CT angiography prior to TAVI procedure using third-generation scanner with wide volume coverage: feasibility, renal safety and diagnostic accuracy for coronary tree

Saudi Heart Association/National Heart Center/Saudi Arabian Cardiac Interventional Society/Saudi Society for Cardiac Surgeons/Saudi Cardiac Imaging Group 2023 TAVI Guidelines

Saudi Arabia has seen a significant improvement in its healthcare system over the past four decades resulting in an increase in life-expectancy. Transcatheter aortic valve implantation (TAVI) has spread widely in Saudi Arabia and has become a routine procedure in many centers. The expanding clinical indications and the availability of the technology have made it possible for many large and intermediate centers all over the country to commence their own TAVI programs. So, the aim of this document is to standardize TAVI practices in different Saudi Arabian centers through reasonable guidelines based on the evaluation and summarization of the best available evidence. The review committee, composed of different experts in several aspects of the management of patient undergoing TAVI, based their recommendations on the reviewed and analyzed evidence and the class and level of recommendations were discussed until a consensus was reached by the panel.

[Local versus locoregional anesthesia in transfemoral TAVI procedures]

INTRODUCTION

Transcatheter aortic valve implantation (TAVI) has become the treatment of choice for the most fragile patients with severe aortic stenosis. The transfemoral route is preferred as the simplest and safest. The aim of our study was to compare the efficacy, tolerance and safety of local vs. locoregional anesthesia in trans-femoral TAVI procedures.

MATERIAL AND METHOD

This was a single-center retrospective study. Patients treated with femoral TAVI between February 25 and November 15, 2022 at the University Hospital of Reims were included, and two groups (local and locoregional anesthesia) were compared.

RESULTS

TAVI success rate (92.9%), death rate (3.0%) and procedure duration (90.5 ± 13.5 minutes) did not differ between groups (p = 0.18, 0.15 and 0.55 respectively). For intra- and post-procedural treatments, the use of sedation, analgesics and benzodiazepines did not differ between groups. The cumulative dose of Remifentanil used per-procedure was lower in the local anesthesia group than in the locoregional anesthesia group (148.6 ± 71.9 mcg vs. 208.9 ± 110.0 mcg; p = 0.025).

CONCLUSIONS

In this non-randomized retrospective study, local and locoregional anesthesia had comparable safety and efficacy in transfemoral TAVI procedures. In a constrained context and with a view to simplification, these results encourage transfemoral TAVIs to be performed under local anaesthesia, and to consider a "PCI-like" approach, without the presence of an anaesthetist, for selected patients without respiratory, musculoskeletal or agitation disorders, or vascular approach difficulties.

Ultra-high-resolution photon-counting detector CT in evaluating coronary stent patency: a comparison to invasive coronary angiography

OBJECTIVES

To determine the diagnostic accuracy of ultra-high-resolution photon-counting detector CT angiography (UHR PCD-CTA) for evaluating coronary stent patency compared to invasive coronary angiography (ICA).

METHODS

Consecutive, clinically referred patients with prior coronary stent implantation were prospectively enrolled between August 2022 and March 2023 and underwent UHR PCD-CTA (collimation, 120 × 0.2 mm). Two radiologists independently analyzed image quality of the in-stent lumen using a 5-point Likert scale, ranging from 1 ("excellent") to 5 ("non-diagnostic"), and assessed all coronary stents for the presence of in-stent stenosis (≥ 50% lumen narrowing). The diagnostic accuracy of UHR PCD-CTA was determined, with ICA serving as the standard of reference.

RESULTS

A total of 44 coronary stents in 18 participants (mean age, 83 years ± 6 [standard deviation]; 12 women) were included in the analysis. In 3/44 stents, both readers described image quality as non-diagnostic, whereas reader 2 noted a fourth stent to have non-diagnostic image quality. In comparison to ICA, UHR PCD-CTA demonstrated a sensitivity, specificity, and accuracy of 100% (95% CI [confidence interval] 47.8, 100), 92.3% (95% CI 79.1, 98.4), and 93.2% (95% CI 81.3, 98.6) for reader 1 and 100% (95% CI 47.8, 100), 87.2% (95% CI 72.6, 95.7), and 88.6% (95% CI 75.4, 96.2) for reader 2, respectively. Both readers observed a 100% negative predictive value (36/36 stents and 34/34 stents). Stent patency inter-reader agreement was 90.1%, corresponding to a substantial Cohen's kappa value of 0.72.

CONCLUSIONS

UHR PCD-CTA enables non-invasive assessment of coronary stent patency with high image quality and diagnostic accuracy.

CLINICAL RELEVANCE STATEMENT

Ultra-high-resolution photon-counting detector CT angiography represents a reliable and non-invasive method for assessing coronary stent patency. Its high negative predictive value makes it a promising alternative over invasive coronary angiography for the rule-out of in-stent stenosis.

KEY POINTS

• CT-based evaluation of coronary stent patency is limited by stent-induced artifacts and spatial resolution. • Ultra-high-resolution photon-counting detector CT accurately evaluates coronary stent patency compared to invasive coronary angiography. • Photon-counting detector CT represents a promising method for the non-invasive rule-out of in-stent stenosis.

CT imaging post-TAVI: Murphy's first law in action-preparing to recognize the unexpected

Transfemoral aortic valve implantation (TAVI) has been long considered the standard of therapy for high-risk patients with severe aortic-stenosis and is now effectively employed in place of surgical aortic valve replacement also in intermediate-risk patients. The potential lasting consequences of minor complications, which might have limited impact on elderly patients, could be more noteworthy in the longer term when occurring in younger individuals. That's why a greater focus on early diagnosis, correct management, and prevention of post-procedural complications is key to achieve satisfactory results. ECG-triggered multidetector computed tomography angiography (CTA) is the mainstay imaging modality for pre-procedural planning of TAVI and is also used for post-interventional early detection of both acute and long-term complications. CTA allows detailed morphological analysis of the valve and its movement throughout the entire cardiac cycle. Moreover, stent position, coronary artery branches, and integrity of the aortic root can be precisely evaluated. Imaging reliability implies the correct technical setting of the computed tomography scan, knowledge of valve type, normal post-interventional findings, and awareness of classic and life-threatening complications after a TAVI procedure. This educational review discusses the main post-procedural complications of TAVI with a specific imaging focus, trying to clearly describe the technical aspects of CTA Imaging in post-TAVI and its clinical applications and challenges, with a final focus on future perspectives and emerging technologies. CRITICAL RELEVANCE STATEMENT: This review undertakes an analysis of the role computed tomography angiography (CTA) plays in the assessment of post-TAVI complications. Highlighting the educational issues related to the topic, empowers radiologists to refine their clinical approach, contributing to enhanced patient care. KEY POINTS: Prompt recognition of TAVI complications, ranging from value issues to death, is crucial. Adherence to recommended scanning protocols, and the optimization of tailored protocols, is essential. CTA is central in the diagnosis of TAVI complications and functions as a gatekeeper to treatment.

CT angiography prior to endovascular procedures: can artificial intelligence improve reporting?

CT angiography prior to endovascular aortic surgery is the standard non-invasive imaging method for evaluation of aortic dimensions and access sites. A detailed report is crucial to a proper planning. We assessed Artificial Intelligence (AI)-algorithm accuracy to measure vessels diameters at CT prior to transcatheter aortic valve implantation (TAVI). CT scans of 50 patients were included. Two Radiologists with experience in vascular imaging together manually assessed diameters at nine landmark positions according to the American Heart Association guidelines: 450 values were obtained. We implemented TOST (Two One-Sided Test) to determine whether the measurements were equivalent to the values obtained from the AI algorithm. When the equivalence bound was a range of ± 2 mm the test showed equivalence for every point; if the range was equal to ± 1 mm the two measurements were not equivalent in 6 points out of 9 (p-value > 0.05), close to the aortic valve. The time for automatic evaluation (average 1 min 47 s) was significantly lower compared with manual measurements (5 min 41 s) (p < 0.01). In conclusion, our results indicate that AI-algorithms can measure aortic diameters at CT prior to endovascular surgery with high accuracy. AI-assisted reporting promises high efficiency, reduced inter-reader variabilities and time saving. In order to perform optimal TAVI procedure planning aortic root analysis could be improved, including annulus dimensions.

Pre-TAVI imaging: an Italian survey by the CT PRotocol optimization (CT-PRO) group

PURPOSE

The purpose of this survey was to evaluate the current state-of-art of pre-TAVI imaging in a large radiological professional community.

METHODS

Between December 2022 and January 2023 all members of the Italian Society of Medical and Interventional Radiology (SIRM) were invited by the CT PRotocol Optimization group (CT-PRO group) to complete an online 24-item questionnaire about pre-TAVI imaging.

RESULTS

557 SIRM members participated in the survey. The greatest part of respondents were consultant radiologists employed in public hospitals and 84% claimed to routinely perform pre-TAVI imaging at their institutions. The most widespread acquisition protocol consisted of an ECG-gated CT angiography (CTA) scan of the aortic root and heart followed by a non-ECG-synchronized CTA of the thorax, abdomen, and pelvis. Contrast agent administration was generally tailored on the patient's body weight with a preference for using high concentration contrast media. The reports were commonly written by radiologists with expertise in cardiovascular imaging, and included all the measurements suggested by current guidelines for adequate pre-procedural planning. About 60% of the subjects affirmed that the Heart Team is present at their institutions, however only 7% of the respondents regularly attended the multidisciplinary meetings.

CONCLUSIONS

This survey defines the current pre-TAVI imaging practice in a large radiological professional community. Interestingly, despite the majority of radiologists follow the current guidelines regarding acquisition and reporting of pre-TAVI imaging studies, there is still a noteworthy absence from multidisciplinary meetings and from the Heart Team.

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.

Transcatheter aortic valve replacement: Past, present, and future

Transcatheter aortic valve replacement (TAVR) has emerged as a ground-breaking, minimally invasive alternative to traditional open-heart surgery, primarily designed for elderly patients initially considered unsuitable for surgical intervention due to severe aortic stenosis. As a result of successful large-scale trials, TAVR is now being routinely applied to a broader spectrum of patients. In deciding between TAVR and surgical aortic valve replacement, clinicians evaluate various factors, including patient suitability and anatomy through preprocedural imaging, which guides prosthetic valve sizing and access site selection. Patient surgical risk is a pivotal consideration, with a multidisciplinary team making the ultimate decision in the patient's best interest. Periprocedural imaging aids real-time visualization but is influenced by anaesthesia choices. A comprehensive postprocedural assessment is critical due to potential TAVR-related complications. Numerous trials have demonstrated that TAVR matches or surpasses surgery for patients with diverse surgical risk profiles, ranging from extreme to low risk. However, long-term follow-up data, particularly in low-risk cases, remains limited, and the applicability of published results to younger patients is uncertain. This review delves into key TAVR studies, pinpointing areas for potential improvement while delving into the future of this innovative procedure. Furthermore, it explores the expanding role of TAVR technology in addressing other heart valve replacement procedures.

Pre-TAVI aortic annulus sizing: comparison between manual and semi-automated new generation software measurements in operators with different experience

OBJECTIVES

Aim of the study is to compare manual and semi-automatic measurements for aortic annulus assessment among different operators.

METHODS

Eighty patients who underwent TAVI were retrospectively enrolled. The measurements manually performed by an experienced reader for aortic annulus (minimum and maximum diameters, perimeter, area), annulus-to-coronary ostia distance and time needed for the whole evaluation, were collected. The same operator (observer 1) and two less experienced readers (observer 2 and 3, with >5 years and 1 year of experience, respectively) assessed the same measurements using a semi-automatic software. Differences between manual and semi-automatic measurements, reading time and suggested valves size derived by CT were compared.

RESULTS

Very good correlations were found between manual and software-aided measurements for aortic annulus area and perimeter in comparison with standard measurements for the three readers (ICC range 0.81-0.98). Good correlations were found for the distance with coronary ostia(0.75-0.79). The same area-derived prosthesis size for manual and semi-automatic measurements was selected in 96% of cases for observer 1; very good correlations were also found for observer 2 and 3 (ICC = 0.89 and 0.88, respectively). Using semi-automatic measurements, the mean time needed for CT images was significantly lower for observers 1 and 2 (1.50 and 1.72versus 3.14 min), respectively.

CONCLUSIONS

Pre-TAVI CT using semi-automatic software allows accurate and reproducible measurements, reducing reconstruction time up to 50% and is reliable even for operators with different experience.

ADVANCES IN KNOWLEDGE

The use of semi-automatic dedicated software for CT in TAVI planning is reliable even for operators without long time experience and allows accurate and reproducible measurements improving pre-TAVI workflow.

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.

Ultra-low radiation dose and contrast volume CT protocol and TAVI-CT score for TAVI planning and outcome

OBJECTIVE

To investigate the feasibility of an ultra-low radiation dose and contrast volume protocol using third-generation dual-source (DS) CT for transcatheter aortic valve implantation (TAVI) planning with coronary artery disease (CAD) assessment, coronary artery calcium score (CACS) and aortic valve calcium score (AVCS) quantification and to evaluate their relationship with TAVI outcome.

METHODS

In this retrospective study were selected 203 patients (131 males, 79.4 ± 5.4 years) underwent to TAVI and at 30- and 90-day follow-up. All patients had performed a third-generation 2 × 192-slices DSCT. The CT protocol included a non-contrast and a contrast high-pitch aortic acquisition for TAVI planning and CAD assessment. Semi-qualitative and quantitative image analysis were performed; the performance in CAD assessment was compared with ICA; the relationship between AVCS and CACS and paravalvular aortic regurgitation (PAR) and major cardiovascular events (MACEs) were evaluated. Mean radiation dose were calculated. Non-parametric tests were used.

RESULTS

Semi-qualitative image analysis was good. Contrast enhancement >500 Hounsfield unit (HU) and contrast-to-noise ratio <20 were obtained in all segments. The diagnostic accuracy in CAD was 89.0%. AVCS was significantly higher in patients with 30-day severe PAR. AVCS and CACS were higher in patients with 90-day MACE complications, respectively, 1904.5 ± 621.3 HU (p < 0.0001) and 769.2 ± 365.5 HU (p < 0.0230). Mean radiation dose was 2.8 ± 0.3 mSv.

CONCLUSION

A TAVI planning ultra-low radiation dose and contrast volume protocol using third-generation DSCT provides highly diagnostic images with CAD assessment, AVCS and CACS quantification and these latter were related with TAVI outcomes.

ADVANCES IN KNOWLEDGE

The proposed protocol using third-generation 2 × 192-slices DSCT allows with an ultra-low radiation dose and contrast volume the TAVI planning and the coronary artery assessment.

Comparison of First-generation and Third-generation Dual-source Computed Tomography for Detecting Coronary Artery Disease in Patients Evaluated for Transcatheter Aortic Valve Replacement

PURPOSE

This study compared image quality and evaluability of coronary artery disease (CAD) in routine preparatory imaging for transcatheter aortic valve replacement using 64-slice (first-generation) to 192-slice (third-generation) dual-source computed tomography(DSCT).

MATERIALS AND METHODS

The CT data sets of 192 patients (122 women, median age 82 y) without severe renal dysfunction or known CAD were analyzed retrospectively. Half were examined using first-generation DSCT (June 2014 to February 2016) and the other half with third-generation DSCT (April 2016 to April 2017). Per protocol, contrast material (110 [110 to 120] vs. 70 [70 to 70] mL, P <0.001) and radiation dose of multiphasic retrospectively gated thoracic CT angiography (dose-length-product, 1001 [707 to 1312] vs. 727 [474 to 1369] mGy×cm, P <0.001) were significantly lower with third-generation DSCT. Significant CAD was defined as CAD-RADS ≥4 by CT. Invasive coronary angiography served as the reference standard (CAD is defined as ≥70% stenosis or fractional flow reserve ≤0.80).

RESULTS

In comparison with first-generation DSCT, third-generation DSCT showed significantly better subjective (3 [interquartile range 2 to 3] vs. 4 [3 to 4.25] on a 5-point scale, P <0.001) and objective image quality (signal-to-noise ratio of left coronary artery 12.8 [9.9 to 16.4] vs. 15.2 [12.4 to 19.0], P <0.001). Accuracy (72.9% vs. 91.7%, P =0.001), specificity (59.7% vs. 88.3%, P <0.001), positive (61.0% vs. 83.3%, P <0.001), and negative predictive value (91.9% vs. 98.2%, P =0.045) for detecting CAD per-patient were significantly better using third-generation DSCT, while sensitivity was similar (92.3% vs. 97.2%, P =0.129).

CONCLUSIONS

Coronary artery evaluation with CT angiography before TAVI is feasible in selected patients. Compared with first-generation DSCT, state-of-the-art third-generation DSCT technology is superior for this purpose, allowing for less contrast medium and radiation dose while providing better image quality and improved diagnostic performance.

Radiation Doses in Cardiovascular Computed Tomography

We discussed the contemporary views on the effects of ionising radiation on living organisms and the process of estimating radiation doses in CT examinations and the definitions of the CTDI, CTDIvol, DLP, SSDE, ED. We reviewed the reports from large analyses on the radiation doses in CT examinations of the coronary arteries prior to TAVI procedures, including the CRESCENT, PROTECTION, German Cardiac CT Registry studies. These studies were carried out over the last 10 years and can help confront the daily practice of performing cardiovascular CT examinations in most centres. The reference dose levels for these examinations were also collected. The methods to optimise the radiation dose included tube voltage reduction, ECG-monitored tube current modulation, iterative and deep learning reconstruction techniques, a reduction in the scan range, prospective study protocols, automatic exposure control, heart rate control, rational use of the calcium score, multi-slices and dual-source and wide-field tomography. We also present the studies that indicated the need to raise the organ conversion factor for cardiovascular studies from the 0.014-0.017 mSv/mGy*cm used for chest studies to date to a value of 0.0264-0.03 mSv/mGy*cm.

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.

Comparison of a High-Pitch Non-ECG-Gated and a Prospective ECG-Gated Protocol for Preprocedural Computed Tomography Imaging Before TAVI/TAVR

PURPOSE

Preprocedural computed tomography (CT) imaging before transcatheter aortic valve implantation/replacement (TAVI/TAVR) requires high diagnostic accuracy without motion artifacts. The aim of this retrospective study is to compare the image quality of a high-pitch non-electrocardiography (ECG)-gated CT protocol used in patients with atrial tachyarrhythmias with a prospectively ECG-gated CT protocol used in patients with sinus rhythm.

MATERIALS AND METHODS

We retrospectively included 108 patients who underwent preprocedural CT imaging before TAVI/TAVR. 52 patients with sinus rhythm were imaged using a prospectively ECG-gated protocol (Group A), and 56 patients with atrial tachyarrhythmias were imaged using the high-pitch non-ECG-gated protocol (Group B). Image quality was rated subjectively by two experienced radiologists and assessed by objective parameters including radiation dose, image noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) at the levels of the aortic root and abdominal aorta.

RESULTS

Subjective image quality was equally good with both CT protocols, and interrater agreement was substantial in both groups but tended to be higher in Group B at the level of the aortic root (Group A: κw = 0.644, Group B: κw = 0.741). With the high-pitch non-ECG-gated CT protocol, image noise was significantly increased (p = 0.001), whereas the SNR, CNR, and radiation dose were significantly decreased (p = 0.002, p = 0.003, and p < 0.001, respectively) at the level of the aortic root compared to the prospectively ECG-gated CT protocol.

CONCLUSION

The high-pitch non-ECG-gated protocol yields images with similar subjective image quality compared with the prospectively ECG-gated CT protocol and allows motion-free assessment of the aortic root for accurate TAVI/TAVR planning. The high-pitch non-ECG-gated protocol may be used as an alternative for preprocedural CT imaging in patients with atrial tachyarrhythmias.

KEY POINTS

· In patients with atrial tachyarrhythmias, a high-pitch non-ECG-gated CT protocol achieves similar subjective image quality compared to a prospective ECG-gated CT protocol.. · At the level of the aortic root, image noise is significantly increased, whereas SNR and CNR are significantly decreased using the high-pitch non-ECG-gated protocol.. · Radiation dose is reduced by 55 % using the high-pitch non-ECG-gated protocol..

CITATION FORMAT

· Shnayien S, Beetz N, Bressem KK et al. Comparison of a High-Pitch Non-ECG-Gated and a Prospective ECG-Gated Protocol for Preprocedural Computed Tomography Imaging Before TAVI/TAVR. Fortschr Röntgenstr 2023; 195: 139 - 147.

Sex-Specific Cell Types and Molecular Pathways Indicate Fibro-Calcific Aortic Valve Stenosis

Background

Aortic stenosis (AS) is the most common valve disorder characterized by fibro-calcific remodeling of leaflets. Recent evidence indicated that there is a sex-related difference in AS development and progression. Fibrotic remodeling is peculiar in women’s aortic valves, while men’s leaflets are more calcified. Our study aimed to assess aortic valve fibrosis (AVF) in a severe AS cohort using non-invasive diagnostic tools and determine whether sex-specific pathological pathways and cell types are associated with severe AS.

Materials and Methods

We have included 28 men and 28 women matched for age with severe AS who underwent echocardiography and cardiac contrast-enhanced computed tomography (CT) before intervention. The calcium and fibrosis volumes were assessed and quantified using the ImageJ thresholding method, indexed calcium and fibrosis volume were calculated by dividing the volume by the aortic annular area. For a deeper understanding of molecular mechanisms characterizing AS disorder, differentially expressed genes and functional inferences between women and men’s aortic valves were carried out on a publicly available microarray-based gene expression dataset (GSE102249). Cell types enrichment analysis in stenotic aortic valve tissues was used to reconstruct the sex-specific cellular composition of stenotic aortic valves.

Results

In agreement with the literature, our CT quantifications showed that women had significantly lower aortic valve calcium content compared to men, while fibrotic tissue composition was significantly higher in women than men. The expression profiles of human stenotic aortic valves confirm sex-dependent processes. Pro-fibrotic processes were prevalent in women, while pro-inflammatory ones, linked to the immune response system, were enhanced in men. Cell-type enrichment analysis showed that mesenchymal cells were over-represented in AS valves of women, whereas signatures for monocytes, macrophages, T and B cells were enriched men ones.

Conclusions

Our data provide the basis that the fibro-calcific process of the aortic valve is sex-specific, both at gene expression and cell type level. The quantification of aortic valve fibrosis by CT could make it possible to perform population-based studies and non-invasive assessment of novel therapies to reduce or halt sex-related calcific aortic valve stenosis (CAVS) progression, acting in an optimal window of opportunity early in the course of the disease.

Computed tomography predictors of structural valve degeneration in patients undergoing transcatheter aortic valve implantation with balloon-expandable prostheses

OBJECTIVES

Computed tomography (CT) provides excellent anatomy assessment of the aortic annulus (AoA) and is utilized for pre-procedural planning of transcatheter aortic valve implantation (TAVI). We sought to investigate if geometrical characteristics of the AoA determined by CT may represent predictors of structural valve degeneration (SVD) in patients undergoing TAVI with balloon-expandable valves.

METHODS

This is a retrospective study on 124 consecutive patients (mean age: 79 ± 7 years; female: 61%) undergoing balloon-expandable TAVI prospectively enrolled in a registry. AoA maximum diameter (D_max), minimum diameter (D_min), and area were assessed using pre-procedural CT. SVD was identified during follow-up with transthoracic echocardiography documenting structural prosthetic valve abnormalities with or without hemodynamic changes.

RESULTS

The mean follow-up was 5.9 ± 1.7 years. SVD was found in 48 out of 124 patients (38%). AoA D_max, D_min, and area were significantly smaller in patients with SVD compared to patients without SVD (25.6 ± 2.2 mm vs. 27.1 ± 2.8 mm, p = 0.012; 20.5 ± 2.1 mm vs. 21.8 ± 2.1 mm, p = 0.001 and 419 ± 77 mm² vs. 467 ± 88 mm², p = 0.002, respectively). At univariable analysis, female sex, BSA, 23-mm prosthetic valve size, D_max < 27.1 mm, and a D_min < 19.9 mm were associated with SVD, whereas at multivariable analysis, only D_min < 19.9 mm (OR = 2.873, 95% CI: 1.191-6.929, p = 0.019) and female sex (OR = 2.659, 95% CI: 1.095-6.458, p = 0.031) were independent predictors of SVD.

CONCLUSIONS

Female sex and AoA D_min < 19.9 mm are associated with SVD in patients undergoing TAVI with balloon-expandable valves. When implanting large prostheses in order to avoid paraprosthetic regurgitation, caution should be observed due to the risk of excessive stretching of the AoA D_min, which may play a role in SVD.

KEY POINTS

• Long-term durability is a concern for transcatheter aortic valve bioprosthesis. • CT provides an excellent assessment of the aortic annulus's geometrical characteristics for prosthesis sizing before transcatheter aortic valve implantation (TAVI). • Female sex and a small minimum aortic annulus diameter measured with CT are independent predictors of structural valve degeneration in patients undergoing TAVI with balloon-expandable valves.

Subclinical leaflet thrombosis after transcatheter aortic valve implantation: no association with left ventricular reverse remodeling at 1-year follow-up

Hypo-attenuated leaflet thickening (HALT) of transcatheter aortic valves is detected on multidetector computed tomography (MDCT) and reflects leaflet thrombosis. Whether HALT affects left ventricular (LV) reverse remodeling, a favorable effect of LV afterload reduction after transcatheter aortic valve implantation (TAVI) is unknown. The aim of this study was to examine the association of HALT after TAVI with LV reverse remodeling. In this multicenter case-control study, patients with HALT on MDCT were identified, and patients without HALT were propensity matched for valve type and size, LV ejection fraction (LVEF), sex, age and time of scan. LV dimensions and function were assessed by transthoracic echocardiography before and 12 months after TAVI. Clinical outcomes (stroke or transient ischemic attack, heart failure hospitalization, new-onset atrial fibrillation, all-cause mortality) were recorded. 106 patients (age 81 ± 7 years, 55% male) with MDCT performed 37 days [IQR 32-52] after TAVI were analyzed (53 patients with HALT and 53 matched controls). Before TAVI, all echocardiographic parameters were similar between the groups. At 12 months follow-up, patients with and without HALT showed a significant reduction in LV end-diastolic volume, LV end-systolic volume and LV mass index (from 125 ± 37 to 105 ± 46 g/m2, p = 0.001 and from 127 ± 35 to 101 ± 27 g/m2, p < 0.001, respectively, p for interaction = 0.48). Moreover, LVEF improved significantly in both groups. In addition, clinical outcomes were not statistically different. Improvement in LVEF and LV reverse remodeling at 12 months after TAVI were not limited by HALT.

Combined Coronary CT-Angiography and TAVI Planning: Utility of CT-FFR in Patients with Morphologically Ruled-Out Obstructive Coronary Artery Disease

Background: Coronary artery disease (CAD) is a frequent comorbidity in patients undergoing transcatheter aortic valve implantation (TAVI). If significant CAD can be excluded on coronary CT-angiography (cCTA), invasive coronary angiography (ICA) may be avoided. However, a high plaque burden may make the exclusion of CAD challenging, particularly for less experienced readers. The objective was to analyze the ability of machine learning (ML)-based CT-derived fractional flow reserve (CT-FFR) to correctly categorize cCTA studies without obstructive CAD acquired during pre-TAVI evaluation and to correlate recategorization to image quality and coronary artery calcium score (CAC). Methods: In total, 116 patients without significant stenosis (≥50% diameter) on cCTA as part of pre-TAVI CT were included. Patients were examined with an electrocardiogram-gated CT scan of the heart and high-pitch scan of the torso. Patients were re-evaluated with ML-based CT-FFR (threshold = 0.80). The standard of reference was ICA. Image quality was assessed quantitatively and qualitatively. Results: ML-based CT-FFR was successfully performed in 94.0% (109/116) of patients, including 436 vessels. With CT-FFR, 76/109 patients and 126/436 vessels were falsely categorized as having significant CAD. With CT-FFR 2/2 patients but no vessels initially falsely classified by cCTA were correctly recategorized as having significant CAD. Reclassification occurred predominantly in distal segments. Virtually no correlation was found between image quality or CAC. Conclusions: Unselectively applied, CT-FFR may vastly increase the number of false positive ratings of CAD compared to morphological scoring. Recategorization was virtually independently from image quality or CAC and occurred predominantly in distal segments. It is unclear whether or not the reduced CT-FFR represent true pressure ratios and potentially signifies pathophysiology in patients with severe aortic stenosis.

Diagnostic accuracy of coronary computed tomography angiography for the evaluation of obstructive coronary artery disease in patients referred for transcatheter aortic valve implantation: a systematic review and meta-analysis

OBJECTIVE

To evaluate the diagnostic accuracy of coronary computed tomography angiography (CCTA) for the evaluation of obstructive coronary artery disease (CAD) in patients referred for transcatheter aortic valve implantation (TAVI).

METHODS

EMBASE, PubMed/MEDLINE, and CENTRAL were searched for studies reporting accuracy of CCTA for the evaluation of obstructive CAD compared with invasive coronary angiography (ICA) as the reference standard. QUADAS-2 tool was used to assess the risk of bias. A bivariate random effects model was used to analyze, pool, and plot the diagnostic performance measurements across studies. Pooled sensitivity, specificity, positive ( + LR) and negative (-LR) likelihood ratio, diagnostic odds ratio (DOR), and hierarchical summary ROC curve (HSROC) were evaluated. Prospero registration number: CRD42021252527.

RESULTS

Fourteen studies (2533 patients) were included. In the intention-to-diagnose patient-level analysis, sensitivity and specificity for CCTA were 97% (95% CI: 94-98%) and 68% (95% CI: 56-68%), respectively, and + LR and -LR were 3.0 (95% CI: 2.1-4.3) and 0.05 (95% CI: 0.03 - 0.09), with DOR equal to 60 (95% CI: 30-121). The area under the HSROC curve was 0.96 (95% CI: 0.94-0.98). No significant difference in sensitivity was found between single-heartbeat and other CT scanners (96% (95% CI: 90 - 99%) vs. 97% (95% CI: 94-98%) respectively; p = 0.37), whereas the specificity of single-heartbeat scanners was higher (82% (95% CI: 66-92%) vs. 60% (95% CI: 46 - 72%) respectively; p < 0.0001). Routine CCTA in the pre-TAVI workup could save 41% (95% CI: 34 - 47%) of ICAs if a disease prevalence of 40% is assumed.

CONCLUSIONS

CCTA proved an excellent diagnostic accuracy for assessing obstructive CAD in patients referred for TAVI; the use of single-heartbeat CT scanners can further improve these findings.

KEY POINTS

• CCTA proved to have an excellent diagnostic accuracy for assessing obstructive CAD in patients referred for TAVI. • Routine CCTA in the pre-TAVI workup could save more than 40% of ICAs. • Single-heartbeat CT scanners had higher specificity than others in the assessment of obstructive CAD in patients referred for TAVI.

Recommendations in pre-procedural imaging assessment for TAVI intervention: SIC-SIRM position paper part 2 (CT and MR angiography, standard medical reporting, future perspectives)

Non-invasive cardiovascular imaging owns a pivotal role in the preoperative assessment of patient candidates for transcatheter aortic valve implantation (TAVI), providing a wide range of crucial information to select the patients who will benefit the most and have the procedure done safely. This document has been developed by a joined group of experts of the Italian Society of Cardiology and the Italian Society of Medical and Interventional Radiology and aims to produce an updated consensus statement about the pre-procedural imaging assessment in candidate patients for TAVI intervention. The writing committee consisted of members and experts of both societies who worked jointly to develop a more integrated approach in the field of cardiac and vascular radiology. Part 2 of the document will cover CT and MR angiography, standard medical reporting, and future perspectives.

CT Image Feature Diagnosis on the Basis of Deep Learning Algorithm for Preoperative Patients and Complications of Transcatheter Aortic Valve Implantation

This work was aimed to explore the role of CT angiography information provided by deep learning algorithm in the diagnosis and complications of the disease focusing on congenital aortic valve disease and severe aortic valve stenosis. 120 patients who underwent ultrasound cardiography for aortic stenosis and underwent transcatheter aortic valve implantation (TAVI) in hospital were selected as the research objects. Patients received CT examination of deep learning algorithm within one week. The measurement methods were long and short diameter method, area method, and perimeter method. The deep learning algorithm was used to measure the long and short diameter, area, and perimeter of the target area before CT image processing. The results showed that the average diameter of long and short diameter measurement was 95% CI (0.84, 0.92), the average diameter of perimeter measurement was 95% CI (0.68, 0.87), and the average diameter of area measurement was 95% CI (0.72, 0.91). Among the 52 patients, 35 cases were hypertension (67%), 13 cases were diabetes (25%), 6 cases were chronic renal insufficiency (Cr > 2 mg/dL) (11%) (2 cases were treated with hemodialysis, 3.8%), 11 patients had chronic pulmonary disease (21%), 9 patients had cerebrovascular disease (17.3%) and atrial flutter and atrial fibrillation. Deep learning can achieve excellent results in CT image processing, and it was of great significance for the diagnosis of TAVI patients, improving the success rate of treatment and the prognosis of patients.

Combined Coronary CT Angiography and Evaluation of Access Vessels for TAVR Patients in Free-Breathing with Single Contrast Medium Injection Using a 16-cm-Wide Detector CT

RATIONALE AND OBJECTIVES

To investigate the feasibility of combining coronary computed tomography (CT) angiography (CCTA) and CTA to evaluate access vessels for transcatheter aortic valve replacement (TAVR) patients in free-breathing and with single contrast medium injection using a 16-cm-wide detector CT.

MATERIALS AND METHODS

One hundred and twenty-one consecutive patients (73.33 ± 6.43 years) referred for TAVR underwent a serious CT scans in free-breathing after one contrast injection: ECG-triggered one-heartbeat axial CCTA, followed by non-ECG-gated neck, thoracic, and abdominal CTA. Patient weight-dependent contrast dose volume at 1.0 mL/kg was used. CT attenuation values of the coronary, neck, aortic, iliac, and femoral arteries were measured and their image quality was evaluated with a 4-point score method. Stenosis (≥50%) in CCTA was evaluated using invasive coronary angiography result as a reference standard. Radiation and contrast doses were assessed.

RESULTS

The total dose-length-product for the entire examination was 411.4 ± 91.2 mGy.cm, and the total contrast dose was 57.3 ± 9.9 mL. There were adequate attenuations (>400 HU) in all arteries, and the peripheral access vessels and aortic annulus were evaluable in all patients. In neck CTA, 5 patients had vascular tortuosity, 6 patients had aberrant arteries and there were 212 plaques and 13 severe stenoses among the patients. In CCTA, on the per-segment, per-vessel, and per-patient analysis, CCTA showed a sensitivity and negative predictive value of (95% and 99%), (95% and 99%), and (96% and 98%), respectively, for the entire patient cohort, and (92% and 98%), (92% and 98%), and (88% and 93%), respectively, for patients with atrial fibrillation or heart rate higher than 75 beats.

CONCLUSION

It is feasible to perform a combined CCTA and CTA for evaluating access vessels for TAVR patients in free-breathing with single contrast injection. This approach generates acceptable image quality for all vessels and a high negative predictive value in excluding coronary artery disease with relatively low radiation and contrast doses.

Transcatheter Aortic Valve Implantation: The Evolving Role of the Radiologist in 2021

BACKGROUND

 Transcatheter aortic valve implantation (TAVI) has gained worldwide acceptance and implementation as an alternative therapeutic option in patients with severe aortic valve stenosis unable to safely undergo surgical aortic valve replacement. This transformative technique places the radiologist in a key position in the pre-procedural assessment of potential candidates for this technique, delivering key anatomical information necessary for patient eligibility and procedural safety. Recent trials also provide encouraging results to potentially extend the indication to patients with safer risk profiles.

METHOD

 The review is based on a PubMed literature search using the search terms "transcatheter heart valve", "TAVI", "TAVR", "CT", "imaging", "MR" over a period from 2010-2020, combined with personal comments based on the author's experience.

RESULTS AND CONCLUSION

 CT plays a prominent role in the pre-procedural workup, delivering as a true 3D imaging modality optimal visualization of the complex anatomy of the aortic root with simultaneous evaluation of the patency of the different access routes. As such, the contribution of CT is key for the determination of patient eligibility and procedural safety. This input is supplementary to the contributions of other imaging modalities and forms an important element in the discussions of the Heart Valve Team. Knowledge of the procedure and its characteristics is necessary in order to provide a comprehensive and complete report. While the role of CT in the pre-procedural evaluation is well established, the contribution of CT and MR and the clinical significance of their findings in the routine follow-up after the intervention are less clear and currently the subject of intense investigation. Important issues remain, including the occurrence and significance of subclinical leaflet thrombosis, prosthetic heart valve endocarditis, and long-term structural valve degeneration.

KEY POINTS

  · CT plays a crucial role in evaluating transcatheter heart valve candidates. · Evaluation must include the dimensions of the aortic root and access paths. · The exact post-procedural role of CT and MRI has not yet been determined..

CITATION FORMAT

· Salgado R, El Addouli H, Budde RP. Transcatheter Aortic Valve Implantation: The Evolving Role of the Radiologist in 2021. Fortschr Röntgenstr 2021; 193: 1411 - 1425.

Combined Coronary CT-Angiography and TAVR Planning for Ruling Out Significant Coronary Artery Disease: Added Value of Machine-Learning-Based CT-FFR

OBJECTIVES

To analyze the ability of machine-learning (ML)-based computed tomography (CT)-derived fractional flow reserve (CT-FFR) to further improve the diagnostic performance of coronary CT angiography (cCTA) for ruling out significant coronary artery disease (CAD) during pre-transcatheter aortic valve replacement (TAVR) evaluation in patients with a high pre-test probability for CAD.

BACKGROUND

CAD is a frequent comorbidity in patients undergoing TAVR. Current guidelines recommend its assessment before TAVR. If significant CAD can be excluded on cCTA, invasive coronary angiography (ICA) may be avoided. Although cCTA is a very sensitive test, it is limited by relatively low specificity and positive predictive value, particularly in high-risk patients.

METHODS

Overall, 460 patients (79.6 ± 7.4 years) undergoing pre-TAVR CT were included and examined with an electrocardiogram-gated CT scan of the heart and high-pitch scan of the vascular access route. Images were evaluated for significant CAD. Patients routinely underwent ICA (388/460), which was omitted at the discretion of the local Heart Team if CAD could be effectively ruled out on cCTA (72/460). CT examinations in which CAD could not be ruled out (CAD⁺) (n = 272) underwent additional ML-based CT-FFR.

RESULTS

ML-based CT-FFR was successfully performed in 79.4% (216/272) of all CAD⁺ patients and correctly reclassified 17 patients as CAD negative. CT-FFR was not feasible in 20.6% because of reduced image quality (37/56) or anatomic variants (19/56). Sensitivity, specificity, positive predictive value, and negative predictive value were 94.9%, 52.0%, 52.2%, and 94.9%, respectively. The additional evaluation with ML-based CT-FFR increased accuracy by Δ+3.4% (CAD⁺: Δ+6.0%) and raised the total number of examinations negative for CAD to 43.9% (202/460).

CONCLUSIONS

ML-based CT-FFR may further improve the diagnostic performance of cCTA by correctly reclassifying a considerable proportion of patients with morphological signs of obstructive CAD on cCTA during pre-TAVR evaluation. Thereby, CT-FFR has the potential to further reduce the need for ICA in this challenging elderly group of patients before TAVR.

Quantifying image quality in chest computed tomography angiography: Evaluation of different contrast-to-noise ratio measurement methods

BACKGROUND

Contrast-to-noise ratio is used to objectively evaluate image quality in chest computed tomography angiography (CTA). Different authors define and measure contrast-to-noise ratio using different methods.

PURPOSE

To summarize and evaluate the different contrast-to-noise ratio calculation formulas in the current literature.

MATERIAL AND METHODS

A systematic review of the recent literature for studies using contrast-to-noise ratio was performed. Contrast-to-noise ratio measurement methods reported by the different authors were recorded and reproduced in three patients who underwent chest CTA in our department for exploring variations among the different measurement methods.

RESULTS

The search resulted in 109 articles, of which 26 were included. The studies involved 69 different measurements and overall, three different formula patterns. In all three, aorta and pulmonary arteries comprised the objects of interest in the numerator. In the denominator, standard deviation of the attenuation of the object of interest itself or of another background were used to reflect image noise. Some authors averaged the ratio values at different levels to obtain global ratio values. Using the object of interest itself for image noise calculation in the denominator compared to the usage of another background caused the most prominent variances of contrast-to-noise ratio between the two different protocols used for the reproduction of the measurements.

CONCLUSION

We recommend using the standard deviation of the attenuation of a background indicator as image noise rather than the object of interest itself for more reliable and comparative values. Global contrast-to-noise ratios based on averaging the values of different measurement levels should be avoided.

Image quality and diagnostic performance evaluation in transcatheter aortic valve implantation candidates with atrial fibrillation using a whole-heart coverage CT scanner

OBJECTIVE

To evaluate the image quality and diagnostic performance for obstructive coronary artery disease of transcatheter aortic valve implantation (TAVI) patients with atrial fibrillation (AF) during TAVI planning CT using a whole-heart coverage CT scanner.

METHODS

Eighty-eight consecutive TAVI candidates with AF (50 men, 74 ± 6 years) who underwent both TAVI planning CT and invasive coronary catheter angiography (ICA) were retrospectively analyzed. With ICA results as the reference standard, the accuracy of TAVI planning CT for lesion detection on a per-vessel and per-patient level was calculated. Meanwhile, image quality, contrast volume, and effective dose (ED) were evaluated. A 5-point visual scale (1-5) was used to assess the subjective image quality. The CT value and signal-to-noise ratio were measured for the left main coronary artery (LM), left anterior descending (LAD), left circumflex (LCX), and right coronary arteries (RCA).

RESULTS

The ED for CCTA was 3.25 ± 1.39 mSv and contrast volume was 58.14 ± 12.34 mL. A total of 1371 (1371/1408 = 97.4%) segments with diameter > 1.5 mm were analyzed. For the subjective evaluation, the mean score was 3.99 ± 0.96 for overall image quality. The mean CT values in LM, RCA, LCX, and LAD were all above 400 HU. For the detection of > 50% stenosis, TAVI planning CT provided on the per-vessel and per-patient basis 97.06% and 100% in sensitivity, 96.23% and 89.06% in specificity, 99.7% and 100% in negative predictive value, and 73.3% and 77.4% in positive predictive value, respectively.

CONCLUSION

TAVI planning CT with whole-heart coverage demonstrates good CCTA image quality and a high sensitivity and NPV in excluding obstructive CAD in TAVI candidates with AF.

KEY POINTS

• Transcatheter aortic valve implantation planning (TAVI) CT with whole-heart coverage enables good image quality of CCTA in TAVI candidates with atrial fibrillation. • Obstructive coronary artery disease may be excluded with high accuracy in transcatheter aortic valve implantation (TAVI) candidates with atrial fibrillation with the usage of whole-heart coverage TAVI planning CT.

Pre-procedural high-pitch coronary CT angiography assessment of patients undergoing transcatheter aortic valve implantation (TAVI) without patient-specific adjustment: analysis of diagnostic performance

AIM

To evaluate the ability to assess the coronary arteries using pre-procedural computed tomography (CT; high-pitch mode) in patients referred for transcatheter aortic valve implantation (TAVI).

METHODS AND MATERIALS

CT and invasive coronary angiography (ICA) were performed pre-TAVI in 100 patients (46 women; 79 ± 5.9 years). CT was performed in prospectively ECG-triggered high-pitch mode after intravenous administration of 70 ml iodinated contrast medium. Image quality was assessed using a four-point scale (graded 0-3). Significant coronary artery stenosis (≥50% diameter) was graded as either present or absent by one observer and in one-third of patients by two observers independently. ICA was the standard of reference. Results were reported per segment and per patient.

RESULTS

Twenty-two percent of patients had known coronary artery disease (CAD). In two cases, a coronary anomaly was detected. Diagnostic image quality (grade 1-3) was achieved in 30.3% of segments. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 75%, 80.5%, 16%, and 98.5%, respectively. Significant coronary stenosis could be ruled out completely in all segments in three patients. The interrater agreement per patient was excellent (kappa = 1).

CONCLUSION

Relevant coronary findings can frequently be observed in high-pitch TAVI-planning CT. Despite the limitations of the technique and in patients referred to pre-TAVI evaluation (rapid heart rate, coronary calcifications, etc.), a valid evaluation of coronary arteries is possible in a considerable proportion of segments with a high NPV; however, few studies were completely free of motion artefacts to dependably exclude CAD using this technique in this challenging group of patients.

DEtection of ProxImal Coronary stenosis in the work-up for Transcatheter aortic valve implantation using CTA (from the DEPICT CTA collaboration)

Objectives

Computed tomography angiography (CTA) is performed routinely in the work-up for transcatheter aortic valve implantation (TAVI), and could potentially replace invasive coronary angiography (ICA) to rule out left main (LM) and proximal coronary stenosis. The objectives were to assess the diagnostic yield and accuracy of pre-TAVI CTA to detect LM and proximal coronary stenosis of ≥ 50% and ≥ 70% diameter stenosis (DS).

Methods

The DEPICT CTA database consists of individual patient data from four studies with a retrospective design that analyzed the diagnostic accuracy of pre-TAVI CTA to detect coronary stenosis, as compared with ICA. Pooled data were used to assess diagnostic accuracy to detect coronary stenosis in the left main and the three proximal coronary segments on a per-patient and a per-segment level. We included 1060 patients (mean age: 81.5 years, 42.7% male).

Results

On ICA, the prevalence of proximal stenosis was 29.0% (≥ 50% DS) and 15.7% (≥ 70% DS). Pre-TAVI CTA ruled out ≥ 50% DS in 51.6% of patients with a sensitivity of 96.4%, specificity of 71.2%, PPV of 57.7%, and NPV of 98.0%. For ≥ 70% DS, pre-TAVI CTA ruled out stenosis in 70.0% of patients with a sensitivity of 96.7%, specificity of 87.5%, PPV of 66.9%, and NPV of 99.0%.

Conclusion

CTA provides high diagnostic accuracy to rule out LM and proximal coronary stenosis in patients undergoing work-up for TAVI. Clinical application of CTA as a gatekeeper for ICA would reduce the need for ICA in 52% or 70% of patients, using a threshold of ≥ 50% or ≥ 70% DS, respectively.

Key Points

• Clinical application of CTA as a gatekeeper for ICA would reduce the need for ICA in 52% or 70% of TAVI patients, using a threshold of ≥ 50% or ≥ 70% diameter stenosis.

• The diagnostic accuracy of CTA to exclude proximal coronary stenosis in these patients is high, with a sensitivity of 96.4% and NPV of 98.0% for a threshold of ≥ 50%, and a sensitivity of 96.7% and NPV of 99.0% for a threshold of ≥ 70% diameter stenosis.

• Atrial fibrillation and heart rate did not significantly affect sensitivity and NPV. However, a heart rate of < 70 b/min during CTA was associated with a significantly improved specificity and PPV.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-08095-2.

Aortic Valve Disease and Associated Complex CAD: The Interventional Approach

Coronary artery disease (CAD) is highly prevalent in patients with severe aortic stenosis (AS). The management of CAD is a central aspect of the work-up of patients undergoing transcatheter aortic valve implantation (TAVI), but few data are available on this field and the best percutaneous coronary intervention (PCI) practice is yet to be determined. A major challenge is the ability to elucidate the severity of bystander coronary stenosis independently of the severity of aortic valve stenosis and subsequent impact on blood flow. The prognostic role of CAD in patients undergoing TAVI is being still debated and the benefits and the best timing of PCI in this context are currently under evaluation. Additionally, PCI in the setting of advanced AS poses some technical challenges, due to the complex anatomy, risk of hemodynamic instability, and the increased risk of bleeding complications. This review aims to provide a comprehensive synthesis of the available literature on myocardial revascularization in patients with severe AS undergoing TAVI. This work can assist the Heart Team in individualizing decisions about myocardial revascularization, taking into account available diagnostic tools as well as the risks and benefits.

Multidetector computed tomography in transcatheter aortic valve replacement: an update on technological developments and clinical applications

INTRODUCTION

Transcatheter aortic valve replacement (TAVR) has revolutionized the treatment of patients with underlying sever aortic valve stenosis across all spectrum of the disease. CT imaging is so crucial to the pre procedural planning, to incorporate the information from the CT imaging in the decision making intraprocedurally and to predict and identity the post procedural complications.Areas covered: In this article, we review available studies on CT role in TAVR procedure and provide update on the technological developments and clinical applications.Expert opinion: CT imaging, with its high resolution, and in particular its utilization in aortic annular measurements, bicuspid aortic valve assessment, hypoattenuated leaflet thickening and valve in valve therapy proved to be the ideal approach to study the mechanisms of aortic stenosis, detection of high-risk anatomy, more accurate risk stratification and thus to allow a personalized catheter based intervention of the affected patients.

Noninvasive Imaging Risk Stratification with Computed Tomography Angiography for Coronary Artery Disease

The recent technological evolution of coronary computed tomography angiography (CTA) with improved sensitivity and high negative predictive value has extended its potential applications as a gatekeeper test before invasive coronary angiography. However, the definition of the most accurate diagnostic algorithms comprising CTA as a first-line strategy for ruling out coronary artery disease and the correct management of the patients according to the results of imaging tests still warrant better definition.

Statement from the North American Society for Cardiovascular Imaging on imaging strategies to reduce the scarcity of healthcare resources during the COVID-19 outbreak

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an evolving global pandemic that is predicted to strain healthcare resources at multiple locations throughout North America and the World. As of April 6, 2020, the apex of infection rates is predicted to occur within 1 to 5 weeks at various locations. Widespread reports of personal protective equipment (PPE) shortages, and healthcare worker exposure to disease have become commonplace. To mitigate this crisis, we are suggesting imaging strategies that aim to use the least PPE, require the smallest number of potential staff exposures, and streamlines utilization of imaging. They are broadly organized by (1) substituting a noninvasive diagnostic test in place of a semi-invasive or invasive diagnostic tests, and (2) consolidating diagnostic imaging.

CT imaging prior to transcatheter aortic valve implantation in the UK

Objective

This cross-sectional observational study sought to describe variations in CT in the context of transcatheter aortic valve implantation (CT-TAVI) as currently performed in the UK.

Methods

408 members of the British Society of Cardiovascular Imaging were invited to complete a 27-item online CT-TAVI survey.

Results

47 responses (12% response rate) were received from 40 cardiac centres, 23 (58%) of which performed TAVI on-site (TAVI centres). Only six respondents (13%) performed high-volume activity (>200 scans per year) compared with 13 (28%) performing moderate (100–200 scans per year) and 27 (59%) performing low (0–99 scans per year) volume activity. Acquisition protocols varied (41% retrospective, 12% prospective with wide padding, 47% prospective with narrow padding), as did the phase of reporting (45% systolic, 37% diastolic, 11% both, 6% unreported). Median dose length product was 675 mGy.cm (IQR 477–954 mGy.cm). Compared with non-TAVI centres, TAVI centres were more likely to report minimum iliofemoral luminal diameter (n=25, 96% vs n=7, 58%, p=0.003) and optimal tube angulation for intervention (n=12, 46% vs n=1, 8%, p=0.02).

Conclusions

This national survey formally describes current CT-TAVI practice in the UK. High-volume activity was only present at one in seven cardiac CT centres. There is wide variation in scan acquisition, scan reporting and radiation dose exposure in cardiac CT centres.

Combined Coronary CT-Angiography and TAVI-Planning: A Contrast-Neutral Routine Approach for Ruling-out Significant Coronary Artery Disease

BACKGROUND

Significant coronary artery disease (CAD) is a common finding in patients undergoing transcatheter aortic valve implantation (TAVI). Assessment of CAD prior to TAVI is recommended by current guidelines and is mainly performed via invasive coronary angiography (ICA). In this study we analyzed the ability of coronary CT-angiography (cCTA) to rule out significant CAD (stenosis ≥ 50%) during routine pre-TAVI evaluation in patients with high pre-test probability for CAD.

METHODS

In total, 460 consecutive patients undergoing pre-TAVI CT (mean age 79.6 ± 7.4 years) were included. All patients were examined with a retrospectively ECG-gated CT-scan of the heart, followed by a high-pitch-scan of the vascular access route utilizing a single intravenous bolus of 70 ml iodinated contrast medium. Images were evaluated for image quality, calcifications, and significant CAD; CT-examinations in which CAD could not be ruled out were defined as positive (CAD+). Routinely, patients received ICA (388/460; 84.3%; Group A), which was omitted if renal function was impaired and CAD was ruled out on cCTA (Group B). Following TAVI, clinical events were documented during the hospital stay.

RESULTS

cCTA was negative for CAD in 40.2% (188/460). Sensitivity, specificity, PPV, and NPV in Group A were 97.8%, 45.2%, 49.6%, and 97.4%, respectively. Median coronary artery calcium score (CAC) was higher in CAD+-patients but did not have predictive value for correct classification of patients with cCTA. There were no significant differences in clinical events between Group A and B.

CONCLUSION

cCTA can be incorporated into pre-TAVI CT-evaluation with no need for additional contrast medium. cCTA may exclude significant CAD in a relatively high percentage of these high-risk patients. Thereby, cCTA may have the potential to reduce the need for ICA and total amount of contrast medium applied, possibly making pre-procedural evaluation for TAVI safer and faster.

CT in planning transcatheter aortic valve implantation procedures and risk assessment

For surgical aortic valve replacement, the Society of Thoracic Surgeons score (STSS) is the reference standard for the prediction of operative risk. In transcatheter aortic valve implantation (TAVI) though, where the procedure itself is minimally invasive, the traditional risk assessment is supplemented by CTA. Through a consistent approach to the acquisition of high-quality images and the standardised reporting of annular measurements and adverse root and vascular features, patients at risk of complications can be identified. In turn, this may allow for a personalised procedural approach and treatment strategies devised to potentially reduce or mitigate this risk. This article provides a systematic and standardised approach to pre-procedural work-up with computed tomography angiography (CTA) and explores the current state of evidence and future areas of development in this rapidly developing field.