Early Biological Valve Failure: Structural Valve Degeneration, Thrombosis, or Endocarditis?

Biological valve failure (BVF) is an inevitable condition that compromises the durability of biological heart valves (BHVs). It stems from various causes, including rejection, thrombosis, and endocarditis, leading to a critical state of valve dysfunction. Echocardiography, cardiac computed tomography, cardiac magnetic resonance, and nuclear imaging play pivotal roles in the diagnostic multimodality workup of BVF. By providing a comprehensive overview of the pathophysiology of BVF and the diagnostic approaches in different clinical scenarios, this review aims to aid clinicians in their decision-making process. The significance of early detection and appropriate management of BVF cannot be overstated, as these directly impact patients' prognosis and their overall quality of life. Ensuring timely intervention and tailored treatments will not only improve outcomes but also alleviate the burden of this condition on patients' life. By prioritizing comprehensive assessments and adopting the latest advancements in diagnostic technology, medical professionals can significantly enhance their ability to manage BVF effectively.

Engineering a New Polymeric Heart Valve Using 3D Printing-TRISKELION.

Background and Objectives: Developing a prosthetic heart valve that combines the advantageous hemodynamic properties of its biological counterpart with the longevity of mechanical prostheses has been a major challenge for heart valve development. Anatomically inspired artificial polymeric heart valves have the potential to combine these beneficial properties, and innovations in 3D printing have given us the opportunity to rapidly test silicone prototypes of new designs to further the understanding of biophysical properties of artificial heart valves. TRISKELION is a promising prototype that we have developed, tested, and further improved in our institution. Materials and Methods: STL files of our prototypes were designed with FreeCad 0.19.2 and 3D printed with an Agilista 3200W (Keyence, Osaka, Japan) using silicones of Shore hardness 35 or 65. Depending on the valve type, the support structures were printed in AR-M2 plastics. The prototypes were then tested using a hemodynamic pulse duplicator (HKP 2.0) simulating an aortic valve cycle at 70 bpm with 70 mL stroke volume (cardiac output 4.9 L/min). Valve opening cycles were visualized with a high-speed camera (Phantom Miro C320). The resulting values led to further improvements of the prototype (TRISKELION) and were compared to a standard bioprosthesis (Edwards Perimount 23 mm) and a mechanical valve (Bileaflet valve, St. Jude Medical). Results: We improved the silicone prototype with currently used biological and mechanical valves measured in our setup as benchmarks. The regurgitation fractions were 22.26% ± 4.34% (TRISKELION) compared to 8.55% ± 0.22% (biological) and 13.23% ± 0.79% (mechanical). The mean systolic pressure gradient was 9.93 ± 3.22 mmHg (TRISKELION), 8.18 ± 0.65 mmHg (biological), and 10.15 ± 0.16 mmHg (mechanical). The cardiac output per minute was at 3.80 ± 0.21 L/min (TRISKELION), 4.46 ± 0.01 L/min (biological), and 4.21 ± 0.05 L/min (mechanical). Conclusions: The development of a heart valve with a central structure proves to be a promising concept. It offers another principle to address the problem of longevity in currently used heart valves. Using 3D printing to develop new prototypes provides a fast, effective, and accurate way to deepen understanding of its physical properties and requirements. This opens the door for translating and combining results into modern prototypes using highly biocompatible polymers, internal structures, and advanced valve layouts.

Mechanical versus biological valve prostheses for left-sided infective endocarditis.

OBJECTIVES: Our aim was to analyse outcomes after implantation of mechanical versus biological valve prostheses in patients presenting with left-sided infective endocarditis. METHODS: We conducted a retrospective single-centre cohort study, analysing adults requiring valve surgery for left-sided infective endocarditis between January 2009 and December 2018 at the Department of Cardiac Surgery, Medical University of Vienna. The primary outcome variable was all-cause mortality. Secondary outcome variables included the occurrence of a combined event (death, stroke, intracerebral bleeding or reoperation) and the risk of re-endocarditis. RESULTS: Among 220 patients, 76 (34.5%) underwent mechanical valve replacement, while 144 (65.5%) underwent biological valve replacement. Recipients of mechanical valve prostheses were younger at the time of surgery and presented with lower European System for Cardiac Operative Risk Evaluation II values. In patients <55 years of age, implantation of a mechanical valve prosthesis was independently associated with significantly lower risk of all-cause mortality (adjusted hazard ratio 0.35, 95% confidence interval 0.15-0.80, P = 0.013). Moreover, this group was at significantly lower risk of a combined event (adjusted hazard ratio 0.38, 95% confidence interval 0.19-0.76, P = 0.006). Implantation of a mechanical valve prosthesis was not associated with increased risk of re-endocarditis. The presence of an annular abscess significantly increased the risk of re-endocarditis (adjusted hazard ratio 3.06, 95% confidence interval 1.40-6.71, P = 0.005). CONCLUSIONS: In patients presenting with left-sided infective endocarditis <55 years of age, implantation of a mechanical valve prosthesis is associated with superior outcomes. A prospective randomized controlled trial is warranted to confirm these results.

Mechanical aortic valve prostheses offer a survival benefit in 50-65 year olds: AUTHEARTVISIT study.

BACKGROUND: The present population-based cohort study investigated long-term mortality after surgical aortic valve replacement (AVR) with bioprosthetic (B) or mechanical aortic valve prostheses (M) in a European social welfare state. METHODS: We analysed patient data from health insurance records covering 98% of the Austrian population between 2010 and 2018. Subsequent patient-level record linkage with national health data provided patient characteristics and clinical outcomes. Further reoperation, myocardial infarction, heart failure and stroke were evaluated as secondary outcomes. RESULTS: A total of 13,993 patients were analysed and the following age groups were examined separately: <50 years (727 patients: 57.77% M, 42.23% B), 50-65 years (2612 patients: 26.88% M, 73.12% B) and >65 years (10,654 patients: 1.26% M, 98.74% B). Multivariable Cox regression revealed that the use of B-AVR was significantly associated with higher mortality in patients aged 50-65 years compared to M-AVR (HR = 1.676 [1.289-2.181], p < 0.001). B-AVR also performed worse in a competing risk analysis regarding reoperation (HR = 3.483 [1.445-8.396], p = 0.005) and myocardial infarction (HR = 2.868 [1.255-6.555], p = 0.012). However, the risk of developing heart failure and stroke did not differ significantly after AVR in any age group. CONCLUSIONS: Patients aged 50-65 years who underwent M-AVR had better long-term survival, and a lower risk of reoperation and myocardial infarction. Even though anticoagulation is crucial in patients with M-AVR, we did not observe significantly increased stroke rates in patients with M-AVR. This evident survival benefit in recipients of mechanical aortic valve prostheses aged <65 years critically questions current guideline recommendations.

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.

The study of dry biological valve crosslinked with a combination of carbodiimide and polyphenol.

The glutaraldehyde crosslinked pericardium has been used in bioprosthetic valves for about 50 years. However, problems such as glutaraldehyde residue and calcification still exist in current commercial products. Non-glutaraldehyde crosslinked dry valve is an important strategy to solve those problems. In this study, a non-glutaraldehyde crosslinked dry biological valve material was obtained by the combined crosslinking of carbodiimide (EDC) and polyphenol. The results showed that the comprehensive properties of EDC and curcumin crosslinked pericardium were superior to glutaraldehyde crosslinked pericardium, including unfolding property, anti-calcification, cytotoxicity, anticoagulant properties, mechanical properties, enzyme degradation resistance and thermal shrinkage temperature. EDC and curcumin crosslinked dry pericardium could flatten after being folded at 40°C for 3 days while glutaraldehyde crosslinked pericardium could not. The calcification of pericardium treated with EDC and curcumin was 1.21 ± 0.36 mg/g in rats after 60 days' subdermal implantation, much lower than that of glutaraldehyde treated control group (22.06 ± 3.17 mg/g).

Numerical simulations of flow patterns in the human left ventricle model with a novel dynamic mesh morphing approach based on radial basis function.

We present a new numerical simulation framework for prediction of flow patterns in the human left ventricle model. In this study, a radial basis function (RBF) mesh morphing method is developed and applied within the finite-volume computational fluid dynamics (CFD) approach. The numerical simulations are designed to closely mimic details of recent tomographic particle image velocimetry (TomoPIV) experiments. The numerically simulated dynamic motions of the left ventricle and tri-leaflet biological mitral valve are emulated through the RBF morphing method. The arbitrary Lagrangian-Eulerian (ALE) based CFD is performed with the RBF-defined deforming wall boundaries. The results obtained show a good agreement with experiments, confirming the reliability and accuracy of the developed simulation framework.

The relation of structural valve deterioration to adverse remodelling and outcome in patients with biological heart valve prostheses.

AIMS: Native valve aortic stenosis is associated with adverse remodelling of the left ventricle and remodelling is stopped or even reversed with aortic valve replacement (AVR). However, the degeneration of bioprostheses and development of structural valve deterioration (SVD) may affect this. METHODS AND RESULTS: To assess the association with SVD, remodelling and outcome 451 patients from a single surgical centre who had undergone AVR with a Mitroflow pericardial bioprosthesis were studied. All patients were assessed in 2014 and a subgroup of patients (N = 327) were re-exanimated again after at least 18 months [median time of 27 (interquartile range, IQR 26-33) months] including echocardiography, measurements of N-terminal pro-brain natriuretic peptide, and assessment of functional status. SVD was based on echocardiography. Moderate SVD was present in 63 patients (14%) and severe SVD in 19 (4%), in the subgroup with follow-up echocardiography 48 patients (15%) patients had moderate to severe SVD at first examination. Patients with SVD had significantly greater increase in left ventricular (LV) mass index [21.6 g/m2 (IQR 5.7-48.3 g/m2) vs. 9.1 g/m2 (-8.6 to 27.3 g/m2), P = 0.01]. Further, patients with SVD had lower LV ejection fraction [55% (IQR 51-62%) vs. 60% (IQR 54-63%), P = 0.01] at follow-up. During follow-up, 94 patients (21%) met the composite endpoint of death or reoperation due to SVD and 41 patient readmitted for heart failure. In multivariable Cox regression analysis, severe SVD [hazard ratio (HR) 2.64 (1.37-5.07), P = 0.004] was associated with composite endpoint, and readmission for heart failure [HR 3.82 (1.53-9.51), P = 0.004]. CONCLUSION: SVD in aortic bioprostheses is associated with adverse LV remodelling and adverse outcome.

Which is the best prosthesis in an isolated or combined tricuspid valve replacement?

OBJECTIVES: The debate concerning the optimal choice of tricuspid position continues. We compared the long-term results of mechanical and biological prostheses in patients who underwent isolated or combined tricuspid valve replacement, at 2 major cardiac surgical centres in central China. METHODS: From January 1999 to December 2018, 338 patients underwent tricuspid valve replacement. Patients were divided into an isolated group or a combined group according to whether their surgery was combined with a left heart valve surgery. Mechanical tricuspid valve replacement was performed in 142 patients (isolated group: 41 vs combined group: 101), and 196 patients underwent bioprosthetic tricuspid valve replacement (isolated group: 145 vs combined group: 51). Operative results, long-term survival and tricuspid valve-related events were compared. RESULTS: Early mortality in the combined group was higher (n = 6, 4%) than that in the isolated group (n = 3, 2%), but no significant difference was observed between the mechanical and biological subgroups. In the isolated group, there was a higher event-free rate in the biological subgroup than in the mechanical subgroup (P = 0.042) and a similar result was also observed for patients without Ebstein's anomaly (P = 0.039). In the combined group, no significant difference was observed (P = 0.98). Survival rates were similar between the mechanical and biological subgroups in both the isolated (P = 0.54) and combined (P = 0.81) groups. Mechanical valves in isolated tricuspid valve replacement were more prone to valve thrombosis and bleeding. CONCLUSIONS: Every decision regarding tricuspid valve prostheses should be individualized, but biological prostheses may be an optimal choice for patients, especially for patients without Ebstein's anomaly, in isolated tricuspid valve replacement.

Percutaneous pulmonary valve implantation in a dysfunctional Trifecta® bioprothesis after high-pressure balloon fracturing.

A percutaneous pulmonary valve-in-valve (PPVIV) implantation in small surgical tissue valves may be limited due to the valve's initial diameter. Fracturing of the valve's integrity by high-pressure balloons may enhance the diameter and facilitate subsequent PPVIV with a large valve. To the best of our knowledge, the Trifecta® valve seemed not to be accessible for fracturing. We report a case of successful 19-mm Trifecta valve fracturing, followed by PPVIV using a 26-mm Edwards SAPIEN 3 valve in pulmonary position. By repetitively using a high-pressure balloon 5 mm larger than the labeled valve size, we were able to fracture the valve's integrity and implant a 26-mm valve thereafter. Therefore, Trifecta valve appears to be suitable for valve ring fracturing and subsequent PPVIV in certain patients.

Perpendicular and turbulent flow after aortic valve replacement: paravalvular or transvalvular leakage? - a case report.

BACKGROUND: Perpendicular transvalvular leakage (TVL) is occasionally observed after aortic valve replacement (AVR) in biological valves with a stent post, often originating from the base of the stent post. However, an observed perpendicular jet flow is not always a TVL. In rare cases, paravalvular leakages (PVLs) can be perpendicular and are present behind a TVL. In the present case, both PVL and TVL existed simultaneously as unusual perpendicular jet flows that originated from sites in close proximity to the stent post. CASE PRESENTATION: A 73-year-old man underwent AVR with a biological valve in the supra-annular position using the non-everting mattress suture technique with pledgets. After weaning from cardiopulmonary bypass (CPB), transesophageal echocardiography (TEE) revealed an unfamiliar perpendicular turbulent flow, similar to reported TVL, originating from the anterior stent post. Further TEE examination revealed a PVL had originated from the site between the sewing ring at the anterior stent post and native annulus attached to a pledget. The space between the sewing ring and annular retained native portion caused the perpendicular turbulent jet. Consequently, two types of perpendicular turbulent flows, TVL and PVL, existed adjacent to each other. After reinstitution of CPB, inspection of the prosthesis itself indicated it to be normal, but there was a region adjacent to the anterior stent post near the right coronary ostium where the tip of the curved Pean forceps entered between the sewing ring and the native annulus. The region was consistent with TEE findings. AVR was performed with the same prosthesis again. After weaning from CPB, immediate TEE revealed that the unusual perpendicular turbulent flows had disappeared and only a few small TVLs were observed. Regarding the disappearance of TVL, we considered that the fabric region of the prosthetic valve was covered with cellular elements to prevent the leak, as it was already used in AVR once and soaked in blood. CONCLUSIONS: Perpendicular turbulent flow raises the possibility of both TVL and PVL in the case of AVR with stented bovine pericardial valves. For a differential diagnosis of TVL or PVL, it is important to know the surgical procedures and valve morphology.

Revisión de la evidencia de estudios de supervivencia de pacientes con prótesis valvular biológica / Review of the evidence in survival studies of patients with a biological valve replacement

Resumen Introducción: las modificaciones en las características estructurales/funcionales de las prótesis valvulares han derivado en un aumento en las curvas de sobrevida/supervivencia de los pacientes, dada la reducción de las tasas de morbilidad y mortalidad posteriores a intervenciones quirúrgicas de las válvulas cardíacas y los cambios sustanciales en la relación costo-efectividad y costo-beneficio de estos procedimientos. Objetivo: conocer la supervivencia de pacientes mayores de 60 años de edad, con prótesis valvular biológica. Materiales y métodos: revisión de estudios de seguimiento publicados en los cuales se evaluó la supervivencia de los pacientes sometidos a reemplazo valvular. Se hizo una búsqueda de artículos científicos registrados en la base de datos PubMed, de acuerdo con los descriptores seleccionados como palabras clave − Prótesis Valvulares Cardíacas/Heart Valve Prosthesis, Bioprótesis/Bioprosthesis, Supervivencia/Survival − en el programa de gestión de referencias EndNote. Se valoró la fuerza de evidencia científica de cada uno de los artículos seleccionados con la escala de McMaster para estudios cuantitativos. Resultados: se obtuvieron 12 referencias y se descartaron 5 (41,7%); calificación global de "fuerte" con la escala de McMaster 7 (58,3%). El tiempo promedio de seguimiento fue de 13,7 años y la razón de masculinidad de 1:0,8. La edad promedio de los pacientes fue 67,2 (rango 60,0-78,5) años. La supervivencia promedio a diez años fue del 65%. Conclusiones: se observa mayor supervivencia entre los pacientes sometidos a reemplazo valvular mecánico versus biológico; sin embargo, la literatura plantea como opción razonable el uso de prótesis biológicas en pacientes mayores de 60 años. Se reconoce, así mismo, la necesidad de hacer más estudios que puedan corroborar los hallazgos.

Abstract Introduction: The modifications in the structural / functional features of replacement valves have led to an increase the survival curves of the patients. This can be seen in the reduction in morbidity and mortality rates after the surgical intervention of the cardiac valves, as well as the substantial changes in the cost-effectivity and cost-benefit ratio of these procedures. Objective: To determine the survival of patients over 60 years of age with a biological valve replacement. Materials and methods: A review of follow-up published studies that evaluated the survival of patients subjected to a valve replacement. A search was made of the scientific articles registered in the PubMed databases, using the selected descriptors as Key words: Heart Valve Prosthesis, Bioprosthesis, Survival, in the references management program-EndNote. The strength of the scientific evidence in each of the selected articles was assessed using the McMaster scale for quantitative studies. Results: A total of 12 references were found and 5 (41.7%) were discarded, and 7 (58.3%) had an overall "strong" score with the McMaster scale. The mean follow-up time was 13.7 years, and the male ratio was 1:0.8. The mean age of the patients was 67.2 (range: 60.0-78.5) years. The mean survival rate at 10 years was 65%. Conclusions: A higher survival was observed between the patients fitted with a mechanical versus a biological valve. However, the literature has established the use of a biological replacement valve as a reasonable option in patients over 60 years of age. It is also recognised that more studies are needed that can corroborate the findings.

Hemodynamic performance and clinical outcome of pericardial Perimount Magna and Porcine Hancock-II valves in aortic position.

BACKGROUND: We investigated hospital and midterm outcome of patients operated for an aortic valve replacement (AVR) with a pericardial Perimount or a Porcine Hancock-II valve. METHODS: We analyzed 353 patients with Perimount Magna (n = 189) or Hancock-II valves (n = 164). Echocardiographic data, hospital outcome, and follow-up were collected and compared. The role of the type of valve on perioperative and midterm outcome was investigated. RESULTS: Mean age was 75.3 ± 6.8 and 74.3 ± 7.1 years (P = .17) for Perimount and Hancock-II group, respectively. Fifty-four Perimount (28.6%) and 24 patients with Hancock-II (14.6%) required urgent procedures (P = .002), including six type-A dissections and five endocarditis. EuroSCORE-II was 3.1 ± 2.7% (Perimount) and 2.7 ± 2.2% (Hancock-II). Combined procedures were performed in 115 Perimount (60.8%) and 71 patients with Hancock (43.3%); redo procedures counted for 1% and 2.4%, respectively (P = .42). Mean valve size was 23.2 ± 1.8 mm for pericardial and 23.6 ± 1.9 mm for porcine valves (P = .08). Hospital mortality (6.3% vs 2.4%; P = .05), kidney failure (11.6% vs 9.8%; P = .73), and new pacemaker implantation rates (6.3% vs 3.0%; P = .21) were higher in the Perimount group reflecting the fact that more urgent, combined, and critical procedures were implanted with a Perimount Magna. Overall, 51 patients died over 60 months (34 Perimount, 17 Hancock), corresponding to a mortality of 5.3 per 100-persons year (95% confidence interval [CI]: 3.8-7.4) and 3.0 (95% CI: 1.8-4.8), respectively. Survival at 5 years was 76% (95% CI: 68-82) and 83% (95% CI: 74-89) in the Perimount and Hancock groups (log-rank test; P = .099). CONCLUSIONS: We confirm a good clinical outcome of patients with AVR with modern pericardial or a porcine bioprosthesis. Despite better hemodynamic, the Perimount does not improve the midterm clinical outcome compared with the porcine valve.

Clinical Application of Bioprosthesis in China: Current Status and Future.

China is one of the countries which have a high incidence of heart valvular disease, but the use of biological valve is limited in China before because the majority of patients are young patients suffering from rheumatic heart disease. The biological valve has a good application prospect in China. On the one hand, the new generation of biological valves have been significantly improved in the aspects of anti-calcification treatment, anti-metabolism, material quality control, valve frame mechanics design, and leaflet sewing technology, and the application effect is improved; on the other hand, surgeons should adapt to the new concept changes, and correctly understand and rationally apply biological valves, master valve repair, atrial fibrillation ablation and other techniques, combined with interventional, minimally invasive techniques, etc., according to the specific conditions of the disease and choose the surgery type to ensure the patients' long-term life quality.

Long-term outcome after mitral valve replacement using biological versus mechanical valves.

BACKGROUND: This study compared long-term outcomes of biological and mechanical mitral valve replacement (MVR) in patients requiring replacement of the mitral valve where repair was not feasible. METHODS: A single-centre registry of patients receiving MVR between 2005 and 2015 was established. Thirty-day mortality and long-term outcomes were analysed and compared. RESULTS: Three hundred twenty four patients underwent MVR (265 biological; 59 mechanical valves). Patients receiving biological valves were older (p < 0.001), had a higher log EuroSCORE (p < 0.001) and received less minimally invasive surgery (p < 0.001). Immediate procedural mortality was 1.9%, which only occurred in the biological valve group. At 30 days, 9.0% of patients had died, 4.0% experienced stroke, 8.0% received a pacemaker and 10.5% suffered an acute renal failure. The rate of re-thoracotomy (14.2%) was lower in the biological (12.5%) than in the mechanical valve group (22.0%; adjOR 0.45 [0.20-1.00]; p = 0.050). Frequent long-term complications were stroke (9.2%) and bleeding (4.8%), with bleeding complications being higher in the mechanical valve group (p = 0.009). During the follow-up period biological valves showed a numerically higher survival rate during the first years, which shifted after 3 years in favour of mechanical valves. At 10 years, survival rates were 62.4% vs. 77.1% in the biological and mechanical valve groups (p = 0.769). Hazard ratio after adjustment was 0.833 (95% CI 0.430-1.615). CONCLUSION: These data confirm that mechanical valve implantation is associated with an increased risk of bleeding. While there was a potential survival benefit during the first years after surgery for patients receiving a biological valves the difference became insignificant after a follow-up of 10 years.

Edwards Inspiris Resilia® valve for mitral replacement in an infant after mechanical valve failure.

We present the surgical implantation of the Edwards Inspiris Resilia® aortic valve in mitral position for mechanical mitral valve failure in a severely ill infant after valve replacement because of anomalous origin of the left coronary artery from the pulmonary artery. The biological valve was chosen because the child could not receive oral anticoagulation and was for several months on heparin infusion. The procedure was safely performed with good haemodynamic result.

Structural valve deterioration in the Mitroflow biological heart valve prosthesis.

OBJECTIVES: Concern has been raised regarding the long-term durability of the Mitroflow biological heart valve prosthesis. Our aim was to assess the incidence of structural valve degeneration (SVD) for the Mitroflow bioprosthesis in a nationwide study in Denmark including all patients alive in Denmark who had received a Mitroflow aortic bioprosthesis since 2000. METHODS: Patients alive in Denmark with a Mitroflow bioprosthesis implanted since January 2000 were invited to participate in a nationwide cross-sectional study with a predefined definition of SVD. Of 1552 patients, 861 patients had died and 47 patients had been reoperated with 40 reoperations due to SVD. The remaining 644 patients were invited for evaluation; 574 patients accepted and were evaluated for SVD. The incidence of SVD was calculated using competing risk regression analysis with death as the competing event. RESULTS: A total of 173 patients were diagnosed with SVD by echocardiography. Of these, 64 (11%) patients had severe SVD and 109 (19%) patients moderate SVD. Severe SVD was associated with the age of the prosthesis and small prosthesis size [Size 21: hazard ratio (95% confidence interval, CI) 2.72 (0.97-8.56), P = 0.06; Size 19: 6.26 (1.63-24.06), P = 0.008]. The cumulative incidences of reoperation or severe SVD at Year 9 were 12.5% for Size 19, 7.6% for Size 21 and 3.1 (1.2-6.4)% for Size 23. Median survival in patients with prosthesis Sizes 23-29 was 6.4 (95% CI 5.7-7.0) years, with Size 21 it was 6.5 (95% CI 5.9-7.1) years and with Size 19 it was 6.9 (95% CI 5.7-8.2) years (P = 0.78). CONCLUSIONS: The incidence of undetected severe SVD was as high as the incidence of operated SVD. The overall risk for SVD is high for the Mitroflow bioprosthesis, especially if the prosthesis is small and older than 5 years.

Heart Valves from Polyester Fibers vs. Biological Tissue: Comparative Study In Vitro.

Transcatheter aortic valve implantation (TAVI) has become a popular alternative technique to surgical valve replacement for critical patients. Biological valve tissue has been used in TAVI procedures for over a decade, with over 100,000 implantations to date. However, with only 6 years follow up, little is known about the long-term durability of biological tissue. Moreover, the high cost of tissue harvesting and chemical treatment procedures favor the development of alternative synthetic valve leaflet materials. Textile polyester is one such material which provides outstanding folding and strength properties combined with proven biocompatibility, and could therefore be considered as a candidate to replace the biological valve leaflets in TAVI procedures. For that purpose, in addition to the mechanical properties, the hemodynamic properties of the synthetic material should be comparable to the properties of biological tissue. An ideal replacement heart valve would provide low static and dynamic regurgitation, ensure laminar flow across the valve, and limit the turbidity of flow downstream of the valve. The purpose of the present work is to compare in vitro the mechanical and hemodynamic performances of textile woven polyester valves with biological ones. Testing results indicate that textile valves trade elasticity for superior mechanical strength, relative to biological tissue. Despite this, the dynamic flexibility of textile valve leaflets strongly resembled what was seen with biological leaflets. Regurgitation, as well as slightly modified turbulent patterns, in textile valves was higher than biological valves due to the increased porosity, but, rapid tissue ingrowth post-implantation would likely mitigate this effect. Together these findings provide additional evidence favoring the use of textile polyester as a synthetic heart valve leaflet material.