Are the Current Doppler Echocardiography Criteria Able to Discriminate Mitral Bileaflet Mechanical Heart Valve Malfunction? An In Vitro Study

2016 ◽  
Vol 40 (5) ◽  
pp. E52-E60 ◽  
Author(s):  
Morgane Evin ◽  
Carine Guivier-Curien ◽  
Philippe Pibarot ◽  
Lyes Kadem ◽  
Régis Rieu
Keyword(s):  
Heart Valve ◽  
Doppler Echocardiography ◽  
Mechanical Heart Valve ◽  
In Vitro Study ◽  
Vitro Study ◽  
Bileaflet Mechanical Heart Valve ◽  
Valve Malfunction

scholarly journals Near Valve Flows and Potential Blood Damage During Closure of a Bileaflet Mechanical Heart Valve

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
L. H. Herbertson ◽  
S. Deutsch ◽  
K. B. Manning
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Mechanical Heart Valve ◽  
In Vitro Study ◽  
Blood Damage ◽  
Bileaflet Mechanical Heart Valve ◽  
Fluid Velocities ◽  
Design Characteristics ◽  
Valve Housing

Blood damage and thrombosis are major complications that are commonly seen in patients with implanted mechanical heart valves. For this in vitro study, we isolated the closing phase of a bileaflet mechanical heart valve to study near valve fluid velocities and stresses. By manipulating the valve housing, we gained optical access to a previously inaccessible region of the flow. Laser Doppler velocimetry and particle image velocimetry were used to characterize the flow regime and help to identify the key design characteristics responsible for high shear and rotational flow. Impact of the closing mechanical leaflet with its rigid housing produced the highest fluid stresses observed during the cardiac cycle. Mean velocities as high as 2.4 m/s were observed at the initial valve impact. The velocities measured at the leaflet tip resulted in sustained shear rates in the range of 1500–3500 s−1, with peak values on the order of 11,000–23,000 s−1. Using velocity maps, we identified regurgitation zones near the valve tip and through the central orifice of the valve. Entrained flow from the transvalvular jets and flow shed off the leaflet tip during closure combined to generate a dominant vortex posterior to both leaflets after each valve closing cycle. The strength of the peripheral vortex peaked within 2 ms of the initial impact of the leaflet with the housing and rapidly dissipated thereafter, whereas the vortex near the central orifice continued to grow during the rebound phase of the valve. Rebound of the leaflets played a secondary role in sustaining closure-induced vortices.

Impact of hypertension on bioprosthetic heart valve calcification – a short-term in vitro study

2012 ◽  
Vol 60 (S 01) ◽  
Author(s):  
M Schleicher ◽  
T Schlichthärle ◽  
JG Mannheim ◽  
A Pfäfflin ◽  
M Schmauder ◽  
...  
Keyword(s):  
Heart Valve ◽  
In Vitro Study ◽  
Vitro Study ◽  
Bioprosthetic Heart Valve ◽  
Short Term ◽  
Valve Calcification

Innovative, Replaceable Heart Valve: Concept, In Vitro Study, and Acute In Vivo Study

2008 ◽  
Vol 32 (3) ◽  
pp. 226-229 ◽  
Author(s):  
Kiyotaka Fukamachi ◽  
Yoshio Ootaki ◽  
Chiyo Ootaki ◽  
Masatoshi Akiyama ◽  
Keiji Kamohara ◽  
...  
Keyword(s):  
Heart Valve ◽  
In Vitro Study ◽  
Vitro Study ◽  
In Vivo Study

Design and in Vitro Performance of a Novel Bileaflet Mechanical Heart Valve Prosthesis

2005 ◽  
Vol 28 (3) ◽  
pp. 256-263 ◽  
Author(s):  
D. Medart ◽  
C. Schmitz ◽  
G. Rau ◽  
H. Reul
Keyword(s):  
Heart Valve ◽  
Mechanical Heart Valve ◽  
Polymeric Materials ◽  
Hydrodynamic Performance ◽  
Heart Valve Prosthesis ◽  
Valve Prosthesis ◽  
Suitable Material ◽  
Bileaflet Mechanical Heart Valve ◽  
In Vitro Performance

Design and in vitro performance of a novel bileaflet mechanical heart valve prosthesis are presented. The novel heart valve exhibits three main design characteristics: (i) The leaflets form a Venturi passage in open position. Thus, a beneficial pressure distribution is obtained and the leaflets are stabilised in opened position. (ii) The orifice inlet is nozzle-shaped. Flow is convectively accelerated and flow separation at the orifice inlet is avoided. (iii) The hinge design facilitates an additional axial movement of the leaflets and leads to a self cleaning effect and enhances washout of the hinges. The design of the leaflet hinges is of main importance for the functional reliability and durability of mechanical heart valves. After manufacturing first prototypes from titanium and polymeric materials the hydrodynamic performance was evaluated according to ISO 5840 and FDA guidelines. Hydrodynamic performance is comparable with the results of commonly available bileaflet mechanical heart valve prostheses. Initial durability tests showed suitable material couples for further long term studies.

Simulations of the Hinge Flow Fields of a Bileaflet Mechanical Heart Valve Under Physiologic Pulsatile Aortic Conditions

2008 ◽  
Author(s):  
Hélène A. Simon ◽  
Liang Ge ◽  
Iman Borazjani ◽  
Fotis Sotiropoulos ◽  
Ajit P. Yoganathan
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Mechanical Heart Valve ◽  
Prosthetic Heart Valve ◽  
Prosthetic Heart Valves ◽  
Valve Design ◽  
Bileaflet Mechanical Heart Valve ◽  
Hinge Flow ◽  
Blood Elements

Native heart valves with limited functionality are commonly replaced by prosthetic heart valves. Since the first heart valve replacement in 1960, more than three million valves have been implanted worldwide. The most widely implanted prosthetic heart valve design is currently the bileaflet mechanical heart valve (BMHV), with more than 130,000 implants every year worldwide. However, studies have shown that this valve design can still cause major complications, including hemolysis, platelet activation, and thromboembolic events. Clinical reports and recent in vitro experiments suggest that these thrombogenic complications are associated with the hemodynamic stresses imposed on blood elements by the complex non-physiologic flow induced by the valve, in particular in the hinge region.

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