Non-physiologic closing of bi-leaflet mechanical heart prostheses requires a new tri-leaflet valve design

Carrel, Thierry; Dembitsky, Walter P.; Mol, Bas A.J.M. de; Obrist, Dominik; Dreyfus, Gilles; Meuris, Bart; Vennemann, Bernhard; Lapeyre, D; Schaff, Hartzell V.

doi:10.1016/j.ijcard.2020.01.056

Cited by 13 publications

(12 citation statements)

References 7 publications

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“…Furthermore, a comparative in-vitro study on leaflet kinematics (Carrel et al. 2020) showed that recent trileaflet valves guarantee slower closing kinematics with respect to BMAVs, implying lower stress levels on blood flow. The present study provides a complementary description of the turbulent features within a recent trileaflet valve design, which corroborates the potential of trileaflet models in generating the more natural valve haemodynamics.…”

Section: Introductionmentioning

confidence: 99%

“…A recent study proved that trileaflet valves provide a more homogeneous core flow with lower global vorticity magnitude and reduced wall shear stress if compared with current bileaflet models (Li, Hegner & Bruecker 2020) with similar implantation position. Furthermore, a comparative in-vitro study on leaflet kinematics (Carrel et al 2020) showed that recent trileaflet valves guarantee slower closing kinematics with respect to BMAVs, implying lower stress levels on blood flow. The present study provides a complementary description of the turbulent features within a recent trileaflet valve design, which corroborates the potential of trileaflet models in generating the more natural valve haemodynamics.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of turbulent features past different mechanical aortic valves

2022

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Flow through mechanical aortic valves (MAVs) has been constantly associated to higher haemolysis and platelet activation levels with respect to native valves, due to non-physiologic haemodynamic features. Both computational and experimental investigations have correlated the blood damage to augmented levels of turbulent stress downstream of MAVs. This study provides a computational estimation, drawn from high-resolution direct numerical simulations, of turbulent and fluctuating viscous stresses in three different MAV configurations, at subsequent stages of the cardiac cycle. The configurations comprise a St. Judes Medical Regent valve (SJMV), a Lapeyre-Triflo FURTIVA valve (LTFV) with three leaflets, and a SJMV with vortex generators (VGs). Non-standard configurations are expected to mitigate the mean stress level on blood constituents reducing the turbulent production. Computations are carried out by means of a finite-difference flow solver with a direct-forcing immersed boundary technique to handle fixed and moving bodies. The VGs are found to provide instabilities which corrupt the Kármán-like vortex shedding downstream of the leaflets, reducing the intensity of turbulent kinetic energy at the peak flow rate, thus lowering the local Reynolds shear stress. Conversely, the LTFV configuration provides comparable haemodynamic performance at peak flow rate but further reduced stress level in the deceleration phase. These interpretations are supported by probability density distributions from three-dimensional fields, and further corroborated by a pointwise mapping of the Taylor length scale and local energy spectra. The outcomes of this study might potentially be exploited to improve the design of new-generation MAVs, with the aim of decreasing the risk of thromboembolic complications.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical investigation of turbulent features past different mechanical aortic valves

2022

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“…Since only fleeting glimpses of prosthetic valve motion can be seen by the unaided eye, we developed a simple technique to quantify high-speed valve motion detail (Basic Leonardo, Figure 1). Described previously, this approach provides important analog data about valve motion [3,[5][6][7][8][9][10][11]. Technical specifications for the current Leonardo sub-system [7]…”

Section: B) Leonardomentioning

confidence: 99%

“…This work provided incentive to refine geometry of a mechanical heart valve (MHV) with blood damage potential reduced to tissue valve levels. Included in these investigations were modified bileaflet [7] and trileaflet designs [6, 10, 11]. Also, this experimental methodology was extended to study thrombogenic potential in transcatheter aortic valve replacement (TAVR) devices [8, 9].…”

Section: Introductionmentioning

confidence: 99%

Violin plot data: A concerto of crucial information on valve thrombogenicity categorized in vitro by valve motion and inferred flow velocity

Scotten

Blundon

Deutsch

et al. 2019

Preprint

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Objectives: We hypothesize that prosthetic valve thrombogenic potential may be inferred by valve regional flow velocity. This metric was used to compare two clinical valves and two experimental prototypes. Methods: Four our clinical and experimental prototype valve models were tested in aortic and mitral sites under pulsatile circulation in a pulse duplicator. An optical approach measuring projected dynamic valve area to gauge valve motion was implemented. Pulsatile pressures and flow rates were measured by conventional techniques and a quasi-steady flow tester was used to measure valve leakage. Regurgitant flow velocity was derived using time-dependent volumetric flow rate / projected dynamic valve area. Since flow velocity and fluid shear force are related through flow velocity gradient, thrombogenic potential for valves that achieve near closure during the forward flow deceleration phase were determined as regurgitant flow velocities relative to the control mechanical valve regurgitant flow velocity of -126 m/s. Analysis of the flow velocity data made use of Vioplot R* and VISIO software packages to provide split violin plots that represent probability of recurrence of data. Results: Thrombogenic potential was made dimensionless and ranged between -0.45 and +1.0. Negative thrombogenic potentials arise when transient rebound of valve occluder is accompanied by water-hammer phenomena. Positive thrombogenic potentials occur during decelerating forward flow. Bioprostheses had lowest thrombogenic potential transient of 0.15. A mock-transcatheter aortic valve replacement incorporating by design a trivial paravalvular leak (~1.35 ml/s) demonstrated a high transient thrombogenic potential of 0.95. Conclusions: Our data reveals distinct thrombogenic potential profile differences between valve models. If our study methods are verifiable, the design of future valves may utilize currently available experimental tools to produce advanced devices with significantly reduced thrombogenic potential.

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“…Looking at the hemodynamics observed in conventional mechanical carbon valve devices, the non-physiologic closing of these bi-leaflet prostheses constitutes an imperative to look for a new tri-leaflet valve design (23). Advanced experimental, numerical and biomolecular blood flow analyses have shown that the reverse flow rather than the forward phase is responsible for platelet activation and micro-thrombus formation.…”

mentioning

confidence: 99%

History, development and clinical perspectives of sutureless and rapid deployment surgical aortic valve replacement

Carrel

Heinisch

2020

Ann Cardiothorac Surg

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Degenerative aortic stenosis is the most frequent valvular heart disease in industrialized countries. Conservative treatment may beneficially influence symptoms but is never successful. Surgical aortic valve replacement (SAVR) was the only recognized treatment option to provide substantially prolonged survival until 2008. Operative mortality of isolated SAVR has been reported as low as 0.5% to 1% in experienced institutions, while long-term survival is close to that observed in a control healthy population of similar age. A multitude of studies have demonstrated the beneficial effects of SAVR with regard to improvement in quality of life and physical performance in the majority of symptomatic patients. In the last decade, transcatheter aortic valve implantation (TAVI) has emerged as an equal treatment modality, first in patients with high surgical risk and more recently in patients with intermediate and low surgical risk. Paravalvular regurgitation and the higher rate of pacemaker implantation remain points of consideration. Additionally, the long-term durability of TAVI devices and occurrence of stroke late after TAVI require additional analyses. Sutureless (SU-SAVR) and rapid deployment valve (R-SAVR) were designed to simplify and accelerate a conventional or less invasive surgical procedure while allowing complete excision of the calcified native valve. From 3 different implants tested more than 10 to 15 years ago, only two are available on the market today: the Perceval ® valve from Liva Nova and the Intuity ® sutureless prosthesis from Edwards Lifesciences. There has been extensive experience with these two devices in previous years and the results obtained are comparable to those observed following the use of conventional implants. The sutureless devices may be of particular interest for more complex and combined surgical procedures. This review summarizes the sutureless (SU-SAVR) and rapid deployment valve technologies and presents a clinical outlook for the patient population managed with these devices.

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Non-physiologic closing of bi-leaflet mechanical heart prostheses requires a new tri-leaflet valve design

Cited by 13 publications

References 7 publications

Numerical investigation of turbulent features past different mechanical aortic valves

Numerical investigation of turbulent features past different mechanical aortic valves

Violin plot data: A concerto of crucial information on valve thrombogenicity categorized in vitro by valve motion and inferred flow velocity

History, development and clinical perspectives of sutureless and rapid deployment surgical aortic valve replacement

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