Coronary computed tomography angiography derived fractional flow reserve and risk of recurrent angina: A 3-year follow-up study

BACKGROUND

The association between coronary computed tomography angiography (CTA) derived fractional flow reserve (FFRCT) and risk of recurrent angina in patients with new onset stable angina pectoris (SAP) and stenosis by CTA is uncertain.

METHODS

Multicenter 3-year follow-up study of patients presenting with symptoms suggestive of new onset SAP who underwent first-line CTA evaluation and subsequent standard-of-care treatment. All patients had at least one ≥30 ​% coronary stenosis. A per-patient lowest FFRCT-value ≤0.80 represented an abnormal test result. Patients with FFRCT ≤0.80 who underwent revascularization were categorized according to completeness of revascularization: 1) Completely revascularized (CR-FFRCT), all vessels with FFRCT ≤0.80 revascularized; or 2) incompletely revascularized (IR-FFRCT) ≥1 vessels with FFRCT ≤0.80 non-revascularized. Recurrent angina was evaluated using the Seattle Angina Questionnaire.

RESULTS

Amongst 769 patients (619 [80 ​%] stenosis ≥50 ​%, 510 [66 ​%] FFRCT ≤0.80), 174 (23 ​%) reported recurrent angina at follow-up. An FFRCT ≤0.80 vs ​> ​0.80 associated to increased risk of recurrent angina, relative risk (RR): 1.82; 95 ​% CI: 1.31-2.52, p ​< ​0.001. Risk of recurrent angina in CR-FFRCT (n ​= ​135) was similar to patients with FFRCT >0.80, 13 ​% vs 15 ​%, RR: 0.93; 95 ​% CI: 0.62-1.40, p ​= ​0.72, while IR-FFRCT (n ​= ​90) and non-revascularized patients with FFRCT ≤0.80 (n ​= ​285) had increased risk, 37 ​% vs 15 ​% RR: 2.50; 95 ​% CI: 1.68-3.73, p ​< ​0.001 and 30 ​% vs 15 ​%, RR: 2.03; 95 ​% CI: 1.44-2.87, p ​< ​0.001, respectively. Use of antianginal medication was similar across study groups.

CONCLUSION

In patients with SAP and coronary stenosis by CTA undergoing standard-of-care guided treatment, FFRCT provides information regarding risk of recurrent angina.

Impact of Smoking on Coronary Volume-to-Myocardial Mass Ratio: An ADVANCE Registry Substudy

Purpose To examine the relationship between smoking status and coronary volume-to-myocardial mass ratio (V/M) among individuals with coronary artery disease (CAD) undergoing CT fractional flow reserve (CT-FFR) analysis. Materials and Methods In this secondary analysis, participants from the ADVANCE registry evaluated for suspected CAD from July 15, 2015, to October 20, 2017, who were found to have coronary stenosis of 30% or greater at coronary CT angiography (CCTA) were included if they had known smoking status and underwent CT-FFR and V/M analysis. CCTA images were segmented to calculate coronary volume and myocardial mass. V/M was compared between smoking groups, and predictors of low V/M were determined. Results The sample for analysis included 503 current smokers, 1060 former smokers, and 1311 never-smokers (2874 participants; 1906 male participants). After adjustment for demographic and clinical factors, former smokers had greater coronary volume than never-smokers (former smokers, 3021.7 mm3 ± 934.0 [SD]; never-smokers, 2967.6 mm3 ± 978.0; P = .002), while current smokers had increased myocardial mass compared with never-smokers (current smokers, 127.8 g ± 32.9; never-smokers, 118.0 g ± 32.5; P = .02). However, both current and former smokers had lower V/M than never-smokers (current smokers, 24.1 mm3/g ± 7.9; former smokers, 24.9 mm3/g ± 7.1; never-smokers, 25.8 mm3/g ± 7.4; P < .001 [unadjusted] and P = .002 [unadjusted], respectively). Current smoking status (odds ratio [OR], 0.74 [95% CI: 0.59, 0.93]; P = .009), former smoking status (OR, 0.81 [95% CI: 0.68, 0.97]; P = .02), stenosis of 50% or greater (OR, 0.62 [95% CI: 0.52, 0.74]; P < .001), and diabetes (OR, 0.67 [95% CI: 0.56, 0.82]; P < .001) were independent predictors of low V/M. Conclusion Both current and former smoking status were independently associated with low V/M. Keywords: CT Angiography, Cardiac, Heart, Ischemia/Infarction Clinical trial registration no. NCT02499679 Supplemental material is available for this article. © RSNA, 2024.

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.

Impact of Coronary CT Angiography-derived Fractional Flow Reserve on Downstream Management and Clinical Outcomes in Individuals with and without Diabetes

Purpose

To compare the clinical use of coronary CT angiography (CCTA)-derived fractional flow reserve (FFR) in individuals with and without diabetes mellitus (DM).

Materials and Methods

This secondary analysis included participants (enrolled July 2015 to October 2017) from the prospective, multicenter, international The Assessing Diagnostic Value of Noninvasive CT-FFR in Coronary Care (ADVANCE) registry (ClinicalTrials.gov identifier, NCT02499679) who were evaluated for suspected coronary artery disease (CAD), with one or more coronary stenosis ≥30% on CCTA images, using CT-FFR. CCTA and CT-FFR findings, treatment strategies at 90 days, and clinical outcomes at 1-year follow-up were compared in participants with and without DM.

Results

The study included 4290 participants (mean age, 66 years ± 10 [SD]; 66% male participants; 22% participants with DM). Participants with DM had more obstructive CAD (one or more coronary stenosis ≥50%; 78.8% vs 70.6%, P < .001), multivessel CAD (three-vessel obstructive CAD; 18.9% vs 11.2%, P < .001), and proportionally more vessels with CT-FFR ≤ 0.8 (74.3% vs 64.6%, P < .001). Treatment reclassification by CT-FFR occurred in two-thirds of participants which was consistent regardless of the presence of DM. There was a similar graded increase in coronary revascularization with declining CT-FFR in both groups. At 1 year, presence of DM was associated with higher rates of major adverse cardiovascular events (hazard ratio, 2.2; 95% CI: 1.2, 4.1; P = .01). However, no between group differences were observed when stratified by stenosis severity (<50% or ≥50%) or CT-FFR positivity.

Conclusion

Both anatomic CCTA findings and CT-FFR demonstrated a more complex pattern of CAD in participants with versus without DM. Rates of treatment reclassification were similar regardless of the presence of DM, and DM was not an adverse prognostic indicator when adjusted for diameter stenosis and CT-FFR.Clinical trial registration no. NCT 02499679Keywords: Fractional Flow Reserve, CT Angiography, Diabetes Mellitus, Coronary Artery Disease Supplemental material is available for this article. See also the commentary by Ghoshhajra in this issue.© RSNA, 2023.

Prognostic Value of Coronary CT Angiography-derived Fractional Flow Reserve on 3-year Outcomes in Patients with Stable Angina

Background The prognostic value of coronary CT angiography (CTA)-derived fractional flow reserve (FFR) beyond 1-year outcomes and in patients with high levels of coronary artery calcium (CAC) is uncertain. Purpose To assess the prognostic value of coronary CTA-derived FFR test results on 3-year clinical outcomes in patients with coronary stenosis and among a subgroup of patients with high levels of CAC. Materials and Methods This study represents a 3-year follow-up of patients with new-onset stable angina pectoris who were consecutively enrolled in the Assessing Diagnostic Value of Noninvasive CT-FFR in Coronary Care, known as ADVANCE (ClinicalTrials.gov: NCT02499679) registry, between December 2015 and October 2017 at three Danish sites. A high CAC was defined as an Agatston score of at least 400. A lesion-specific coronary CTA-derived FFR value of 2 cm with distal-to-stenosis value at or below 0.80 represented an abnormal test result. The primary end point was a composite of all-cause death and nonfatal spontaneous myocardial infarction. Event rates were estimated using the one-sample binomial model, and relative risk was compared between participants stratified by results of coronary CTA-derived FFR. Results This study included 900 participants: 523 participants with normal results (mean age, 64 years ± 9.6 [SD]; 318 male participants) and 377 with abnormal results from coronary CTA-derived FFR (mean age, 65 years ± 9.6; 264 male participants). The primary end point occurred in 11 of 523 (2.1%) and 25 of 377 (6.6%) participants with normal and abnormal coronary CTA-derived FFR results, respectively (relative risk, 3.1; 95% CI: 1.6, 6.3; P < .001). In participants with high CAC, the primary end point occurred in four of 182 (2.2%) and 19 of 212 (9.0%) participants with normal and abnormal coronary CTA-derived FFR results, respectively (relative risk, 4.1; 95% CI: 1.4, 11.8; P = .001). Conclusion In individuals with stable angina, a normal coronary CTA-derived FFR test result identified participants with a low 3-year risk of all-cause death or nonfatal spontaneous myocardial infarction, both in the overall cohort and in participants with high CAC scores. Clinical trial registration no. NCT02499679 Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Sinitsyn in this issue.

Cardiovascular imaging research priorities

OBJECTIVES

Two interlinked surveys were organised by the British Heart Foundation Data Science Centre, which aimed to establish national priorities for cardiovascular imaging research.

METHODS

First a single time point public survey explored their views of cardiovascular imaging research. Subsequently, a three-phase modified Delphi prioritisation exercise was performed by researchers and healthcare professionals. Research questions were submitted by a diverse range of stakeholders to the question 'What are the most important research questions that cardiovascular imaging should be used to address?'. Of these, 100 research questions were prioritised based on their positive impact for patients. The 32 highest rated questions were further prioritised based on three domains: positive impact for patients, potential to reduce inequalities in healthcare and ability to be implemented into UK healthcare practice in a timely manner.

RESULTS

The public survey was completed by 354 individuals, with the highest rated areas relating to improving treatment, quality of life and diagnosis. In the second survey, 506 research questions were submitted by diverse stakeholders. Prioritisation was performed by 90 researchers or healthcare professionals in the first round and 64 in the second round. The highest rated questions were 'How do we ensure patients have equal access to cardiovascular imaging when it is needed?' and 'How can we use cardiovascular imaging to avoid invasive procedures'. There was general agreement between healthcare professionals and researchers regarding priorities for the positive impact for patients and least agreement for their ability to be implemented into UK healthcare practice in a timely manner. There was broad overlap between the prioritised research questions and the results of the public survey.

CONCLUSIONS

We have identified priorities for cardiovascular imaging research, incorporating the views of diverse stakeholders. These priorities will be useful for researchers, funders and other organisations planning future research.

Coronary Volume to Left Ventricular Mass Ratio in Patients With Hypertension

The coronary vascular volume to left ventricular mass (V/M) ratio assessed by coronary computed tomography angiography (CCTA) is a promising new parameter to investigate the relation of coronary vasculature to the myocardium supplied. It is hypothesized that hypertension decreases the ratio between coronary volume and myocardial mass by way of myocardial hypertrophy, which could explain the detected abnormal myocardial perfusion reserve reported in patients with hypertension. Individuals enrolled in the multicenter ADVANCE (Assessing Diagnostic Value of Noninvasive FFRCT in Coronary Care) registry who underwent clinically indicated CCTA for analysis of suspected coronary artery disease with known hypertension status were included in current analysis. The V/M ratio was calculated from CCTA by segmenting the coronary artery luminal volume and left ventricular myocardial mass. In total, 2,378 subjects were included in this study, of whom 1,346 (56%) had hypertension. Left ventricular myocardial mass and coronary volume were higher in subjects with hypertension than normotensive patients (122.7 ± 32.8 g vs 120.0 ± 30.5 g, p = 0.039, and 3,105.0 ± 992.0 mm3 vs 2,965.6 ± 943.7 mm3, p <0.001, respectively). Subsequently, the V/M ratio was higher in patients with hypertension than those without (26.0 ± 7.6 mm3/g vs 25.3 ± 7.3 mm3/g, p = 0.024). After correcting for potential confounding factors, the coronary volume and ventricular mass remained higher in patients with hypertension (least square) mean difference estimate: 196.3 (95% confidence intervals [CI] 119.9 to 272.7) mm3, p <0.001, and 5.60 (95% CI 3.42 to 7.78) g, p <0.001, respectively), but the V/M ratio was not significantly different (least square mean difference estimate: 0.48 (95% CI -0.12 to 1.08) mm3/g, p = 0.116). In conclusion, our findings do not support the hypothesis that the abnormal perfusion reserve would be caused by reduced V/M ratio in patients with hypertension.

The journal of cardiovascular computed tomography: A year in review: 2022

This review aims to summarize key articles published in the Journal of Cardiovascular Computed Tomography (JCCT) in 2022, focusing on those that had the most scientific and educational impact. The JCCT continues to expand; the number of submissions, published manuscripts, cited articles, article downloads, social media presence, and impact factor continues to grow. The articles selected by the Editorial Board of the JCCT in this review highlight the role of cardiovascular computed tomography (CCT) to detect subclinical atherosclerosis, assess the functional relevance of stenoses, and plan invasive coronary and valve procedures. A section is dedicated to CCT in infants and other patients with congenital heart disease, in women, and to the importance of training in CT. In addition, we highlight key consensus documents and guidelines published in JCCT last year. The Journal values the tremendous work by authors, reviewers, and editors to accomplish these contributions.

Prognostic value of FFRCT in patients with stable chest pain – a 3-year follow-up of the ADVANCE-DK registry

Introduction

The short-term safety of using coronary CT angiography (CTA) derived fractional flow reserve (FFRCT) to guide downstream testing after CTA is well documented. Whether the prognostic information provided by FFRCT can be extended to sustained follow-up and to patients with a high degree of coronary artery calcification (CAC) is unknown.

Purpose

To evaluate the association between FFRCT and clinical outcomes in new onset stable symptomatic patients with coronary stenosis up to 3 years after CTA index testing.

Methods

Multicenter 3-year follow-up study of 900 patients from the Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care (ADVANCE) registry at three Danish sites, the “ADVANCE-DK Registry”. All patients had at least one ≥30% coronary stenosis by CTA and underwent subsequent core laboratory FFRCT analysis by HeartFlow. The criterium for an abnormal FFRCT test result was an FFRCT value ≤0.80 (2 cm distal to stenosis). High CAC was defined as a CAC score ≥400. The primary endpoint (PE) was a composite of all-cause death and spontaneous myocardial infarction (MI). The secondary endpoint (SE) was a composite of cardiovascular (CV) death and spontaneous MI. Events were adjudicated by an independent clinical committee.

Results

Patient characteristics are given in Table 1. Coronary stenosis ≥50% was present in 750 (83%) patients. In total 36 patients suffered a PE (all-cause death, n=24; MI, n=12) and 22 an SE (CV death, n=10; MI, n=12). An abnormal vs a normal FFRCT test result was associated with an increased risk of the PE and of the SE both overall and in patients with high CAC; PE (all), 6.6% vs 2.1%, relative risk (RR): 3.1; 95% CI: 1.6–6.3, p&lt;0.001, SE (all), 5.0% vs 0.6%, RR: 8.7; 95% CI: non assessable, p&lt;0.001, PE (high CAC), 9.0% vs 2.2%, RR: 4.1; 85% CI: 1.4–11.8, p=0.001, and SE (high CAC), 6.6% vs 0.5%, RR: 12.0; 95% CI: non assessable, p=0.01, respectively, Figure 1. The observed increased risk in patients with an abnormal vs a normal FFRCT test result persisted after adjustment for degree of stenosis by CCTA (&lt; / ≥50%) and amount of CAC (&lt; / ≥400): PE, adjusted RR: 2.5; 95% CI: 1.2–5.2, p=0.02, and SE, adjusted RR: 8.0; 95% CI: 2.1–30.2, p=0.002.

Conclusion

Patients with stable chest pain, stenosis by CTA and a normal FFRCT test result have a low risk of adverse outcomes during 3 years of follow-up. An abnormal FFRCT identifies patients at increased risk of death or spontaneous MI. These associations are consistent in patients with high levels of CAC.

Funding Acknowledgement

Type of funding sources: None.

FFRCT and recurrent symptoms in patients with stable chest pain

Introduction

The major benefit of coronary revascularization when compared with optimal medical treatment (OMT) in patients with stable chest pain (CP) relates to improvement of symptoms and reduction of reinterventions. Non-invasive methods are warranted to discriminate between patients at low and high risk of recurrent CP for subsequent guidance of antianginal treatment (invasive or OMT).

Purpose

To evaluate the association between coronary CT angiography (CTA) derived fractional flow reserve (FFRCT), recurrent CP and quality of life (QOL) in patients with new onset stable CP and stenosis by CTA.

Methods

Multicenter cohort 3-year follow-up sub-study of 769 patients from the Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care (ADVANCE) registry at three Danish sites, the “ADVANCE-DK Registry”. All patients had at least one ≥30% coronary stenosis by CTA and underwent subsequent core laboratory FFRCT analysis by HeartFlow. An abnormal FFRCT was defined as the lowest in vessel FFRCT value ≤0.80. Patients were classified according to completeness of revascularization by FFRCT: 1) completely revascularized (CR-FFRCT), all coronary arteries with an abnormal FFRCT test result revascularized; 2) incompletely revascularized (IR-FFRCT), ≥1 coronary artery with an abnormal FFRCT test result not revascularized. All patients completed the Seattle Angina Questionnaire (SAQ-7), the EuroQol questionnaire (EQ-5D-5L) and graded (0–100) overall health using the EQ VAS scale at 3-year follow-up. Recurrent CP was defined as CP within the last 4 weeks prior to this follow-up.

Results

Patient characteristics are given in Table 1. At follow-up 23% patients reported recurrent CP. An abnormal vs a normal FFRCT increased the risk of recurrent CP, 27% vs 15%, RR: 1.82; 95% CI: 1.31–2.52, p&lt;0.001. Amongst patients with abnormal FFRCT, revascularization (+/−) was associated to a numerical, but not statistical significantly, reduced risk of recurrent CP, 23% vs 30%, RR: 0.76; 95% CI: 0.56–1.03, p=0.07. IR-FFRCT vs CR-FFRCT had a higher risk for recurrent CP, 31% vs 13%, RR: 2.34; 95% CI: 1.48–3.68, p&lt;0.001, whilst no difference was observed for CR-FFRCT vs normal FFRCT, 13% vs 15%, RR: 0.92; 95% CI: 0.54–1.54, p=0.74. IR-FFRCT vs CR-FFRCT or normal FFRCT, had lower SAQ-7, EQ-5D-5L and EQ-VAS scores, Table 1, all p&lt;0.005. Scores for three selected SAQ-7 domains are shown in Figure 1. Use of antianginal medicine was higher in IR-FFRCT compared to CR-FFRCT and normal FFRCT, mean ± SD: 1.2±0.05 vs 1.0±0.04, p=0.02.

Conclusion

An abnormal FFRCT identifies patients with an increased risk of recurrent CP up to 3 years after index testing. Completeness of revascularization by FFRCT reclassifies patients with abnormal FFRCT into groups with low and high risk for recurrent CP and impaired QOL.

Funding Acknowledgement

Type of funding sources: None.

Completeness of revascularization by FFRCT and prognosis in stable chest pain

Introduction

Major randomized trials of patients with stable chest pain (CP) demonstrated no prognostic benefits of coronary revascularization over optimal medical treatment (OMT). However, in a recent large-scale study, completeness of revascularization was associated with a reduced risk of all-cause death and non-fatal myocardial infarction (MI).

Purpose

To evaluate the association between completeness of revascularization relative to the result of coronary CT angiography (CTA) derived fractional flow reserve (FFRCT) and 3-year prognosis in patients with new onset stable CP and coronary stenosis.

Methods

Multicenter cohort 3-year follow-up sub-study of 900 patients from the Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care (ADVANCE) registry at three Danish sites, the “ADVANCE-DK Registry”. All patients had at least one ≥30% coronary stenosis by CTA and underwent subsequent core laboratory FFRCT analysis by HeartFlow. The FFRCT result was abnormal when ≤0.80 (2 cm distal to stenosis). Patients were classified according to completeness of revascularization by FFRCT: 1) completely revascularized (CR-FFRCT), all coronary arteries with an abnormal FFRCT test result revascularized; 2) incompletely revascularized (IR-FFRCT), ≥1 coronary artery with an abnormal FFRCT test result not revascularized. The primary endpoint (PE) was a composite of all-cause death and spontaneous MI. The secondary endpoint (SE) was a composite of cardiovascular (CV) death and spontaneous MI.

Results

Patient characteristics are given in Table 1. In total 36 (4.0%) patients suffered a PE (all-cause death, n=24; MI, n=12) and 22 (2.4%) an SE (CV death, n=10; MI, n=12). Overall, an abnormal vs a normal FFRCT test result was associated with an increased risk of both the PE, 6.6% vs 2.1%, relative risk (RR): 3.1; 95% CI: 1.6–6.3, p&lt;0.001 and of the SE, 5.0% vs 0.6%, RR: 8.7; 95% CI: non assessable, p&lt;0.001. In patients with abnormal FFRCT, revascularization vs no revascularization did not reduce the risk of the PE or the SE (data not shown). Patients with IR-FFRCT vs CR-FFRCT had a numerical, but not statistical significantly, increased risk of the PE, 8.6% vs 4.2%, RR: 2.14; 95% CI: 0.87–5.26, p=0.10), and an increased risk of the SE, 7.1% vs 2.4%, RR: 3.13; 95% CI: 1.02–9.63, p=0.04, Figure 1. In CR-FFRCT versus normal FFRCT no difference in the risk of the PE or the SE was observed, Figure 1. Univariate sensitivity analyses performed in the IR-FFRCT group did not reveal any differences in the risk of the PE or the SE after adjustment for neither statin therapy at follow-up (−/+), baseline risk variables (&lt; / ≥3), amount of CAC (&lt; / ≥400), degree of stenosis by CTA (&lt; / ≥50%) nor referral to ICA (−/+).

Conclusion

In symptomatic patients with coronary stenosis by CTA, incomplete revascularization determined by FFRCT is associated with an increased risk of adverse cardiovascular outcomes compared to complete revascularization.

Funding Acknowledgement

Type of funding sources: None.

Cardiac computed tomography-derived coronary artery volume to myocardial mass

In the absence of disease impacting the coronary arteries or myocardium, there exists a linear relationship between vessel volume and myocardial mass to ensure balanced distribution of blood supply. This balance may be disturbed in diseases of either the coronary artery tree, the myocardium, or both. However, in contemporary evaluation the coronary artery anatomy and myocardium are assessed separately. Recently the coronary lumen volume to myocardial mass ratio (V/M), measured noninvasively using coronary computed tomography angiography (CTCA), has emerged as an integrated measure of myocardial blood supply and demand in vivo. This has the potential to yield new insights into diseases where this balance is altered, thus impacting clinical diagnoses and management. In this review, we outline the scientific methodology underpinning CTCA-derived measurement of V/M. We describe recent studies describing alterations in V/M across a range of cardiovascular conditions, including coronary artery disease, cardiomyopathies and coronary microvascular dysfunction. Lastly, we highlight areas of unmet research need and future directions, where V/M may further enhance our understanding of the pathophysiology of cardiovascular disease.

Trans-lesional fractional flow reserve gradient as derived from coronary CT improves patient management: ADVANCE registry

BACKGROUND

The role of change in fractional flow reserve derived from CT (FFRCT) across coronary stenoses (ΔFFRCT) in guiding downstream testing in patients with stable coronary artery disease (CAD) is unknown.

OBJECTIVES

To investigate the incremental value of ΔFFRCT in predicting early revascularization and improving efficiency of catheter laboratory utilization.

MATERIALS

Patients with CAD on coronary CT angiography (CCTA) were enrolled in an international multicenter registry. Stenosis severity was assessed as per CAD-Reporting and Data System (CAD-RADS), and lesion-specific FFRCT was measured 2 ​cm distal to stenosis. ΔFFRCT was manually measured as the difference of FFRCT across visible stenosis.

RESULTS

Of 4730 patients (66 ​± ​10 years; 34% female), 42.7% underwent ICA and 24.7% underwent early revascularization. ΔFFRCT remained an independent predictor for early revascularization (odds ratio per 0.05 increase [95% confidence interval], 1.31 [1.26-1.35]; p ​< ​0.001) after adjusting for risk factors, stenosis features, and lesion-specific FFRCT. Among the 3 models (model 1: risk factors ​+ ​stenosis type and location ​+ ​CAD-RADS; model 2: model 1 ​+ ​FFRCT; model 3: model 2 ​+ ​ΔFFRCT), model 3 improved discrimination compared to model 2 (area under the curve, 0.87 [0.86-0.88] vs 0.85 [0.84-0.86]; p ​< ​0.001), with the greatest incremental value for FFRCT 0.71-0.80. ΔFFRCT of 0.13 was the optimal cut-off as determined by the Youden index. In patients with CAD-RADS ≥3 and lesion-specific FFRCT ≤0.8, a diagnostic strategy incorporating ΔFFRCT >0.13, would potentially reduce ICA by 32.2% (1638-1110, p ​< ​0.001) and improve the revascularization to ICA ratio from 65.2% to 73.1%.

CONCLUSIONS

ΔFFRCT improves the discrimination of patients who underwent early revascularization compared to a standard diagnostic strategy of CCTA with FFRCT, particularly for those with FFRCT 0.71-0.80. ΔFFRCT has the potential to aid decision-making for ICA referral and improve efficiency of catheter laboratory utilization.

Prognostic value of coronary computed tomography angiographic derived fractional flow reserve: a systematic review and meta-analysis

Objectives

To obtain more powerful assessment of the prognostic value of fractional flow reserve_CT testing we performed a systematic literature review and collaborative meta-analysis of studies that assessed clinical outcomes of CT-derived calculation of FFR (FFR_CT) (HeartFlow) analysis in patients with stable coronary artery disease (CAD).

Methods

We searched PubMed and Web of Science electronic databases for published studies that evaluated clinical outcomes following fractional flow reserve_CT testing between 1 January 2010 and 31 December 2020. The primary endpoint was defined as ‘all-cause mortality (ACM) or myocardial infarction (MI)’ at 12-month follow-up. Exploratory analyses were performed using major adverse cardiovascular events (MACEs, ACM+MI+unplanned revascularisation), ACM, MI, spontaneous MI or unplanned (>3 months) revascularisation as the endpoint.

Results

Five studies were identified including a total of 5460 patients eligible for meta-analyses. The primary endpoint occurred in 60 (1.1%) patients, 0.6% (13/2126) with FFR_CT>0.80% and 1.4% (47/3334) with FFR_CT ≤0.80 (relative risk (RR) 2.31 (95% CI 1.29 to 4.13), p=0.005). Likewise, MACE, MI, spontaneous MI or unplanned revascularisation occurred more frequently in patients with FFR_CT ≤0.80 versus patients with FFR_CT >0.80. Each 0.10-unit FFR_CT reduction was associated with a greater risk of the primary endpoint (RR 1.67 (95% CI 1.47 to 1.87), p<0.001).

Conclusions

The 12-month outcomes in patients with stable CAD show low rates of events in those with a negative FFR_CT result, and lower risk of an unfavourable outcome in patients with a negative test result compared with patients with a positive test result. Moreover, the FFR_CT numerical value was inversely associated with outcomes.

The clinical utility of FFRCT stratified by age

BACKGROUND

CT coronary angiography (CTA) with Fractional Flow Reserve as determined by CT (FFR_CT) is a safe alternative to invasive coronary angiography. A negative FFR_CT has been shown to have low cardiac event rates compared to those with a positive FFR_CT. However, the clinical utility of FFR_CT according to age is not known.

METHODS

Patients' in the ADVANCE (Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care) registry, were stratified into those ≥65 or <65 years of age. The impact of FFR_CT on clinical decision-making, as assessed by patient age, was determined by evaluating patient management using CTA results alone, followed by site investigators submitting a report on the treatment plan based upon the newly provided FFR_CT data. Outcomes at 1-year post CTA were assessed, including major adverse cardiovascular events (myocardial infarction, all-cause mortality or unplanned hospitalization for ACS leading to revascularisation) and total revascularisation. Positive FFR_CT was deemed to be ​≤ ​0.8.

RESULTS

FFR_CT was calculated in 1849 (40.6%) subjects aged <65 and 2704 (59.4%) ​≥ ​65 years of age. Subjects ≥65 years were more likely to have anatomic obstructive disease on CTA (≥50% stenosis), compared to those aged <65 (69.7% and 73.2% respectively, p ​= ​0.008). There was a similar graded increase in recommended and actual revascularisation with either CABG or PCI, with declining FFR_CT strata for subjects above and below the age of 65. MACE and revascularisation rates were not significantly different for those ​≥ ​or <65, regardless of FFR_CT positivity or stenosis severity <50% or ≥50%. With a negative FFR_CT result, and anatomical stenosis ≥50%, those ​≥ ​and <65 years of age, had similar rates of MACE (0.2% for both, p ​= ​0.1) and revascularisation (8.7% and 10.4% respectively p ​= ​0.4). Logistic regression analysis, with age as a continuous variable, and adjustment for Diamond Forrester Risk, baseline FFR_CT and treatment (CABG, PCI, medical therapy), indicated a statistically significant, but small increase in the odds of a MACE event with increasing age (OR 1.04, 95% CI 1.006-1.08, p ​= ​0.02). Amongst patients with a FFR_CT > 0.80, there was no effect of age on the odds of revascularisation.

CONCLUSION

The findings of this study point to a low risk of MACE events or need for revascularisation in those aged ​≥ ​or <65 with a FFR_CT>0.80, despite the higher incidence of anatomic obstructive CAD in those ≥65 years. The findings show the clinical usefulness and outcomes of FFR_CT are largely constant regardless of age.

Sex Differences in Coronary Computed Tomography Angiography-Derived Fractional Flow Reserve: Lessons From ADVANCE

OBJECTIVES

This study is to determine the management and clinical outcomes of patients investigated with coronary computed tomography angiography (CCTA)-derived fractional flow reserve (FFR_CT) according to sex.

BACKGROUND

Women are underdiagnosed with conventional ischemia testing, have lower rates of obstructive coronary artery disease (CAD) at invasive coronary angiography (ICA), yet higher mortality compared to men. Whether FFR_CT improves sex-based patient management decisions compared to CCTA alone is unknown.

METHODS

Subjects with symptoms and CAD on CCTA were enrolled (2015 to 2017). Demographics, symptom status, CCTA anatomy, coronary volume to myocardial mass ratio (V/M), lowest FFR_CT values, and management plans were captured. Endpoints included reclassification rate between CCTA and FFR_CT management plans, incidence of ICA demonstrating obstructive CAD (≥50% stenosis) and revascularization rates.

RESULTS

A total of 4,737 patients (n = 1,603 females, 33.8%) underwent CCTA and FFR_CT. Women were older (age 68 ± 10 years vs. 65 ± 10 years; p < 0.0001) with more atypical symptoms (41.5% vs. 33.9%; p < 0.0001). Women had less obstructive CAD (65.4% vs. 74.7%; p < 0.0001) at CCTA, higher FFR_CT (0.76 ± 0.10 vs. 0.73 ± 0.10; p < 0.0001), and lower likelihood of positive FFR_CT ≤ 0.80 for the same degree stenosis (p < 0.0001). A positive FFR_CT ≤0.80 resulted in equal referral to ICA (n = 510 [54.5%] vs. n = 1,249 [56.5%]; p = 0.31), but more nonobstructive CAD (n = 208 [32.1%] vs. n = 354 [24.5%]; p = 0.0003) and less revascularization (n = 294 [31.4%] vs. n = 800 [36.2%]; p < 0.0001) in women, unless the FFR_CT was ≤0.75 where revascularization rates were similar (n = 253 [41.9%] vs. n = 715 [46.4%]; p = 0.06). Women have a higher V/M ratio (26.17 ± 7.58 mm³/g vs. 24.76 ± 7.22 mm³/g; p < 0.0001) that is associated with higher FFR_CT independent of degree stenosis (p < 0.001). Predictors of revascularization included stenosis severity, FFR_CT, symptoms, and V/M ratio (p < 0.001) but not female sex (p = 0.284).

CONCLUSIONS

FFR_CT differs between the sexes, as women have a higher FFR_CT for the same degree of stenosis. In FFR_CT-positive CAD, women have less obstructive CAD at ICA and less revascularization, which is associated with higher V/M ratio. The findings suggest that CAD and FFR_CT variations by sex need specific interpretation as these differences may affect therapeutic decision making and clinical outcomes. (Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care [ADVANCE]; NCT02499679).

Effect of Coronary Computed Tomography Angiography-Derived Fractional Flow Reserve on Physicians' Clinical Behavior - Differences Between Sites With and Without Appropriate Use Criteria as Designated by the Japanese Reimbursement System

Background: Coronary computed tomography angiography (CCTA)-derived fractional flow reserve (FFR_CT) is an established tool for identifying lesion-specific ischemia that is now approved for use by the Japanese insurance system. However, current clinical reimbursement is strictly limited to institutions with designated appropriate use criteria (AUC). This study assessed differences in physicians’ behavior (e.g., use and interpretation of FFR_CT, final management) according to Japanese AUC and non-AUC site designation.

Methods and Results: Of 5,083 patients in the ADVANCE Registry, 1,829 from Japan were enrolled in this study. Physicians’ behavior after interrogating CCTA and FFR_CT was analyzed separately according to AUC and non-AUC site designation. Compared with AUC sites, patients referred for FFR_CT from non-AUC sites had a higher rate of negative FFR_CT, less severe anatomic stenosis, and a slightly lower rate of management plan reclassification (51.2% vs. 61.3%), with near-identical utility in both groups. Actual care corresponded equally well to post-FFR_CT plans in both groups. The likelihood of revascularization for positive or negative FFR_CT was similar between the 2 groups. Importantly, AUC and non-AUC sites were equally unlikely to revascularize patients with negative FFR_CT and stenosis >50% or patients with positive FFR_CT and stenosis <50%.

Conclusions: Compared with AUC sites, non-AUC sites had lower disease burden and reclassification of management plans, but nearly identical clinical integration. Actual care corresponded equally well to post-FFR_CT recommendations at both sites.

Temporal changes in FFRCT-Guided Management of Coronary Artery Disease - Lessons from the ADVANCE Registry

BACKGROUND

The ADVANCE registry is a large prospective study of outcomes and resource utilization in patients undergoing coronary computed tomography angiography (CCTA) and CT-based fractional flow reserve (FFR_CT). As experience with new technologies and practices develops over time, we investigated temporal changes in the use of FFR_CT within the ADVANCE registry.

METHODS

5083 patients with coronary artery disease (CAD) on CCTA were prospectively enrolled in the ADVANCE registry and were divided into 3 equally sized cohorts based on the temporal order of enrollment per site. Demographics, CCTA and FFR_CT findings, and clinical outcomes through 1-year follow-up, were recorded and compared between tertiles.

RESULTS

The number of patients with a ≥70% stenosis on CCTA was similar over time (33.6%, 30.9%, and 33.8% for cohort 1-3). The rate of positive FFR_CT ≤0.80 was higher for cohorts 2 (67.3%) and 3 (74.6%) than for cohort 1 (57.1%, p < 0.001). Invasive FFR rates decreased from 25.8% to 22.4% between cohort 1 and 3 (p = 0.023). Moreover, patients with a FFR_CT ≤0.80 were less frequently referred for invasive coronary angiography (ICA) (from 62.9% to 52.9%, p < 0.001), and underwent fewer revascularizations between cohort 1 and 3 (from 41.9% to 32.0%, p < 0.001). The prevalence of major events was low (1.2%) and similar between cohorts.

CONCLUSIONS

Growing experience with FFR_CT improved the likelihood of identifying hemodynamically significant CAD and safely reduced the need for ICA and revascularization in patients with anatomically significant disease even in the instance of an abnormal FFR_CT.

Fractional Flow Reserve Derived from CT: The State of Play in 2020

Fractional flow reserve derived from CT is a rapidly developing technique, with an increasing burden of literature supporting its potential role in the workup of patients suspected of having coronary artery disease.

Coronary CT Angiography-derived Fractional Flow Reserve Testing in Patients with Stable Coronary Artery Disease: Recommendations on Interpretation and Reporting

Noninvasive fractional flow reserve derived from coronary CT angiography (FFRCT) is increasingly used in patients with coronary artery disease as a gatekeeper to the catheterization laboratory. While there is emerging evidence of the clinical benefit of FFRCT in patients with moderate coronary disease as determined with coronary CT angiography, there has been less focus on interpretation, reporting, and integration of FFRCT results into routine clinical practice. Because FFRCT analysis provides a plethora of information regarding pressure and flow across the entire coronary tree, standardized criteria on interpretation and reporting of the FFRCT analysis result are of crucial importance both in context of the clinical adoption and in future research. This report represents expert opinion and recommendation on a standardized FFRCT interpretation and reporting approach. Published under a CC BY 4.0 license.

Real-world clinical utility and impact on clinical decision-making of coronary computed tomography angiography-derived fractional flow reserve: lessons from the ADVANCE Registry

AIMS

Non-invasive assessment of stable chest pain patients is a critical determinant of resource utilization and clinical outcomes. Increasingly coronary computed tomography angiography (CCTA) with selective CCTA-derived fractional flow reserve (FFRCT) is being used. The ADVANCE Registry, is a large prospective examination of using a CCTA and FFRCT diagnostic pathway in real-world settings, with the aim of determining the impact of this pathway on decision-making, downstream invasive coronary angiography (ICA), revascularization, and major adverse cardiovascular events (MACE).

METHODS AND RESULTS

A total of 5083 patients with symptoms concerning for coronary artery disease (CAD) and atherosclerosis on CCTA were enrolled at 38 international sites from 15 July 2015 to 20 October 2017. Demographics, symptom status, CCTA and FFRCT findings, treatment plans, and 90 days outcomes were recorded. The primary endpoint of reclassification between core lab CCTA alone and CCTA plus FFRCT-based management plans occurred in 66.9% [confidence interval (CI): 64.8-67.6] of patients. Non-obstructive coronary disease was significantly lower in ICA patients with FFRCT ≤0.80 (14.4%) compared to patients with FFRCT >0.80 (43.8%, odds ratio 0.19, CI: 0.15-0.25, P < 0.001). In total, 72.3% of subjects undergoing ICA with FFRCT ≤0.80 were revascularized. No death/myocardial infarction (MI) occurred within 90 days in patients with FFRCT >0.80 (n = 1529), whereas 19 (0.6%) MACE [hazard ratio (HR) 19.75, CI: 1.19-326, P = 0.0008] and 14 (0.3%) death/MI (HR 14.68, CI 0.88-246, P = 0.039) occurred in subjects with an FFRCT ≤0.80.

CONCLUSIONS

In a large international multicentre population, FFRCT modified treatment recommendation in two-thirds of subjects as compared to CCTA alone, was associated with less negative ICA, predicted revascularization, and identified subjects at low risk of adverse events through 90 days.

CMR quantitation of change in mitral regurgitation following transcatheter aortic valve replacement (TAVR): impact on left ventricular reverse remodeling and outcome

Current echocardiographic data reporting the impact of concomitant mitral regurgitation (MR) on outcome in patients who undergo transcatheter aortic valve replacement (TAVR) are conflicting. Using cardiovascular magnetic resonance (CMR) imaging, this study aimed to assess the impact of MR severity on cardiac reverse remodeling and patient outcome. 85 patients undergoing TAVR with CMR pre- and 6 m post-TAVR were evaluated. The CMR protocol included cines for left (LV) and right ventricular (RV) volumes, flow assessment, and myocardial scar assessment by late gadolinium enhancement (LGE). Patients were dichotomised according to CMR severity of MR fraction at baseline (‘non-significant’ vs ‘significant’) and followed up for a median duration of 3 years. Forty-two (49%) patients had ‘significant MR’ at baseline; they had similar LV and RV size and function compared to the ‘non-significant MR’ group but had greater LV mass at baseline. In those with significant MR at baseline, 77% (n = 32) had a reduction in MR post-TAVR, moving them into the ‘non-significant’ category at 6-months, with an overall reduction in MR fraction from 34 to 17% (p < 0.001). Improvement in MR was not associated with more favourable cardiac reverse remodeling when compared with the ‘non-improvers’. Significant MR at baseline was not associated with increased mortality at follow-up. Significant MR is common in patients undergoing TAVR and improves in the majority post-procedure. Improvement in MR was not associated with more favourable LV reverse remodeling and baseline MR severity was not associated with mortality.

The impact of trans-catheter aortic valve replacement induced left-bundle branch block on cardiac reverse remodeling

BACKGROUND

Left bundle branch block (LBBB) is common following trans-catheter aortic valve replacement (TAVR) and has been linked to increased mortality, although whether this is related to less favourable cardiac reverse remodeling is unclear. The aim of the study was to investigate the impact of TAVR induced LBBB on cardiac reverse remodeling.

METHODS

48 patients undergoing TAVR for severe aortic stenosis were evaluated. 24 patients with new LBBB (LBBB-T) following TAVR were matched with 24 patients with a narrow post-procedure QRS (nQRS). Patients underwent cardiovascular magnetic resonance (CMR) prior to and 6 m post-TAVR. Measured cardiac reverse remodeling parameters included left ventricular (LV) size, ejection fraction (LVEF) and global longitudinal strain (GLS). Inter- and intra-ventricular dyssynchrony were determined using time to peak radial strain derived from CMR Feature Tracking.

RESULTS

In the LBBB-T group there was an increase in QRS duration from 96 ± 14 to 151 ± 12 ms (P < 0.001) leading to inter- and intra-ventricular dyssynchrony (inter: LBBB-T 130 ± 73 vs nQRS 23 ± 86 ms, p < 0.001; intra: LBBB-T 118 ± 103 vs. nQRS 13 ± 106 ms, p = 0.001). Change in indexed LV end-systolic volume (LVESVi), LVEF and GLS was significantly different between the two groups (LVESVi: nQRS -7.9 ± 14.0 vs. LBBB-T -0.6 ± 10.2 ml/m2, p = 0.02, LVEF: nQRS +4.6 ± 7.8 vs LBBB-T -2.1 ± 6.9%, p = 0.002; GLS: nQRS -2.1 ± 3.6 vs. LBBB-T +0.2 ± 3.2%, p = 0.024). There was a significant correlation between change in QRS and change in LVEF (r = -0.434, p = 0.002) and between change in QRS and change in GLS (r = 0.462, p = 0.001). Post-procedure QRS duration was an independent predictor of change in LVEF and GLS at 6 months.

CONCLUSION

TAVR-induced LBBB is associated with less favourable cardiac reverse remodeling at medium term follow up. In view of this, every effort should be made to prevent TAVR-induced LBBB, especially as TAVR is now being extended to a younger, lower risk population.

Cardiovascular magnetic resonance evaluation of symptomatic severe aortic stenosis: association of circumferential myocardial strain and mortality

BACKGROUND

It is unknown whether circumferential strain is associated with prognosis after treatment of aortic stenosis (AS). We aimed to characterise strain in severe AS, using myocardial tagging cardiovascular magnetic resonance (CMR), prior to and following Transcatheter Aortic Valve Implantation (TAVI) and Surgical Aortic Valve Replacement (SAVR), and determine whether abnormalities in strain were associated with outcome.

METHODS

CMR was performed pre- and 6 m post-intervention in 98 patients (52 TAVI, 46 SAVR; 77 ± 8 years) with severe AS. TAVI patients were older (80.9 ± 6.4 vs. 73.0 ± 7.0 years, p < 0.01) with a higher STS score (2.06 ± 0.6 vs. 6.03 ± 3.4, p < 0.001). Tagged cine images were acquired at the basal, mid and apical LV levels with a complementary spatial modulation of magnetization (CSPAMM) pulse sequence. Circumferential strain, strain rate and rotation were calculated using inTag© software.

RESULTS

No significant change in basal or mid LV circumferential strain, or of diastolic strain rate, was seen following either intervention. However, a significant and comparable decline in LV torsion and twist was observed (SAVR: torsion 14.08 ± 8.40 vs. 7.81 ± 4.51, p < 0.001, twist 16.17 ± 7.01 vs.12.45 ± 4.78, p < 0.01; TAVI: torsion 14.43 ± 4.66 vs. 11.20 ± 4.62, p < 0.001, twist 16.08 ± 5.36 vs. 12.36 ± 5.21, p < 0.001) which likely reflects an improvement towards normal physiology following relief of AS. Over a maximum 6.0y follow up, there were 23 (16%) deaths following valve intervention. On multivariable Cox analysis, baseline mid LV circumferential strain was significantly associated with all-cause mortality (hazard ratio, 1.03; 1.01-1.05; p = 0.009) independent of age, LV ejection fraction and STS mortality risk score. ROC analysis indicated a mid LV circumferential strain > -18.7% was associated with significantly reduced survival.

CONCLUSION

TAVI and SAVR procedures are associated with comparable declines in rotational LV mechanics at 6 m, with largely unchanged strain and strain rates. Pre-operative peak mid LV circumferential strain is associated with post-operative mortality.

Myocardial strain and symptom severity in severe aortic stenosis: insights from cardiovascular magnetic resonance

BACKGROUND

Symptomatic severe aortic stenosis (AS) is a class I indication for replacement in patients when left ventricular ejection fraction (LVEF) is preserved. However, symptom reporting is often equivocal and decision making can be challenging. We aimed to quantify myocardial deformation using cardiovascular magnetic resonance (CMR) in patients classified by symptom severity.

METHODS

Forty-two patients with severe AS referred to heart valve clinic were studied using tagged CMR imaging. All had preserved LVEF. Patients were grouped by symptoms as either "none/mild" (n=21, NYHA class I, II) or "significant" (n=21, NYHA class III, IV, angina, syncope) but were comparable for age (72.8±5.4 vs. 71.0±6.8 years old, P=0.345), surgical risk (EuroSCORE II: 1.90±1.7 vs. 1.31±0.4, P=0.302) and haemodynamics (peak aortic gradient: 55.1±20.8 vs. 50.4±15.6, P=0.450). Thirteen controls matched in age and LVEF were also studied. LV circumferential strain was calculated using inTag^© software and longitudinal strain using feature tracking analysis.

RESULTS

Compared to healthy controls, patients with severe AS had significantly worse longitudinal and circumferential strain, regardless of symptom status. Patients with "significant" symptoms had significantly worse peak longitudinal systolic strain rates (-83.352±24.802%/s vs. -106.301±43.276%/s, P=0.048) than those with "no/mild" symptoms, with comparable peak longitudinal strain (PLS), peak circumferential strain and systolic and diastolic strain rates.

CONCLUSIONS

Patients with severe AS who have no or only mild symptoms exhibit comparable reduction in circumferential and longitudinal fibre function to those with significant symptoms, in whom AVR is clearly indicated. Given these findings of equivalent subclinical dysfunction, reportedly borderline symptoms should be handled cautiously to avoid potentially adverse delays in intervention.

Right ventricular function following surgical aortic valve replacement and transcatheter aortic valve implantation: A cardiovascular MR study

OBJECTIVE

The response of the RV following treatment of aortic stenosis is poorly defined, reflecting the challenge of accurate RV assessment. Cardiovascular magnetic resonance (CMR) is the established reference for imaging of RV volumes, mass and function. We sought to define the impact of transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) upon RV function in patients treated for severe aortic stenosis using CMR.

METHODS

A 1.5T CMR scan was performed preoperatively and 6months postoperatively in 112 (56 TAVI, 56 SAVR; 76±8years) high-risk severe symptomatic aortic stenosis patients across two UK cardiothoracic centres.

RESULTS

TAVI patients were older (80.4±6.7 vs. 72.8±7.2years, p<0.05) with a higher STS score (2.13±0.73 vs. 5.54±3.41%, p<0.001). At 6months, SAVR was associated with a significant increase in RV end systolic volume (33±10 vs. 37±10ml/m², p=0.008), and decrease in RV ejection fraction (58±8 vs. 53±8%, p=0.005) and tricuspid annular plane systolic excursion (22±5 vs. 14±3mm, p<0.001). Only 4 (7%) SAVR patients had new RV late gadolinium hyper-enhancement with no new cases seen in the TAVI patients at 6months. Longer surgical cross-clamp time was the only predictor of increased RV end systolic volume at 6months. Post-TAVI, there was no observed change in RV volumes or function. Over a maximum 6.3year follow-up, 18(32%) of TAVI patients and 1(1.7%) of SAVR patients had died (p=0.001). On multivariable Cox analysis, the RV mass at 6m post-TAVI was independently associated with all-cause mortality (HR 1.359, 95% CI 1.108-1.666, p=0.003).

CONCLUSIONS

SAVR results in a deterioration in RV systolic volumes and function associated with longer cross-clamp times and is not fully explained by suboptimal RV protection during cardiopulmonary bypass. TAVI had no adverse impact upon RV volumes or function.

Assessment of aortic stiffness by cardiovascular magnetic resonance following the treatment of severe aortic stenosis by TAVI and surgical AVR

BACKGROUND

Aortic stiffness is increasingly used as an independent predictor of adverse cardiovascular outcomes. We sought to compare the impact of transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) upon aortic vascular function using cardiovascular magnetic resonance (CMR) measurements of aortic distensibility and pulse wave velocity (PWV).

METHODS AND RESULTS

A 1.5 T CMR scan was performed pre-operatively and at 6 m post-intervention in 72 patients (32 TAVI, 40 SAVR; age 76 ± 8 years) with high-risk symptomatic severe aortic stenosis. Distensibility of the ascending and descending thoracic aorta and aortic pulse wave velocity were determined at both time points. TAVI and SAVR patients were comparable for gender, blood pressure and left ventricular ejection fraction. The TAVI group were older (81 ± 6.3 vs. 72.8 ± 7.0 years, p < 0.05) with a higher EuroSCORE II (5.7 ± 5.6 vs. 1.5 ± 1.0 %, p < 0.05). At 6 m, SAVR was associated with a significant decrease in distensibility of the ascending aorta (1.95 ± 1.15 vs. 1.57 ± 0.68 × 10(-3)mmHg(-1), p = 0.044) and of the descending thoracic aorta (3.05 ± 1.12 vs. 2.66 ± 1.00 × 10(-3)mmHg(-1), p = 0.018), with a significant increase in PWV (6.38 ± 4.47 vs. 11.01 ± 5.75 ms(-1), p = 0.001). Following TAVI, there was no change in distensibility of the ascending aorta (1.96 ± 1.51 vs. 1.72 ± 0.78 × 10(-3)mmHg(-1), p = 0.380), descending thoracic aorta (2.69 ± 1.79 vs. 2.21 ± 0.79 × 10(-3)mmHg(-1), p = 0.181) nor in PWV (8.69 ± 6.76 vs. 10.23 ± 7.88 ms(-1), p = 0.301) at 6 m.

CONCLUSIONS

Treatment of symptomatic severe aortic stenosis by SAVR but not TAVI was associated with an increase in aortic stiffness at 6 months. Future work should focus on the prognostic implication of these findings to determine whether improved patient selection and outcomes can be achieved.

Sex-related differences in left ventricular remodeling in severe aortic stenosis and reverse remodeling after aortic valve replacement: A cardiovascular magnetic resonance study

BACKGROUND

Cardiac adaptation to aortic stenosis (AS) appears to differ according to sex, but reverse remodeling after aortic valve replacement has not been extensively described. The aim of the study was to determine using cardiac magnetic resonance imaging whether any sex-related differences exist in AS in terms of left ventricular (LV) remodeling, myocardial fibrosis, and reverse remodeling after valve replacement.

METHODS

One hundred patients (men, n = 60) with severe AS undergoing either transcatheter or surgical aortic valve replacement underwent cardiac magnetic resonance scans at baseline and 6 months after valve replacement.

RESULTS

Despite similar baseline comorbidity and severity of AS, women had a lower indexed LV mass than did men (65.3 ± 18.4 vs 81.5 ± 21.3 g/m(2), P < .001) and a smaller indexed LV end-diastolic volume (87.3 ± 17.5 vs 101.2 ± 28.6 mL/m(2), P = .002) with a similar LV ejection fraction (58.6% ± 10.2% vs 54.8% ± 12.9%, P = .178). Total myocardial fibrosis mass was similar between sexes (2.3 ± 4.1 vs 1.3 ± 1.1 g, P = .714), albeit with a differing distribution according to sex. After aortic valve replacement, men had more absolute LV mass regression than did women (18.3 ± 10.6 vs 12.7 ± 8.8 g/m(2), P = .007). When expressed as a percentage reduction of baseline indexed LV mass, mass regression was similar between the sexes (men 21.7% ± 10.1% vs women 18.4% ± 11.0%, P = .121). There was no sex-related difference in postprocedural LV ejection fraction or aortic regurgitation. Sex was not found to be a predictor of LV reverse remodeling on multiple regression analysis.

CONCLUSIONS

There are significant differences in the way that male and female hearts adapt to AS. Six months after aortic valve replacement, there are no sex-related differences in reverse remodeling, but superior reverse remodeling in men as a result of their more adverse remodeling profile at baseline.

Consequence of cerebral embolism after transcatheter aortic valve implantation compared with contemporary surgical aortic valve replacement: effect on health-related quality of life

BACKGROUND

Incidence of cerebral microinfarcts is higher after transcatheter aortic valve implantation (TAVI) compared with surgical aortic valve replacement (SAVR). It is unknown whether these lesions persist and what direct impact they have on health-related quality of life. The objective was to identify predictors of cerebral microinfarction and measure their effect on health-related quality of life during 6 months after TAVI when compared with SAVR.

METHODS AND RESULTS

Cerebral MRI was conducted at baseline, post procedure, and 6 months using diffusion-weighted imaging. Health-related quality of life was measured at baseline, 30 days, and 6 months with short form-12 health outcomes and EuroQol 5 dimensions questionnaires. One hundred eleven patients (TAVI, n=71; SAVR, n=40) were studied. The incidence (54 [77%] versus 17 [43%]; P=0.001) and number (3.4±4.9 versus 1.2±1.8; P=0.001) of new microinfarcts were greater after TAVI than after SAVR. The total volume per microinfarct was smaller in TAVI than in SAVR (0.23±0.24 versus 0.76±1.8 mL; P=0.04). The strongest associations for microinfarction were: TAVI (arch atheroma grade: r=0.46; P=0.0001) and SAVR (concomitant coronary artery bypass grafting: r=-0.33; P=0.03). Physical component score in TAVI increased after 30 days (32.1±6.6 versus 38.9±7.0; P<0.0001) and 6 months (40.4±9.3; P<0.0001); the improvement occurred later in SAVR (baseline: 34.9±10.6; 30 days: 35.9±10.2; 6 months: 42.8±11.2; P<0.001). After TAVI, there were no differences in the short form-12 health outcome scores according to the presence or size of new cerebral infarction.

CONCLUSIONS

Cerebral microinfarctions are more common after TAVI compared with SAVR but seem to have no negative effect on early (30 days) or medium term (6 months) health-related quality of life. Aortic atheroma (TAVI) and concomitant coronary artery bypass grafting (SAVR) are independent risk factors for cerebral microinfarction.

Sex Differences in Aortic Stenosis and Outcome Following Surgical and Transcatheter Aortic Valve Replacement

Aortic stenosis is the commonest valve defect in the developed world and is associated with a high mortality once symptomatic. There is a difference in the way that male and female hearts remodel in the face of chronic pressure overload: women develop a concentrically hypertrophied, small cavity left ventricle (LV), whereas men are more prone to the development of eccentric hypertrophy. At a cellular level, there is an increase in collagen and metalloproteinase gene expression in males suggesting a different regulation of extracellular volume composition according to sex. Male hearts with aortic stenosis appear to have more fibrosis than their female comparators. The trigger for this appears to be in part related to estrogen receptor signaling, but other factors such as renin-angiotensin activation, nitric oxide, and circulating noradrenaline levels may also be implicated. Treatment options include surgical valve replacement (SAVR) and more recently transcatheter aortic valve replacement (TAVR). Female sex may be a risk factor for adverse outcome following SAVR and conversely appears to confer a survival advantage when undergoing TAVR. Whether the lower mortality seen following TAVR in women compared with men (despite their increased age and frailty) reflects their longer life expectancy, smaller annular size (and less post-TAVR aortic regurgitation), more favorable LV reverse remodeling, or more likely, a combination of these factors remains to be established.

Quantitative three-dimensional cardiovascular magnetic resonance myocardial perfusion imaging in systole and diastole

BACKGROUND

Two-dimensional (2D) perfusion cardiovascular magnetic resonance (CMR) remains limited by a lack of complete myocardial coverage. Three-dimensional (3D) perfusion CMR addresses this limitation and has recently been shown to be clinically feasible. However, the feasibility and potential clinical utility of quantitative 3D perfusion measurements, as already shown with 2D-perfusion CMR and positron emission tomography, has yet to be evaluated. The influence of systolic or diastolic acquisition on myocardial blood flow (MBF) estimates, diagnostic accuracy and image quality is also unknown for 3D-perfusion CMR. The purpose of this study was to establish the feasibility of quantitative 3D-perfusion CMR for the detection of coronary artery disease (CAD) and to compare systolic and diastolic estimates of MBF.

METHODS

Thirty-five patients underwent 3D-perfusion CMR with data acquired at both end-systole and mid-diastole. MBF and myocardial perfusion reserve (MPR) were estimated on a per patient and per territory basis by Fermi-constrained deconvolution. Significant CAD was defined as stenosis ≥70% on quantitative coronary angiography.

RESULTS

Twenty patients had significant CAD (involving 38 out of 105 territories). Stress MBF and MPR had a high diagnostic accuracy for the detection of CAD in both systole (area under curve [AUC]: 0.95 and 0.92, respectively) and diastole (AUC: 0.95 and 0.94). There were no significant differences in the AUCs between systole and diastole (p values >0.05). At stress, diastolic MBF estimates were significantly greater than systolic estimates (no CAD: 3.21 ± 0.50 vs. 2.75 ± 0.42 ml/g/min, p < 0.0001; CAD: 2.13 ± 0.45 vs. 1.98 ± 0.41 ml/g/min, p < 0.0001); but at rest, there were no significant differences (p values >0.05). Image quality was higher in systole than diastole (median score 3 vs. 2, p = 0.002).

CONCLUSIONS

Quantitative 3D-perfusion CMR is feasible. Estimates of MBF are significantly different for systole and diastole at stress but diagnostic accuracy to detect CAD is high for both cardiac phases. Better image quality suggests that systolic data acquisition may be preferable.

Assessment of ischaemic burden in angiographic three-vessel coronary artery disease with high-resolution myocardial perfusion cardiovascular magnetic resonance imaging

Aims

This study compared the myocardial ischaemic burden (MIB) in patients with angiographic three-vessel coronary artery disease (3VD) using high-resolution and standard-resolution myocardial perfusion cardiovascular magnetic resonance (perfusion CMR) imaging.

Methods and results

One hundred and five patients undergoing coronary angiography had two separate stress/rest perfusion CMR studies, one with standard-resolution (2.5 mm in-plane) and another with high-resolution (1.6 mm in-plane). Quantitative coronary angiography was used to define patients with angiographic 3VD. Perfusion CMR images were anonymized, randomly ordered and visually reported by two observers acting in consensus and blinded to all clinical and angiographic data. Perfusion was graded in each segment on a four-point scale and summed to produce a perfusion score and estimate of MIB for each patient. In patients with angiographic 3VD (n = 35), high-resolution acquisition identified more abnormal segments (7.2 ± 3.8 vs. 5.3 ± 4.0; P = 0.004) and territories (2.4 ± 0.9 vs. 1.6 ± 1.1; P = 0.002) and a higher overall perfusion score (20.1 ± 7.7 vs. 11.9 ± 9.4; P < 0.0001) per patient compared with standard-resolution. The number of segments with subendocardial ischaemia was greater with high-resolution acquisition (195 vs. 101; P < 0.0001). Hypoperfusion in all three territories was identified in 57% of 3VD patients by high-resolution compared with only 29% by standard-resolution (P = 0.04). The area-under-the-curve (AUC) for detecting angiographic 3VD using the estimated MIB was significantly greater with high-resolution than standard-resolution acquisition (AUC = 0.90 vs. 0.69; P < 0.0001).

Conclusion

In patients with angiographic 3VD, the ischaemic burden detected by perfusion CMR is greater with high-resolution acquisition due to better detection of subendocardial ischaemia. High-resolution perfusion CMR may therefore be preferred for risk stratification and management of this high-risk patient group.