Computed Tomography Imaging in the Context of Transcatheter Aortic Valve Implantation (TAVI)/Transcatheter Aortic Valve Replacement (TAVR)

Utility of CT in the diagnosis of prosthetic valve abnormalities

BACKGROUND

Patients with prosthetic heart valves (PHV) are at an increased risk of endocarditis and dysfunction. Knowledge about the etiology of dysfunction and extent of endocarditis can have distinct treatment implications. Echocardiography has limitations due to PHV-related artifacts. We hypothesized that computed tomography (CT) will have incremental value over echocardiography for evaluation of PHV abnormalities with surgical findings as the reference standard.

METHODS

Consecutive patients with PHV that had a reoperation for valve replacement, had a contrast chest CT and echocardiogram within 1 year of the reoperation, between 2010 and 2018 at a single academic center formed the study cohort. CTs and echocardiograms were assessed for potential etiologies of dysfunction (valve degeneration, pannus and thrombus); and for extent of endocarditis (vegetation, abscess, and pseudoaneurysm).

RESULTS

Seventy-three patients (65.8% male, mean age 62.1 ± 16.5 years) formed the study cohort. The indication for reoperation was PHV dysfunction in 51 and PHV endocarditis in 22. Compared to echocardiography, CT diagnosed the etiology of PHV dysfunction in 17 (33.3%) more patients (9 valve degeneration, 8 pannus). In the PHV endocarditis cohort, CT failed to detect one vegetation and one abscess, whereas echocardiography failed to detect 1 abscess. In combination, CT and echocardiography demonstrated all the vegetations and abscesses.

CONCLUSION

CT may provide superior characterization in comparison to echocardiography for the identification of the cause of prosthetic valve dysfunction, and complementary information to echocardiography for the evaluation of prosthetic valve endocarditis.

Contemporary Surgical and Transcatheter Management of Mitral Annular Calcification

BACKGROUND

The presence of mitral annular calcification (MAC) in patients with mitral valve (MV) stenosis or regurgitation is a difficult scenario for surgeons and the heart team. Patients with MAC most often have a significant number of comorbidities that exclude them as surgical candidates. This review highlights the various contemporary techniques available to manage MAC during treatment of the MV.

METHODS

This study is a focused review of the anatomy, pathology, and management of MAC. The review describes the surgical and transcatheter techniques with outcomes, where available.

RESULTS

The incidence of MAC is between 5% and 42% in patients with severe MV disease. The pathophysiology underlying MAC is not yet clear, but it most likely is related to processes of inflammation and atherosclerosis. Surgical techniques can be grouped into those in which the MAC is completely resected en bloc and those in which the MAC is incompletely resected or left in situ. Transcatheter therapies are feasible in some patients, but they have been limited by the anatomic constraints of MAC; most importantly left ventricular outflow tract obstruction and paravalvular regurgitation.

CONCLUSIONS

Surgeons as part of the heart team now have a range of techniques to manage MAC in those patients with severe MV disease. Transcatheter therapies may increase the options for patients whose surgical risk is too high.

How valvular calcification can affect the outcomes of transcatheter aortic valve implantation

Introduction In transcatheter aortic valve implantation (TAVI), assessment of aortic valve calcification is not as standardized as aortic annulus measurement. Aortic valve calcification is important for stable anchoring of the prosthesis to the aortic annulus. However, excessive aortic valve calcification is related to procedural complications. Areas covered This review covers the methods to assess aortic valve calcification and the implications of aortic valve calcium burden for TAVI outcomes. We performed a systematic review of the literature in Pubmed and secondary sources. Furthermore, future perspectives on how to integrate aortic valve calcification assessment in the management of patients with aortic stenosis is discussed. Expert opinion Thorough assessment of the aortic valve and aortic root components including aortic valve calcification is key in the planning of TAVI. Aortic valve calcification load, location and extension are important contributors to paravalvular regurgitation. Asymmetric calcification burden with greater calcification of the left-coronary cusp related to higher need of permanent pacemaker implantation. Patients with moderate and severe left ventricular outflow tract/subannular calcification are more susceptible to aortic annular rupture. Periprocedural dislodgement of calcium form cusps and commissures is one of the main reasons of coronary artery ostial occlusion during transcatheter aortic valve implantation. Abbreviations Ao, aorta; LA, left atrium; LAA, left atrial appendage; LV, left ventricle; LVOT, left ventricular outflow tract; THV, transcatheter heart valve.

Assessment and management of coronary artery disease in patients undergoing transcatheter aortic valve replacement

PURPOSE OF REVIEW

Coronary artery disease (CAD) is commonly observed in patients undergoing transcatheter aortic valve replacement (TAVR). Significant variability exists across institutions for strategies used for CAD diagnosis and its management. The heart team often relies upon traditional practice patterns and the decision for revascularization by percutaneous coronary intervention (PCI) is influenced by patient, angiographic, operator, and system-related factors.

RECENT FINDINGS

Contemporary coronary tomography angiography (CTA) shows significant promise for detection of clinically important CAD and preliminary data support CTA use for TAVR patients. The prognostic implications of CAD in a TAVR population remain unclear with studies showing conflicting data for the benefits of PCI. Recent trials show that medical management is an effective initial treatment strategy for stable CAD, a finding likely also applicable for asymptomatic and stable TAVR patients. In addition, PCI performed pre-TAVR, concomitant with TAVR or after TAVR has been shown to produce similar outcomes. Dual antiplatelet therapy (DAPT) is mandated after PCI but associated with increased risk of bleeding in TAVR population with accumulating evidence for single antiplatelet therapy (SAPT) post-TAVR unless DAPT or anticoagulation is indicated for another reason.

SUMMARY

Although coronary angiography remains the predominant modality for CAD assessment, CTA is increasingly being used in TAVR patients. There is limited evidence to guide CAD management in TAVR patients with significant variability in practice patterns. Medical therapy is recommended for asymptomatic and stable CAD patients with applicability for TAVR population. Despite prior concerns, recent studies suggest successful coronary access post-TAVR and similar outcomes for PCI offered pre-TAVR, concomitant with TAVR and post-TAVR settings. Safety of DAPT should be an important consideration for PCI in TAVR patients. Ongoing studies will determine the preferred testing for CAD diagnosis, benefit of revascularization, timing of PCI, and optimum antithrombotic therapy for TAVR populations.

Multimodality imaging in bicuspid aortic valve

Bicuspid aortic valve (BAV) patients are at increased risk of valve dysfunction and ascending aorta aneurysm. Imaging techniques are essential to establish diagnosis, identify complications and indicate surgical treatment. Transthoracic echocardiography (TTE) is the imaging technique of choice to diagnose BAV, valve morphotype and valvular dysfunction in clinical practice. However, it can be less precise in assessing the aortic root and proximal ascending aorta, and visualization of the mid-distal ascending aorta and the arch may be difficult in some adults where cardiac magnetic resonance (CMR) and computed tomography, using multiplanar reconstructions, are better at assessing aortic diameters. Although valvular dysfunction is very variable, almost half of the patients have more than mild aortic valve disease. TTE is the most effective and accurate test for evaluating the severity of valvular dysfunction and guiding appropriate management decisions. Aorta dilation is a common finding in patients with BAV. The pattern of aortic dimensions has been categorized in three aortic phenotypes: no-dilation phenotype, ascending aorta phenotype and root phenotype. Controversial data exist regarding the relationship between BAV morphology and aorta dilation phenotype. The assessment of aortic stiffness (measuring distensibility or the velocity of propagation of flow) has raised special interest in order to predict progressive aorta dilation. However, current data indicates that BAV aortas do not show altered stiffness compared to those associated with a tricuspid valve with a similar aorta size. Moreover, novel 4D-flow CMR sequences have been crucial in the evaluation of abnormal ascending aorta flow, showing that flow in the aorta of BAV patients is asymmetric and includes the formation of large vortices. Such flow abnormalities are thought to produce changes in wall shear stress which has been associated with extracellular matrix dysregulation. The key points to understand familial screening and the recommendations for establishing the follow-up and therapeutic management of BAV patients are exposed in the review. The main objective of this article is to review the advantages and limitations of the imaging techniques in the diagnosis and management of BAV and the best strategies in the use of multimodality imaging.

Reliability and Influence on Decision Making of fully-automated vs. semi-automated Software Packages for Procedural Planning in TAVI

Precise procedural planning is crucial to achieve excellent results in patients undergoing Transcatheter aortic valve implantation (TAVI). The aim of this study was to compare the semi-automated 3mensio (3 m) software to the fully-automated HeartNavigator3 (HN) software. We randomly selected 100 patients from our in-house TAVI-registry and compared aortic annulus and perimeter as well as coronary distances between 3m-measurements and post-hoc HN-measurements. Finally, we retrospectively simulated prosthesis choice based on HN-measurements and analyzed the differences compared to routinely used 3 m based strategy. We observed significant differences between the two software packages regarding area (3 m 464 ± 88 mm², HN 482 ± 96 mm², p < 0.001), perimeter (3 m 77 ± 7 mm, HN 79 ± 8 mm, p < 0.001) and coronary distances (LCA: 3 m 13 ± 3 mm, HN 12 ± 3 mm, p < 0.001; RCA: 3 m 16 ± 3 mm, HN 15 ± 3 mm, p < 0.001). Prosthesis choice simulation based on newly obtained HN-measurements would have led to a decision change in 18% of patients, with a further reduction to 4% following manual adjustment of HN-measurements. The fully-automatic HN-software provides higher values for annular metrics and lower annulus-to-coronary-ostia distances compared to 3m-software. Measurement differences did not influence clinical outcome. Both, the HN-software and the 3m-software are sophisticated, reliable and easy to use for the clinician. Manual adjustment of HN-measurements may increase precision in complex aortic annulus anatomy.

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.

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.

Automatic Detection of the Aortic Annular Plane and Coronary Ostia from Multidetector Computed Tomography

Anatomic landmark detection is crucial during preoperative planning of transcatheter aortic valve implantation (TAVI) to select the proper device size and assess the risk of complications. The detection is currently a time-consuming manual process influenced by the image quality and subject to operator variability. In this work, we propose a novel automatic method to detect the relevant aortic landmarks from MDCT images using deep learning techniques. We trained three convolutional neural networks (CNNs) with 344 multidetector computed tomography (MDCT) acquisitions to detect five anatomical landmarks relevant for TAVI planning: the three basal attachment points of the aortic valve leaflets and the left and right coronary ostia. The detection strategy used these three CNN models to analyse a single MDCT image and yield three segmentation volumes as output. These segmentation volumes were averaged into one final segmentation volume, and the final predicted landmarks were obtained during a postprocessing step. Finally, we constructed the aortic annular plane, defined by the three predicted hinge points, and measured the distances from this plane to the predicted coronary ostia (i.e., coronary height). The methodology was validated on 100 patients. The automatic landmark detection was able to detect all the landmarks and showed high accuracy as the median distance between the ground truth and predictions is lower than the interobserver variations (1.5 mm [1.1–2.1], 2.0 mm [1.3–2.8] with a paired difference −0.5 ± 1.3 mm and p value <0.001). Furthermore, a high correlation is observed between predicted and manually measured coronary heights (for both R² = 0.8). The image analysis time per patient was below one second. The proposed method is accurate, fast, and reproducible. Embedding this tool based on deep learning in the preoperative planning routine may have an impact in the TAVI environments by reducing the time and cost and improving accuracy.

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.

Retrospectively ECG-gated helical vs. non-ECG-synchronized high-pitch CTA of the aortic root for TAVI planning

Background

Multidetector computed tomography (MDCT) plays a key role in patient assessment prior to transcatheter aortic valve implantation (TAVI). However, to date no consensus has been established on what is the optimal pre-procedural imaging protocol. Variability in pre-TAVI acquisition protocols may lead to discrepancies in aortic annulus measurements and may potentially influence prosthesis size selection.

Purpose

The current study evaluates the magnitude of differences in aortic annulus measurements using max-systolic, end-diastolic, and non-ECG-synchronized imaging, as well as the impact of method on prosthesis size selection.

Material and methods

Fifty consecutive TAVI-candidates, who underwent retrospectively-ECG-gated CT angiography (CTA) of the aortic root, directly followed by non-ECG-synchronized high-pitch CT of the entire aorta, were retrospectively included. Aortic root dimensions were assessed at each 10% increment of the R-R interval (0–100%) and on the non-ECG-synchronized scan. Dimensional changes within the cardiac cycle were evaluated using a 1-way repeated ANOVA. Agreement in measurements between max-systole, end-diastole and non-ECG-synchronized scans was assessed with Bland-Altman analysis.

Results

Maximal dimensions of the aortic root structures and minimum annulus-coronary ostia distances were measured during systole. Max-systolic measurements were significantly and substantially larger than end-diastolic (p<0.001) and non-ECG-synchronized measurements (p<0.001). Due to these discrepancies, the three methods resulted in the same prosthesis size selection in only 48–62% of patients.

Conclusions

The systematic differences between max-systolic, end-diastolic and non-ECG-synchronized measurements for relevant aortic annular dimensions are both statistically significant and clinically relevant. Imaging strategy impacts prosthesis size selection in nearly half the TAVI-candidates. End-diastolic and non-ECG-synchronized imaging does not provide optimal information for prosthesis size selection. Systolic image acquisition is necessary for assessment of maximal annular dimensions and minimum annulus-coronary ostia distances.

MDCT planning of trans catheter aortic valve implantation (TAVI): determination of optimal c-arm angulation

A fluoroscopic view perpendicular to the aortic valve annulus is required during transcatheter aortic valve implantation (TAVI) for obtaining an optimal deployment of the bioprosthesis. By predicting c-arm angulation, pre-procedural MDCT could decrease the number of aortograms, shorten the time of the procedure and reduce the amount of intra-arterial contrast agent. The aim of our study was to assess the accuracy of MDCT in predicting c-arm angulation at the cath. lab. In this single center study, we investigated MDCT prediction of c-arm angulation in patients having undergone a TAVI procedure using SAPIEN 3® (Edwards Lifesciences, USA). Prior to the procedure, an experienced radiologist had reported the angulation using dedicated software (CT_report). After the procedure, a blinded experienced radiologist retrospectively measured the angles using the same method (CT_study). Interobserver variability was drawn from the comparison between CT_report and CT_study. Then, the mean angular difference between the predicted MDCT angles (CT_study) was compared to the working view recorded at the cath. lab. Seventy-nine patients (M/F = 0.65; mean age: 85.2 years ± 5.3) were included. Interobserver variability was 5.9 ± 6.1°. The mean absolute difference between MDCT and fluoroscopy was 8.8 ± 7.1°. The present study showed that MDCT could predict the coplanar fluoroscopic angles prior to TAVI using a balloon-expandable bioprosthesis Sapien 3® placed via a transfemoral approach with a mean angular difference of 8.8 ± 7.1°. Reproducibility was considered good as the mean difference between two independent measures was 5.9 ± 6.1°.

Radiation Dose Reduction in Preprocedural CT Imaging for TAVI/TAVR Using a Novel 3-Phase Protocol: A Single Institution's Experience

PURPOSE

 To retrospectively investigate the effectiveness of a novel 3-phase protocol for computed tomography (CT) before transcatheter aortic valve implantation/transcatheter aortic valve replacement (TAVI/TAVR) in terms of radiation dose and image quality.

MATERIALS AND METHODS

 A total of 107 nonrandomized patients (81 ± 7.4 years) scheduled for TAVI/TAVR underwent preprocedural CT on an 80-row CT scanner. 55 patients underwent a combined ECG-synchronized spiral scan of the chest and non-ECG-synchronized spiral scan of the abdomen/pelvis as recommended by the Society of Cardiovascular Computed Tomography (SCCT). 52 patients underwent an updated 3-phase variable helical pitch (vHP3) protocol combining a non-ECG-synchronized spiral scan of the upper thoracic aperture, followed by a prospective ECG-synchronized spiral scan of the heart, and a non-ECG-synchronized abdominal/pelvic spiral scan. The radiation dose was determined from an automatically generated protocol based on the CT dose index (CTDI). Objective image quality in terms of vessel attenuation and image noise was measured, and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Subjective image quality was evaluated using a 4-point scale and compared for interrater agreement using Cohen's weighted kappa coefficient (κw). All data were compared and statistically analyzed.

RESULTS

 Use of the novel 3-phase vHP3 protocol reduced the dose-length product (DLP) from 1256.58 ± 619.05 mGy*cm to 790.90 ± 238.15 mGy*cm, reducing the effective dose (E) from 21.36 ± 10.52 mSv to 13.44 ± 4.05 mSv and size-specific dose estimates (SSDE) from 20.85 ± 7.29 mGy to 13.84 ± 2.94 mGy (p < 0.001). There were no significant differences in objective and subjective image quality between the two protocols and between the two readers.

CONCLUSION

 The novel 3-phase vHP3 protocol significantly reduces the radiation dose of preprocedural TAVI/TAVR CT without a loss of image quality.

KEY POINTS

  · The use of a novel 3-phase protocol for preprocedural TAVI/TAVR CT reduces radiation dose by 37 % compared to a combined ECG-synchronized and non-ECG-synchronized spiral CT protocol.. · Objective image quality remains unaffected as image noise, SNR, and CNR did not differ significantly between the two protocols. The average attenuation of the aortic root and abdominal aorta exceeded 450 HU in both protocols.. · The average subjective image quality ratings were good to excellent for both protocols with almost perfect to substantial interrater agreement..

CITATION FORMAT

· Shnayien S, Bressem KK, Beetz NL et al. Radiation Dose Reduction in Preprocedural CT Imaging for TAVI/TAVR Using a Novel 3-Phase Protocol: A Single Institution's Experience. Fortschr Röntgenstr 2020; 192: 1174 - 1182.

Sinus of Valsalva Aneurysms: A State-of-the-Art Imaging Review

Cardiovascular imaging has an important role in the assessment and management of aortic root and thoracic aorta ectasia and aneurysms. Sinus of Valsalva aneurysms are rare entities. Unique complications associated with sinus of Valsalva aneurysms make them different from traditional aortic root aneurysms. Established guidelines on the diagnosis and management of sinus of Valsalva aneurysms are lacking. This article reviews the applications of multimodality cardiovascular imaging (echocardiography, cardiac computed tomography, and cardiac magnetic resonance imaging) for the dedicated assessment and imaging-guided management of sinus of Valsalva aneurysms.

The implications and requirements of transcatheter aortic valve replacement in low-risk patients

Transcatheter aortic valve replacement (TAVR) is a transformative technology that has changed the management of patients with severe, symptomatic aortic stenosis. The use of TAVR in intermediate- to high-risk patients has been validated in several rigorously performed, randomized clinical trials. Recent studies using newer generation devices have demonstrated the noninferiority of TAVR as compared with surgical aortic valve replacement in low-risk patients, supporting the increased utilization and expansion of TAVR. The use of TAVR in low-risk patients has important implications and requires a multifaceted approach that includes a highly functional multidisciplinary heart team for careful patient selection; a need to understand and help mitigate certain key complications, such as stroke, paravalvular regurgitation, and conduction disturbances; careful data collection for continual outcome assessment and improvement; and the necessary expertize and procedural volume to maintain excellent outcomes and ensure optimal clinical care pathways.

Reduced Leaflet Motion after Transcatheter Aortic-Valve Replacement

BACKGROUND

Subclinical leaflet thickening and reduced leaflet motion of bioprosthetic aortic valves have been documented by four-dimensional computed tomography (CT). Whether anticoagulation can reduce these phenomena after transcatheter aortic-valve replacement (TAVR) is not known.

METHODS

In a substudy of a large randomized trial, we randomly assigned patients who had undergone successful TAVR and who did not have an indication for long-term anticoagulation to a rivaroxaban-based antithrombotic strategy (rivaroxaban [10 mg] plus aspirin [75 to 100 mg] once daily) or an antiplatelet-based strategy (clopidogrel [75 mg] plus aspirin [75 to 100 mg] once daily). Patients underwent evaluation by four-dimensional CT at a mean (±SD) of 90±15 days after randomization. The primary end point was the percentage of patients with at least one prosthetic valve leaflet with grade 3 or higher motion reduction (i.e., involving >50% of the leaflet). Leaflet thickening was also assessed.

RESULTS

A total of 231 patients were enrolled. At least one prosthetic valve leaflet with grade 3 or higher motion reduction was found in 2 of 97 patients (2.1%) who had scans that could be evaluated in the rivaroxaban group, as compared with 11 of 101 (10.9%) in the antiplatelet group (difference, -8.8 percentage points; 95% confidence interval [CI], -16.5 to -1.9; P = 0.01). Thickening of at least one leaflet was observed in 12 of 97 patients (12.4%) in the rivaroxaban group and in 33 of 102 (32.4%) in the antiplatelet group (difference, -20.0 percentage points; 95% CI, -30.9 to -8.5). In the main trial, the risk of death or thromboembolic events and the risk of life-threatening, disabling, or major bleeding were higher with rivaroxaban (hazard ratios of 1.35 and 1.50, respectively).

CONCLUSIONS

In a substudy of a trial involving patients without an indication for long-term anticoagulation who had undergone successful TAVR, a rivaroxaban-based antithrombotic strategy was more effective than an antiplatelet-based strategy in preventing subclinical leaflet-motion abnormalities. However, in the main trial, the rivaroxaban-based strategy was associated with a higher risk of death or thromboembolic complications and a higher risk of bleeding than the antiplatelet-based strategy. (Funded by Bayer; GALILEO-4D ClinicalTrials.gov number, NCT02833948.).

Cardiac CT: why, when, and how : Update 2019

PURPOSE

The aim of this study was to review established and emerging techniques of cardiac computed tomography (CT) and their clinical applications with a special emphasis on new techniques, recent trials, and guidelines.

TECHNOLOGICAL INNOVATIONS

Cardiac CT has made great strides in recent years to become an ever more robust and safe imaging technique. The improvements in spatial and temporal resolution are equally important as the substantial reduction in radiation exposure, which has been achieved through prospective ECG-triggering, low tube voltage scanning, tube current modulation, and iterative reconstruction techniques. CT-derived fractional flow reserve and CT myocardial perfusion imaging are novel, investigational techniques to assess the hemodynamic significance of coronary stenosis.

ESTABLISHED AND EMERGING INDICATIONS

In asymptomatic patients at risk for coronary artery disease, CT coronary artery calcium scoring is useful to assess cardiovascular risk and guide the intensity of risk factor modification. Coronary CT angiography is an excellent noninvasive test to rule out obstructive coronary artery disease in patients with stable chest pain. In acute chest pain with normal ECG and normal cardiac enzymes, cardiac CT can safely rule out acute coronary syndrome although its benefit and role in this indication remains controversial. Cardiac CT is the established standard for planning transcatheter aortic valve implantation and-increasingly-minimally invasive mitral valve procedures.

PRACTICAL RECOMMENDATIONS

Our review makes practical recommendations on when and how to perform cardiac CT and provides templates for structured reporting of cardiac CT examinations.

Accuracy of Non-Electrocardiographically Gated Thoracic CT Angiography for Right Atrial and Right Ventricular Enlargement

PURPOSE

To assess the role of long-axis (LA) and short-axis (SA) measurements of the right atrium (RA) and right ventricle (RV) at non-electrocardiographically (ECG) gated thoracic CT angiography for identification of RA enlargement and RV enlargement.

MATERIALS AND METHODS

This study was a retrospective case review of 138 patients who underwent both non-ECG-gated CT angiography and ECG-gated CT angiography concurrently from November 2016 through November 2018. The SA and LA of the RA and RV were measured by two observers blinded to the ECG-gated CT angiography data. ECG-gated CT angiography-derived RA end-systolic and RV end-diastolic volumes were used as standard of reference to derive cutoff values for diagnosis of RA and RV enlargement.

RESULTS

In this study, 138 patients were evaluated (70 men, 68 women; mean age, 70.0 years ± 18.4 [standard deviation]; mean body mass index, 29.3 kg/m² ± 8.1). Of these patients, ECG-gated CT angiography revealed 36.2% had RA enhancement and 19.0% had RV enhancement. The best predictor of RA enhancement was the product of atrial LA and SA measurements, for which a threshold value of 3210 mm² yielded a 94% sensitivity and 81.8% specificity (area under the curve [AUC], 0.92). A threshold of 55.5 mm for LA diameter had 86% sensitivity and 78.4% specificity in identifying RA enlargement. RV enlargement could be predicted if the SA diameter was greater than 48.5 mm (76.9% sensitivity and 64.9% specificity) and with a body surface area indexed value of 27.0 mm/m² (92.3% sensitivity and 74.8% specificity [AUC, 0.87]).

CONCLUSION

RA and RV enlargement can be accurately diagnosed by using non-ECG-gated CT angiography.© RSNA, 2019Supplemental material is available for this article.

CT and MR imaging prior to transcatheter aortic valve implantation: standardisation of scanning protocols, measurements and reporting-a consensus document by the European Society of Cardiovascular Radiology (ESCR)

Abstract

Transcatheter aortic valve replacement (TAVR) is a minimally invasive alternative to conventional aortic valve replacement in symptomatic patients with severe aortic stenosis and contraindications to surgery. The procedure has shown to improve patient’s quality of life and prolong short- and mid-term survival in high-risk individuals, becoming a widely accepted therapeutic option which has been integrated into current clinical guidelines for the management of valvular heart disease. Nevertheless, not every patient at high-risk for surgery is a good candidate for TAVR. Besides clinical selection, which is usually established by the Heart Team, certain technical and anatomic criteria must be met as, unlike in surgical valve replacement, annular sizing is not performed under direct surgical evaluation but on the basis of non-invasive imaging findings. Present consensus document was outlined by a working group of researchers from the European Society of Cardiovascular Radiology (ESCR) and aims to provide guidance on the utilisation of CT and MR imaging prior to TAVR. Particular relevance is given to the technical requirements and standardisation of the scanning protocols which have to be tailored to the remarkable variability of the scanners currently utilised in clinical practice; recommendations regarding all required pre-procedural measurements and medical reporting standardisation have been also outlined, in order to ensure quality and consistency of reported data and terminology.

Key Points

• To provide a reference document for CT and MR acquisition techniques, taking into account the significant technological variation of available scanners.

• To review all relevant measurements that are required and define a step-by-step guided approach for the measurements of different structures implicated in the procedure.

• To propose a CT/MR reporting template to assist in consistent communication between various sites and specialists involved in the procedural planning.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06357-8) contains supplementary material, which is available to authorized users.

Identification of Patients With Heart Failure From Test Bolus of Computed Tomography Angiography in Patients Undergoing Preoperative Evaluation for Transcatheter Aortic Valve Replacement

PURPOSE

Identify a measurable parameter from test bolus of computed tomography angiography that can differentiate aortic stenosis patients with normal systolic function from those with heart failure and reduced ejection fraction (HFrEF).

MATERIALS AND METHODS

This retrospective study included patients (undergoing evaluation for transcatheter aortic valve replacement) who had retrospective electrocardiogram-gated cardiac computed tomography angiography using test bolus. The measured variables were time to peak contrast enhancement in the pulmonary artery (PAtime), in the ascending (AsAotime) and descending aorta (DsAotime). From these, the pulmonary transit time (PTT: difference between time to peak enhancement in the ascending aorta to peak enhancement in the main pulmonary artery), aortic transit time (ATT: difference between time to peak enhancement in the descending aorta to time to peak enhancement in the ascending aorta) and DsAotime-PAtime were also calculated. Biventricular volumes and function were calculated.The subjects were classified on the basis of ventricular ejection fractions: normal (EF>50%), midrange (EF 40% to 50%), and HF patients with reduced EF (EF<40%). Continuous variables were compared between all groups using ordinary 1-way analysis of variance, while sex was compared using the Fisher exact test. The unpaired t tests were used to compare between the normal and HF groups. Receiver operating characteristic analysis was used in predicting decreased cardiac function (EF<40% vs. EF>50%).

RESULTS

AsAotime and PTT were significant predictors of low biventricular EF when controlling for sex and body mass index (AsAotime: odds ratio=0.74 [95% confidence interval=0.61-0.91], P=0.005; PTT: odds ratio=0.64 95% confidence interval=0.46-0.88], P=0.006). A threshold of 23 seconds for AsAotime resulted in 72.1% sensitivity and 71.4% specificity, and 79.1% sensitivity and 64.3% specificity for DsAotime.

CONCLUSIONS

The time to peak contrast enhancement from the test bolus images correlates with cardiac function. Decreased biventricular systolic dysfunction can be predicted if the time to peak contrast enhancement is >23 seconds in the ascending or descending aorta.

Aortic roots assessment by an automated three-dimensional transesophageal echocardiography: an intra-individual comparison

To evaluate the accuracy, reproducibility, and transcatheter heart valve (THV) sizing efficiency of an automated 3-dimensional transesophageal echocardiographic (3D-TEE) post-processing software in the assessments of aortic roots, intra-individually compared with multidetector computed tomography (MDCT). We prospectively studied 67 patients with normal aortic roots. We measured diameters of aortic annulus (AA), sinus of Valsalva (SOV), and sino-tubular junction (STJ) by full-automated and semi-automated methods using 3D-TEE datasets, then compared them to corresponding transthoracic echocardiography and MDCT values. THV sizes were chosen based on echocardiography and MDCT measurements according to recommended criterion. Taking MDCT planimetered diameters as reference, the full-automated (r: 0.4745-0.8792) and semi-automated (r: 0.6647-0.8805) 3D-TEE measurements were linearly correlated (p < 0.0001). The average differences between semi-automated or full-automated measurements and reference were 0.3 mm or 1.3 mm for AA, - 1.9 mm or - 0.5 mm for SOV, and - 0.1 mm or 1.9 mm for STJ, respectively. The intra-class correlation coefficients of semi-automated method were 0.79-0.96 (intra-observer) and 0.75-0.92 (inter-observer). THV sizing by semi-automated measurements using echocardiographic criteria was larger than that by MDCT measurements using MDCT criteria (p < 0.0001) but equivalent (p > 0.05) if both using MDCT standards. The new automated 3D-TEE software allows modeling and quantifying aortic roots with high reproducibility. Measurements by the semi-automated method closely approximate and well correlate with the corresponding MDCT, thus THV sizing by this modeled 3D-TEE measurements should adopt recommended MDCT criteria but not echocardiographic criteria. The full-automated 3D-TEE segmentations are yet immature. (Semi-automated assessMent of Aortic Roots by Three-dimensional transEsophageal echocaRdiography [SMARTER], NCT02724709).