For example TTK chitra valve still uses single leaflet valve, whereas SJM uses bi-leaflet.But could not find the advantages of mono-leaflet over bi-leaflet?
ACC/AHA Guidelines have historically required elevated anticoagulation regimen for mono-leaflet valves versus bi-leaflet valves. So, for aortic mono-leaflets INR of 2.5 - 3.5 and for mitral mono-leaflets 3.0 - 4.0 . Mono-leaflet valves can be positioned to accommodate eccentricity of flow through the valves, but also, if oriented incorrectly, can generate some very poor hemodynamics. Mono-leaflet valves run the risk of impingement of suture tails if they are not cut closely enough to the knot. Mono-leaflet valves are louder than bi-leaflet valves. There really is no benefit of mono-leaflet valves over bi-leaflet valves, unless you are a 'purest' and feel that correctly oriented mono-leaflet valve in the mitral position mimics nature's 'rudder' effect of the anterior mitral leaflet....and therefore mimics natural flow in the mitral position. Mono-leaflet valves have fallen away mostly because of the above.
I agee with Mark here. Sheer mechanical stress on monoleaflet valve could well a predisposition to thrombosis and thats why higher anticoagulation and could affect the valve longevity as well.
Great point Syed. Turbulence of flow and Sheer stress on RBCs lead to increased thrombogenicity of monoleaflet valves, thus necessitating higher anticoagulation levels in the Guidelines.
http://www.omicsonline.org/open-access/oral-anticoagulation-after-mechanical-heart-valve-replacement-low-intensity-regimen-2155-9880-5-319.php?aid=27204
Gives a great explanation of effects requiring monoleaflet valves to require higher anticoagulation.
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