Standardized Definition of Structural Valve Degeneration for Surgical and Transcatheter Bioprosthetic Aortic Valves

Brillouin confocal microscopy to determine biomechanical properties of SULEEI-treated bovine pericardium for application in cardiac surgery

BACKGROUND

Heart valves are exposed to a highly dynamic environment and underlie high tensile and shear forces during opening and closing. Therefore, analysis of mechanical performance of novel heart valve bioprostheses materials, like SULEEI-treated bovine pericardium, is essential and usually carried out by uniaxial tensile tests. Nevertheless, major drawbacks are the unidirectional strain, which does not reflect the in vivo condition and the deformation of the sample material. An alternative approach for measurement of biomechanical properties is offered by Brillouin confocal microscopy (BCM), a novel, non-invasive and three-dimensional method based on the interaction of light with acoustic waves.

OBJECTIVE

BCM is a powerful tool to determine viscoelastic tissue properties and is, for the first time, applied to characterize novel biological graft materials, such as SULEEI-treated bovine pericardium. Therefore, the method has to be validated as a non-invasive alternative to conventional uniaxial tensile tests.

METHODS

Vibratome sections of SULEEI-treated bovine pericardium (decellularized, riboflavin/UV-cross-linked and low-energy electron irradiated) as well as native and GA-fixed controls (n = 3) were analyzed by BCM. In addition, uniaxial tensile tests were performed on equivalent tissue samples and Young's modulus as well as length of toe region were analyzed from stress-strain diagrams. The structure of the extracellular matrix (ECM), especially collagen and elastin, was investigated by multiphoton microscopy (MPM).

RESULTS

SULEEI-treated pericardium exhibited a significantly higher Brillouin shift and hence higher tissue stiffness in comparison to native and GA-fixed controls (native: 5.6±0.2 GHz; GA: 5.5±0.1 GHz; SULEEI: 6.3±0.1 GHz; n = 3, p < 0.0001). Similarly, a significantly higher Young's modulus was detected in SULEEI-treated pericardia in comparison to native tissue (native: 30.0±10.4 MPa; GA: 31.8±10.7 MPa; SULEEI: 42.1±7.0 MPa; n = 3, p = 0.027). Native pericardia showed wavy and non-directional collagen fibers as well as thin, linear elastin fibers generating a loose matrix. The fibers of GA-fixed and SULEEI-treated pericardium were aligned in one direction, whereat the SULEEI-sample exhibited a much denser matrix.

CONCLUSION

BCM is an innovative and non-invasive method to analyze elastic properties of novel pericardial graft materials with special mechanical requirements, like heart valve bioprostheses.

Serial echocardiographic evaluation of the Perimount Magna Ease prosthesis

Background

The Carpentier-Edwards Perimount Magna Ease prosthesis (PME) represents the latest generation of stented bioprostheses used for surgical aortic valve replacement (SAVR). The aim of our study was to evaluate the long-term clinical outcome and hemodynamic performance of the prosthesis with a focus on the incidence and course of structural valve deterioration (SVD) by serial echocardiographic examinations.

Methods

SAVR with the PME was performed in 58 consecutive patients between 2007 and 2008. Transthoracic echocardiography was performed preoperatively, at discharge and annually during a 10-year follow-up at the German Heart Center Munich.

Results

Mean age at surgery was 62±14 years. At discharge (n=57), the overall mean pressure gradient (MPG) and effective orifice area (EOA) were 15.8±4.1 mmHg and 1.8±0.4 cm², respectively. Moderate patient-prosthesis mismatch (PPM) was present in 18 patients (32%) and severe PPM in 6 patients (11%) at discharge. Ten years following SAVR (n=33), the overall MPG was 16.6±7.3 mmHg and EOA was 1.3±0.4 cm².Thirty-day and late mortality was 2% (n=1) and 21% (n=12), respectively. Survival at 1, 5, and 10 years was 94.7%±3.3%, 91.1%±4.1%, and 77.3%±5.9%, respectively. Freedom from reoperation at 10 years was 88.8%±4.7%. Ten years after PME implantation the cumulative incidence of any SVD, severe SVD, and bioprosthetic valve failure (BVF) was 25%±6%, 14%±5%, and 16%±5%, respectively.

Conclusions

The PME shows an excellent hemodynamic performance over the course of 10 years with development of clinically relevant SVD as late as 6 years post implant, and a 10-year incidence of severe SVD of 14%.

Reintervention rates following bioprosthetic surgical aortic valve replacement-a Danish Nationwide Cohort Study

OBJECTIVES

Updated European guidelines recommend annual echocardiographic evaluation after bioprosthetic surgical aortic valve replacement (bio-SAVR). Given the increased demand on health care resources, only clinically relevant controls can be prioritized. We therefore aimed to explore reintervention rates following bio-SAVR.

METHODS

From the nationwide Danish Register of Surgical Procedures, we identified all patients ≥40 years with isolated bio-SAVR ± concomitant coronary artery bypass graft surgery (CABG) during 2000-2016. In 90-day reintervention-free survivors, we assessed aortic valve reintervention rates (primary outcome) and all-cause mortality rates (secondary outcome) at 1, 3 and 5 years with total follow-up until 31 December 2017 and further estimated annual theoretical echocardiographic control visits.

RESULTS

In 10 518 patients with bio-SAVR (+CABG 39.7%), we observed low reintervention rates at 1, 3 and 5 years, but with high rates of all-cause mortality; i.e. 5-year reintervention rate of 3.7/1000 person-years (≤1.5%) and 5-year mortality rate of 21.7/1000 person-years. Accounting for the competing risk of death, 5-year rates were inversely related to age group and remained relatively low across all age categories but increased gradually in the long term. A significant proportion of reinterventions were presumed due to infectious endocarditis (48% at 3 years, 37% at 5 years). With annual transthoracic echocardiography, the theoretical ratio of echocardiographies per reintervention in the first 5 years was 248, and 425 when endocarditis events were excluded.

CONCLUSION

Reintervention rates within the first 5 years following bio-SAVR were relatively rare, and with a substantial number due to endocarditis.

Left Ventricle Mass Regression After Surgical or Transcatheter Aortic Valve Replacement in Veterans

BACKGROUND

Differences in left ventricular mass regression (LVMR) between transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR) have not been studied. We present clinical and echocardiographic data from veterans who underwent TAVR and SAVR, evaluating the degree of LVMR and its association with survival.

METHODS

We retrospectively reviewed TAVR (n = 194) and SAVR (n = 365) procedures performed in veterans from 2011 to 2019. After 1:1 propensity matching, we evaluated mortality and secondary outcomes. Echocardiographic data (median follow-up 957 days, interquartile range 483-1652 days) were used to evaluate LVMR, its association with survival, and predictors of LVMR.

RESULTS

There was no difference between SAVR and TAVR patients in mortality (for up to 8 years), stroke at 30 days, myocardial infarction, renal failure, prolonged ventilation, reoperation, or structural valve deterioration. SAVR patients (67.3% [101 of 150]) were more likely to have LVMR than TAVR patients (55.7% [44 of 79], P = .11). The magnitude of LVMR was greater for the SAVR patients (median, -23.3%) than for the TAVR patients (median, -17.8%, P = .062). SAVR patients with LVMR had a survival advantage over SAVR patients without LVMR (P = .016). However, LVMR was not associated with greater survival in TAVR patients (P = .248).

CONCLUSIONS

SAVR patients were more likely to have LVMR and had a greater magnitude of LVMR than TAVR patients. LVMR was associated with better survival in SAVR patients, but not in TAVR patients.

Structural valve deterioration after aortic valve replacement with the Trifecta valve

OBJECTIVES

Despite promising short- and mid-term results for durability of the Trifecta valve, contradictory reports of early structural valve deterioration (SVD) do exist. We investigated the incidence of SVD after surgical aortic valve replacement (SAVR) with the Trifecta in our single-centre experience.

METHODS

Data of 347 consecutive patients (mean age 71.6 ± 9.5 years, 63.4% male) undergoing SAVR with the Trifecta between 2011 and 2017 were analysed. Clinical and echocardiographic reports were obtained with a median follow-up of 41 months (1114 patient years).

RESULTS

Isolated SAVR was performed in 122 patients (35.2%), whereas 225 patients (64.8%) underwent concomitant procedures. The median EuroSCORE II was 4.0 (0.9; 7.1) and 30-day mortality was 3.7% (n = 13). Kaplan-Meier estimates for the freedom of overall mortality at 1, 5 and 7 years were 88.7 ± 1.7%, 73.7 ± 2.6% and 64.7 ± 4.2%, respectively. SVD was observed in 25 patients (7.2%) with a median time to first diagnosis of 73 months. Freedom of SVD was 92.5 ± 0.9% at 5 years and 65.5 ± 7.1% at 7 years. Thirteen patients underwent reintervention for SVD (6 re-SAVR, 7 valve-in-valve), resulting in a freedom of reintervention for the SVD of 98.5 ± 1.1% at 5 years and 76.9 ± 6.9% at 7 years.

CONCLUSIONS

We herein report one of the highest rates of SVD after SAVR with the Trifecta. These data indicate that the durability of the prosthesis decreases at intermediate to long-term follow-up, leading to considerable rates of reintervention due to SVD.

Leaflet stress quantification of porcine vs bovine surgical bioprostheses: an in vitro study

Calcified aortic stenoses are among the most prevalent form of cardiovascular diseases in the industrialized countries. This progressive disease, with no effective medical therapy, ultimately requires aortic valve replacement - either a surgical or very recently transcatheter aortic valve implantation. Increase leaflet mechanical stress is one of the main determinants of the structural deterioration of bioprosthetic aortic valves. We applied a coupled in vitro/in silico method to compare the timing, magnitude, and regional distribution of leaflet mechanical stress in porcine versus pericardial bioprostheses (Mosaic and Trifecta). A double activation simulator was used for in vitro testing of a bioprosthesis with externally mounted pericardium (Abbott, Trifecta) and a bioprosthesis with internally mounted porcine valve (Medtronic, Mosaic). A non-contact system based on stereophotogammetry and digital image correlation (DIC) with high spatial and temporal resolution (2000 img/s) was used to visualize the valve leaflet motion and perform the three-dimensional analysis. A finite element model of the valve was developed, and the leaflet deformation obtained from the DIC analysis was applied to the finite element model calculate local leaflet mechanical stress throughout the cardiac cycle. The maximum leaflet stress was higher with the pericardial versus the porcine bioprosthesis (2.03 vs. 1.30 MPa) For both bioprostheses the highest values of leaflet stress occurred during diastole and were primarily observed in the upper leaflet edge near the commissures and to a lesser extent in the mid-portion of the leaflet body. In conclusion, the coupled in vitro/in silico method described in this study shows that the highest levels of leaflet stress occur in the regions of the commissures and mid-portion of the leaflet body. This method may have important insight with regard to bioprosthetic valve durability. Our results suggest that, compared to porcine bioprostheses, those with externally mounted pericardium have higher leaflet mechanical stress, which may translate into shorter durability.

Collagen fibre-mediated mechanical damage increases calcification of bovine pericardium for use in bioprosthetic heart valves

In cases of aortic stenosis, bioprosthetic heart valves (BHVs), with glutaraldehyde-fixed bovine pericardium leaflets (GLBP), are often implanted to replace the native diseased valve. Widespread use of BHVs, however, is restricted due to inadequate long-term durability, owing specifically to premature leaflet failure. Mechanical fatigue damage and calcification remain the primary leaflet failure modes, where glutaraldehyde treatment is known to accelerate calcification. The literature in this area is limited, with some studies suggesting mechanical damage increases calcification and others that they are independent degenerative mechanisms. In this study, specimens which were non-destructively pre-sorted according to collagen fibre architecture and uniaxially cyclically loaded until failure or 1 million cycles, were placed in an in vitro calcification solution. The weakest specimen group (those with fibres aligned perpendicular to the load) had statistically significantly higher volumes of calcification when compared to those with a high fatigue life. Moreover, SEM imaging revealed that ruptured and damaged fibres presented calcium binding sites; resulting in 4 times more calcification in fractured samples in comparison to those which did not fail by fatigue. To the authors' knowledge, this study quantifies for the first time, that mechanical damage drives calcification in commercial-grade GLBP and that calcification varies spatially according to localised damage levels. These findings illustrate that not only is calcification of GLBP exacerbated by fatigue damage, but that both failure phenomena are underpinned by the collagen fibre organisation. Consequently, controlling for GLBP collagen fibre architecture in leaflets could minimise the progression of these primary failure modes in patient BHVs. STATEMENT OF SIGNIFICANCE: Mechanical damage and calcification are the primary premature failure modes of glutaraldehyde-fixed bovine pericardial (GLBP) leaflets in bioprosthetic heart valves. In this study, commercial-grade GLBP specimens which were uniaxially cyclically loaded to failure or 1 million cycles, were placed in an in vitro calcification solution. MicroCT and SEM analysis showed that localised calcification levels varied spatially according to damage, where ruptured fibres offered additional calcium binding sites. Furthermore, specimens with a statistically significant lower fatigue life were associated with statistically significant higher calcification. This study revealed that mechanical damage drives calcification of GLBP. Non-destructive pre-screening of collagen fibres demonstrated that both the fatigue life and calcification potential of commercial-grade GLBP, are underpinned by the collagen fibre architecture.

Mortality and Reoperation Risk After Bioprosthetic Aortic Valve Replacement in Young Adults With Congenital Heart Disease

Bioprosthetic aortic valve replacement (bAVR) in patients with congenital heart disease is challenging due to age, size and complexity. Our objective was to assess survival and identify predictors of re-operation. Data were retrospectively collected for 314 patients undergoing bAVR at 8 centers from 2000-2014. Kaplan-Meier estimation of time to re-operation and Cox regression were utilized. Average age was 45.2 years (IQR 17.8-71.1) and 30% were <21. Indications were stenosis (48%), regurgitation (28%) and mixed (18%). Twenty-eight (9%) underwent prior AVR. Median valve size was 23mm (IQR 21, 25). Implanted valves included CE (Carpentier-Edwards) Perimount (47%), CE Magna/Magna Ease (29%), Sorin Mitroflow (9%), St Jude (2%) and other (13%). Median follow-up was 2.9 (IQR 1.2, 5.7) years. Overall, 11% required re-operation, 35% of whom had a Mitroflow and 65% were <21 years old. Time to re-operation varied among valve type (p=0.020). Crude 3-year rate was 20% in patients ≤21. Smaller valve size indexed to BSA was associated with re-operation (21.7 vs. 23.5 mm/m²). Predictors of reintervention by multivariable analysis were younger age (29% increase in hazard per 5-year decrease, p<0.001), Mitroflow (HR=4 to 8 versus other valves), and smaller valve size (20% increase in hazard per 1 mm decrease, p=0.002). The overall 1, 3 and 5-year survival rates were 94%, 90% and 85% without differences by valve (p=0.19). A concerning reduction in 5-year survival after bAVR is shown. Re-operation is common and varies by age and valve type. Further research is needed to guide valve choice and improve survival.

Impact of Predilation During Transcatheter Aortic Valve Replacement: Insights From the PARTNER 3 Trial

[Figure: see text].

Increased utilization of bioprosthetic aortic valve technology:Trends, drivers, controversies and future directions

Introduction: Bioprosthetic valves (BPV) implanted surgically or by transcatheter valve implantation (TAVI) comprise an overwhelming majority of substitute aortic valves implanted worldwide.Areas Covered: Prominent drivers of this trend are: 1) BPV patients have generally better outcomes than those with a mechanical valve, and remain largely free of anticoagulation and its consequences; 2) BPV durability has improved over the years; and 3) the expanding use of TAVI and valve-in-valve (VIV) procedures permitting interventional management of structural valve degeneration (SVD). Nevertheless, key controversies exist: 1) optimal anticoagulation regimens for surgical and TAVI BPVs; 2) the incidence, mechanisms and mitigation strategies for SVD; 3) the use of VIV for treatment of SVD, and 4) valve selection recommendations for difficult cohorts, (e.g. patients 50-70 years, patients <50, childbearing age women). This communication reviews trends in and drivers of BPV utilization, current controversies, and future directions affecting BPV use.Expert Opinion: Long-term data are needed in several areas related to aortic BPV use, including anticoagulation/antiplatelet therapy, especially following TAVI. TAVI and especially VIV durability and optimal use warrant will benefit greatly from long-term data. Certain populations may benefit from such high-quality data on multi-year outcomes, particularly younger patients.

Bioprosthetic aortic valve diameter and thickness are directly related to leaflet fluttering: Results from a combined experimental and computational modeling study

OBJECTIVE

Bioprosthetic heart valves (BHVs) are commonly used in surgical and percutaneous valve replacement. The durability of percutaneous valve replacement is unknown, but surgical valves have been shown to require reintervention after 10 to 15 years. Further, smaller-diameter surgical BHVs generally experience higher rates of prosthesis-patient mismatch, which leads to higher rates of failure. Bioprosthetic aortic valves can flutter in systole, and fluttering is associated with fatigue and failure in flexible structures. The determinants of flutter in BHVs have not been well characterized, despite their potential to influence durability.

METHODS

We use an experimental pulse duplicator and a computational fluid-structure interaction model of this system to study the role of device geometry on BHV dynamics. The experimental system mimics physiological conditions, and the computational model enables precise control of leaflet biomechanics and flow conditions to isolate the effects of variations in BHV geometry on leaflet dynamics.

RESULTS

Both experimental and computational models demonstrate that smaller-diameter BHVs yield markedly higher leaflet fluttering frequencies across a range of conditions. The computational model also predicts that fluttering frequency is directly related to leaflet thickness. A scaling model is introduced that rationalizes these findings.

CONCLUSIONS

We systematically characterize the influence of BHV diameter and leaflet thickness on fluttering dynamics. Although this study does not determine how flutter influences device durability, increased flutter in smaller-diameter BHVs may explain how prosthesis-patient mismatch could induce BHV leaflet fatigue and failure. Ultimately, understanding the effects of device geometry on leaflet kinematics may lead to more durable valve replacements.

Hemodynamically significant prosthesis-patient mismatch can be predicted and is associated with early prosthetic valve dysfunction in aortic bioprosthesis

OBJECTIVES

To evaluate the accuracy of predicted prosthesis-patient mismatch (PPM) regarding actual PPM measured postoperatively. To assess the association between PPM and prosthetic valve dysfunction.

METHODS

Retrospective cohort study including adult patients after aortic valve replacement surgery with a biological prosthesis. Predicted PPM status was determined using mean reference effective orifice area indexed to total body surface (iEOA), without considering reference standard deviations. Postoperative PPM status was determined by measuring iEOA within the first 60 postoperative days. Prosthetic valve dysfunction was defined as thrombosis, pannus, valve degeneration, and/or disruption.

RESULTS

205 patients were enrolled between January 2003 and June 2017: predicted PPM was absent in 52 patients (25.4%), moderate in 137 patients (66.8%), and severe in 16 patients (7.8%). After surgery, the actual postoperative iEOA was measured: 53 (25.9%) did not have PPM, 73 had moderate PPM (35.6%), and 79 had severe PPM (38.5%). Predicted PPM identified the presence of hemodynamically significant actual postoperative PPM (OR = 2.56; 95%CI 1.30-5.05; P = .006), though not its degree of severity. Prosthetic valve dysfunction was more frequent among patients with hemodynamically significant PPM (53.9% vs. 11.3%; P < .001), compared to those without PPM. The association between PPM and prosthetic valve dysfunction was maintained after adjusting for gender, age, and ever-smoking (OR = 9.03; P < .001). The incidence of thrombosis or pannus was also nonsignificantly higher in patients with moderate or severe PPM.

CONCLUSIONS

Predicted PPM identifies the presence, possibly not the severity, of actual postoperative PPM. Moderate or severe PPM is associated with prosthetic valve dysfunction. Actual postoperative prosthesis-patient mismatch measured within 60 postoperative days showed a distinctive hemodynamic profile and presented a stronger association with prosthetic valve dysfunction than predicted prosthesis-patient mismatch. A. Echocardiographic follow-up in patients according to the actual postoperative PPM measured within 60 postoperative days. B. Prediction of prosthetic valve dysfunction based on preoperative predicted PPM or on actual postoperative PPM within 60 postoperative days. PPM: prosthesis-patient mismatch. OR: Odds ratio.

Long-term survival after Carpentier-Edwards Perimount aortic valve replacement in Western Denmark: a multi-centre observational study

Background

This study describes the long-term survival, risk of reoperation and clinical outcomes of patients undergoing solitary surgical aortic valve replacement (SAVR) with a Carpentier-Edwards Perimount (CE-P) bioprosthetic in Western Denmark. The renewed interest in SAVR is based on the questioning regarding the long-term survival since new aortic replacement technique such as transcatheter aortic-valve replacement (TAVR) probably have shorter durability, why assessment of long-term survival could be a key issue for patients.

Methods

From November 1999 to November 2013 a cohort of a total of 1604 patients with a median age of 73 years (IQR: 69–78) undergoing solitary SAVR with CE-P in Western Denmark was obtained November 2018 from the Western Danish Heart Registry (WDHR). The primary endpoint was long-term survival from all-cause mortality. Secondary endpoints were survival free from major adverse cardiovascular and cerebral events (MACCE), risk of reoperation, cause of late death, patient-prothesis mismatch, risk of AMI, stroke, pacemaker or ICD implantation and postoperative atrial fibrillation (POAF). Time-to-event analysis was performed with Kaplan-Meier curve, cumulative incidence function was performed with Nelson-Aalen cumulative hazard estimates. Cox regression was applied to detect risk factors for death and reoperation.

Results

In-hospital mortality was 2.7% and 30-day mortality at 3.4%. The 5-, 10- and 15-year survival from all-cause mortality was 77, 52 and 24%, respectively. Survival without MACCE was 80% after 10 years. Significant risk factors of mortality were small valves, smoking and EuroSCORE II ≥4%. The risk of reoperation was < 5% after 7.5 years and significant risk factors were valve prosthesis-patient mismatch and EuroSCORE II ≥4%.

Conclusions

Patients undergoing aortic valve replacement with a Carpentier-Edwards Perimount valve shows a very satisfying long-term survival. Future research should aim to investigate biological valves long-term durability for comparison of different SAVR to different TAVR in long perspective.

Evaluation and Management of Aortic Stenosis in Chronic Kidney Disease: A Scientific Statement From the American Heart Association

Aortic stenosis with concomitant chronic kidney disease (CKD) represents a clinical challenge. Aortic stenosis is more prevalent and progresses more rapidly and unpredictably in CKD, and the presence of CKD is associated with worse short-term and long-term outcomes after aortic valve replacement. Because patients with advanced CKD and end-stage kidney disease have been excluded from randomized trials, clinicians need to make complex management decisions in this population that are based on retrospective and observational evidence. This statement summarizes the epidemiological and pathophysiological characteristics of aortic stenosis in the context of CKD, evaluates the nuances and prognostic information provided by noninvasive cardiovascular imaging with echocardiography and advanced imaging techniques, and outlines the special risks in this population. Furthermore, this statement provides a critical review of the existing literature pertaining to clinical outcomes of surgical versus transcatheter aortic valve replacement in this high-risk population to help guide clinical decision making in the choice of aortic valve replacement and specific prosthesis. Finally, this statement provides an approach to the perioperative management of these patients, with special attention to a multidisciplinary heart-kidney collaborative team-based approach.

Fifty years of the pericardial valve: Long-term results in the aortic position

It is now 50 years since the development of the first pericardial valve in 1971. In this time significant progress has been made in refining valve design aimed at improving the longevity of the prostheses. This article reviews the current literature regarding the longevity of pericardial heart valves in the aortic position. Side by side comparisons of freedom from structural valve degeneration are made for the valves most commonly used in clinical practice today, including stented, stentless, and sutureless valves. Strategies to reduce structural valve degeneration are also discussed including methods of tissue fixation and anti-calcification, ways to minimise mechanical stress on the valve, and the role of patient prosthesis mismatch.

Current Therapeutic Options in Aortic Stenosis

Aortic stenosis is the most common valvular disease requiring valve replacement. Valve replacement therapies have undergone progressive evolution since the 1960s. Over the last 20 years, transcatheter aortic valve replacement has radically transformed the care of aortic stenosis, such that it is now the treatment of choice for many, particularly elderly, patients. This review provides an overview of the pathophysiology, presentation, diagnosis, indications for intervention, and current therapeutic options for aortic stenosis.

Valve Academic Research Consortium 3: updated endpoint definitions for aortic valve clinical research

Aims 

The Valve Academic Research Consortium (VARC), founded in 2010, was intended to (i) identify appropriate clinical endpoints and (ii) standardize definitions of these endpoints for transcatheter and surgical aortic valve clinical trials. Rapid evolution of the field, including the emergence of new complications, expanding clinical indications, and novel therapy strategies have mandated further refinement and expansion of these definitions to ensure clinical relevance. This document provides an update of the most appropriate clinical endpoint definitions to be used in the conduct of transcatheter and surgical aortic valve clinical research.

Methods and results 

Several years after the publication of the VARC-2 manuscript, an in-person meeting was held involving over 50 independent clinical experts representing several professional societies, academic research organizations, the US Food and Drug Administration (FDA), and industry representatives to (i) evaluate utilization of VARC endpoint definitions in clinical research, (ii) discuss the scope of this focused update, and (iii) review and revise specific clinical endpoint definitions. A writing committee of independent experts was convened and subsequently met to further address outstanding issues. There were ongoing discussions with FDA and many experts to develop a new classification schema for bioprosthetic valve dysfunction and failure. Overall, this multi-disciplinary process has resulted in important recommendations for data reporting, clinical research methods, and updated endpoint definitions. New definitions or modifications of existing definitions are being proposed for repeat hospitalizations, access site-related complications, bleeding events, conduction disturbances, cardiac structural complications, and bioprosthetic valve dysfunction and failure (including valve leaflet thickening and thrombosis). A more granular 5-class grading scheme for paravalvular regurgitation (PVR) is being proposed to help refine the assessment of PVR. Finally, more specific recommendations on quality-of-life assessments have been included, which have been targeted to specific clinical study designs.

Conclusions 

Acknowledging the dynamic and evolving nature of less-invasive aortic valve therapies, further refinements of clinical research processes are required. The adoption of these updated and newly proposed VARC-3 endpoints and definitions will ensure homogenous event reporting, accurate adjudication, and appropriate comparisons of clinical research studies involving devices and new therapeutic strategies.

Valve Academic Research Consortium 3: Updated Endpoint Definitions for Aortic Valve Clinical Research

AIMS

The Valve Academic Research Consortium (VARC), founded in 2010, was intended to (i) identify appropriate clinical endpoints and (ii) standardize definitions of these endpoints for transcatheter and surgical aortic valve clinical trials. Rapid evolution of the field, including the emergence of new complications, expanding clinical indications, and novel therapy strategies have mandated further refinement and expansion of these definitions to ensure clinical relevance. This document provides an update of the most appropriate clinical endpoint definitions to be used in the conduct of transcatheter and surgical aortic valve clinical research.

METHODS AND RESULTS

Several years after the publication of the VARC-2 manuscript, an in-person meeting was held involving over 50 independent clinical experts representing several professional societies, academic research organizations, the US Food and Drug Administration (FDA), and industry representatives to (i) evaluate utilization of VARC endpoint definitions in clinical research, (ii) discuss the scope of this focused update, and (iii) review and revise specific clinical endpoint definitions. A writing committee of independent experts was convened and subsequently met to further address outstanding issues. There were ongoing discussions with FDA and many experts to develop a new classification schema for bioprosthetic valve dysfunction and failure. Overall, this multi-disciplinary process has resulted in important recommendations for data reporting, clinical research methods, and updated endpoint definitions. New definitions or modifications of existing definitions are being proposed for repeat hospitalizations, access site-related complications, bleeding events, conduction disturbances, cardiac structural complications, and bioprosthetic valve dysfunction and failure (including valve leaflet thickening and thrombosis). A more granular 5-class grading scheme for paravalvular regurgitation (PVR) is being proposed to help refine the assessment of PVR. Finally, more specific recommendations on quality-of-life assessments have been included, which have been targeted to specific clinical study designs.

CONCLUSIONS

Acknowledging the dynamic and evolving nature of less-invasive aortic valve therapies, further refinements of clinical research processes are required. The adoption of these updated and newly proposed VARC-3 endpoints and definitions will ensure homogenous event reporting, accurate adjudication, and appropriate comparisons of clinical research studies involving devices and new therapeutic strategies.

Detecting native and bioprosthetic aortic valve disease using 18F-sodium fluoride: Clinical implications

Calcific aortic valve disease is the most common valvular disease and confers significant morbidity and mortality. There are currently no medical therapies that successfully halt or reverse the disease progression, making surgical replacement the only treatment currently available. The majority of patients will receive a bioprosthetic valve, which themselves are prone to degeneration and may also need replaced, adding to the already substantial healthcare burden of aortic stenosis. Echocardiography and computed tomography can identify late-stage manifestations of the disease process affecting native and bioprosthetic aortic valves but cannot detect or quantify early molecular changes. 18F-fluoride positron emission tomography, on the other hand, can non-invasively and sensitively assess disease activity in the valves. The current review outlines the pivotal role this novel molecular imaging technique has played in improving our understanding of native and bioprosthetic aortic valve disease, as well as providing insights into its feasibility as an important future research and clinical tool.

Radiation-Induced Vascular Disease-A State-of-the-Art Review

Since the 1990s, there has been a steady increase in the number of cancer survivors to an estimated 17 million in 2019 in the US alone. Radiation therapy today is applied to a variety of malignancies and over 50% of cancer patients. The effects of ionizing radiation on cardiac structure and function, so-called radiation-induced heart disease (RIHD), have been extensively studied. We review the available published data on the mechanisms and manifestations of RIHD, with a focus on vascular disease, as well as proposed strategies for its prevention, screening, diagnosis, and management.

Impact of pre-existing comorbidities on outcomes of patients undergoing surgical aortic valve replacement - rationale and design of the international IMPACT registry

Background

Degenerative aortic valve disease accounts for 10–20% of all cardiac surgical procedures. The impact of pre-existing comorbidities on the outcome of patients undergoing surgical aortic valve replacement (SAVR) needs further research.

Methods

The IMPACT registry is a non-interventional, prospective, open-label, multicenter, international registry with a follow-up of 5 years to assess the impact of pre-existing comorbidities of patients undergoing SAVR with the INSPIRIS RESILIA aortic valve on outcomes. IMPACT will be conducted across 25 sites in Austria, Germany, The Netherlands and Switzerland and intends to enroll approximately 500 patients. Patients will be included if they are at least 18 years of age and are scheduled to undergo SAVR with the INSPIRIS RESILIA Aortic Valve with or without concomitant ascending aortic root replacement and/or coronary bypass surgery. The primary objective is to determine all-cause mortality at 1, 3, and 5 years post SAVR. Secondary objectives include cardiac-related and valve-related mortality and structural valve deterioration including hemodynamics and durability, valve performance and further clinical outcomes in the overall study population and in specific patient subgroups characterized by the presence of chronic kidney disease, hypertension, metabolic syndrome and/or chronic inflammation.

Discussion

IMPACT is a prospective, multicenter European registry, which will provide much-needed data on the impact of pre-existing comorbidities on patient outcomes and prosthetic valve performance, and in particular the performance of the INSPIRIS RESILIA, in a real-world setting. The findings of this study may help to support and expand appropriate patient selection for treatment with bioprostheses.

Trial registration

ClinicalTrials.gov identifier: NCT04053088.

The current diagnosis and treatment of patients with aortic valve stenosis

Aortic valve stenosis (AS) is the third most frequent cardiovascular abnormality after coronary artery disease and hypertension. A bicuspid aortic valve is the most common cause for AS until seventh decade and calcific valve degeneration is responsible thereafter. In symptomatic patients, The risk of death increases from ≤1%/year to 2%/month. An echo valve area ≤1 cm², peak transaortic velocity ≥4 m/s, mean valve gradient ≥40 mmHg and/or computerized tomography valve calcium score >2000 Agatston units (AU) for males or more than 1200 AU for females indicate severe AS. AS stages and management are discussed. Valve replacement is based on surgical risk, valve durability/hemodynamics, need for anticoagulation and patient preferences. EuroSCORE ≥20%, Society of Thoracic Surgeons Predicted Risk of Mortality ≥8% and co-morbidities indicate high surgical risk. Surgery is recommended for low-intermediate risk patients. Transcatheter aortic valve implantation is an alternative in older patients at low, intermediate, high or prohibitive risk. Transaortic valve implantation/replacement trials are summarized.

Model studies of advanced glycation end product modification of heterograft biomaterials: The effects of in vitro glucose, glyoxal, and serum albumin on collagen structure and mechanical properties

Glutaraldehyde cross-linked heterograft tissues, bovine pericardium (BP) or porcine aortic valves, are the leaflet materials in bioprosthetic heart valves (BHV) used in cardiac surgery for heart valve disease. BHV fail due to structural valve degeneration (SVD), often with calcification. Advanced glycation end products (AGE) are post-translational, non-enzymatic reaction products from sugars reducing proteins. AGE are present in SVD-BHV clinical explants and are not detectable in un-implanted BHV. Prior studies modeled BP-AGE formation in vitro with glyoxal, a glucose breakdown product, and serum albumin. However, glucose is the most abundant AGE precursor. Thus, the present studies investigated the hypothesis that BHV susceptibility to glucose related AGE, together with serum proteins, results in deterioration of collagen structure and mechanical properties. In vitro experiments studied AGE formation in BP and porcine collagen sponges (CS) comparing ¹⁴C-glucose and ¹⁴C-glyoxal with and without bovine serum albumin (BSA). Glucose incorporation occurred at a significantly lower level than glyoxal (p<0.02). BSA co-incubations demonstrated reduced glyoxal and glucose uptake by both BP and CS. BSA incubation caused a significant increase in BP mass, enhanced by glyoxal co-incubation. Two-photon microscopy of BP showed BSA induced disruption of collagen structure that was more severe with glucose or glyoxal co-incubation. Uniaxial testing of CS demonstrated that glucose or glyoxal together with BSA compared to controls, caused accelerated deterioration of viscoelastic relaxation, and increased stiffness over a 28-day time course. In conclusion, glucose, glyoxal and BSA uniquely contribute to AGE-mediated disruption of heterograft collagen structure and deterioration of mechanical properties.

Bicuspid-Associated Aortic Root Aneurysm: Mid to Long-Term Outcomes of David V Versus the Bio-Bentall Procedure

David V valve-sparing root replacement (VSRR) and bio-Bentall (BB) are increasingly performed for aortic root aneurysms associated with a bicuspid aortic valve (BAV). However, durability remains a concern in both procedures. We compared the 10-year outcomes of VSRR vs BB for BAV-associated root aneurysms. A retrospective review identified 134 patients with a BAV-associated root aneurysm who underwent VSRR (n = 65) or BB (n = 69) from 2005 to 2019. Patients with aortic stenosis, endocarditis, previous aortic valve replacement, and emergent cases were excluded. Propensity-score matching was performed, resulting in 2 risk-adjusted groups (n = 40 per group). Median follow-up was 6.21 (1.43-8.28) years. The VSRR cohort was younger (46.0 years vs 56.0 years, P < 0.001) and had a lower incidence of at least moderate aortic insufficiency (AI) (78.5% vs 92.8%, P = 0.02). The incidence of Marfan syndrome, aortic root diameter, and ascending aortic diameter were similar. In-hospital mortality was 1.5% (n = 1) and 1.4% (n = 1) for VSRR and BB, respectively. There was no difference between VSRR and BB in 10-year survival (98.3% [95% confidence interval (CI): 88.6-99.8%] vs 96.2% [95% CI: 85.5-99.0%], P = 0.567) and aortic valve reintervention at 10 years (16.1% [95% CI: 6.3-29.8%] vs 12.9% [95% CI: 3.7-28.0%], P = 0.309). The most common reason for valve reintervention in both groups was AI. Survival and valve reintervention at 10 years were similar in the matched cohort. David V VSRR yields similar mid to long-term outcomes to BB for select patients with a BAV-associated aortic root aneurysm in regards to survival and reintervention rates. Further studies comparing longer term outcomes between root replacement techniques and native valve durability are needed.

New Challenging Scenarios in Transcatheter Aortic Valve Implantation: Valve-in-valve, Bicuspid and Native Aortic Regurgitation

Transcatheter aortic valve implantation (TAVI) is the most frequently performed structural technique in the field of interventional cardiology. Initially, this procedure was only used in patients with severe symptomatic aortic stenosis and prohibitive risk. Now, barely one decade after its introduction, TAVI indications extend to low- and intermediate-risk patients. Despite these advances, several challenging scenarios are still on the periphery of the evidence base for TAVI. These include valve-in-valve procedures, lower-risk patients with bicuspid aortic valve and the treatment of pure aortic regurgitation. Whereas the valve-in-valve indication has expanded rapidly, evidence for the use of TAVI compared with conventional surgery for bicuspid aortic valve is limited, including the best choice of device should TAVI be used. Evidence for TAVI in pure aortic regurgitation is still anecdotal because of suboptimal outcomes. Operators worldwide have described variations in the TAVI procedural technique to achieve commissural alignment and to minimise the rate of pacemaker use through cusp overlap implantation. In light of the potential clinical benefits, this may also be an area of further development. This review aims to discuss the current evidence available supporting the use of TAVI for these new indications.

Higher Acceleration/Ejection Time Ratio Predicts Impaired Outcome in Aortic Valve Stenosis

BACKGROUND

Acceleration time (AT)/ejection time (ET) ratio is a marker of aortic valve stenosis (AS) severity and predicts outcome in moderate-severe AS.

METHODS

We explored the association of increased AT/ET ratio on prognosis in 1530 asymptomatic patients with presumably mild-moderate AS, normal ejection fraction, and without known diabetes or cardiovascular disease. Patients were part of the SEAS study (Simvastatin Ezetimibe Aortic Stenosis). Patients were grouped according to the optimal AT/ET ratio threshold to predict cardiovascular death and heart failure hospitalization. Low-gradient severe AS was identified as combined valve area ≤1.0 cm² and mean gradient <40 mm Hg. Outcome was assessed in Cox regression analyses, and results are reported as hazard ratio and 95% CI.

RESULTS

Higher AT/ET ratio was significantly associated with lower systolic blood pressure, lower left ventricular ejection fraction, lower stress-corrected midwall shortening, low flow, and with higher left ventricular mass and higher peak aortic jet velocity. AT/ET ratio ≥0.32 provided the optimal cutoff for predicting incident cardiovascular death and heart failure hospitalization in the total study sample. In patients with low-gradient severe AS, this threshold was >0.32. AT/ET ratio ≥0.32 had a 79% higher risk of cardiovascular death and heart failure hospitalization (hazard ratio, 1.79 [95% CI, 1.20-2.68]). In patients with low-gradient severe AS, AT/ET ratio >0.32 was associated with a 2-fold higher risk of cardiovascular death and heart failure hospitalization (hazard ratio, 2.15 [95% CI, 1.22-3.77]).

CONCLUSIONS

In asymptomatic nonsevere AS and low-gradient severe AS, higher AT/ET ratio was associated with increased cardiovascular morbidity and mortality. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00092677.

Safety and efficacy of repeat transcatheter aortic valve replacement for the treatment of transcatheter prosthesis dysfunction

Introduction: Transcatheter aortic valve replacement (TAVR) has recently expanded toward the treatment of younger patients with lower surgical risk and longer life expectancy. Thus, transcatheter heart valve (THV) durability has become a central issue, and an important increase in the number of TAVR-in-TAVR is expected in the coming years. Areas covered: Overview of the current status of TAVR-in-TAVR for the treatment of THV dysfunction, focusing on safety and efficacy of repeat TAVR procedures. Expert opinion: An accurate analysis of the pre-procedure cardiac computed tomography, incorporating new parameters such as the position of the top of the first THV in relation to the sinotubular-junction, will be necessary to assess the risk of coronary occlusion. Subsequent coronary angiography will be necessary in a proportion of TAVR-in-TAVR patients, but coronary access may be very difficult or even impossible in some of them. Therefore, the choice between TAVR and SAVR in young low-risk patients should incorporate the potential need for treating coronary events at mid- to long-term follow-up. Likewise, the choice of the valve type and the implantation position at the time of the first TAVR procedure should take into account the possibility of TAVR-in-TAVR in the future.Abbreviations ACS: acute coronary syndrome; CO: coronary obstruction; EOA: effective orifice area; SAVR: surgical aortic valve replacement; SVD: structural valve degenerationTAVR: transcatheter aortic valve replacement; THV: transcatheter heart valve.

TAVR: A Review of Current Practices and Considerations in Low-Risk Patients

Transcatheter aortic valve replacement (TAVR) is an established treatment for severe, symptomatic, aortic stenosis (AS) in patients of all risk categories and now comprises 12.5% of all aortic valve replacements. TAVR is a less invasive alternative to traditional surgical aortic valve replacement (SAVR), with equivalent or superior outcomes. The use of TAVR has increased rapidly. The success and increase in use of TAVR are a result of advances in technology, greater operator experience, and improved outcomes. Indications have recently expanded to include patients considered to be at low risk for SAVR. While TAVR outcomes have improved, remaining challenges include the management of coexistent coronary artery disease, prevention of periprocedural stroke, and issue of durability. These issues are even more relevant for low-risk, younger patients.

Premature Structural Failure of Trifecta Bioprosthesis in Midterm Follow-up: A Single-Center Study

BACKGROUND

A cluster of aortic bioprosthetic valve failures, most of which were Trifecta bioprostheses, was observed in Southampton General Hospital, Southampton, United Kingdom. This study was performed to assess whether the cluster represents a significant failure of this valve model or whether there is a selection bias that can explain the failure of these valves.

METHODS

This retrospective study evaluated all bioprosthetic aortic valve replacement operations performed between 2011 and 2016 inclusive in our center. The study compared the performance of the Trifecta valve (Abbott, Abbott Park, IL) with that of Perimount (Edwards Lifesciences, Irvine, CA), Perimount Magna Ease, and Mitroflow (LivaNova, London, United Kingdom) bioprostheses. In addition, the study analyzed patient-related and valve-related risk factors for early failure in the failed valves.

RESULTS

A total of 2807 bioprosthetic aortic valve replacements were performed. Of these, 836 were Trifecta valves, 1031 were Perimount, 449 were Perimount Magna Ease, and 351 were Mitroflow valves. A total of 24 Trifecta valves had premature structural failure, a number significantly higher than seen with Perimount or Perimount Magna Ease (no failure, P < .001 and P < .005, respectively) valves and the Mitroflow valve (1 failure, P < .05). There was no difference in the incidence of endocarditis or death. At the time of valve failure, 17 (71%) of the failed Trifecta valves had moderate or severe regurgitation, and the average peak gradient was 61 ± 29 mm Hg. The median failed prosthetic size was 23 mm. One failed valve had severe patient-prosthesis mismatch. The mean time to failure was 4.5 ± 1.7 years.

CONCLUSIONS

The Trifecta bioprosthesis has an increased incidence of early structural valve failure, which is significantly higher than that of Perimount, Perimount Magna Ease, or Mitroflow. No patient-related or valve-related cause for the failure could be identified.