Durability of pericardial versus porcine bioprosthetic heart valves

Late Outcomes of Porcine and Pericardial Bioprostheses After Mitral Valve Replacement in 1162 Patients

BACKGROUND

Debate continues regarding the superiority of porcine vs pericardial bioprostheses, and data relevant to this comparison are scant. This study compared late survival and structural valve deterioration of porcine and pericardial mitral valve prostheses.

METHODS

Adults undergoing mitral valve replacement with 1 first-generation porcine valve model and 1 pericardial valve line were reviewed from a prospectively maintained institutional database between 1976 and 2020. Multivariable regression and Cox proportional hazards analysis were used to compare late outcomes.

RESULTS

Of 1162 consecutive patients, 612 (53%) received porcine valves and 550 (47%) received pericardial valves. At 10 years, patient survival (porcine, 36% ± 2%; pericardial, 38% ± 3%; P = .5) and cumulative incidence of mitral valve structural deterioration (porcine, 18% ± 2%; pericardial, 19% ± 3%; P = .3) were similar. The structural failure mode was more likely severe mitral stenosis in pericardial valves (35 of 50 [70%] vs 38 of 106 [36%]; P < .001), and it was more likely severe mitral regurgitation in porcine valves (80 of 106 [75%] vs 19 of 50 [38%]; P < .0001). After adjustment, structural deterioration was associated with younger patient age (P < .001) but not valve type. At 10 years, porcine valves demonstrated a higher cumulative incidence of mitral reoperation (19% ± 2% vs 9% ± 2%; P < .001) and reoperation for structural deterioration (15% ± 1% vs 6% ± 2%; P = .007).

CONCLUSIONS

This study demonstrated similar rates of 10-year survival and structural deterioration with porcine and pericardial bioprostheses in mitral valve replacement. The study suggests a lack of major improvement in durability of mitral bioprosthetic valves over time. The failure mode may have a greater influence on surgeon decision making regarding valve choice.

Ten-year Durability, Hemodynamic Performance, and Clinical Outcomes after Transcatheter Aortic Valve Implantation Using a Self-expanding Device

INTRODUCTION

The expansion of transcatheter aortic valve implantation (TAVI) to low-risk and younger patients has increased the relevance of the long-term durability of transcatheter heart valves (THV). The present study aims to assess the 10-year durability, hemodynamic performance, and clinical outcomes after TAVI using the CoreValve system.

METHODS

An analysis from a prospective registry with predefined clinical and echocardiographic follow-up included 302 patients who underwent TAVI with the CoreValve system between 2007 and 2015. Bioprosthetic valve failure (BVF) was defined as any bioprosthetic valve dysfunction-related death, re-intervention, or severe hemodynamic valve deterioration.

RESULTS

At the time of TAVI, the mean age was 80.41 ± 7.01 years, and the Society of Thoracic Surgeons (STS) score was 6.13 ± 5.23%. At latest follow-up (median [IQR]: 5 [2-7] years), cumulative all-cause mortality rates at 3, 5, 7, and 10 years was 23.7%, 40%, 65.8%, and 89.8%, respectively. Mean aortic valve area and transvalvular gradient post-TAVI and at 5, 7, and 10 years were 1.94, 1.87, 1.69, and 1.98 cm2 (p = 0.236) and 8.3, 9.0, 8.2, and 10.1 mmHg (p = 0.796), respectively. Overall, 11 patients had BVF, of whom six had structural valve deterioration (SVD). The 10-year actual and actuarial freedom from BVF was 96.1% and 78.8%, and from SVD was 97.9% and 80.9%, respectively. Three patients developed significant non-SVD due to severe paravalvular leakage, and two patients were diagnosed with infective endocarditis.

CONCLUSION

Using an early-generation self-expanding bioprosthesis, we documented durable hemodynamic performance and low rates of BVF and SVD up to 10 years after TAVI.

Transcatheter or surgical aortic valve implantation: 10-year outcomes of the NOTION trial

BACKGROUND AND AIMS

Transcatheter aortic valve implantation (TAVI) has become a viable treatment option for patients with severe aortic valve stenosis across a broad range of surgical risk. The Nordic Aortic Valve Intervention (NOTION) trial was the first to randomize patients at lower surgical risk to TAVI or surgical aortic valve replacement (SAVR). The aim of the present study was to report clinical and bioprosthesis outcomes after 10 years.

METHODS

The NOTION trial randomized 280 patients to TAVI with the self-expanding CoreValve (Medtronic Inc.) bioprosthesis (n = 145) or SAVR with a bioprosthesis (n = 135). The primary composite outcome was the risk of all-cause mortality, stroke, or myocardial infarction. Bioprosthetic valve dysfunction (BVD) was classified as structural valve deterioration (SVD), non-structural valve dysfunction (NSVD), clinical valve thrombosis, or endocarditis according to Valve Academic Research Consortium-3 criteria. Severe SVD was defined as (i) a transprosthetic gradient of 30 mmHg or more and an increase in transprosthetic gradient of 20 mmHg or more or (ii) severe new intraprosthetic regurgitation. Bioprosthetic valve failure (BVF) was defined as the composite rate of death from a valve-related cause or an unexplained death following the diagnosis of BVD, aortic valve re-intervention, or severe SVD.

RESULTS

Baseline characteristics were similar between TAVI and SAVR: age 79.2 ± 4.9 years and 79.0 ± 4.7 years (P = .7), male 52.6% and 53.8% (P = .8), and Society of Thoracic Surgeons score < 4% of 83.4% and 80.0% (P = .5), respectively. After 10 years, the risk of the composite outcome all-cause mortality, stroke, or myocardial infarction was 65.5% after TAVI and 65.5% after SAVR [hazard ratio (HR) 1.0; 95% confidence interval (CI) 0.7-1.3; P = .9], with no difference for each individual outcome. Severe SVD had occurred in 1.5% and 10.0% (HR 0.2; 95% CI 0.04-0.7; P = .02) after TAVI and SAVR, respectively. The cumulative incidence for severe NSVD was 20.5% and 43.0% (P < .001) and for endocarditis 7.2% and 7.4% (P = 1.0) after TAVI and SAVR, respectively. No patients had clinical valve thrombosis. Bioprosthetic valve failure occurred in 9.7% of TAVI and 13.8% of SAVR patients (HR 0.7; 95% CI 0.4-1.5; P = .4).

CONCLUSIONS

In patients with severe AS and lower surgical risk randomized to TAVI or SAVR, the risk of major clinical outcomes was not different 10 years after treatment. The risk of severe bioprosthesis SVD was lower after TAVR compared with SAVR, while the risk of BVF was similar.

Long-term outcomes of bioprosthetic valves in the mitral position a systematic review of studies published over the last 20 years

OBJECTIVES

Although the use of bioprostheses for mitral valve replacement (bMVR) is on the rise, their long-term durability is not well described. Defining bMVR durability will be instrumental in setting the standard against which the performance of transcatheter mitral replacement is to be judged against. The authors of this systematic review aimed to identify, assess the quality and review the outcomes in studies reporting on long-term outcomes after bMVR published over the last 20 years.

METHODS

Medline, Embase and Cochrane CENTRAL were searched for studies that have reported outcomes beyond a minimum of 5 years of follow-up after bMVR. Cohort characteristics, definitions of structural valve deterioration (SVD) and outcomes were summarized. The risk of bias in included studies was assessed using the Cochrane QUIPS tool.

RESULTS

Twenty-one studies, including 15 833 patients, were identified. Sixty-four percent of all implants were porcine and the remaining bovine pericardial. Freedom from SVD at 10 years ranged from 58.9% to 100% and at 15 years from 58.3% to 93%. Freedom from reoperation ranged from 65% to 98.7% at 10 years and 78.5% to 91% at 15 years. Information on native valve pathology or dominant haemodynamic lesion was missing in 25% and 66% of studies, respectively. Reports of postoperative echocardiography were lacking, despite the heavy reliance on echocardiography for SVD diagnosis.

CONCLUSIONS

There is considerable variability in reporting bMVR long-term outcomes. As such, it is difficult to generate an unbiased, generalizable understanding of long- term outcomes after bMVR across the spectrum of mitral disease phenotypes.

Differential Immune Response to Bioprosthetic Heart Valve Tissues in the α1,3Galactosyltransferase-Knockout Mouse Model

Structural valve deterioration (SVD) of bioprosthetic heart valves (BHVs) has great clinical and economic consequences. Notably, immunity against BHVs plays a major role in SVD, especially when implanted in young and middle-aged patients. However, the complex pathogenesis of SVD remains to be fully characterized, and analyses of commercial BHVs in standardized-preclinical settings are needed for further advancement. Here, we studied the immune response to commercial BHV tissue of bovine, porcine, and equine origin after subcutaneous implantation into adult α1,3-galactosyltransferase-knockout (Gal KO) mice. The levels of serum anti-galactose α1,3-galactose (Gal) and -non-Gal IgM and IgG antibodies were determined up to 2 months post-implantation. Based on histological analyses, all BHV tissues studied triggered distinct infiltrating cellular immune responses that related to tissue degeneration. Increased anti-Gal antibody levels were found in serum after ATS 3f and Freedom/Solo implantation but not for Crown or Hancock II grafts. Overall, there were no correlations between cellular-immunity scores and post-implantation antibodies, suggesting these are independent factors differentially affecting the outcome of distinct commercial BHVs. These findings provide further insights into the understanding of SVD immunopathogenesis and highlight the need to evaluate immune responses as a confounding factor.

Long-Term Outcomes of Bovine versus Porcine Mitral Valve Replacement: A Multicenter Analysis

Introduction

Recent national guidelines recommending mitral valve replacement (MVR) for severe secondary mitral regurgitation have resulted in an increased utilization of mitral bioprosthesis. There is a paucity of data on how longitudinal clinical outcomes vary by prosthesis type. We examined long-term survival and risk of reoperation between patients having bovine vs. porcine MVR. Study Design. A retrospective analysis of MVR or MVR + coronary artery bypass graft (CABG) from 2001 to 2017 among seven hospitals reporting to a prospectively maintained clinical registry was conducted. The analytic cohort included 1,284 patients undergoing MVR (801 bovine and 483 porcine). Baseline comorbidities were balanced using 1 : 1 propensity score matching with 432 patients in each group. The primary end point was all-cause mortality. Secondary end points included in-hospital morbidity, 30-day mortality, length of stay, and risk of reoperation.

Results

In the overall cohort, patients receiving porcine valves were more likely to have diabetes (19% bovine vs. 29% porcine; p < 0.001), COPD (20% bovine vs. 27% porcine; p=0.008), dialysis or creatinine >2 mg/dL (4% bovine vs. 7% porcine; p=0.03), and coronary artery disease (65% bovine vs. 77% porcine; p < 0.001). There was no difference in stroke, acute kidney injury, mediastinitis, pneumonia, length of stay, in-hospital morbidity, or 30-day mortality. In the overall cohort, there was a difference in long-term survival (porcine HR 1.17 (95% CI: 1.00-1.37; p=050)). However, there was no difference in reoperation (porcine HR 0.56 (95% CI: 0.23-1.32; p=0.185)). In the propensity-matched cohort, patients were matched on all baseline characteristics. There was no difference in postoperative complications or in-hospital morbidity and 30-day mortality. After 1 : 1 propensity score matching, there was no difference in long-term survival (porcine HR 0.97 (95% CI: 0.81-1.17; p=0.756)) or risk of reoperation (porcine HR 0.54 (95% CI: 0.20-1.47; p=0.225)).

Conclusions

In this multicenter analysis of patients undergoing bioprosthetic MVR, there was no difference in perioperative complications and risk of reoperation of long-term survival after matching.

Outcomes of bovine versus porcine surgical aortic valve replacement

INTRODUCTION

There are no guidelines regarding the use of bovine pericardial or porcine valves for aortic valve replacement, and prior studies have yielded conflicting results. The current study sought to compare short- and long-term outcomes in propensity-matched cohorts of patients undergoing isolated aortic valve replacement (AVR) with bovine versus porcine valves.

METHODS

This was a retrospective study utilizing an institutional database of all isolated bioprosthetic surgical aortic valve replacements performed at our center from 2010 to 2020. Patients were stratified according to type of bioprosthetic valve (bovine pericardial or porcine), and 1:1 propensity-score matching was applied. Kaplan-Meier survival estimation and multivariable Cox regression for mortality were performed. Cumulative incidence functions were generated for all-cause readmissions and aortic valve reinterventions.

RESULTS

A total of 1502 patients were identified, 1090 (72.6%) of whom received a bovine prosthesis and 412 (27.4%) of whom received a porcine prosthesis. Propensity-score matching resulted in 412 risk-adjusted pairs. There were no significant differences in clinical or echocardiographic postoperative outcomes in the matched cohorts. Kaplan-Meier survival estimates were comparable, and, on multivariable Cox regression, valve type was not significantly associated with long-term mortality (hazard ratio: 1.02, 95% confidence interval: 0.74, 1.40, p = .924). Additionally, there were no significant differences in competing-risk cumulative incidence estimates for all-cause readmissions (p = .68) or aortic valve reinterventions (p = .25) in the matched cohorts.

CONCLUSION

The use of either bovine or porcine bioprosthetic aortic valves yields comparable postoperative outcomes, long-term survival, freedom from reintervention, and freedom from readmission.

Prosthetic cardiac valves: history and review of cardiac prostheses clinically available in Japan

Recently developed prosthetic valves are reliable and essential for the treatment of valvular heart disease. The mechanical valve evolved remarkably following the introduction of pyrolite carbon material, which enabled the creation of a bileaflet form incorporated with a pivot mechanism. The improved durability of the biological valve is attributed mainly to the development of a tissue fixation process and anti-calcification treatments. However, optimal antithrombogenicity and durability have not yet been achieved for either prosthetic valve type. To select the most suitable prosthetic valve for each individual patient from among the many clinically available prosthetic valves, it is necessary to have a thorough understanding of the characteristics of each valve.

Two-Year Clinical Follow-Up Assessment of the Novel Cingular Surgical Bovine Pericardial Valve

Objectives: To evaluate the 2-year clinical safety and hemodynamic outcomes of the Cingular bovine pericardial bioprosthesis. Methods: A prospective, multicenter, single-arm trial was conducted in patients who required aortic or mitral valve replacement. From March 2016 to October 2017, 197 patients were implanted with the Cingular bovine pericardial valve at five sites in China. The clinical outcomes and hemodynamic performance were assessed through a 2-year follow-up. Clinical safety events were reviewed by an independent clinical events committee, and echocardiographic data were assessed by an independent core laboratory. Results: The mean age was 66.9 ± 4.9 years. The 2-year survival rate was 96.4%. A complete 2-year clinical follow-up was achieved in 189 of 190 survivors. No case of structural valve deterioration, major perivalvular leak, prosthetic valve endocarditis, or valve-related reoperation was seen. For the aortic valve, the mean pressure gradient observed was 12.5 ± 4.0 mm Hg, and the effective orifice area (EOA) was 2.0 ± 0.3 cm2. For the smaller size aortic valves, 19 mm and 21 mm, respective mean EOA values of 1.7 ± 0.2 cm2 and 1.8 ± 0.2 cm2 were found. The values for mean pressure gradient and mean EOA for mitral bioprostheses were 4.0 ± 1.4 mm Hg and 2.2 ± 0.3 cm2, respectively. There was no significant change between 1-year and 2-year hemodynamic performance. Conclusions: The Cingular bovine pericardial valve showed favorable clinical safety and hemodynamic outcomes over a 2-year follow-up. Further follow-up is required to validate the long-term durability.

Modes of the bioprosthetic valve failure of the porcine and pericardial valves in the mitral position

OBJECTIVES

This study was conducted to examine the incidence and modes of the bioprosthetic valve failure of the porcine valve in the mitral position and compare them with those of the pericardial valve.

METHODS

This study included 240 patients (116 men [48.3%]; mean age, 74.87 ± 6.61 years) who underwent mitral valve replacement using the St. Jude Medical Epic bioprosthesis (Epic) (N = 125) or Carpentier-Edwards Perimount (CEP) pericardial valve (N = 115) from January 2000 to December 2020.

RESULTS

The median clinical follow-up durations in the Epic and CEP groups were 54.5 months (range, 0-111 months) and 81.5 months (range, 0-194 months), respectively. Structural valve degeneration (SVD) was observed in 9 patients (7.2%) in the Epic group and 11 patients (9.6%) in the CEP group. The rates of freedom from SVD at 3, 5 and 7 years were 97.7%, 90.5% and 75.5% in the Epic group and 100.0%, 96.1% and 90.0% in the CEP group, respectively. SVD reoperation was performed for 7 patients (5.6%) in the Epic group and 6 patients (5.2%) in the CEP group. The rates of freedom from SVD reoperation at 3, 5 and 7 years were 97.7%, 90.5% and 75.5% in the Epic group and 100%, 96.1% and 90.0% in the CEP group, respectively. Epic SVD was predominantly due to leaflet tearing, whereas CEP SVD was predominantly due to leaflet calcification and adhesion to the subvalvular apparatus.

CONCLUSIONS

SVD of the porcine valve was predominantly due to leaflet tearing. The rate of reoperation for SVD was slightly higher for the porcine valve in the mitral position than for the pericardial valve at adjusted survival analysis.

Late leaflet dehiscence in a bovine bioprosthesis-mimicked COVID-19 infection

Symptoms mimicking COVID-19 infection, pulmonary emboli, or septicemia delayed diagnosis of aortic bioprosthesis failure. A 71-year-old man was admitted emergently with shortness of breath, fever, cough, and chest pain. Echocardiography performed after 2 days showed diastolic regurgitation in an aortic perimount pericardial bioprosthesis implanted 12 years previously. An urgent reoperation disclosed that one pericardial cusp was torn from the stent of the valve. We have not previously encountered sudden pericardial leaflet dehiscence of an internally mounted pericardial valve that caused heart failure and found no literature report like our finding.

Comparative analysis of structural valve deterioration and long-term clinical outcomes after bovine pericardial versus porcine bioprosthetic mitral valve replacement

Background

This study aimed to compare long-term outcomes, including durability, after bovine pericardial valve replacement with those after porcine mitral valve replacement (MVR).

Methods

We enrolled 309 patients who underwent MV replacement (mean age: 65.8±11.5 years; 68.9% females) with Carpentier-Edwards PERIMOUNT bovine pericardial valves (bovine MVR group, n=241) or Hancock II porcine bioprosthesis (porcine MVR group, n=68). The mean clinical and echocardiographic follow-up durations were 81.4±60.0 and 57.8±53.3 months, respectively. Structural valve deterioration (SVD) was defined as prosthetic mitral valve (MV) regurgitation or stenosis of greater than moderate degree combined with a motion limitation, tear, or perforation of prosthetic valve leaflet on follow-up echocardiography. Propensity score (PS)-adjusted multivariable analyses were performed.

Results

Thirty-day mortality rate was 6.4% (20/309 patients). SVD occurred in 50 patients (33 and 17 patients in the bovine and porcine MV replacement groups, respectively). Cumulative incidences of SVD at 5, 10, and 15 years were 3.2%, 15.9%, and 32.4%, respectively, in the bovine MVR group and 1.9%, 15.3%, and 41.7%, respectively, in the porcine MVR group. Cumulative incidences of SVD in the two groups were not different in competing risk analysis (P=0.23). Other clinical outcomes including overall survival and cumulative incidences of cardiac death and MV-related events were not statistically significantly different between the groups in PS-adjusted multivariable analyses.

Conclusions

Long-term clinical outcomes including SVD were not different between the bovine and porcine bioprosthesis MVR groups during average 7 years of clinical follow-up after MVR.

Freestyle Aortic Bioprostheses in Patients 60 Years old and Younger

Evaluate outcomes of the Freestyle stentless aortic bioprosthesis in patients 60 years old and younger. All patients, 60 years old and younger, between January 1, 1998 to December 31, 2015 who underwent implantation of a Freestyle aortic valve at a single institution were reviewed. Medical records and telephone interviews were utilized for data collection. 515 patients were identified with an average age of 51.3 years. Mean follow up was 11.1 years. 225 full root replacements and 290 subcoronary implants were performed. Overall survival, including patients with concomitant procedures, at 15 years was 63.7% (95% CI 58.3-68.5). Isolated subcoronary implants (58%,167/290) had a 15-year survival of 71.6% (95% CI 62.6-78.7) vs 78.4% (95% CI 69.7, 84.9) for isolated root replacements (63%,141/225) which was not statistically significant (P = 0.397). No significant difference in operative SVD at 15 years occurred between full root replacements 37.6% (95% CI 27.2-50.2) vs subcoronary implants 39.4% (95% CI31.1, 49.0). 110 patients required reoperation solely for intrinsic SVD. 93% (102/110) failed due to aortic insufficiency. Of reoperative interventions for SVD, 37% (41/110) of patients required urgent reoperation and 4.5% (5/110) required emergent reoperation. Pseudoaneurysms developed in six of the full root replacements. Freestyle aortic valves have a high rate of acute failure requiring urgent or emergent reintervention in patients 60 years old and younger. This has led our group to shift practice away from their implantation.

Clinical and Technical Challenges of Prosthesis-Patient Mismatch After Transcatheter Aortic Valve Implantation

Prosthesis-patient mismatch (PPM) is present when the effective area of a prosthetic valve inserted into a patient is inferior to that of a normal human valve; the hemodynamic consequence of a valve too small compared with the size of the patient's body is the generation of higher than expected transprosthetic gradients. Despite evidence of increased risk of short- and long-term mortality and of structural valve degeneration in patients with PPM after surgical aortic valve replacement, its clinical impact in patients subject to transcatheter aortic valve implantation (TAVI) is yet unclear. We aim to review and update on the definition and incidence of PPM after TAVI, and its prognostic implications in the overall population and in higher-risk subgroups, such as small aortic annuli or valve-in-valve procedures. Last, we will focus on the armamentarium available in order to reduce risk of PPM when planning a TAVI procedure.

Comparative analysis of structural valve deterioration after bioprosthetic tricuspid valve replacement: Bovine pericardial versus porcine valves

This study was conducted to compare the occurrence and the risk factors of structural valve deterioration (SVD) after bioprosthetic tricuspid valve replacement (TVR) between bovine pericardial valves and porcine valves. One-hundred and thirty-four TVR patients were enrolled; 108 patients underwent TVR with bovine pericardial bioprostheses (BTVR group) and 26 underwent TVR with porcine bioprostheses (PTVR group). The early results and long-term clinical outcomes were compared. The median follow-up duration was 90 (interquartile range: 33-135) months. Propensity score (PS) adjusted Cox regression and competing risk analyses were performed. The mean ages of the BTVR and PTVR groups were 62.2 ± 10.7 and 57.3 ± 13.9 years, respectively. The overall survival and cumulative incidence of cardiac death in the BTVR group were similar to those in the PTVR group (hazard ratio [95% confidence interval] = 1.399 [0.500-3.922] and 0.742 [0.249-2.212], respectively). SVD was significantly more frequent in the BTVR group (17.544 [1.070-243.902], P = .045). The tricuspid valve reoperation rate was significantly higher in the BTVR group (38.462 [2.591-476.190], P = .008). The cumulative incidence of SVD after bioprosthetic TVR was higher when using bovine pericardial valves than when using porcine valves.

Association of Bioprosthetic Aortic Valve Leaflet Calcification on Hemodynamic and Clinical Outcomes

BACKGROUND

The prognostic value of aortic valve calcification (AVC) measured by using multidetector computed tomography imaging has been well validated in native aortic stenosis, and sex-specific thresholds have been proposed. However, few data are available regarding the impact of leaflet calcification on outcomes after biological aortic valve replacement (AVR).

OBJECTIVES

The goal of this study was to analyze the association of quantitative bioprosthetic leaflet AVC with hemodynamic and clinical outcomes, as well as its possible interaction with sex.

METHODS

From 2008 to 2010, a total of 204 patients were prospectively enrolled with a median of 7.0 years (interquartile range: 5.1 to 9.2 years) after biological surgical AVR. AVC measured by using the Agatston method was indexed to the cross-sectional area of aortic annulus measured by echocardiography to calculate the AVC density (AVCd). Presence of hemodynamic valve deterioration (HVD; increase in mean gradient [MG] ≥10 mm Hg and/or increase in transprosthetic regurgitation ≥1) was assessed by echocardiography in 137 patients at the 3-year follow-up. The primary clinical endpoint was mortality or aortic valve re-intervention.

RESULTS

There was no significant sex-related difference in the relationship between bioprosthetic AVCd and the progression of MG. Baseline AVCd showed an independent association with HVD at 3 years. During follow-up, there were 134 (65.7%) deaths (n = 100) or valve re-interventions (n = 47). AVCd ≥58 AU/cm² was independently associated with an increased risk of mortality or aortic valve re-intervention (adjusted hazard ratio: 2.23; 95% confidence interval: 1.44 to 3.35; p < 0.001). The AVCd threshold combined with an MG progression threshold of 10 mm Hg amplified the stratification of patients at risk (log-rank, p < 0.001). The addition of AVCd threshold into the prediction model including traditional risk factors improved outcome prediction (net classification improvement: 0.25, p = 0.04; likelihood ratio test, p < 0.001).

CONCLUSIONS

Aortic bioprosthetic leaflet calcification is strongly and independently associated with HVD and the risk of death or aortic valve re-intervention. As opposed to native aortic stenosis, there is no sex-related differences in the relationship between AVCd and hemodynamic or clinical outcomes.

Bovine pericardial versus porcine stented replacement mitral valves: early hemodynamic performance and clinical results of a randomized comparison of the Perimount and the Mosaic valves

Background

To compare the hemodynamic and clinical outcomes following mitral valve replacement with the Perimount valve with those of the Mosaic valve.

Methods

A total of 145 consecutive patients with rheumatic heart valve disease who underwent single bioprosthetic mitral valve replacement were randomized to receive either the Perimount (n=72) valve or the Mosaic bioprosthesis (n=73). The mean age of patients was 72.1 years (range, 58-89 years) with a sex distribution of 55.2% female and 44.8% male. Patients underwent follow up transthoracic echocardiography at 3 months and 1 year postoperatively. We compared demographics, preoperative clinical data, operative data, hemodynamic profiles, and clinical outcomes.

Results

The cross-clamp time was similar, with 50.7±15.3 minutes for the Perimount and 50.7±21.8 minutes for the Mosaic bioprosthesis. The total bypass time was also similar, with 91.3±25.7 minutes for the Perimount and 87.8±25.6 minutes for the Mosaic valve. The peak and mean pressure gradients were lower in the Perimount group for all valve sizes and the difference was statistically significant at 1 year. The effective orifice area (EOA) was slightly larger in the Perimount valve (1.98±0.21 vs. 1.89±0.71 cm², P=0.538) postoperatively, but there was no significant difference at 1 year. There were no differences in preoperative or postoperative left atrium diameter (LAD), left ventricular diastolic diameter (LVDD), left ventricular systolic diameter (LVSD), left ventricular ejection fraction (LVEF), pulmonary artery pressure (PAP). The mortality and major complications rate were similar between the two groups.

Conclusions

The Perimount prostheses is superior to the Mosaic prostheses after mitral valve replacement, achieving statistically significant lower gradients and larger EOA when compared on the basis of manufacturer-labeled valve sizes. Both valves appear to provide satisfactory clinical results.

Early Basal Cuspal Tear of a Porcine Bioprosthetic Mitral Valve Causing Massive Mitral Regurgitation

Although porcine mitral bioprostheses provide predictably good long-term outcomes, unexpected leaflet tears leading to abrupt haemodynamic changes may occur. Here, we report on a patient who was presented with acute dyspnea due to a cuspal tear of a porcine bioprosthetic mitral valve causing severe mitral regurgitation. Her condition was subsequently complicated by a systemic infection, probably pneumonia, and was successfully managed with an urgent redo-mitral valve replacement.

Structural Valve Deterioration Is Linked to Increased Immune Infiltrate and Chemokine Expression

We aim to investigate whether structural valve deterioration (SVD) of bioprosthetic xenogenic tissue heart valves (XTHVs) is associated with increased immune cell infiltration and whether co-expression of several chemokines correlates with this increase in immune infiltrate. Explanted XTHVs from patients undergoing redo valve replacement for SVD were obtained. Immunohistochemical, microscopic, and gene expression analysis approaches were used. XTHVs (n = 37) were obtained from 32 patients (mean 67.7 years) after a mean time of 11.6 years post-implantation. Significantly increased immune cellular infiltration was observed in the explanted SVD valves for all immune cell types examined, including T cells, macrophages, B cells, neutrophils, and plasma cells, compared to non-SVD controls. Furthermore, a significantly increased chemokine gradient in explanted SVD valves accompanied immune cell infiltration. These data suggest the development of SVD is associated with a significantly increased burden of immune cellular infiltrate correlated to the induction of a chemokine gradient around the XHTV, representing chronic immune rejection.Graphical abstract Proposed interaction between innate and adaptive immunity leading to the development of structural valve deterioration in xenogenic tissue heart valves.

Natural History of a Carpentier-Edwards Pericardial Aortic Valve Replaced after 25 Years for Structural Valve Degeneration

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SVD is a main limitation of bioprostheses.

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Routine use of bioprostheses in younger patients (<60 years of age) is controversial.

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Data on the durability of surgical aortic bioprostheses beyond 20 years are limited.

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We report exceptional durability of an aortic bioprosthesis replaced after 25 years.

[Safety of biological valves for aortic valve replacement: A systematic review and meta-analysis]

OBJECTIVE

To provide a comprehensive and contemporary overview of the long-term safety outcomes after aortic valve replacements (AVR) with conventional biological heart valve (stented or stentless).

METHODS

English databases (Medline, Embase, Web of Science, CENTRAL, and ClinicalTrial.gov) and Chinese databases (CNKI, VIP, WanFang, and SinoMed) were searched systemically from January 1, 2000 to January 26, 2019. Eligible randomized controlled trials, non-randomized clinical trials, cohort studies (retrospective or prospective), and unselected case series were included. Strict screening of the obtained literature was conducted to extract relevant data by two reviewers. Other inclusion criteria were studied reporting on outcomes of AVR with biological valves (stented or stentless), with or without coronary artery bypass grafting (CABG) or valve repair procedure, with mean follow-up length equal to or longer than 5 years. We excluded studies that reported only a specific patient group (e.g., patients with renal failure, or pregnancy), without the report of biological valve type, or with study population size less than 100. The meta-analysis was performed using Stata 14.0 software.

RESULTS

In this study, 53 papers (in total 57 study groups) involving 47 803 patients were included. (1) The all-cause mortality was 6.33/100 patient-years (95%CI: 5.85-6.84). Subgroup analysis showed that the mortality rates of porcine and bovine valve prostheses were 5.69/100 patient-years (95%CI: 5.05-6.41) and 7.29/100 patient-years (95%CI: 6.53-8.13), respectively. The all-cause mortality rates for stented and stentless valve were 6.69/100 patient-years (95%CI: 6.12-7.30) and 5.21/100 patient-years (95%CI: 4.43-6.14), respectively. (2) The incidence rate of thromboembolism was 1.16/100 patient-years (95%CI: 0.96-1.40), the incidence rate of permanent pacemaker (PPM) implantation was 1.08/100 patient-years (95%CI: 0.75-1.54), the incidence rate of stroke was 0.74/100 patient-years (95%CI: 0.51-1.06), the incidence rate of structural valve dysfunction (SVD) was 0.73/100 patient-years (95%CI: 0.59-0.91), the incidence rate of major bleeding was 0.52/100 patient-years (95%CI: 0.41-0.65), the incidence rate of endocarditis was 0.38/100 patient-years (95%CI: 0.33-0.44), and the incidence rate of non-structural valve dysfunction (NSVD) was 0.20/100 patient-years (95%CI: 0.13-0.31). The total reoperation rate for biological aortic valve was 0.77/100 patient-years (95%CI: 0.65-0.91), and the SVD related reoperation rate was 0.46/100 patient-years (95%CI: 0.36-0.58).

CONCLUSION

The all-cause mortality for conventional biological AVR was 6.33/100 patient-years. Thromboembolism, PPM implantation, reoperation, stroke, and SVD were major long term complications.

4D Flow MRI hemodynamic benchmarking of surgical bioprosthetic valves

PURPOSE

We exploited 4-dimensional flow magnetic resonance imaging (4D Flow), combined with a standardized in vitro setting, to establish a comprehensive benchmark for the systematic hemodynamic comparison of surgical aortic bioprosthetic valves (BPVs).

MATERIALS AND METHODS

4D Flow analysis was performed on two small sizes of three commercialized pericardial BPVs (Trifecta™ GT, Carpentier-Edwards PERIMOUNT Magna and Crown PRT®). Each BPV was tested over a clinically pertinent range of continuous flow rates within an in vitro MRI-compatible system, equipped with pressure transducers. In-house 4D Flow post-processing of the post-valvular velocity field included the quantification of BPV effective orifice area (EOA), transvalvular pressure gradients (TPG), kinetic energy and viscous energy dissipation.

RESULTS

The 4D Flow technique effectively captured the 3-dimensional flow pattern of each device. Trifecta exhibited the lowest range of velocity and kinetic energy, maximized EOA (p < 0.0001) and minimized TPGs (p ≤ 0.015) if compared with Magna and Crown, these reporting minor EOA difference s (p ≥ 0.042) and similar TPGs (p ≥ 0.25). 4D Flow TPGs estimations strongly correlated against ground-truth data from pressure transducers; viscous energy dissipation proved to be inversely proportional to the fluid jet penetration.

CONCLUSION

The proposed 4D Flow analysis pinpointed consistent hemodynamic differences among BPVs, highlighting the not negligible effect of device size on the fluidynamic outcomes. The efficacy of non-invasive 4D Flow MRI protocol could shed light on how standardize the comparison among devices in relation to their actual hemodynamic performances and improve current criteria for their selection.

Long-Term Outcomes of Mosaic Versus Perimount Mitral Replacements: 17-Year Follow-Up of 940 Implants

BACKGROUND

The objective of this study was to compare long-term outcomes of Mosaic (Medtronic, Minneapolis, MN) porcine mitral valves to Carpentier-Edwards (Edwards Lifesciences, Irving, CA) bovine pericardial mitral valves.

METHODS

From 2001 through 2017 at a single institution, 940 patients received a mitral bioprosthesis, of which 463 (49.3%) were porcine and 477 (50.7%) were bovine pericardial. Retrospective review of the procedure and the postoperative clinical course, including echocardiography, through August 2018 were analyzed. All consecutive mitral valve replacements over the study period were included. Follow-up was 99% (929 patients) complete for a total of 6045 patient-years (mean, 6.4 ± 4.5 years). A propensity-matched cohort of 802 mitral bioprosthesis was used for outcome analyses.

RESULTS

Operative mortality of the 940 patients was 5.4% (n = 51) and incidence of postoperative stroke was 2.1% (n = 20). Overall survival of the propensity-matched patients at 10 and 15 years was 49.7% (95% confidence interval [CI] 45.5%-53.7%) and 23.3% (95% CI 17.9%-29.3%), respectively. Survival at 15 years was 24.0% (95% CI 18.0%-30.5%) for porcine and 16.5% (95% CI 5.5%-32.6%) for bovine implants, which was not significantly different (P = .67). Overall cumulative incidence for reoperative structural valve deterioration at 15 years was 7.9% (95% CI 4.7%-12.3%) for porcine valves versus 13.2% (95% CI 8.1%-19.5%) for pericardial valves (P < .001). For patients age younger than 65 years, structural valve deterioration at 15 years was 15.8% (95% CI 7.4%-27.0%) versus 30.2% (95% CI 15.1%-46.8%) for porcine and pericardial valves, respectively (P = .009). Overall average time to reoperation for structural valve deterioration for porcine valves was 11.1 ± 2.3 years vs 6.8 ± 2.3 years for bovine pericardial valves (P < .001).

CONCLUSIONS

In long-term follow-up, of patients younger than 65 years of age undergoing mitral valve replacement, bovine pericardial valves experienced earlier and more frequent structural valve deterioration than porcine valves.

Durability of Mitral Valve Bioprostheses: A Meta-Analysis of Long-Term Follow-up Studies

BACKGROUND

Porcine and pericardial valves exhibited similar freedom from structural valve deterioration after aortic valve replacement. Limited data exist regarding their durability at long-term follow-up in the mitral position.

METHODS

A literature search was performed through online databases. Papers reporting freedom from tissue valve deterioration after mitral valve replacement with a follow-up longer than 5 years were retrieved. Four porcine valves (Carpentier-Edwards [Edwards Lifesciences, Irvine, CA] and Hancock, Hancock II, and Mosaic [Medtronic, Inc, Minneapolis, MN]) and 1 pericardial prosthesis (Carpentier-Edwards) were the objects of the study. The structural valve deterioration (SVD) rate per year was calculated for each type of prosthesis. Kaplan-Meier curves and log-rank test analysis were performed to compare the long-term durability of porcine and pericardial valves.

RESULTS

Forty full-text papers including more than 15,000 patients were considered for the meta-analysis. Porcine valves were generally implanted in younger patients in the first period after their introduction. The mean age of the patients receiving a mitral bioprosthesis increased from 50 to 70 years over the decades. In patients operated after 1980 who had similar mean age at the time of implant, freedom from SVD was higher in the group of porcine valves with Mosaic prosthesis, showing the lowest rate of SVD. Long-term survival was higher for Mosaic porcine and Carpentier pericardial valves.

CONCLUSIONS

In surgical populations that underwent mitral valve replacement after 1980 with new generation tissue valves and similar mean age at the implant time, we found, at long-term follow-up, a higher freedom from SVD in the group of porcine prostheses.

The Additional Value of Three-Dimensional Transesophageal Echocardiography in the Diagnosis of Unusual Complication of Bioprosthetic Mitral Valve

Primary tissue failure of bioprosthetic mitral valves due to cusp perforations or ruptures is an unusual complication on short-term follow-up. An 88-year-old male with a known history of mitral regurgitation (MR) treated with bioprosthetic valve replacement in 2016 was referred to our center for recurrent heart failure. The two-dimensional (2D) transthoracic echocardiography documented an intraprosthetic jet of regurgitation without identifying a clear morphological mechanism, nor quantifying precisely the mitral insufficiency. 3D transesophageal echocardiography (TOE) with the tool FlexiSlice added relevant information by providing insights into the pathophysiological mechanisms of MR. The present case emphasizes the importance of 3D TOE as a fundamental tool for the diagnostic algorithm of bioprosthetic valves failure, even in the more demanding cases.

Intermediate-term outcomes after aortic valve replacement with a novel RESILIATM tissue bioprosthesis

Background

The durability of bioprosthetic heart valves is limited by structural valve deterioration (SVD) due to long-term calcification. A novel bioprosthetic tissue (RESILIA^TM) has been developed which, in preclinical studies, has shown reduced calcification. The purpose of this study was to evaluate the intermediate-term clinical outcomes and hemodynamic performance of this tissue.

Methods

A prospective, single-arm, observational trial was conducted in patients who required surgical aortic valve replacement (AVR). Between July 2011 and February 2013, 133 patients were implanted at two sites in Poland. Hemodynamic performance and clinical outcomes were assessed annually through 4 years of follow-up. All safety events were adjudicated by an independent Clinical Events Committee, and echocardiographic data were evaluated by a core laboratory.

Results

Patients were 65.3±13.5 years old and 26% were ≤60 years old. The average follow-up was 3.8±1.1 (median: 4.1; IQR, 4.0-4.3) years. Early (≤30 day) and late (>30 day) all-cause mortality rates were 2.3% (n=3) and 3.2% late patient-years (n=16), respectively. There were no cases of early or late SVD. There was one early case of major paravalvular leak (0.8%), and no late cases. At 4 years, the mean gradient was 14.5±7.4 mmHg and the effective orifice area was 1.6±0.4 cm², both markedly improved from baseline. At 4 years, the New York Heart Association functional class had improved from baseline in 54.5% of patients.

Conclusions

The aortic bioprosthesis with novel RESILIA^TM tissue demonstrated excellent hemodynamic performance and safety outcomes over 4 years. Longer follow-up will be important to confirm the durability of this bioprosthesis.

The Use of Biological Heart Valves

BACKGROUND

Biological heart-valve prostheses have undergone continuous devel- opment up to the present, and technological advances have been made in catheter- assisted valve systems (transcatheter aortic valve implantation, TAVI) and minimally invasive routes of application. These parallel trends have led to major changes in therapeutic strategies, widening the spectrum of patients who are candidates for biological aortic valve implantation.

METHODS

This review is based on pertinent publications retrieved by a systematic search in PubMed employing the search terms "conventional biological aortic pros- thesis," "rapid deployment prosthesis," and "transcatheter aortic valve implantation/ replacement."

RESULTS

Among biological heart-valve prostheses, a distinction is drawn between stented (conventional, rapid-deployment, and catheter-assisted) and non-stented types. The long-term durability of conventional, surgically implantable biological valve protheses is by far the best documented: the reported 5-year reoperation rates range from 13.4% to 36.6%, and the pacemaker implantation rate is ca. 4%. Rapid-deployment prostheses combine the advantages of conventional and ca- theter-assisted techniques and facilitate minimally invasive approaches. The TAVI method is currently recommended for high- and intermediate-risk patients, while conventional valve replacement remains the method of choice for those at low risk. Rapid-deployment and TAVI prostheses is associated with a higher pacemaker im- plantation rate than conventional prostheses: these rates are 8.5-15.3% for TAVI and 6.0-8.8% for rapid-deployment valves. The intermediate-term durability of catheter-assisted and rapid-deployment prostheses appears promising, but their long-term durability is still unclear.

CONCLUSION

The further development of biological heart-valve prostheses in the form of improved conventional, transcatheter, and rapid-deployment prostheses now enables individualized treatment. Before any such procedure is performed, the car- diac team must assess the patient's risk profile and the advantages and disadvan- tages of each type of prosthesis to determine which is best.

Transcatheter aortic valve-in-valve implantation for failed surgical bioprosthetic valves. A minimalist approach without contrast aortography or echocardiographic guidance

OBJECTIVES

To demonstrate safety, feasibility and short-term clinical outcomes after transcatheter aortic valve-in-valve (ViV) implantation under local anesthesia without contrast aortography or echocardiographic guidance.

BACKGROUND

Transcatheter ViV implantation is an emerging treatment modality for patients with degenerative surgical bioprostheses. Given the radiopaque properties of the surgical aortic valve (SAV) frame, ViV procedures can often be performed with fluoroscopic guidance alone.

METHODS

ViV implantation was performed in 37 patients with SAV failure under local anesthesia without contrast aortography. Clinical and echocardiographic data were obtained at baseline, discharge, and 30 days.

RESULTS

Mean age was 74 ± 10 years and STS predicted risk of mortality was 5.6 ± 2.4%. Mean transaortic gradient decreased from 39.4 ± 15.5 mmHg to 13 ± 6.3 mmHg at discharge (p < .001), and 20 ± 7.5 mmHg at 30 days (p < .001 compared to baseline), aortic valve area increased from 0.9 ± 0.3 cm² to 1.2 ± 0.4 cm² at 30 days (p = .007). No patient had more than mild aortic regurgitation. Hospital discharge occurred at a median of 2.6 ± 4.4 days. At 30-day follow-up there were no deaths, myocardial infarctions, strokes, repeat hospital admissions for heart failure, or renal failure. One patient (2.7%) required a new pacemaker. 93% of the patients were in New York Heart Association functional class I or II.

CONCLUSIONS

Transcatheter aortic ViV implantation for selected patients with degenerative surgical bioprostheses under local anesthesia without aortography or echocardiographic guidance is feasible and safe.

Midterm Clinical Outcomes of the St Jude Medical Epic Porcine Bioprosthesis in the Mitral Position

BACKGROUND

The aim of this single-center study was to report the midterm clinical outcomes and hemodynamic performance of the St Jude Medical Epic porcine bioprosthesis, a tricomposite glutaraldehyde-preserved porcine bioprosthesis, in mitral position.

METHODS AND RESULTS

Between January 2011 and March 2017, 117 patients (62 men, 55 women; mean age, 66.7±12.8 years) who underwent mitral valve replacement (MVR) with the Epic valve were retrospectively analyzed for early and mid-term morbidity and mortality. The mean follow-up period was 2.6±1.7 years. Three operative deaths occurred, and the operative mortality rate was 2.6%. Sixteen patients died during the follow-up period. On Kaplan-Meier analysis, freedom from all-cause death and major adverse cardiovascular and cerebrovascular events at 5-year follow-up were 80.9% and 54.8%, respectively. There were 6 reoperations: 2 for structural valve deterioration (SVD), 2 for prosthetic valve endocarditis, and 2 for thrombosis. Freedom from valve-related reoperation and SVD at 5 years were 89.0% and 93.1%, respectively. On multivariate analysis, age ≥71 years (HR, 6.78; 95% CI: 2.12-25.2, P<0.01), and NYHA functional class ≥III (HR, 3.20; 95% CI: 1.03-10.4, P=0.04) were independent predictors for all-cause death. Mean mitral pressure gradient at 1 year and 2 years were 5.1±1.9 mmHg and 4.5±1.4 mmHg, respectively.

CONCLUSIONS

Mid-term clinical results and durability of the Epic valve in the mitral position are satisfactory.

In vivo functional assessment of a novel degradable metal and elastomeric scaffold-based tissue engineered heart valve

OBJECTIVE

Ideal heart valve solutions aim to provide thrombosis-free durability. A scaffold-based polycarbonate urethane urea tissue-engineered heart valve designed to mimic native valve microstructure and function was used. This study examined the acute in vivo function of a stented tissue-engineered heart valve in a porcine model.

METHODS

Trileaflet valves were fabricated by electrospinning polycarbonate urethane urea using double component fiber deposition. The tissue-engineered heart valve was mounted on an AZ31 magnesium alloy biodegradable stent frame. Five 80-kg Yorkshire pigs underwent open tissue-engineered heart valve implantation on cardiopulmonary bypass in the pulmonary position. Tissue-engineered heart valve function was echocardiographically evaluated immediately postimplant and at planned study end points at 1, 4, 8, and 12 hours. Explanted valves underwent biaxial mechanical testing and scanning electron microscopy for ultrastructural analysis and thrombosis detection.

RESULTS

All 5 animals underwent successful valve implantation. All were weaned from cardiopulmonary bypass, closed, and recovered until harvest study end point except 1 animal that was found to have congenital tricuspid valve dysplasia and that was euthanized postimplant. All 5 cases revealed postcardiopulmonary bypass normal leaflet function, no regurgitation, and an average peak velocity of 2 m/s, unchanged at end point. All tissue-engineered heart valve leaflets retained microstructural architecture with no platelet activation or thrombosis by scanning electron microscopy. There was microscopic evidence of fibrin deposition on 2 of 5 stent frames, not on the tissue-engineered heart valve. Biaxial stress examination revealed retained postimplant mechanics of tissue-engineered heart valve fibers without functional or ultrastructural degradation.

CONCLUSIONS

A biodegradable elastomeric heart valve scaffold for in situ tissue-engineered leaflet replacement is acutely functional and devoid of leaflet microthrombosis.

Stented versus Stentless Aortic Valve Replacement in Patients with Small Aortic Root

Objective

The aim of the study was to compare hemodynamic and perioperative outcomes of stented against stentless aortic valve replacement in patients with small aortic root (21 mm or less).

Methods

A comprehensive search was undertaken among the four major databases (PubMed, Embase, Scopus, and Ovid) to identify all randomized and nonrandomized controlled trials comparing stentless to stented bioprosthetic valves in small aortic root patients. Odds ratios, weighted mean differences, or standardized mean differences and their 95% confidence intervals were analyzed.

Results

A total of seven studies with a total of 965 patients fulfilled the inclusion criteria. There was no significant difference in preoperative baselines including mean age between both groups ( P = 0.08), peak aortic valve gradient ( P = 0.06), and effective orifice area ( P = 0.28), whereas higher mean aortic valve gradient in the stented group ( P = 0.007). No difference in cardiopulmonary bypass time ( P = 0.74), aortic cross-clamp times ( P = 0.88), intensive care unit stay ( P = 0.13), and stroke rate ( P = 0.56) were noted. However, stented group of patients showed higher rate of patient prosthesis mismatch ( P = 0.0001) and longer total hospital stay ( P = 0.002). Postoperatively, stentless group showed lower peak and mean aortic valve gradient ( P = 0.003 and P = 0.008, respectively) with a better effective orifice area ( P < 0.00001) at 6 months of follow-up. Mortality rates while in-hospital and at 1 year were similar in both groups ( P = 0.94 and P = 0.86, respectively).

Conclusions

Stentless aortic valves offer superior short-term hemodynamic outcomes in patients with small aortic root when compared with stented aortic valves. Although both groups have similar perioperative complications rates, stentless valves bring about a shorter hospital stay. A further large multicenter randomized controlled trial should address the longer-term benefit of stentless aortic valve over stented valve.

A Non-Invasive Material Characterization Framework for Bioprosthetic Heart Valves

Computational modeling and simulation has become more common in design and development of bioprosthetic heart valves. To have a reliable computational model, considering accurate mechanical properties of biological soft tissue is one of the most important steps. The goal of this study was to present a non-invasive material characterization framework to determine mechanical propertied of soft tissue employed in bioprosthetic heart valves. Using integrated experimental methods (i.e., digital image correlation measurements and hemodynamic testing in a pulse duplicator system) and numerical methods (i.e., finite element modeling and optimization), three-dimensional anisotropic mechanical properties of leaflets used in two commercially available transcatheter aortic valves (i.e., Edwards SAPIEN 3 and Medtronic CoreValve) were characterized and compared to that of a commonly used and well-examined surgical bioprosthesis (i.e., Carpentier-Edwards PERIMOUNT Magna aortic heart valve). The results of the simulations showed that the highest stress value during one cardiac cycle was at the peak of systole in the three bioprostheses. In addition, in the diastole, the peak of maximum in-plane principal stress was 0.98, 0.96, and 2.95 MPa for the PERIMOUNT Magna, CoreValve, and SAPIEN 3, respectively. Considering leaflet stress distributions, there might be a difference in the long-term durability of different TAV models.

Biomaterial characterization of off-the-shelf decellularized porcine pericardial tissue for use in prosthetic valvular applications

Fixed pericardial tissue is commonly used for commercially available xenograft valve implants, and has proven durability, but lacks the capability to remodel and grow. Decellularized porcine pericardial tissue has the promise to outperform fixed tissue and remodel, but the decellularization process has been shown to damage the collagen structure and reduce mechanical integrity of the tissue. Therefore, a comparison of uniaxial tensile properties was performed on decellularized, decellularized-sterilized, fixed, and native porcine pericardial tissue versus native valve leaflet cusps. The results of non-parametric analysis showed statistically significant differences (p < .05) between the stiffness of decellularized versus native pericardium and native cusps as well as fixed tissue, respectively; however, decellularized tissue showed large increases in elastic properties. Porosity testing of the tissues showed no statistical difference between decellularized and decell-sterilized tissue compared with native cusps (p > .05). Scanning electron microscopy confirmed that valvular endothelial and interstitial cells colonized the decellularized pericardial surface when seeded and grown for 30 days in static culture. Collagen assays and transmission electron microscopy analysis showed limited reductions in collagen with processing; yet glycosaminoglycan assays showed great reductions in the processed pericardium relative to native cusps. Decellularized pericardium had comparatively low mechanical properties among the groups studied; yet the stiffness was comparatively similar to the native cusps and demonstrated a lack of cytotoxicity. Suture retention, accelerated wear, and hydrodynamic testing of prototype decellularized and decell-sterilized valves showed positive functionality. Sterilized tissue could mimic valvular mechanical environment in vitro, therefore making it a viable potential candidate for off-the-shelf tissue-engineered valvular applications.

Bioprosthetic aortic valve durability in the era of transcatheter aortic valve implantation

The main limitation of bioprosthetic valves is their limited durability, which exposes the patient to the risk of aortic valve reintervention. Transcatheter aortic valve implantation (TAVI) is considered a reasonable alternative to surgical aortic valve replacement (SAVR) in patients with intermediate or high surgical risk. TAVI is now rapidly expanding towards the lower risk populations. Although the results of midterm durability of the transcatheter bioprostheses are encouraging, their long-term durability remains largely unknown. The objective of this review article is to present the definition, mechanisms, incidence, outcome and management of structural valve deterioration of aortic bioprostheses with specific emphasis on TAVI. The structural valve deterioration can be categorised into three stages: stage 1: morphological abnormalities (fibrocalcific remodelling and tear) of bioprosthesis valve leaflets without hemodynamic valve deterioration; stage 2: morphological abnormalities and moderate hemodynamic deterioration (increase in gradient and/or new onset of transvalvular regurgitation); and stage 3: morphological abnormalities and severe hemodynamic deterioration. Several specifics inherent to the TAVI including valve oversizing, manipulation, delivery, positioning and deployment may cause injuries to the valve leaflets and increase leaflet mechanical stress, which may limit the long-term durability of transcatheter bioprostheses. The selection of the type of aortic valve replacement and bioprosthesis should thus take into account the ratio between the demonstrated durability of the bioprostheses versus the life expectancy of the patient. Pending the publication of robust data on long-term durability of transcatheter bioprostheses, it appears reasonable to select SAVR with a bioprosthesis model that has well-established long-term durability in patients with low surgical risk and long life expectancy.

Biological aortic valve replacement: advantages and optimal indications of stentless compared to stented valve substitutes. A review

Controversy still surrounds the optimal biological valve substitute for aortic valve replacement. In light of the current literature, we review advantages and optimal indications of stentless compared to stented aortic bio-prostheses. Recent meta-analyses, prospective randomized controlled trials and retrospective studies comparing the most frequently used stentless and stented aortic bio-prostheses were analyzed. In the present review, the types and implantation techniques of the bio-prosthesis that are seldom taken into account by most studies and reviews were integrated in the interpretation of the relevant reports. For stentless aortic root bio-prostheses, full-root vs. sub-coronary implantation offered better early transvalvular gradients, effective orifice area and left ventricular mass regression as well as late freedom from structural valve deterioration in retrospective studies. Early mortality and morbidity did not differ between the stentless and stented aortic bio-prostheses. Early transvalvular gradients, effective orifice area and regression of left ventricular hypertrophy were significantly better for stentless, especially as full-root, compared to stented bio-prostheses. The long-term valve-related survival for stentless aortic root and Toronto SPV bio-prosthesis was as good as that for stented pericardial aortic bio-prostheses. For full-root configuration this survival advantage was statistically significant. There seems to be not one but different ideal biological valve substitutes for different subgroups of patients. In patients with small aortic root or exposed to prosthesis-patient mismatch full-root implantation of stentless bio-prostheses may better meet functional needs of individual patients. Longer follow-ups on newer generation of stented bio-prostheses are needed for comparison of their hemodynamic performance with stentless counterparts especially in full-root configuration.

Sudden bioprostethic mitral valve dysfunction years after implantation: 3 cases and review of the literature

Mitral valve replacement is a common procedure. Degeneration of the valve is a complication that usually develops progressively. We discuss three cases of patients who underwent mitral valve replacement by means of a porcine bioprosthesis and who developed sudden and severe mitral regurgitation years after implantation.