The 2nd generation EVR valve has a new delivery system and a new radial force. This new design has improved the delivery profile, which has resulted in reduced paravalvular leaks and higher device success rates. It also features an extended sealing skirt, which has reduced the risk of postdilation.
The EVR valve is an encapsulated solenoid assembly. It is secured to the upper valve housing 26 of a vacuum regulator valve 14. The valve assembly is energized by the current flow through a coil winding 32. The ends of the coil winding are electrically connected to terminal blades 33. The coil winding enables a preload on the armature bias spring 160, which urges the diaphragm valve assembly 92 downward.
The bobbin 30 is made of non-magnetic nylon-tape material. It has a central bore 36 that serves as an air passageway. The central bore is surrounded by a lower segment 66, which surrounds the armature 46. The cylindrical shape of the armature has a plurality of radially spaced notches 86 along the peripheral edge.
The damping ring 110 has one or more damping orifices 120. This ring is located above the reference chamber 108, which is positioned below the armature 46. The evr valve damping orifices are designed to provide a limited amount of restrictive flow to balance the vacuum pressure.
The EVR has an integrated purge flow regulator. This provides continuous controlled flow characteristics independent of manifold vacuum. This valve can be calibrated by making simple calibration adjustments to the vacuum regulator valve 14. The armature 46 is urged by gravity to “open” the valve position. The vapor management valve 10 is not in use. In addition, it is equipped with a closure member 116 that controls the flow from the input port to the output port. The vapor management valve is not designed to be used as a retrofitted device, but it can be adapted for this application.
The EVR is a self-expanding transcatheter aortic bioprosthesis that is available in two versions: the CV, which has a self-expandable nitinol frame, and the EVR, which is a new generation of bioprosthesis. Both have a small insertion profile, which is convenient for patients with challenging iliofemoral anatomy. Its smaller size reduces sheath to femoral artery ratio, and is associated with lower vascular complications.
The EVR is offered in a variety of cooling capacities, ranging from 0.3-65 kW. The delivery profile is shorter than that of the CV, which is intended for a smaller patient population. It is also available with the option to recapture, which enables the prosthesis to be delivered to the intended location 3-5 mm below the native annulus.
The new EVR valve has a more consistent radial force, an expanded sealing skirt, and a new delivery system. It has been tested in clinical trials and offers a more consistent radial force, decreased paravalvular leaks, and higher device success rates. It also has an option to recapture the valve during deployment, which may prevent a suboptimal deployment.