Among other things, there are disclosed embodiments of a valve implant that in particular examples are implantable within a blood vessel, which include a first set of elongate members, a second set of elongate members, and a hood affixed to the first set of elongate members. The first set of elongate members is resiliently deformable, and their distal ends are flared radially outward. The distal ends of the second set of elongate members are distal to the ends of the first set of elongate members. The hood is affixed to the first set of elongate members, and seals against the interior wall of the blood vessel in an expanded configuration. When blood flows from the proximal to the distal side of the valve implant, it presses on the hood, compressing the first set of elongate members, breaking the seal.
