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Background: The etiology of transcatheter aortic valve (TAV) degeneration is poorly understood, particularly noncalcific mechanisms., Objectives: The authors sought to investigate noncalcific and calcific mechanisms of TAV degeneration and evaluate their impact on leaflet function by bench testing, imaging, and histology., Methods: TAV explants were obtained from the EXPLANT THV registry and clinical institutions. Hydrodynamic assessment was performed using a heart valve pulse duplicator system under physiological conditions. Micro-computed tomography, high-resolution photography, high speed video, and hematoxylin and eosin staining were used to evaluate the morphological appearance, leaflet kinematics, and calcium burden of TAVs., Results: A total of 14 explants were evaluated: 10 self-expanding CoreValve/Evolut TAVs (Medtronic), 3 balloon-expandable SAPIEN 3 TAVs (Edwards Lifesciences), and 1 mechanically expandable Lotus TAV (Boston Scientific). The median patient age at explantation was 73.0 years (Q1-Q3: 64.5-80.0 years), with a time to explantation of 4 years 1 month (1 year 5 months to 4 years 11 months). Six TAV explants were found to have leaflet calcification (162.4 mm 3 ; 58.8-603.0 mm 3 ), and 8 had no calcification detectable by micro-computed tomography and histology. All samples had impaired leaflet kinematics. There was no significant difference in the hydrodynamic mean gradient between calcified (47.2 mm Hg; 26.6-74.1 mm Hg) and noncalcified (27.6 mm Hg; 15.2-36.7 mm Hg; P = 0.28) TAVs. Leaflet calcification had a weak but nonsignificant association with the hydrodynamic mean gradient (r = 0.42; P = 0.14)., Conclusions: TAV function can be severely impacted by noncalcific and calcific mechanisms of tissue degeneration. Importantly, functional stenosis can occur in TAVs in the absence of obvious and significant calcification., Competing Interests: Funding Support and Author Disclosures This work was supported by Medtronic, USA, and the Cardiovascular Translational Laboratory, Canada. Dr Sathananthan is the chief medical officer for Interventional Cardiology Therapies from Boston Scientific; a consultant to Medtronic and Edwards Lifesciences; has received speaking fees from Edwards Lifesciences, and NVT; and has received research support from Medtronic, Edwards Lifesciences, and Vivitro Labs. Mr Nigade, Dr Spencer, and Mr Navarro are employees and shareholders of Medtronic. Dr Meier has received an institutional grant from Edwards Lifesciences. Dr Pirelli is a consultant and receives speakers honoraria from Medtronic and Edwards Lifesciences. Dr Webb is a consultant to and has received research funding from Edwards Lifesciences, Abbott, and ViVitro Labs. Dr Wood is a consultant and receives unrestricted grant support from Medtronic, Edwards Lifesciences, and Abbott Vascular. Dr Lutter is a consultant to Medtronic, Edwards Lifesciences, and Abbott. Dr Puehler is a consultant to Abbott. Dr Tang has received speaker honoraria and served as a physician proctor, consultant, advisory board member, TAVR publications committee member, APOLLO trial screening committee member and IMPACT MR steering committee member for Medtronic, has received speaker honoraria and served as a physician proctor, consultant, advisory board member and TRILUMINATE trial anatomic eligibility and publications committee member for Abbott Structural Heart, has served as an advisory board member for Boston Scientific and JenaValve, a consultant and physician screening committee member for Shockwave Medical, a consultant for NeoChord, Peija Medical and Shenqi Medical Technology, and has received speaker honoraria from Siemens Healthineers. Dr Fukuhara is a consultant for Medtronic, Terumo Aortic, and Artivion. Dr Sellers is a consultant for Medtronic, Edwards Lifesciences, and Anteris; and has received research support from Medtronic, Edwards Lifesciences, Vivitro Labs, and HeartFlow. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Aortic blood flow patterns are closely linked to the morphology and function of the left ventricle, aortic valve and aorta. These flow patterns demonstrate the exceptional adaptability of the cardiovascular system to maintain blood circulation under a broad range of haemodynamic workloads and can be altered in various pathophysiological states. For instance, normal ascending aortic systolic flow is predominantly laminar, whereas abnormal aortic systolic flow is associated with increased eccentricity, vorticity and flow reversal. These flow abnormalities result in reduced aortic conduit function and increased energy loss in the cardiovascular system. Emerging evidence details the association of these flow patterns with loss of aortic compliance, which leads to adverse left ventricular remodelling, poor tissue perfusion, and an increased risk of morbidity and death. In this Perspective article, we review the evidence for the link between aortic flow-related abnormalities and cardiovascular disease and how these changes in aortic flow patterns are emerging as a therapeutic target for aortic valve intervention in first-in-human studies., (© 2023. Springer Nature Limited.)

Background: CT measurement of supra-annular area (SA) has been proposed as an alternative to annular area (AA) for sizing of trancatheter valves in biscuspid aortic valves (BAV). This study examines the reproducibility of SA and AA measurements and their potential impact on downstream transcatheter heart valve sizing and clinical outcomes., Methods: 44 consecutive patients (mean age: 73 ± 15 years, 57% male) undergoing CTA with subsequent SAPIEN 3 valve insertion for severe bicuspid aortic stenosis (AS) were included. AA was measured at the basal ring. SA was measured by generating a circle defined by the intercommisural distance. AA and SA were measured by 2 independent observers. Baseline characteristics, TAVR procedural data, and discharge echocardiography data were collected., Results: The SA was significantly larger than the AA (562 ± 146mm2 vs. 518 ± 112mm2,p = 0.013). Interobserver agreement was high using both techniques (ICC AA = 0.98,p < 0.001; SA = 0.80,p < 0.001), but with narrower limits of agreement with AA measurements (mean difference (limits of agreement): AA = -3mm2 (22; 19), SA = -16mm2 (-92; 76)). AA-based device sizing demonstrated substantial agreement with final valve inserted (κ = 0.72,p < 0.001), while SA demonstrated fair agreement (κ = 0.40,p < 0.001). There was no difference in post TAVR gradients, paravalvular leakage or valve success between patients with concordant sizing between AA and SA, and those in whom SA would have suggested an alternate valve size., Conclusions: Supra-annular sizing is less reproducible than annular sizing, with no difference in procedural complication rates in patients in whom supra-annular sizing would have altered the device size used. These results suggest no role for supra-annular sizing in current clinical practice., Competing Interests: Declaration of competing interest Drs. Webb, Blanke, Leipsic, and Wood are consultants to and have received research support from Edwards Life-sciences. Dr. Blanke has served as a consultant for Neovasc, Tendyne, and Circle Cardiovascular Imaging. Dr. Leipsic has received support through his institutional core laboratory from Edwards, Medtronic, Abbott, and Neovasc; and has served as a consultant for and has stock options in CIRCL CVI and Heartflow. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2020 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)

Background: Bioprosthetic aortic valve degeneration is increasingly common, often unheralded, and can have catastrophic consequences., Objectives: The authors sought to assess whether 18 F-fluoride positron emission tomography (PET)-computed tomography (CT) can detect bioprosthetic aortic valve degeneration and predict valve dysfunction., Methods: Explanted degenerate bioprosthetic valves were examined ex vivo. Patients with bioprosthetic aortic valves were recruited into 2 cohorts with and without prosthetic valve dysfunction and underwent in vivo contrast-enhanced CT angiography, 18 F-fluoride PET, and serial echocardiography during 2 years of follow-up., Results: All ex vivo, degenerate bioprosthetic valves displayed 18 F-fluoride PET uptake that colocalized with tissue degeneration on histology. In 71 patients without known bioprosthesis dysfunction, 14 had abnormal leaflet pathology on CT, and 24 demonstrated 18 F-fluoride PET uptake (target-to-background ratio 1.55 [interquartile range (IQR): 1.44 to 1.88]). Patients with increased 18 F-fluoride uptake exhibited more rapid deterioration in valve function compared with those without (annualized change in peak transvalvular velocity 0.30 [IQR: 0.13 to 0.61] vs. 0.01 [IQR: -0.05 to 0.16] ms -1 /year; p < 0.001). Indeed 18 F-fluoride uptake correlated with deterioration in all the conventional echocardiographic measures of valve function assessed (e.g., change in peak velocity, r = 0.72; p < 0.001). Each of the 10 patients who developed new overt bioprosthesis dysfunction during follow-up had evidence of 18 F-fluoride uptake at baseline (target-to-background ratio 1.89 [IQR: 1.46 to 2.59]). On multivariable analysis, 18 F-fluoride uptake was the only independent predictor of future bioprosthetic dysfunction., Conclusions: 18 F-fluoride PET-CT identifies subclinical bioprosthetic valve degeneration, providing powerful prediction of subsequent valvular dysfunction and highlighting patients at risk of valve failure. This technique holds major promise in the diagnosis of valvular degeneration and the surveillance of patients with bioprosthetic valves. (18F-Fluoride Assessment of Aortic Bioprosthesis Durability and Outcome [18F-FAABULOUS]; NCT02304276)., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Amid rapid growth in transcatheter valvular interventions computed tomography (CT) has emerged as a pivotal noninvasive imaging resource that can be used throughout many stages of the transcatheter heart valve process, enhancing procedural success and efficacy. It affords a three-dimensional assessment of the aortic and challenging saddle-shaped mitral annulus, facilitating appropriate device selection, sizing, and preprocedural prediction angles for prosthetic deployment. Postprocedural imaging allows documentation of procedural success, evaluation of prosthesis positioning, and identifying asymptomatic complications. This article provides an overview of the role of CT in both trancatheter aortic valve repair (TAVR) and transcatheter mitral valve replacement (TMVR)., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objectives: This study investigated processes causing leaflet thickening and structural valve degeneration (SVD)., Background: Although transcatheter aortic valve replacement (TAVR) has changed the treatment of aortic stenosis, concerns remain regarding SVD, potentially related to valve thrombosis and thickening, based on studies using computed tomography (CT). Detailed histological analyses are provided to help attain insights into these processes., Methods: Explanted transcatheter heart valves (THVs) were evaluated for thrombosis, fibrosis, and calcification for quantification of leaflet thickness. Immunohistochemical and microscopy approaches were used to investigate SVD-associated mechanisms., Results: THVs (n = 23) were obtained from 22 patients (median 81 years of age; 50% male) from 0 to 2,583 days post TAVR. Maximal leaflet thickness increased relative to implant duration (ρ = 0.427; p = 0.027). THVs explanted after >2 years were thicker than those explanted after <2 years (p = 0.007). All THVs had adherent thrombus on both aortic and ventricular sides, which beyond 60 days was seen in combination with fibrosis and beyond 4 years had calcification. Early thrombus formation (<60 days) occurred despite rapid endothelialization with an abnormal hyperplastic phenotype. Fibrosis was observed in 6 patients on both the aortic and the ventricular THV surfaces, remodeled over time, and was associated with matrix metalloproteinase-1 expression. Five THVs showed overt calcification associated with adherent thrombus and fibrosis., Conclusions: There is a time-dependent degeneration of THVs consisting of thrombus formation, endothelial hyperplasia, fibrosis, tissue remodeling, proteinase expression, and calcification. Future investigation is needed to further understand these mechanisms contributing to leaflet thickening and SVD., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose of Review: Recent advancements in transcatheter valvular interventions have resulted in a growing demand for advanced cardiac imaging to help guide these procedures., Recent Findings: Both echocardiography and multi-detector computed tomography have played essential roles in the maturation of transcatheter aortic valve replacement and are now building on these experiences and helping inform the nascent field of transcatheter mitral interventions. Advanced imaging is essential to aid in the diagnosis and determination of the mechanism of mitral regurgitation. In addition, they are integral to annular sizing, determination of the suitability of patient anatomy for specific devices and increasingly important in the determination of the risk of left ventricular outflow tract obstruction and providing appropriate patient-specific fluoroscopic angulation in advance of the procedure.

The success and continued rapid clinical integration of transcatheter valve technologies relies on imaging modalities to guide safe and effective device deployment. In particular, cardiac imaging, using both echocardiography and CT, is an integral resource for the multidisciplinary team. These modalities can provide valuable insight for the proceduralist at each stage of transcatheter-based valve insertion, as they can be used reliably to define the anatomy of interest and its relationship to surrounding structures, determine accurate device sizing, assess patients for valve-in-valve procedures, and screen for adverse features or procedural contraindications. We provide an overview of some of the key aspects of the use of CT and echocardiography in the context of transcatheter aortic valve replacement (TAVR), as well as transcatheter mitral valve replacement (TMVR).

Objectives: This study sought to determine if indexed effective orifice area (EOAi), using left ventricular outflow tract measured from computed tomography (EOAi CT ), reclassified prosthesis-patient mismatch (PPM) compared with conventional echocardiogram-defined measurements (EOAi TTE )., Background: PPM does not predict mortality following transcatheter aortic valve replacement (TAVR). However, it is unknown if the EOAi CT of the left ventricular outflow tract improves risk stratification., Methods: A total of 765 TAVR patients from the PARTNER II (Placement of Aortic Transcatheter Valves II) trial S3i cohort were evaluated. EOAi was calculated using the continuity equation, and the left ventricular outflow tract area was derived from baseline computed tomography. Traditional echocardiographic categories defined PPM: absent (>0.85 cm 2 /m 2 ), moderate (≥0.65 and ≤0.85 cm 2 /m 2 ), or severe (≤0.65 cm 2 /m 2 ). Correlation of EOAi CT and EOAi TTE to 1-year outcomes was performed., Results: The incidence of PPM was 24% with EOA CT compared with 45% with EOAi TTE . Only 6% of PPM was graded severe by EOAi CT compared with 9% by EOAi TTE . EOAi TTE , but not EOAi CT , defined PPM showed association with reduced left ventricular mass regression (p = 0.03 vs. p = 0.52). There was no association between PPM and death or rehospitalization at 1 year with either modality. EOA CT was associated with minor stroke at 1 year (log-rank p = 0.04), and EOAi TTE with stroke/transient ischemic attack (log-rank p = 0.030). Furthermore, when subjects with mild or greater paravalvular regurgitation were excluded, the presence of PPM did not show association with any outcome., Conclusions: EOAi CT downgrades frequency and severity of PPM in patients after TAVR, and was not associated with mortality 1 year after TAVR. EOAi TTE , but not EOAi CT , was associated with less left ventricular mass regression., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)