The Pivotal Role of Imaging in TAVR Procedures

Echocardiographic assessment of aortic regurgitation: a practical guideline from the British Society of Echocardiography

Aortic regurgitation is the third most common valve lesion with increasing prevalence secondary to an ageing population. Transthoracic echocardiography plays a vital role in the identification and assessment of aortic regurgitation and proves essential in monitoring severity and determining the timing of intervention. Building on the foundations of previous British Society of Echocardiography (BSE) recommendations, this BSE guideline presents an update on how to approach an echocardiographic assessment of aortic regurgitation. It provides a practical, step-by-step guide to facilitate a comprehensive, high-quality echocardiographic assessment of aortic regurgitation. It discusses commonly encountered echocardiography-based challenges with suggestions regarding how this information is relevant in the interpretation and grading of regurgitation severity. Additionally, the value of other cardiac imaging modalities is discussed. The guideline concludes with an overview of aortic regurgitation in the clinical context, addressing chronic versus acute aortic regurgitation, which features prompt referral for intervention, and the consequences of combined valve disease.

Coronary CT angiography instead of invasive angiography before TAVI: Feasibility and outcomes

AIMS

Concomitant coronary artery disease (CAD) is frequent in transcatheter aortic valve implantation (TAVI) candidates. Despite societal recommendations of performing invasive coronary angiography (ICA) for coronary assessment in the pre-TAVI diagnostic workup, the prognostic value of ICA and beneficial effect of revascularization in these patients remains unclear. We aimed to determine feasibility and outcomes following a strategy of cardiac CT + coronary CT angiography (cCTA) rather than cardiac CT + ICA before TAVI.

METHODS AND RESULTS

We performed a single-center, observational cohort study including all patients, without previous coronary intervention, referred to TAVI between April 2020 and November 2021. CAD was assessed by cCTA, and only patients with proximal stenosis >70 %, or left main stenosis >50 %, or cCTA was non-evaluable regarding proximal segments were subsequently referred to ICA. 240 patients were included in the study. No adverse effects to pre-cCTA-scan nitroglycerin administration were observed. On cCTA, 92 % of the patients had atheroscerosis. 191 (80 %) patients had cCTA only performed, while 49 (20 %) patients underwent subsequent ICA. During a median (range) follow-up of 15 (6-25) months, no difference in procedural complication rates, mortality rates, or number of unplanned ICA was observed between patients evaluated with only cCTA vs cCTA+ICA.

CONCLUSIONS

Upfront cCTA instead of ICA for assessment of obstructive CAD in the diagnostic workup of patients with severe aortic stenosis referred to TAVI is feasible, safe, and with similar procedural and clinical outcomes. Randomized studies are warranted to further validate the safety of using CTA rather than ICA for coronary assessment in TAVI candidates.

Predicting pressure gradient using artificial intelligence for transcatheter aortic valve replacement

Objective

After transcatheter aortic valve replacement, the mean transvalvular pressure gradient indicates the effectiveness of the therapy. The objective is to develop artificial intelligence to predict the post-transcatheter aortic valve replacement aortic valve pressure gradient and aortic valve area from preprocedural echocardiography and computed tomography data.

Methods

A retrospective study was conducted on patients who underwent transcatheter aortic valve replacement due to aortic valve stenosis. A total of 1091 patients were analyzed for pressure gradient predictions (mean age 76.8 ± 9.2 years, 57.8% male), and 1063 patients were analyzed for aortic valve area predictions (mean age 76.7 ± 9.3 years, 57.2% male). An artificial intelligence learning model was trained (training: n = 663 patients, validation: n = 206 patients) and tested (testing: n = 222 patients) to predict pressure gradient, and a separate artificial intelligence learning model was trained (training: n = 640 patients, validation: n = 218 patients) and tested (testing: n = 205 patients) for predicting aortic valve area.

Results

The mean absolute error for pressure gradient and aortic valve area predictions was 3.0 mm Hg and 0.45 cm2, respectively. Valve sheath size, body surface area, and age were determined to be the top 3 predictors for pressure gradient, and valve sheath size, left ventricular ejection fraction, and aortic annulus mean diameter were identified to be the top 3 predictors of post-transcatheter aortic valve replacement aortic valve area. A training dataset size of more than 500 patients demonstrated good robustness of the artificial intelligence models for pressure gradient and aortic valve area.

Conclusions

The artificial intelligence-based algorithm has demonstrated potential in predicting post-transcatheter aortic valve replacement transvalvular pressure gradient predictions for patients with aortic valve stenosis. Further studies are necessary to differentiate pressure gradient between valve types.

TAVI-PREP: A Deep Learning-Based Tool for Automated Measurements Extraction in TAVI Planning

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is a less invasive alternative to open-heart surgery for treating severe aortic stenosis. Despite its benefits, the risk of procedural complications necessitates careful preoperative planning.

METHODS

This study proposes a fully automated deep learning-based method, TAVI-PREP, for pre-TAVI planning, focusing on measurements extracted from computed tomography (CT) scans. The algorithm was trained on the public MM-WHS dataset and a small subset of private data. It uses MeshDeformNet for 3D surface mesh generation and a 3D Residual U-Net for landmark detection. TAVI-PREP is designed to extract 22 different measurements from the aortic valvular complex. A total of 200 CT-scans were analyzed, and automatic measurements were compared to the ones made manually by an expert cardiologist. A second cardiologist analyzed 115 scans to evaluate inter-operator variability.

RESULTS

High Pearson correlation coefficients between the expert and the algorithm were obtained for most parameters (0.90-0.97), except for left and right coronary height (0.8 and 0.72, respectively). Similarly, the mean absolute relative error was within 5% for most measurements, except for left and right coronary height (11.6% and 16.5%, respectively). A greater consensus was observed among experts than when compared to the automatic approach, with TAVI-PREP showing no discernable bias towards either the lower or higher ends of the measurement spectrum.

CONCLUSIONS

TAVI-PREP provides reliable and time-efficient measurements of the aortic valvular complex that could aid clinicians in the preprocedural planning of TAVI procedures.

Evolving computed tomography angiography for aortic valve replacement: Optimizing transcatheter and surgical therapies

Transcatheter aortic valve replacement (TAVR) has transformed the treatment of aortic stenosis and pre-procedure planning relies heavily on advanced imaging. Multidetector computed tomography angiography, the "TAVR CT," facilitates essential planning steps of measuring the aortic root for valve sizing and feasibility and assessment of potential access vessels, making it the guideline gold standard in preprocedural TAVR work up. This Impact of Advanced Imaging Techniques on Cardiac Surgery article will examine the development of TAVR CT, illustrate the current impact and utility, and highlight potential areas of future growth. Clinicians who keep informed of these changes and can become proficient with TAVR CT analyses will offer patients the most optimal results and fuel future therapeutic growth.

Balloon-Expandable TAVR Bioprostheses: Area or Perimeter Sizing? A Prospective Pilot Study

Objective. In TAVR, area sizing is used for balloon-expandable (BE) valves, whereas self-expanding valves are sized to annulus perimeter. For BE valves, this seems illogical: these frames force a circular shape even on an ellipsoid annulus. This can potentially lead to relative undersizing when area sizing is being applied. We developed a perimeter-based sizing algorithm to evaluate the safety and feasibility of perimeter sizing for the Myval BE valve. Methods. In this prospective single-center study, 60 patients with severe aortic stenosis treated with the Myval BE valve were included. Perimeter sizing was used with limited oversizing of 3.7% ± 1.3% compared to the annulus perimeter. After TAVR, clinical outcomes were evaluated at 30 days and 1 year. An echocardiographic follow-up took place at 30 days. Results. At 30 days, the need for PPI and stroke occurred in 2% and 3% of the patients, respectively. Moreover, cardiac death and moderate-severe PVL were absent. At 1-year, cardiac death and stroke were observed in 3% and 8% of the patients, respectively. In 33.3% of the patients, a larger valve size was implanted compared to the valve size calculated by area sizing. Conclusions. Perimeter sizing with the Myval BE valve leads to substantial use of larger valve sizes and favorable clinical outcomes, with low PPI and the absence of significant PVL. A randomized controlled trial is being planned to prove the superiority of this alternative sizing method.

Use of virtual reality for procedural planning of transcatheter aortic valve replacement

This study sought to evaluate the impact of virtual reality (VR) tools in procedural planning of transcatheter aortic valve replacement. A prospective study involving 11 patients referred for transcatheter aortic valve replacement was conducted. A multidetector computed tomography was used to acquire and segment the anatomy of the access route and landing zone. From the information obtained with the multidetector computed tomography in DICOM format, we built a virtual platform (VisuaMed, Techer Team, Valencia, Spain) that contains all the clinical information of the patients and a virtualized model of their anatomy. Wearing VR devices, the professional was able to 'walk inside' the anatomy in an interactive and immersive way. Decisions after the evaluation of routine clinical images were compared with those after experience with VR models and intraprocedural findings.

Preoperative TAVR Planning: How to Do It

Transcatheter aortic valve replacement (TAVR) is a well-established treatment option for patients with severe symptomatic aortic stenosis (AS) whose procedural efficacy and safety have been continuously improving. Appropriate preprocedural planning, including aortic valve annulus measurements, transcatheter heart valve choice, and possible procedural complication anticipation is mandatory to a successful procedure. The gold standard for preoperative planning is still to perform a multi-detector computed angiotomography (MDCT), which provides all the information required. Nonetheless, 3D echocardiography and magnet resonance imaging (MRI) are great alternatives for some patients. In this article, we provide an updated comprehensive review, focusing on preoperative TAVR planning and the standard steps required to do it properly.

Imaging Modalities Employed in the TAVR Procedure With a Focus on CTA: What the Radiologist Needs to Know

RATIONALE AND OBJECTIVES

Aortic stenosis (AS) is one of the most common valvular heart disease. Symptomatic AS is associated with a high mortality rate which prompts fast intervention. The introduction of transcatheter aortic valve replacement (TAVR) has drastically improved the outcome of high surgical risk for mortality patients with severe AS. However, this procedure requires the employment of multimodality imaging in the pre-procedural planning, intra-procedural optimization, and post-procedural follow-up stages. This also requires an accurate understanding of the indications, measurements, strength, and limitations of each imaging modality during the different TAVR stages.

CONCLUSION

In this review, we aim to outline to radiologists the evidence-based approach and indications of different imaging modalities through the pre, peri, and post TAVR stages.

The role of far-field intravascular ultrasound in transcatheter aortic valve replacement

Precise and accurate characterization of the aortic valve complex is a vital step in the procedure planning for transcatheter aortic valve replacement (TAVR). Far-field intravascular ultrasound (IVUS) is a novel technology that can be utilized to assess aortic valve annulus and predict paravalvular leak, with comparable results to multi-detector computed tomography-the current gold standard in the preprocedural planning in TAVR. Far-field IVUS carries the advantage of minimal contrast use and lower radiation exposure. In this commentary, we describe two cases of far-field IVUS use during TAVR procedures and review its role as a complementary tool to current the imaging modalities used in TAVR.

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.

Transcatheter aortic valve implantation results are not superimposable to surgery in patients with aortic stenosis at low surgical risk

BACKGROUND

The aim of this meta-analysis was to compare the impact of transcatheter aortic valve implantation (TAVI) vs. surgical aortic valve replacement (SAVR) in patients with severe aortic valve stenosis (AS) at low surgical risk.

METHODS

All randomized controlled trials (RCTs) and observational studies (Obs) published from January 2014 until March 31st, 2020 were retrieved through the PubMed computerized database and at the site https://www.

CLINICALTRIALS

com. The relative risk (RR) with the 95% confidence interval (CI) was used to evaluate the effect of the intervention under comparison. The primary endpoints were all-cause 30-day mortality and 1-year mortality. The 30-day safety endpoints were: stroke, acute kidney injury stage 2 or 3, major bleeding, moderate/severe paravalvular leak, need for new permanent pacemaker (PM) implantation.

RESULTS

After detailed review 9 studies, related to 4 RCTs and 5 Obs, were selected. The overall analysis of RCTs plus Obs showed a significantly lower 30-day mortality for TAVI (RR = 0.55; 95% CI 0.45-0.68, p < 0.00001; I2 = 0%). However, an increased risk of new PM implantation (RR = 2.87; 95% CI 2.01-3.67, p < 0.00001, I2 = 0%) and of paravalvular leak (RR = 7.28; 95% CI 3.83-13.81, p < 0.00001, I2 = 0%) was observed in TAVI compared to SAVR. On the contrary, a lower incidence of major bleeding (RR = 0.38; 95% CI 0.27-0.54, p < 0.00001, I2 = 0%) and of acute kidney injury was observed (RR = 0.33; 95% CI 0.19-0.56, p < 0.0001, I2 = 0%) in TAVI.

CONCLUSIONS

TAVI and SVAR in the treatment of AS in the patients at low surgical risk are not superimposable. In particular, if 30-day and 1-year mortality, major bleeding and acute kidney injury were significantly lower for TAVI, the need of new PM implantation and paravalvular leak were significantly lower in SAVR. Consequently, we suggest the need of more trials to evaluate the effectiveness of TAVI as routine therapeutic procedure in the treatment of patients with low surgical risk AS.

Transcatheter aortic valve replacement: impact of pre-procedural FEops HEARTguide assessment on device size selection in borderline annulus size cases

OBJECTIVES

The aim of this study is to evaluate device size selection in patients within the borderline annulus size range undergoing transcatheter aortic valve replacement (TAVR) and to assess if pre-procedural patient-specific computer simulation will lead to the selection of a different device size than standard of care.

BACKGROUND

In TAVR, appropriate device sizing is imperative. In borderline annulus size cases no standardised technique for tailored device size selection is currently available. Pre-procedural patient-specific computer simulation can be used, predicting the risk for paravalvular leakage (PVL) and need for permanent pacemaker implantation (PPI).

METHODS

In this multicentre retrospective study, 140 patients in the borderline annulus size range were included. Hereafter, device size selection was left to the discretion of the operator. After TAVR, in 24 of the 140 patients, patient-specific computer simulation calculated the most appropriate device size expected to give the lowest risk for PVL and need for PPI. In these 24 patients, device size selection based on patient-specific computer simulation was compared with standard-of-care device size selection relying on a standardised matrix (Medtronic).

RESULTS

In a significant proportion of the 140 patients (26.4%) a different device size than recommended by the matrix was implanted. In 10 of the 24 patients (41.7%) in whom a computer simulation was performed, a different device size was recommended than by means of the matrix.

CONCLUSIONS

Device size selection in patients within the borderline annulus size range is still ambiguous. In these patients, patient-specific computer simulation is feasible and can contribute to a more tailored device size selection.

A New WATCHMAN Sizing Algorithm Utilizing Cardiac CTA

BACKGROUND

The WATCHMAN left atrial appendage (LAA) occlusion device has emerged as an alternative for anticoagulation in patients with non-valvular atrial fibrillation who cannot tolerate oral anticoagulation therapy. Cardiac computed tomography (CTA) is increasingly being utilized to guide WATCHMAN device sizing, however no consensus algorithm exists. We present our experience with a new cardiac CTA LAA ostium area based sizing algorithm.

METHODS

This is a single center, prospective study analyzing consecutive patients who underwent cardiac CTA and WATCHMAN device implantation between March 2017 and October 2019 at University Hospitals Cleveland Medical Center. Patients baseline characteristics, procedural data, and clinical outcomes were collected and analyzed.

RESULTS

115 patients were included in our study. The mean age of our population was 76.5 years ±8.3 years. 70.4% of our patients had preserved ejection fraction. The predominant indication for device implantation was gastrointestinal bleeding in 57.4% of patients. The mean CHADSVASC score was 4.68 ± 1.4. The procedure success rate was 99.1% and the mean number of device used per case of 1.15 ± 0.4 devices. Our CTA LAA ostium area based sizing algorithm accurately predicted the final deployed WATCHMAN device size in 95.6% of cases.

CONCLUSION

Our study demonstrates that cardiac CTA LAA ostium area based sizing algorithm is highly accurate at predicting WATCHMAN device size and demonstrates excellent clinical outcomes with lower device utilization per case than what is reported in literature.

Comparison of Deep Sedation and General Anesthesia With an Endotracheal Tube for Transcaval Transcatheter Aortic Valve Replacement: A Pioneering Institution's Experience

OBJECTIVES

Transcaval transcatheter aortic valve replacement (TC-TAVR) is an alternative approach to transcatheter aortic valve replacement involving deployment of the bioprosthetic valve via a conduit created from the inferior vena cava to the descending aorta in patients for whom the traditional transfemoral approach is not feasible. By analyzing the largest known cohort of TC-TAVR patients, the authors wished to compare hospital length of stay and post-procedure outcomes between patients who underwent the procedure under deep sedation (DS) and patients who underwent general anesthesia with an endotracheal tube.

DESIGN

Retrospective, single-center study.

SETTING

Henry Ford Hospital in Detroit, MI.

PARTICIPANTS

Patients undergoing TC-TAVR from 2015 to 2018.

MEASUREMENTS AND MAIN RESULTS

Seventy-nine patients were included in the analysis, which consisted of 38 under general anesthesia with an endotracheal tube and 41 under DS. The sample was divided into a general anesthesia (GA) group and DS group. There were no significant differences in implant success rate or post-procedure outcomes, including in-hospital mortality (p = 0.999) and major vascular complication rate (p = 0.481), between the two groups. Patients in the GA group stayed a median of 24 hours longer in the intensive care unit (ICU) (p < 0.001) and one day longer in the hospital (p = 0.046) after the procedure compared to patients in the DS group. The median procedure time was significantly lower (135 minutes) in the DS group compared to the GA group (167 minutes, p < 0.001).

CONCLUSIONS

Patients undergoing TC-TAVR under DS had similar postoperative outcomes and shorter post-procedure hospital and ICU lengths of stay compared to general anesthesia. In the authors' experience, DS is the preferred anesthetic technique for TC-TAVR.

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.

Bench to bedside defining calcific aortic valve disease: osteocardiology

INTRODUCTION

For years, calcific aortic valve disease (CAVD) was thought to be due to a degenerative process, but recent scientific discoveries have proven it to be an active process. Understanding the cellular mechanisms for the development of disease and translating the cellular changes critical in the development of calcific phenotypes. The use of multimodality imaging has been the gold standard to define the development of calcification to determine the timing of therapy.

AREAS COVERED

This review will discuss the scientific literature in a new and evolving field known as osteocardiology, which specifically defines the cellular mechanisms involved in the development of the osteogenic phenotype in the heart and vasculature. The work in this field has been highlighted by the calcific aortic valve disease working group at the NIH. This review will discuss the appropriate use criteria for multimodality imaging techniques to identify early cellular and hemodynamic disease progression in the aortic valve to help determine the timing of therapy, the osteocardiology theory.

EXPERT OPINION

The authors will provide their background in basic science and clinical medicine to support the opinions in this paper.

The emerging applications of cardiovascular magnetic resonance imaging in transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is an alternative to surgical aortic valve replacement in selected patients with severe symptomatic aortic stenosis (AS) and high surgical risk. The planning and follow-up of TAVI requires an array of imaging techniques, each has advantages and limitations. Echocardiography and multidetector computer tomography (MDCT) have established applications in patient selection and procedure guidance, but are limited in some patients. TAVI applications of cardiovascular magnetic resonance imaging (CMRI) are emerging. CMRI can provide the structural and functional imaging details required for TAVI procedure in away comparable or superior to that obtained by echocardiography and MDCT combined. In this review, we look at the continuously evolving role of CMRI as a complimentary or an alternative to more established imaging techniques and address the advantages and disadvantages of CMRI in this setting. We discuss the role of CMRI in selecting anatomically suitable patients for the TAVI procedure and in the post-TAVI follow-up with particular emphasis on its applications for assessing AS severity and haemodynamic impact, vascular imaging for TAVI access route, quantification of paravalvular leaks and LV remodelling in the post TAVI setting as well as providing imaging biomarkers tool for AS risk-stratification.

Does transcatheter aortic valve alignment matter?

Objective

This study investigates the effect of transcatheter aortic valve (TAV) angular alignment on the postprocedure haemodynamics. TAV implantation has emerged as an effective alternative to surgery when treating valve dysfunction. However, the benefit of avoiding surgery is paid back by the inability to remove the native diseased leaflets and accurately position the device in relation to the aortic root, and the literature has shown the root anatomy and substitute position can play an essential role on valve function.

Methods

A commercial TAV was placed in a silicone mock aortic root in vitro, including mock native leaflets, and either aligned commissure-to-commissure or in maximum misalignment. Haemodynamic performance data at various stroke volumes were measured, and Particle Image Velocimetry analysis was performed at a typical stroke volume for rest conditions. The two configurations were also studied without mock native leaflets, for comparison with previous in vitro studies.

Results

Haemodynamic performance data were similar for all configurations. However, imaging analysis indicated that valve misalignment resulted in the central jet flow not extending to the root wall in the native commissures’ vicinity, replaced by a low shear flow, and a reduction of upper sinus flow of 40%, increasing flow stagnation in the sinus.

Conclusions

TAV misalignment did not result in a significant change in valve hydrodynamic performance, but determined some change in the fluid flow patterns, which may promote pathological scenarios, such as increased thrombogenicity of blood flow within the sinuses of Valsalva, and plaque formation around the lumen of the sinotubular junction.

Elastin-Dependent Aortic Heart Valve Leaflet Curvature Changes During Cyclic Flexure

The progression of calcific aortic valve disease (CAVD) is characterized by extracellular matrix (ECM) remodeling, leading to structural abnormalities and improper valve function. The focus of the present study was to relate aortic valve leaflet axial curvature changes as a function of elastin degradation, which has been associated with CAVD. Circumferential rectangular strips (L × W = 10 × 2.5 mm) of normal and elastin-degraded (via enzymatic digestion) porcine AV leaflets were subjected to cyclic flexure (1 Hz). A significant increase in mean curvature (p < 0.05) was found in elastin-degraded leaflet specimens in comparison to un-degraded controls at both the semi-constrained (50% of maximum flexed state during specimen bending and straightening events) and fully-constrained (maximally-flexed) states. This significance did not occur in all three flexed configurations when measurements were performed using either minimum or maximum curvature. Moreover, the mean curvature increase in the elastin-degraded leaflets was most pronounced at the instance of maximum flexure, compared to un-degraded controls. We conclude that the mean axial curvature metric can detect distinct spatial changes in aortic valve ECM arising from the loss in bulk content and/or structure of elastin, particularly when there is a high degree of tissue bending. Therefore, the instance of maximum leaflet flexure during the cardiac cycle could be targeted for mean curvature measurements and serve as a potential biomarker for elastin degradation in early CAVD remodeling.

Usefulness of skeletal muscle area detected by computed tomography to predict mortality in patients undergoing transcatheter aortic valve replacement: a meta-analysis study

Measures of sarcopenia, such as low muscle mass measured from the readily available preoperative computed tomography (CT) images, have been recently suggested as a predictor of outcomes in patients undergoing transcatheter aortic valve replacement (TAVR). However, results of these studies are variable and, therefore, we performed a systematic review of current literature to evaluate sarcopenia as a predictor of outcome post TAVR. The search was carried out in electronic databases between 2008 and 2018. We identified studies that reported CT-derived skeletal muscle area (SMA) and survival outcomes post TAVR. Studies were evaluated for the incidence of early (≤ 30 days) and late all-cause mortality (> 30 days) post TAVR. Eight studies with 1881 patients were included (mean age of 81.8 years ± 12, 55.9% men). Mean body mass index was (28.2 kg/m² ± 1.1), mean Society of Thoracic Surgeons risk score (7.0 ± 0.6), and mean albumin level was (3.8 g/dL ± 0.1). Higher SMA was associated with lower long-term mortality [odds ratio (OR) 0.49, 95% confidence interval (CI) 0.28-0.83, p = 0.049], compared with low SMA. Also, higher SMA was associated with lower early mortality but was not statistically significant (OR 0.72; 95% CI 0.44-1.18; p = 0.285). CT-derived SMA provides value in predicting post-TAVR long-term outcomes for patients undergoing TAVR. This is a simple risk assessment tool that may help in making treatment decisions and help identifying and targeting high-risk patients with interventions to improve muscle mass prior to and following the procedures.