFR) for coronary artery disease (CAD) evaluation during preprocedural planning in patients undergoing transcatheter aortic valve replacement (TAVR). Materials and Methods In this retrospective single-center study, 434 patients scheduled for TAVR between 2018 and 2020 were screened for study inclusion; a relevant proportion of patients (35.0% [152 of 434]) was not suitable for evaluation due to insufficient imaging properties. A total of 112 patients (mean age, 82.1 years ± 6.7 [SD]; 58 [52%] men) were included in the study. Invasive angiography findings, coronary CT angiography results, and Agatston score were acquired and compared with on-site CT-FFR computation for evaluation of CAD and prediction of major adverse cardiovascular events (MACE) within a 24-month follow-up. Results Hemodynamic relevant CAD, as suggested by CT-FFR of 0.80 or less, was found in 41 of 70 (59%) patients with stenosis of 50% or more. MACE occurred in 23 of 112 (20.5%) patients, from which 14 of 23 had stenoses with CT-FFR of 0.80 or less (hazard ratio [HR], 3.33; 95% CI: 1.56, 7.10; P = .002). CT-FFR remained a significant predictor of MACE after inclusion in a multivariable model with relevant covariables (HR, 2.89; 95% CI: 1.22, 6.86; P = .02). An Agatston score of 1000 Agatston units or more (HR, 2.25; 95% CI: 0.98, 5.21; P = .06) and stenoses of 50% or more determined via invasive angiography (HR, 0.94; 95% CI: 0.41, 2.17; P = .88) were not significant predictors of MACE. Conclusion Compared with conventional CAD markers, CT-FFR better predicted adverse outcomes after TAVR. A relevant portion of the screened cohort, however, was not suitable for CT-based CAD evaluation. Keywords: CT, Transcatheter Aortic Valve Implantation/Replacement (TAVI/TAVR), Cardiac, Coronary Arteries, Outcomes Analysis © RSNA, 2024 See also the commentary by Weir-McCall and Pugliese in this issue.

Feasibility and Utility of Anatomical and Physiological Evaluation of Coronary Disease With Cardiac CT in Severe Aortic Stenosis (FUTURE-AS Registry): Rationale and Design

Background

Coronary artery disease (CAD) in patients with severe aortic stenosis (AS) is common and may be associated with worse outcomes. Computed tomography coronary angiography (CTCA) and fractional flow reserve derived from computed tomography (FFRCT) are tools for comprehensive coronary assessment. The utility and safety of CTCA and FFRCT in the work-up for transcatheter aortic valve replacement (TAVR) is not established, especially in an evolving landscape that involves younger TAVR patients. The FUTURE-AS Registry will assess the utility and safety of cardiac-optimized CTCA and FFRCT to evaluate CAD and guide referral for downstream invasive coronary angiography (ICA) in patients with severe AS being considered for TAVR.

Methods

FUTURE-AS is an international, prospective, multicenter registry of patients with severe AS referred for TAVR being assessed for CAD with CTCA and FFRCT. The primary end point is the per-patient sensitivity and negative predictive value of CTCA and FFRCT for identifying anatomical and physiologically significant CAD compared to ICA and invasive FFR. The safety end point is the incidence of symptomatic hypotension or bradycardia requiring intervention following the administration of nitroglycerin or β-blocker medications. Feasibility end points include the incidence of noninterpretable CTCA scans and CTCA scans not adequate for FFR analysis. Other utility end points include specificity, positive predictive value, and accuracy of CTCA and FFRCT. Lastly, the potential of a CTCA and FFRCT guided strategy to defer pre-TAVR ICA will be assessed.

Conclusions

FUTURE-AS will characterize the utility, safety, and feasibility of CTCA and FFRCT for coronary assessment pre-TAVR.

Utility of Coronary Computed Tomography Angiography in Patients Undergoing Transcatheter Aortic Valve Implantation: A Meta-Analysis and Meta-Regression Based on Published Data from 7458 Patients

BACKGROUND

Coronary CT angiography (CCTA) may detect coronary artery disease (CAD) in transcatheter aortic valve implantation (TAVI) patients and may obviate invasive coronary angiography (ICA) in selected patients. We assessed the diagnostic accuracy of CCTA for detecting CAD in TAVI patients based on published data.

METHODS

Meta-analysis and meta-regression were performed based on a comprehensive electronic search, including relevant studies assessing the diagnostic accuracy of CCTA in the setting of TAVI patients compared to ICA. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were calculated on a patient and per segment level.

RESULTS

Overall, 27 studies (total of 7458 patients) were included. On the patient level, the CCTA's pooled sensitivity and NPV were 95% (95% CI: 93-97%) and 97% (95% CI: 95-98%), respectively, while the specificity and PPV were at 73% (95% CI: 62-82%) and 64% (95% CI: 57-71%), respectively. On the segmental coronary vessel level, the sensitivity and NPV were 90% (95% CI: 79-96%) and 98% (95% CI: 97-99%).

CONCLUSIONS

This meta-analysis highlights CCTA's potential as a first-line diagnostic tool although its limited PPV and specificity may pose challenges when interpreting heavily calcified arteries. This study underscores the need for further research and protocol standardization in this area.

Interrater variability of ML-based CT-FFR during TAVR-planning: influence of image quality and coronary artery calcifications

Objective

To compare machine learning (ML)-based CT-derived fractional flow reserve (CT-FFR) in patients before transcatheter aortic valve replacement (TAVR) by observers with differing training and to assess influencing factors.

Background

Coronary computed tomography angiography (cCTA) can effectively exclude CAD, e.g. prior to TAVR, but remains limited by its specificity. CT-FFR may mitigate this limitation also in patients prior to TAVR. While a high reliability of CT-FFR is presumed, little is known about the reproducibility of ML-based CT-FFR.

Methods

Consecutive patients with obstructive CAD on cCTA were evaluated with ML-based CT-FFR by two observers. Categorization into hemodynamically significant CAD was compared against invasive coronary angiography. The influence of image quality and coronary artery calcium score (CAC) was examined.

Results

CT-FFR was successfully performed on 214/272 examinations by both observers. The median difference of CT-FFR between both observers was -0.05(-0.12-0.02) (p < 0.001). Differences showed an inverse correlation to the absolute CT-FFR values. Categorization into CAD was different in 37/214 examinations, resulting in net recategorization of Δ13 (13/214) examinations and a difference in accuracy of Δ6.1%. On patient level, correlation of absolute and categorized values was substantial (0.567 and 0.570, p < 0.001). Categorization into CAD showed no correlation to image quality or CAC (p > 0.13).

Conclusion

Differences between CT-FFR values increased in values below the cut-off, having little clinical impact. Categorization into CAD differed in several patients, but ultimately only had a moderate influence on diagnostic accuracy. This was independent of image quality or CAC.

Multislice computerized tomography coronary angiography can be a comparable tool to intravascular ultrasound in evaluating "true" coronary artery bifurcations

Aim

Coronary bifurcation atherosclerosis depends on its angles, flow, and extensive branching. We investigate the ability of CT coronary angiography (CTCA) to determine atherosclerotic plaque characteristics of "true" bifurcation compared with intravascular ultrasound (IVUS) and the influence on side branch (SB) fate after percutaneous coronary intervention (PCI).

Methods and results

The study included 70 patients with 72 "true" bifurcations. Most of the bifurcations were in the left anterior descending-diagonal (Dg) territory [50 out of 72 (69.4%)]. Longitudinal plaque evaluation at the polygon of confluence [carina and 5 mm proximal and distal in the main branch (MB)] showed that carina side MB and SB plaque had occurred with the lowest incidence with fibro-lipid structure (115 ± 63 HU and 89 ± 73 HU, p < 0.001 for all). Bland-Altman analysis showed a discrepancy in measuring mainly the lumen area between CTCA and IVUS in proximal MB [lumen 5.10, 95% CI (95% confidence interval, 4.53-5.68) mm2, p < 0.001; vessel -1.42, 95% CI (-2.63 to -0.21) mm2, p = 0.023], carina MB [lumen 3.74, 95% CI (3.37-4.10) mm2, p < 0.001; vessel -0.48, 95% CI (-1.45 to 0.48) mm2, p = 0.322], and distal MB [lumen 4.72, 95% CI (4.27-5.18) mm2, p < 0.001; vessel 0.62, 95% CI (-0.53 to 1.77) mm2, p = 0.283]. A significant correlation existed between average plaque density on CTCA with a percentage of calcified plaque on IVUS tissue characterization (proximal r = 0.307/p = 0.024, carina 0.469/0.008, distal 0.339/0.024, minimal lumen diameter 0.318/0.020). Circumferential plaque in the proximal MB segment remained an independent predictor of SB compromise [OR 3.962 (95% CI 1.170-13.418)].

Conclusion

Detection and characterization of atherosclerotic plaque by CTCA in non-left main "true" coronary bifurcations can provide useful information about bifurcation anatomy and plaque distribution that can predict outcomes after provisional stenting, thus guiding the interventional strategy to bifurcation PCI.

Basing on the machine learning model to analyse the coronary calcification score and the coronary flow reserve score to evaluate the degree of coronary artery stenosis

AIM

To obtain the coronary artery calcium score (CACS) for each branch in coronary artery computed tomography angiography (CCTA) examination combined with the flow fraction reserve (FFR) of each branch in the coronary artery detected by CT and apply a machine learning model (ML) to analyse and predict the severity of coronary artery stenosis.

METHODS

All patients who underwent coronary computed tomography angiography (CCTA) from January 2019 to April 2022 in the HOSPITAL (T.C.M) AFFILIATED TO SOUTHWEST MEDICAL UNIVERSITY) were retrospectively screened, and their sex, age, characteristics of lipid-containing lesions, coronary calcium score (CACS) and CT-FFR values were collected. Five machine learning models, random forest (RF), k-nearest neighbour algorithm (KNN), kernel logistic regression, support vector machine (SVM) and radial basis function neural network (RBFNN), were used as predictive models to evaluate the severity of coronary stenosis.

RESULTS

Among the five machine learning models, the SVM model achieved the best prediction performance, and the prediction accuracy of mild stenosis was up to 90%. Second, age and male sex were important influencing factors of increasing CACS and decreasing CT-FFR. Moreover, the critical CACS value of myocardial ischemia >200.70 was calculated.

CONCLUSION

Through computer machine learning model analysis, we prove the importance of CACS and FFR in predicting coronary stenosis, especially the prominent vector machine model, which promotes the application of artificial intelligence computer learning methods in the field of medical analysis.

Effectiveness of Pre-TAVR CTA as a Screening Tool for Significant CAD Before TAVR

BACKGROUND

Computed tomography angiography (CTA) and invasive coronary angiography (ICA) are routinely performed before transcatheter aortic valve replacement (TAVR) to assess aortic root anatomy and screen for coronary artery disease (CAD), respectively.

OBJECTIVES

This study explored the efficacy of CTA as a screening tool for significant proximal CAD before TAVR.

METHODS

With proper ethical oversight, patients undergoing TAVR at Cleveland Clinic with a preprocedural CTA and invasive coronary angiography (ICA), and no prior percutaneous intervention, were identified from 2015 to 2021. Blinded to ICA results, the authors reviewed the left main, proximal left anterior descending coronary artery, proximal left circumflex coronary artery, and proximal right coronary artery by CTA coronary reconstruction to assess for nonsignificant stenosis (0% to 49%), moderate stenosis (50% to 69%), and severe stenosis (≥70%). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Cohen Kappa statistic were analyzed.

RESULTS

2,217 patients (53.4% male, age 79.2 ± 8.5 years) met inclusion criteria. CTA evaluation revealed a sensitivity of 90%, specificity of 92%, PPV of 74%, and NPV of 97% for detecting ≥50% stenosis. Using a ≥70% stenosis cutoff, evaluation revealed a sensitivity of 91%, specificity of 97%, PPV of 83%, and NPV of 99%. Assessment of bypass graft patency revealed a sensitivity of 86%, specificity of 97%, PPV of 84%, and NPV of 98%. Cohen Kappa analysis indicated substantial to near perfect agreement between pre-TAVR CTA and ICA.

CONCLUSIONS

Pre-TAVR CTA has a high NPV for high-grade proximal stenosis of each coronary artery. As a result, CTA can be used as a screening tool to rule out significant proximal CAD in patients undergoing TAVR.

Combined CT Coronary Artery Assessment and TAVI Planning

Computed tomography angiography (CTA) of the aorta and the iliofemoral arteries is crucial for preprocedural planning of transcatheter aortic valve implantation (TAVI) in patients with severe aortic stenosis (AS), because it provides details on a variety of aspects required for heart team decision-making. In addition to providing relevant diagnostic information on the degree of aortic valve calcification, CTA allows for a customized choice of the transcatheter heart valve system and the TAVI access route. Furthermore, current guidelines recommend the exclusion of relevant coronary artery disease (CAD) prior to TAVI. The feasibility of coronary artery assessment with CTA in patients scheduled for TAVI has been established previously, and accumulating data support its value. In addition, fractional flow reserve determined from CTA (CT-FFR) and machine learning-based CT-FFR were recently shown to improve its diagnostic yield for this purpose. However, the utilization of CTA for coronary artery evaluation remains limited in this specific population of patients due to the relatively high risk of CAD coexistence with severe AS. Therefore, the current diagnostic work-up prior to TAVI routinely includes invasive catheter coronary angiography at most centers. In this article, the authors address technological prerequisites and CT protocol considerations, discuss pitfalls, review the current literature regarding combined CTA coronary artery assessment and preprocedural TAVI evaluation, and provide an overview of unanswered questions and future research goals within the field.

Myocardial Evaluation in Patients with Aortic Stenosis by Cardiac Computed Tomography

BACKGROUND

 Aortic valve stenosis (AVS) is one of the most prevalent pathologies affecting the heart that can curtail expected survival and quality of life if not managed appropriately.

CURRENT STATUS

 Cardiac computed tomography (CT) has long played a central role in this subset, mostly for severity assessment and for procedural planning. Although not as widely accepted as other imaging modalities for functional myocardial assessment [i. e., transthoracic echocardiogram (TTE), cardiac magnetic resonance (CMR)], this technique has recently increased its clinical application in this regard.

FUTURE OUTLOOK

 The ability to provide morphological, functional, tissue, and preprocedural information highlights the potential of the "all-in-one" concept of cardiac CT as a potential reality for the near future for AVS assessment. In this review article, we sought to analyze the current applications of cardiac CT that allow a full comprehensive evaluation of aortic valve disease.

KEY POINTS

  · Noninvasive myocardial tissue characterization stopped being an exclusive feature of cardiac magnetic resonance.. · Emerging acquisition methods make cardiac CT an accurate and widely accessible imaging modality.. · Cardiac CT has the potential to become a "one-stop" exam for comprehensive aortic stenosis assessment..

CITATION FORMAT

· Gama FF, Patel K, Bennett J et al. Myocardial Evaluation in Patients with Aortic Stenosis by Cardiac Computed Tomography. Fortschr Röntgenstr 2023; DOI: 10.1055/a-1999-7271.

[How to select the best device using pre-TAVR CT scan]

Transcatheter aortic valve replacement or TAVR has become the gold standard for the treatment of symptomatic and severe aortic valve stenosis in elderly patients. Although the role of computed tomography imaging was initially limited to the determination of the optimal vascular approach, it has progressively matured to become the pilar of TAVR work-up while being standardized by consensus conferences. The list of evaluated elements includes aortic annulus diameter, the optimal projection curve, the number of aortic leaflets, the severity and localization of calcifications, coronary ostial height, membranous septum length and aortic angulation. The proper and cautious evaluation of these elements may help evaluating the risk for the main periprocedural complications such as coronary obstruction, annular rupture, permanent pacemaker implantation or procedural failure and selecting the optimal transcatheter heart valve and its size, according to the patient's specific anatomy. In this review, we detail how the evaluation of these parameters may impact the selection of the transcatheter heart valve.

Current Concepts and Future Applications of Non-Invasive Functional and Anatomical Evaluation of Coronary Artery Disease

Over the last decades, significant advances have been achieved in the treatment of coronary artery disease (CAD). Proper non-invasive diagnosis and appropriate management based on functional information and the extension of ischemia or viability remain the cornerstone in the fight against adverse CAD events. Stress echocardiography and single photon emission computed tomography are often used for the evaluation of ischemia. Advancements in non-invasive imaging modalities such as computed tomography (CT) coronary angiography and cardiac magnetic resonance imaging (MRI) have not only allowed non-invasive imaging of coronary artery lumen but also provide additional functional information. Other characteristics regarding the plaque morphology can be further evaluated with the latest modalities achieving a morpho-functional evaluation of CAD. Advances in the utilization of positron emission tomography (PET), as well as software advancements especially regarding cardiac CT, may provide additional prognostic information to a more evidence-based treatment decision. Since the armamentarium on non-invasive imaging modalities has evolved, the knowledge of the capabilities and limitations of each imaging modality should be evaluated in a case-by-case basis to achieve the best diagnosis and treatment decision. In this review article, we present the most recent advances in the noninvasive anatomical and functional evaluation of CAD.