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A virtual workshop was organized by the Heart Valve Collaboratory to identify areas of expert consensus, areas of disagreement, and evidence gaps related to bioprosthetic aortic valve hemodynamics. Impaired functional performance of bioprosthetic aortic valve replacement is associated with adverse patient outcomes; however, this assessment is complicated by the lack of standardization for labelling, definitions, and measurement techniques, both after surgical and transcatheter valve replacement. Echocardiography remains the standard assessment methodology because of its ease of performance, widespread availability, ability to do serial measurements over time, and correlation with outcomes. Management of a high gradient after replacement requires integration of the patient's clinical status, physical examination, and multimodality imaging in addition to shared patient decisions regarding treatment options. Future priorities that are underway include efforts to standardize prosthesis sizing and labelling for both surgical and transcatheter valves as well as trials to characterize the consequences of adverse hemodynamics., Competing Interests: Funding Support and Author Disclosures Dr Herrmann has received institutional research funding from Abbott, Boston Scientific, Edwards Lifesciences, Highlife, Medtronic, and WL Gore; has received consulting fees from Edwards Lifesciences, Medtronic, Wells Fargo, and WL Gore; and has equity in Holistick Medical and Microinterventional Devices. Dr Pibarot has received funding from Edwards Lifesciences, Medtronic, Pi-Cardia, and Cardiac Phoenix for echocardiography core laboratory analyses and research studies in the field of transcatheter valve therapies, for which he received no personal compensation. Dr Hahn has received speaker fees from Abbott Structural and Edwards Lifesciences; has institutional consulting contracts for which she receives no direct compensation with Abbott Structural, Boston Scientific, Edwards Lifesciences, Medtronic, and Novartis; has served on the Scientific Advisory Board for Novartis; and has equity in Navigate. Dr Tang is a physician proctor and consultant for Medtronic; has served as a consultant and physician advisory board member for Abbott Structural Heart; has served as a consultant for NeoChord; and has served as a physician advisory board member for JenaValve. Dr Abbas has received research grants and consulting fees from Edwards Lifesciences. Dr Playford has received investigator-initiated research funding from Edwards Lifesciences, Pfizer, Novartis, Actelion, Bayer, and GlaxoSmithKline; is Chief Medical Advisor for Echo IQ; and has been a physician advisory board member for Edwards Lifesciences and AstraZeneca. Dr Ruel is a physician proctor for Medtronic (MICS CABG) and for Edwards Lifesciences (MICS AVR); has served as a steering committee member for Cryolife (PROACT Xa trial); and is a recipient of research funds from Medtronic (MIST trial). Dr Jilaihawi is a consultant to Boston Scientific, Edwards Lifesciences, and Medtronic; and has received grant/research support from Abbott Vascular, Edwards Lifesciences, and Medtronic. Dr Sathananthan is a consultant for and has received institutional research funding from Edwards Lifesciences and Medtronic; and has received speaker fees from NVT. Dr Wood is a consultant for and his institution (CCI-CIC) receives grant support from Edwards Lifesciences, Abbott Vascular, and Medtronic. Dr Bax’s institution (Department of Cardiology, LUMC, the Netherlands) has received research grants from Medtronic, Biotronik, Edwards Lifesciences, and Boston Scientific. Dr Rodes-Cabau has received institutional research grants from Edwards Lifesciences, Medtronic, and Boston Scientific. Dr Del Nido is cofounder of Autus Valve Technologies, Inc. Dr Dweck is a consultant to Edwards Lifesciences and Medtronic; has received research funding from Edwards Lifesciences and Medtronic; and has received speaker fees from NVT. Dr Kaneko is a consultant for Edwards, Medtronic, Abbott, and 4C Medical. Dr Latib is a consultant for Medtronic, Edwards Lifesciences, Boston Scientific, and Abbott. Dr Moat is a full-time employee of Abbott Structural Heart, Inc. Dr Modine has received research grants from Edwards Lifesciences and Medtronic; and is a consultant for Abbott, Edwards Lifesciences, Medtronic, and Microport. Dr Popma is a full-time employee of Medtronic, Inc. Dr Smith has received institutional grants from Edwards Lifesciences, Medtronic, Abbott, and Cryolife; has received advisory board fees from Edwards Lifesciences; and has received speaking honoraria from Medtronic, Cryolife, Abbott, and Edwards Lifesciences. Dr Thomas is a full-time employee of Edwards Lifesciences. Dr Yoganathan is a Principal Consultant to CardioMed Device Consultants LLC in the Structural Heart Valve area; is on the Scientific Advisory Board of Foldax Inc; and has served as Educational Consultant to Boston Scientific, Edwards Lifesciences, Abbott Cardiovascular, and Livanova. Dr Mack has served as a co-principal investigator for clinical trials for Abbott and Edwards Lifesciences; and has served as study chair for a trial for Medtronic; all roles were uncompensated. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Bioprosthetic valve dysfunction (BVD) and bioprosthetic valve failure (BVF) may be caused by structural or nonstructural valve dysfunction. Both surgical and transcatheter bioprosthetic valves have limited durability because of structural valve deterioration. The main objective of this summary of experts participating in a virtual workshop was to propose standardized definitions for nonstructural and structural BVD and BVF following aortic or mitral biological valve replacement with the goal of facilitating research reporting and implementation of these terms in clinical practice. Definitions of structural BVF, based on valve reintervention or death, underestimate the true incidence of BVF. However, definitions solely based on the presence of high transprosthetic gradient at a given echocardiogram during follow-up overestimate the incidence of structural BVD and BVF. Definitions of aortic or mitral structural BVD must therefore include the confirmation by imaging of permanent structural changes to the leaflets alongside evidence of deterioration in valve hemodynamic function at echocardiography follow-up., Competing Interests: Funding Support and Author Disclosures Dr Pibarot has received funding from Edwards Lifesciences, Medtronic, Pi-Cardia, and Cardiac Phoenix for echocardiography core laboratory analyses and research studies in the field of transcatheter valve therapies, for which he received no personal compensation; and has received lecture fees from Edwards Lifesciences and Medtronic. Dr Herrmann has received institutional research funding from Abbott, Boston Scientific, Edwards Lifesciences, Highlife, Medtronic, and WL Gore; has received consulting fees from Edwards Lifesciences, Medtronic, Wells Fargo, and WL Gore; and has equity in Holistick Medical and Microinterventional Devices. Dr Hahn has received speaker fees from Abbott Structural, Edwards Lifesciences, and Philips Healthcare; has institutional consulting contracts for which she receives no direct compensation with Abbott Structural, Boston Scientific, Edwards Lifesciences, Medtronic and Novartis; and has equity in Navigate. Dr Abbas has received research grants and consulting fees from Edwards Lifesciences. Dr Dweck has served as a consultant to Edwards Lifesciences and Medtronic; has received research funding from Edwards Lifesciences and Medtronic; and has received speaking fees from NVT. Dr Leipsic has served as a consultant for Circle CVI and MVRX; and has received institutional funding for CT core laboratory analyses from Edwards Lifesciences, Neovasc, Abbott, Medtronic, Boston Scientific, PI Cardia, and Conformal. Dr Rogers has served as a consultant and physician proctor for Edwards Lifesciences and Medtronic; has served as an advisory board member for Medtronic; and holds equity interest in Transmural Systems. Dr Sathananthan has served as a consultant to Edwards Lifesciences and Medtronic; has received research funding from Edwards Lifesciences and Medtronic; and has received speaking fees from NVT. Dr Guerrero has received institutional research grant support from Edwards Lifesciences. Dr Ternacle has served as a consultant for Philips Healthcare and Abbott Medical. Dr Barbanti has served as a consultant for Edwards Lifesciences and Boston Scientific. Dr Généreux has served as a consultant and advisor for and received speaker fees from Abbott Vascular, Abiomed, BioTrace Medical, and Medtronic; has served as a consultant for Boston Scientific, GE Healthcare, iRhythm Technologies, Opsens, Siemens, and Teleflex; has served as a consultant, PI Eclipse Trial, for Cardiovascular System Inc; has served as a consultant, advisor, and proctor for and received speaker fees and research grant from Edwards LifeSciences for the PI EARLY-TAVR and PI PROGRESS trials; has served as a consultant for and has equity in Pi-Cardia, Puzzle Medical, Saranas, and Soundbite Medical Inc; has served as a consultant for and received speaker fees from Shockwave; and has served as a consultant for the PI Feasibility study for 4C Medical. Dr Kaneko has served as a consultant for Edwards Lifesciences, Medtronic, and Abbott Structural. Dr Wood has served as a consultant to and his institution (CCI-CIC) receives grant support from Edwards Lifesciences, Abbott Vascular, and Medtronic. Dr Gillam has served as a consultant to Philips and Bracco; is an advisory board member for Edwards Lifesciences; and has core lab contracts with Edwards Lifesciences, Medtronic, and Abbott for which she receives no direct compensation. Dr Reardon has served as a consultant for Medtronic, Boston Scientific, Abbott Medical, and Gore Medical; all fees for such are to his department. Dr Rodes-Cabau has received institutional research grants from Edwards Lifesciences, Medtronic, and Boston Scientific. Dr Thourani has performed consulting/research for Abbott Vascular, Boston Scientific, Cryolife, Edwards Lifesciences, Medtronic, and Shockwave. Dr Bax’s institution (Department of Cardiology, LUMC, the Netherlands) has received research grants from Medtronic, Biotronik, Edwards Lifesciences, and Boston Scientific. Dr Mack has served as a co-principal investigator for clinical trials for Abbott and Edwards Lifesciences; and has served as study chair for a trial for Medtronic; all roles were uncompensated. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Transcatheter aortic valves (TAV) are symmetrically designed, but they are often not deployed inside cylindrical conduits with circular cross-sectional areas. Many TAV patients have heavily calcified aortic valves, which often result in deformed prosthesis geometries after deployment. We investigated the effects of deformed valve annulus configurations on a surgical bioprosthetic valve as a model for TAV. We studied valve leaflet motions, stresses and strains, and analog hydrodynamic measures (using geometric methods), via finite element (FE) modeling. Two categories of annular deformations were created to approximate clinical observations: (1) noncircular annulus with valve area conserved, and (2) under-expansion (reduced area) compared to circular annulus. We found that under-expansion had more impact on increasing stenosis (with geometric orifice area metrics) than noncircularity, and that noncircularity had more impact on increasing regurgitation (with regurgitation orifice area metrics) than under-expansion. We found durability predictors (stress/strain) to be the highest in the commissure regions of noncircular configurations such as EllipMajor (noncircular and under-expansion areas). Other clinically relevant performance aspects such as leaflet kinematics and coaptation were also investigated with the noncircular configurations. This study provides a framework for choosing the most challenging TAV deformations for acute and long-term valve performance in the design and testing phase of device development., (Copyright © 2020 by ASME.)

Purpose: Hydrodynamic performance testing is one of the core in vitro assessments required by the ISO 5840 series of standards for all prosthetic heart valves. A round-robin study carried out in 2005 in accordance with ISO 5840:2005 revealed significant variabilities in prosthetic heart valve hydrodynamic performance measurements among the participating laboratories. In order to re-examine the inter-laboratory variability based on the "state-of-the-art" under ISO 5840-1 and 5840-2:2015, the ISO Cardiac Valve Working Groups decided in 2016 to repeat the round-robin study., Methods: A total of 13 international laboratories participated in the study. The test valves were chosen to be the St. Jude Medical Masters Series mechanical valves (19 mm aortic, 25 mm aortic, 25 mm mitral, and 31 mm mitral), which were circulated among the laboratories. The testing was conducted according to a common test run sequence, with prespecified flow conditions., Results: The study revealed improved, yet still significant variability among different laboratories as compared to the 2005 study. The coefficient of variation ranged from 7.7 to 21.6% for the effective orifice area, from 10.1 to 32.8% for the total regurgitant fraction, and from 14.7 to 45.5% for the mean transvalvular pressure gradient., Conclusions: The study revealed the ambiguities in the current versions of the ISO 5840 series of standards and the shortcomings of some participating laboratories. This information has allowed the ISO Working Group to incorporate additional clarifying language into the ISO 5840-1, -2, and -3 standards that are currently under revision to improve in vitro assessments. The results presented here can also be used by the testing laboratories to benchmark pulse duplicator systems and to train and certify testing personnel.

After implantation of a transcatheter bioprosthetic heart valve its original circular circumference may become distorted, which can lead to changes in leaflet coaptation and leaflets that are stretched or sagging. This may lead to early structural deterioration of the valve as seen in some explanted transcatheter heart valves. Our in vitro study evaluates the effect of leaflet deformations seen in elliptical configurations on the damage patterns of the leaflets, with circular valve deformation as the control. Bovine pericardial tissue heart valves were subjected to accelerated wear testing under both circular (N = 2) and elliptical (N = 4) configurations. The elliptical configurations were created by placing the valve inside custom-made elliptical holders, which caused the leaflets to sag or stretch. The hydrodynamic performance of the valves was monitored and high resolution images were acquired to evaluate leaflet damage patterns over time. In the elliptically deformed valves, sagging leaflets experienced more damage from wear compared to stretched leaflets; the undistorted leaflets of the circular valves experienced the least leaflet damage. Free-edge thinning and tearing were the primary modes of damage in the sagging leaflets. Belly region thinning was seen in the undistorted and stretched leaflets. Leaflet and fabric tears at the commissures were seen in all valve configurations. Free-edge tearing and commissure tears were the leading cause of valve hydrodynamic incompetence. Our study shows that mechanical wear affects heart valve pericardial leaflets differently based on whether they are undistorted, stretched, or sagging in a valve configuration. Sagging leaflets are more likely to be subjected to free-edge tear than stretched or undistorted leaflets. Reducing leaflet stress at the free edge of non-circular valve configurations should be an important factor to consider in the design and/or deployment of transcatheter bioprosthetic heart valves to improve their long-term performance.

Although generally manufactured as circular devices with symmetric leaflets, transcatheter heart valves can become non-circular post-implantation, the impact of which on the long-term durability of the device is unclear. We investigated the effects of five non-circular (EllipMajor, EllipMinor, D-Shape, TriVertex, TriSides) annular configurations on valve leaflet stresses and valve leaflet deformations through finite element analysis. The highest in-plane principal stresses and strains were observed under an elliptical configuration with an aspect ratio of 1.25 where one of the commissures was on the minor axis of the ellipse. In this elliptical configuration (EllipMinor), the maximum principal stress increased 218% and the maximum principal strain increased 80% as compared with those in the circular configuration, and occurred along the free edge of the leaflet whose commissures were not on the minor axis (i.e., the "stretched" leaflet). The D-Shape configuration was similar to this elliptical configuration, with the degree to which the leaflets were stretched or sagging being less than the EllipMinor configuration. The TriVertex and TriSides configurations had similar leaflet deformation patterns in all three leaflets and similar to the Circular configuration. In the D-Shape, TriVertex, and TriSides configurations, the maximum principal stress was located near the commissures similar to the Circular configuration. In the EllipMinor and EllipMajor configurations, the maximum principal stress occurred near the center of the free edge of the "stretched" leaflets. These results further affirm recommendations by the International Standards Organization (ISO) that pre-clinical testing should consider non-circular configurations for transcatheter valve durability testing.

Submission of data regarding the cavitation potential of a mechanical heart valve is recommended by the U.S. Food and Drug Administration in the device-review process. An acoustic method has long been proposed for cavitation detection. However, the question as to whether such a method can differentiate the cavitation noise from the mechanical closing sound has not been sufficiently addressed. In this study, cavitation near a Medtronic Hall tilting disc valve was investigated in a pressurized pulsatile duplicator. The purpose of pressurizing the testing chambers was to prevent cavitation under a normally cavitating loading condition to isolate the mechanical closing sound. By comparing the sound signals before and after pressurization, some noticeable differences were found between them. In the time domain, the intensity of the sound under a cavitating condition was much higher. In the frequency domain, the energy distribution of a sound signal was distinctively different depending on whether cavitation occurred or not. The valve closing sound had a large amount of energy in the low-frequency range (less than about 25 kHz). When cavitation took place, the sound energy shifted toward the high-frequency range (from 25 to 500 kHz).

Objective: More than 200,000 aortic valve replacements are performed annually worldwide. We describe changes in the aortic valve replacement population during 10 years in a large registry and analyze outcomes., Methods: The Society of Thoracic Surgeons National Database was queried for all isolated aortic valve replacements between January 1, 1997, and December 31, 2006. After exclusion for endocarditis and missing age or sex data, 108,687 isolated aortic valve replacements were analyzed. Time-related trends were assessed by comparing distributions of risk factors, valve types, and outcomes in 1997 versus 2006. Differences in case mix were summarized by comparing average predicted mortality risks with a logistic regression model. Differences across subgroups and time were assessed., Results: There was a dramatic shift toward use of bioprosthetic valves. Aortic valve replacement recipients in 2006 were older (mean age 65.9 vs 67.9 years, P < .001) with higher predicted operative mortality risk (2.75 vs 3.25, P < .001); however, observed mortality and permanent stroke rate fell (by 24% and 27%, respectively). Female sex, age older than 70 years, and ejection fraction less than 30% were all related to higher mortality, higher stroke rate and longer postoperative stay. There was a 39% reduction in mortality with preoperative renal failure., Conclusions: Morbidity and mortality of isolated aortic valve replacement have fallen, despite gradual increases in patient age and overall risk profile. There has been a shift toward bioprostheses. Women, patients older than 70 years, and patients with ejection fraction less than 30% have worse outcomes for mortality, stroke, and postoperative stay.

Cavitation on a mechanical heart valve (MHV) is attributable to transient regional pressure drop at the instant of valve closure. As a cavitation bubble collapses, it emits shock waves, which have the characteristics of high frequency oscillations (HFO) on a pressure time trace. The potential for such HFO bursts to cause material damage on an MHV can be measured by the cavitation impulse I, which is defined as the area under the trace of the HFO bursts. In the present study, experiments were conducted on a bileaflet MHV in a durability tester, operated at pulse rates from 300-1,000 bpm. In each case, the transient pressure near an occluder was monitored for 60,000 beats via a transducer. The peak pressure drop Pm and the corresponding cavitation impulse I obtained for the 60,000 beat sequence are found to resemble sample records of two stationary stochastic processes, each of which follows a log normal distribution. Their first order probability density functions are estimated from the records. The correlation is investigated between I and Pm associated with each beat, which is found to be of statistical significance.

Background and Aim of the Study: Cavitation damage has been observed on mechanical heart valves (MHVs) undergoing accelerated testing. Cavitation itself can be modeled as a stochastic process, as it varies from beat to beat of the testing machine. This in-vitro study was undertaken to investigate the statistical characteristics of MHV cavitation., Methods: A 25-mm St. Jude Medical bileaflet MHV (SJM 25) was tested in an accelerated tester at various pulse rates, ranging from 300 to 1,000 bpm, with stepwise increments of 100 bpm. A miniature pressure transducer was placed near a leaflet tip on the inflow side of the valve, to monitor regional transient pressure fluctuations at instants of valve closure. The pressure trace associated with each beat was passed through a 70 kHz high-pass digital filter to extract the high-frequency oscillation (HFO) components resulting from the collapse of cavitation bubbles. Three intensity-related measures were calculated for each HFO burst: its time span; its local root-mean-square (LRMS) value; and the area enveloped by the absolute value of the HFO pressure trace and the time axis, referred to as cavitation impulse. These were treated as stochastic processes, of which the first-order probability density functions (PDFs) were estimated for each test rate., Results: Both the LRMS value and cavitation impulse were log-normal distributed, and the time span was normal distributed. These distribution laws were consistent at different test rates., Conclusion: The present investigation was directed at understanding MHV cavitation as a stochastic process. The results provide a basis for establishing further the statistical relationship between cavitation intensity and time-evolving cavitation damage on MHV surfaces. These data are required to assess and compare the performance of MHVs of different designs.