scholarly journals Hydrodynamic performance of a novel suturelessprosthetic aortic valve

2020 ◽  
Vol 22 (2) ◽  
pp. 117-124
Author(s):  
K. Yu. Klyshnikov ◽  
E. A. Ovcharenko ◽  
Yu. A. Kudryavtseva ◽  
L. S. Barbarash
Keyword(s):  
Aortic Valve ◽  
Prosthetic Heart Valve ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Effective Orifice Area ◽  
Orifice Area ◽  
Comparative Aspect ◽  
Hydrodynamic Study ◽  
Valve In Valve

The aim of the study was an in vitro hydrodynamic study of the developed prosthetic heart valve of the second generation, designed to carry out an implantation using «valve-in-valve» method. Material and methods. Prototypes of the developed prosthesis were studied under simulated physiological conditions of the heart using a Vivitro Labs pulse duplicator (Canada) in a comparative aspect with «UniLine» clinical commercial aortic valve bioprosthesis (Russia). Samples were tested by simulating sutureless implantation procedure. Results. The developed valves showed satisfactory hydrodynamic characteristics – for all cases of «implantation» from the position of the average trans-prosthetic gradient (6.1–11.1 mm Hg) and the effective orifice area (1.60–1.81 cm2 ). The analysis of the regurgitation fraction allowed us to determine the optimal sizes for implantation using «valvein-valve» method, which subsequently will form the basis of sizing guidelines for size selection. A qualitative analysis of the leaflet’s work demonstrated the presence of slight asymmetry for a number of prostheses – in case of mismatch of sizes when simulating «valve-in-valve» procedure. Conclusion. The tests demonstrate the viability of the developed design from the standpoint of hydrodynamic efficiency and determines the basic rules of selecting a prosthesis for reimplantation relative to the primary valve.

scholarly journals Experimental substantiation of the design of a prosthetic heart valve for «valve-in-valve» implantation

2017 ◽  
Vol 19 (2) ◽  
pp. 69-77
Author(s):  
K. Yu. Klyshnikov ◽  
E. A. Ovcharenko ◽  
A. N. Stasev ◽  
T. V. Glushkova ◽  
Yu. A. Kudryavtseva ◽  
...  
Keyword(s):  
Heart Valve ◽  
Prosthetic Heart Valve ◽  
Hydrodynamic Characteristics ◽  
Implantation Technique ◽  
Effective Orifice Area ◽  
Test Machine ◽  
Critical Surface ◽  
Valve Prosthesis ◽  
Valve In Valve ◽  
Valve Implantation

The aim of the study was to perform a series of in vitro tests of a prototype of the developing heart valve prosthesis to evaluate its functional characteristics. Materials and methods. In this work we have used the frames and full prototypes of the prosthesis, consisting of a stent-like stainless steel support frame with mounted biological leaflets and cover. The authors evaluated the calculated and experimental forces necessary for the displacement of the sutureless implanted prosthesis using the test machine under uniaxial tension. The risk of defects and damages to the supporting framework as a result of implantation was evaluated by scanning electron microscopy. The hydrodynamic characteristics of the prosthesis were investigated under physiological conditions and «valvein-valve» implantation. Evaluation of the ergonomics and applicability of the proposed construction on the cadaver heart model of cattle was carried out. Results. As a result of the forces assessment, it was found that the force required to shear the prosthesis was 3.12 ± 0.37 N, while the calculated value was 1.7 N, which is significantly lower than the obtained value. The comparison of the images obtained with small and large magnifications demonstrated the absence of critical surface defects. Additional analysis under the super-large magnifications also did not reveal problem areas. During the hydrodynamic study, it was shown that the average transplant gradient increased slightly from 2.8–3.4 to 3.2–4.5 mm Hg for the initial prosthesis and the «valve-in-valve» complex, respectively. The decrease of the effective orifice area was 6–9% relative to the initial one. Evaluation of the implantation technique demonstrated the consistency of the approach: the use of the developed holder in combination with the balloon implantation system made it possible to position the prosthesis throughout the procedure. Conclusion. The series of tests demonstrates the consistency of the developed design, intended for the replacement of a failed prosthetic valve of the heart with the «valve-in-valve» implantation.

scholarly journals Hemodynamic influence of design parameters of novel venous valve prostheses

2018 ◽  
Vol 4 (1) ◽  
pp. 149-151
Author(s):  
Michael Stiehm ◽  
Stefanie Kohse ◽  
Kerstin Schümann ◽  
Sebastian Kaule ◽  
Stefan Siewert ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Lower Limbs ◽  
Hydrodynamic Performance ◽  
Design Parameters ◽  
Effective Orifice Area ◽  
Valve Prosthesis ◽  
Venous Valve ◽  
Orifice Area ◽  
Valve Prostheses

AbstractVenous ulcers of the lower limbs are one clinical manifestation of chronic venous insufficiency. Currently, there is no venous valve prosthesis available. This study presents novel venous valve prostheses made of threedimensional electrospun fibrous nonwoven leaflets. The aim of this study was to prove the feasibility of the manufacturing process as well as to investigate design features of the venous valve prostheses from a hemodynamic point of view. An adapted pulse duplicator system (ViVitrolabs, Victoria, BC, CA) was used for characterization of the hydrodynamic performance. For eight different venous valve prototypes flow rate, effective orifice area and regurgitation fraction was investigated in vitro. In particular, tricusp valve designs showed an up to 40% higher effective orifice area as well as 15% higher maximum flowrate compared to bicusp valve designs. However, the regurgitation fraction of the bicusp valve designs is up to 86% lower compared to tricusp valve. Additionally, the hemodynamic performance of the tricuspid valves showed a high sensitivity regarding the leaflet length. Bicuspid valves are less sensitive to changes of design parameters, more sufficient and therefore highly reliable.

scholarly journals An in vitro comparison of internally versus externally mounted leaflets in surgical aortic bioprostheses

2019 ◽  
Vol 30 (3) ◽  
pp. 417-423 ◽  
Author(s):  
Michiel D Vriesendorp ◽  
Rob A F de Lind van Wijngaarden ◽  
Vivek Rao ◽  
Michael G Moront ◽  
Himanshu J Patel ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
In Vitro Study ◽  
Hydrodynamic Performance ◽  
Wear Testing ◽  
Effective Orifice Area ◽  
Close Monitoring ◽  
Orifice Area ◽  
Prosthetic Valves

Abstract OBJECTIVES To improve haemodynamic performance, design modifications of prosthetic valves have been proposed with each new generation of valves. These different designs also impact the amount of mechanical wear, because mechanical stresses are distributed differently. Because long-term evidence for new prosthetic valves is lacking, this in vitro study compared hydrodynamic performance and durability among 3 currently available bioprosthetic valves with internally (IMLV) or externally mounted leaflets (EMLV). METHODS Prostheses of the internally mounted Medtronic Avalus and Carpentier-Edwards Perimount Magna Ease valves were compared to prostheses of the externally mounted Abbott Trifecta valve. For each labelled size (e.g. 19, 21 and 23) of the 3 types, 3 valves underwent accelerated wear testing for up to 600 million cycles, corresponding to ∼15 years of simulated wear. The valves underwent hydrodynamic testing and visual inspection. RESULTS EMLV had the largest effective orifice area and lowest pressure gradient for each labelled size at baseline and 600 million cycles; the effective orifice area and the pressure gradient were equivalent for the 2 types of IMLV. Five of 9 EMLVs had at least 1 hole or tear in the leaflet tissue around the stent posts, which resulted in severe regurgitation at 500 million cycles in 2 cases. All IMLVs were intact at 600 million cycles with minimal tissue wear. CONCLUSIONS EMLV showed superior hydrodynamic performance but inferior mechanical durability compared to IMLV after 600 million cycles of testing. The primary failures were because of significant mechanical abrasion in the commissural region, which may warrant close monitoring of EMLV during long-term follow-up.

Incidence, predictors and clinical outcomes of residual stenosis after aortic valve-in-valve

Heart ◽  
2018 ◽  
Vol 104 (10) ◽  
pp. 828-834 ◽  
Author(s):  
Sabine Bleiziffer ◽  
Magdalena Erlebach ◽  
Matheus Simonato ◽  
Philippe Pibarot ◽  
John Webb ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Clinical Outcomes ◽  
Effective Orifice Area ◽  
Term Survival ◽  
Orifice Area ◽  
Long Term Effect ◽  
Valve In Valve ◽  
Independent Risk Factors ◽  
Transcatheter Device

ObjectiveWe aimed to analyse the incidence of prosthesis–patient mismatch (PPM) and elevated gradients after aortic valve in valve (ViV), and to evaluate predictors and associations with clinical outcomes of this adverse event.MethodsA total of 910 aortic ViV patients were investigated. Elevated residual gradients were defined as ≥20 mm Hg. PPM was identified based on the indexed effective orifice area (EOA), measured by echocardiography, and patient body mass index (BMI). Moderate and severe PPM (cases) were defined by European Association of Cardiovascular Imaging (EACVI) criteria and compared with patients without PPM (controls).ResultsModerate or greater PPM was found in 61% of the patients, and severe in 24.6%. Elevated residual gradients were found in 27.9%. Independent risk factors for the occurrence of lower indexed EOA and therefore severe PPM were higher gradients of the failed bioprosthesis at baseline (unstandardised beta −0.023; 95% CI −0.032 to –0.014; P<0.001), a stented (vs a stentless) surgical bioprosthesis (unstandardised beta −0.11; 95% CI −0.161 to –0.071; P<0.001), higher BMI (unstandardised beta −0.01; 95% CI −0.013 to –0.007; P<0.001) and implantation of a SAPIEN/SAPIEN XT/SAPIEN 3 transcatheter device (unstandardised beta −0.064; 95% CI −0.095 to –0.032; P<0.001). Neither severe PPM nor elevated gradients had an association with VARC II-defined outcomes or 1-year survival (90.9% severe vs 91.5% moderate vs 89.3% none, P=0.44).ConclusionsSevere PPM and elevated gradients after aortic ViV are very common but were not associated with short-term survival and clinical outcomes. The long-term effect of poor post-ViV haemodynamics on clinical outcomes requires further evaluation.

scholarly journals Reclassification of prosthesis–patient mismatch after transcatheter aortic valve replacement using predicted vs. measured indexed effective orifice area

2020 ◽  
Vol 22 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Julien Ternacle ◽  
Leonardo Guimaraes ◽  
Flavien Vincent ◽  
Nancy Côté ◽  
Mélanie Côté ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Valve Replacement ◽  
Clinical Outcomes ◽  
Valve Replacement ◽  
Transcatheter Aortic Valve Replacement ◽  
Effective Orifice Area ◽  
Orifice Area ◽  
Transcatheter Aortic Valve ◽  
Device Implantation ◽  
Valve In Valve

Abstract Aims The objective was to compare the incidence and impact on outcomes of measured (PPMM) vs. predicted (PPMP) prosthesis–patient mismatch following transcatheter aortic valve replacement (TAVR). Methods and results All consecutives patients who underwent TAVR between 2007 and 2018 were included. Effective orifice area (EOA) was measured by Doppler-echocardiography using the continuity equation and predicted according to the normal reference for each model and size of valve. PPM was defined using EOA indexed (EOAi) to body surface area as moderate if ≤0.85 cm2/m2 and severe if ≤ 0.65 cm2/m2 (respectively, ≤ 0.70 and ≤ 0.55 cm2/m2 if body mass index ≥ 30 kg/m2). The outcome endpoints were high residual gradient (≥20 mmHg) and the composite of cardiovascular mortality and hospital readmission for heart failure at 1 year. Overall, 1088 patients underwent a TAVR (55% male, age 79.1 ± 8.4 years, and STS score 6.6 ± 4.7%); balloon-expandable device was used in 83%. Incidence of moderate (10% vs. 27%) and severe (1% vs. 17%) PPM was markedly lower when defined by predicted vs. measured EOAi (P &lt; 0.001). Balloon-expandable device implantation (OR: 1.90, P = 0.029) and valve-in-valve procedure (n = 118; OR: 3.21, P &lt; 0.001) were the main factors associated with PPM occurrence. Compared with measured PPM, predicted PPM showed stronger association with high residual gradient. Severe measured or predicted PPM was not associated with clinical outcomes. Conclusion The utilization of the predicted EOAi reclassifies the majority of patients with PPM to no PPM following TAVR. Compared with measured PPM, predicted PPM had stronger association with haemodynamic outcomes, while both methods were not associated with clinical outcomes.

scholarly journals A NEWLY DEVELOPED TRI-LEAFLET POLYMERIC HEART VALVE PROSTHESIS

2015 ◽  
Vol 15 (02) ◽  
pp. 1540009 ◽  
Author(s):  
FRANCESCO DE GAETANO ◽  
PAOLA BAGNOLI ◽  
ADRIANO ZAFFORA ◽  
ANNA PANDOLFI ◽  
MARTA SERRANI ◽  
...  
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Prosthetic Heart Valve ◽  
Element Model ◽  
Effective Orifice Area ◽  
Valve Prosthesis ◽  
Flow Conditions ◽  
Orifice Area ◽  
Mechanical Valves

The potential of polymeric heart valves (PHV) prostheses is to combine the hemodynamic performances of biological valves with the durability of mechanical valves. The aim of this work is to design and develop a new tri-leaflet prosthetic heart valve (HV) made from styrenic block copolymers. A computational finite element model was implemented to optimize the thickness of the leaflets, to improve PHV mechanical and hydrodynamic performances. Based on the model outcomes, 8 prototypes of the designed valve were produced and tested in vitro under continuous and pulsatile flow conditions, as prescribed by ISO 5840 Standard. A specially designed pulse duplicator allowed testing the PHVs at different flow rates and frequency conditions. All the PHVs met the requirements specified in ISO 5840 Standard in terms of both regurgitation and effective orifice area (EOA), demonstrating their potential as HV prostheses.

scholarly journals Prosthesis-patient mismatch after aortic valve in valve procedure: incidence, predictors and clinical outcomes

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
L Fusini ◽  
M Muratori ◽  
S Ghulam Ali ◽  
P Gripari ◽  
C Cefalu" ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Clinical Outcomes ◽  
Effective Orifice Area ◽  
Orifice Area ◽  
Funding Sources ◽  
Prosthetic Valves ◽  
Transcatheter Aortic Valve ◽  
Frequent Finding ◽  
Valve In Valve ◽  
Funding Acknowledgements

Abstract Funding Acknowledgements Type of funding sources: None. Background. Transcatheter aortic valve-in-valve (TAVI ViV) implantation is an appealing treatment option for patients with degenerated bioprostheses. However, elevated residual gradients after TAVI ViV procedure are very common. These are an unwanted effects of prosthesis-patient mismatch (PPM). Currently, the actual incidenceof PPM, its predictors and its clinical outcomes have not been completely investigated. Purpose. The aims of this study was to investigate the incidence, predictors and clinical outcome of PPM and therefore of elevated gradients after TAVI ViV. Methods. 75 patients (age 78 ± 9 years, 36 male), who underwent TAVI-ViV due to failed aortic biological valve (60 stented, 15 stentless), were enrolled. Mechanism of bioprosthetic valve failure was stenosis (34 cases, 45%), regurgitation (24 cases, 32%) or combination (17 cases, 23%). Elevated residual gradients were defined as a mean DP&gt; 20 mmHg. PPM was identified by the indexed effective orifice area (EOAi) measured by echocardiography (moderate PPM if 0.65 &lt; EOAi &lt; 0.85 cm²/m²; severe PPM if EOAi &lt; 0.6 cm²/m²). Results. ViV TAVI was feasible in all patients, 33 patients (44%) were implanted with a balloon-expandable valve and 42 (56%) with a self-expandable valve. Post-procedural post-ballooning was performed in 16 out of 42 patients (38%) receiving a self-expandable valve. Post-operative mean DP&gt; 20 mmHg was found in 35 patients (48%). Moderate PPM was found in 24 cases (33%) and severe PPM in 15 (20%). A logistic regression analyses identified small size of surgical prosthesis (size &lt; 23 mm) [OR: 6.061(2.127-17.267), p = 0.001] and failed stented valve [OR: 20.727(2.522-170.364), p = 0.005] as independent predictors for the occurrence PPM. Interestingly PPM did not affect early and 1 years mortality (1 years mortality 1.3 %), while mortality was higher in pts with stentless prostheses (9%) Conclusions. PPM is a frequent finding after ViV procedures. Despite elevated residual gradients, TAVI ViV resolved prosthetic dysfunction and PPM did not affect mortality.  Therefore, this procedure represents a promising new option for patients with failed biological prosthetic valves.

scholarly journals Impact of aortic annulus geometry according to ISO 5840:2019 (draft) on hydrodynamic performance of transcatheter aortic valve prostheses

2020 ◽  
Vol 6 (3) ◽  
pp. 454-457
Author(s):  
Jan Oldenburg ◽  
Sebastian Kaule ◽  
Stefan Siewert ◽  
Klaus-Peter Schmitz ◽  
Michael Stiehm ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Hydrodynamic Performance ◽  
Performance Criteria ◽  
Modular System ◽  
Effective Orifice Area ◽  
In Vitro Test ◽  
Transcatheter Aortic Valve ◽  
Valve Prostheses ◽  
Hydrodynamic Testing

AbstractTo assess the hydrodynamic performance of transcatheter aortic valve prostheses (TAVP), in vitro test using pulse duplicators is required. Test conditions as well as minimum performance criteria are specified in ISO 5840- 3:2013 and ISO 5840-3:2019-draft. In the 2019 published draft, modifications regarding hydrodynamic testing are proposed. Among others, the geometrical configuration of the fixation has changed, with the intention to improve the anatomical representation as well as the comparability of results from different test laboratories. We analyzed the consequences of altered annulus fixations regarding native leaflets as well as a step in the proximal area of the protheses to prevent their migration. The analyses were conducted with regard to the degree of calcification of the annulus ring on hydrodynamic parameters. By using 3D stereolithography printing technology, molds for casting of silicone elastomer of annulus models with and without native leaflets were manufactured. A modular system enabled us to use the same annulus ring to model the degree of calcification as well as different step sizes. We performed in vitro hydrodynamic testing according to ISO 5840-3:2019-draft of a selfexpandable valve prototype with porcine pericardial leaflets by using a commercially available pulse duplicator system. As expected, regurgitation increases with increasing degree of calcification, whereby the use of a step has no influence on the backflow of fluid during diastole. The effective orifice area (EOA) of the valve showed a clear tendency with respect to radial protrusion of the step. The EOA decreased as the radial protrusion increased. We also present a suggestion to prevent migration without affecting the general test results, by using a novel step design. We also found that the novel annulus model with native leaflet drastically reduced the regurgitation.

scholarly journals The Usefulness of [18F]F-Fluorodeoxyglucose and [18F]F-Sodium Fluoride Positron Emission Tomography Imaging in the Assessment of Early-Stage Aortic Valve Degeneration after Transcatheter Aortic Valve Implantation (TAVI)—Protocol Description and Preliminary Results

2021 ◽  
Vol 10 (3) ◽  
pp. 431
Author(s):  
Danuta Sorysz ◽  
Rafał Januszek ◽  
Anna Sowa-Staszczak ◽  
Anna Grochowska ◽  
Marta Opalińska ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Emission Tomography ◽  
Effective Orifice Area ◽  
Orifice Area ◽  
Transcatheter Aortic Valve ◽  
Positron Emission ◽  
Pet Ct ◽  
Transvalvular Gradient ◽  
Valve Implantation

Transcatheter aortic valve implantation (TAVI) is now a well-established treatment for severe aortic stenosis. As the number of procedures and indications increase, the age of patients decreases. However, their durability and factors accelerating the process of degeneration are not well-known. The aim of the study was to verify the possibility of using [18F]F-sodium fluoride ([18F]F-NaF) and [18F]F-fluorodeoxyglucose ([18F]F-FDG) positron emission tomography/computed tomography (PET/CT) in assessing the intensity of TAVI valve degenerative processes. In 73 TAVI patients, transthoracic echocardiography (TTE) at initial (before TAVI), baseline (after TAVI), and during follow-up, as well as transesophageal echocardiography (TEE) and PET/CT, were performed using [18F]F-NaF and [18F]F-FDG at the six-month follow-up (FU) visit as a part of a two-year FU period. The morphology of TAVI valve leaflets were assessed in TEE, transvalvular gradients and effective orifice area (EOA) in TTE. Calcium scores and PET tracer activity were counted. We assessed the relationship between [18F]F-NaF and [18F]F-FDG PET/CT uptake at the 6 = month FU with selected indices e.g.,: transvalvular gradient, valve type, EOA and insufficiency grade at following time points after the TAVI procedure. We present the preliminary PET/CT ([18F]F-NaF, [18F]F-FDG) results at the six-month follow-up period as are part of an ongoing study, which will last two years FU. We enrolled 73 TAVI patients with the mean age of 82.49 ± 7.11 years. A significant decrease in transvalvular gradient and increase of effective orifice area and left ventricle ejection fraction were observed. At six months, FU valve thrombosis was diagnosed in four patients, while 7.6% of patients refused planned controls due to the COVID-19 pandemic. We noticed significant correlations between valve types, EOA and transaortic valve gradients, as well as [18F]F-NaF and [18F]F-FDG uptake in PET/CT. PET/CT imaging with the use of [18F]F-FDG and [18F]F-NaF is intended to be feasible, and it practically allows the standardized uptake value (SUV) to differentiate the area containing the TAVI leaflets from the SUV directly adjacent to the ring calcifications and the calcified native leaflets. This could become the seed for future detection and evaluation capabilities regarding the progression of even early degenerative lesions to the TAVI valve, expressed as local leaflet inflammation and microcalcifications.

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