Covered flow modifying apparatus

A flow modifying apparatus comprising:

• a plurality of struts coupled together to form a radially expandable frame having a first end portion and a second end portion, wherein the first end portion and the second end portion are radially expandable into expanded first and second end portions, respectively, wherein the flow modifying apparatus extends from a first end of the radially expandable frame to a second end of the radially expandable frame;
• a reduced diameter portion of the expandable frame disposed between the first end portion and the second end portion, wherein the reduced diameter portion comprises a fluid flow through passage, wherein when the first and second end portions have expanded into the expanded first and second end portions, the first and second expanded end portions each comprise flared portions that flare outwardly from the reduced diameter portion toward the first and second ends, respectively, of the radially expandable frame;
• and
• a cover covering at least a portion of the flared portion of the first end portion, wherein the cover is spaced from the reduced diameter portion, wherein the reduced diameter portion modifies fluid flow therethrough immediately upon implantation thereof and forms a pressure gradient between the first end and the reduced diameter portion of the expandable frame.