An implantable frame comprises a plurality of corner structures configured to decrease pressure to the vessel wall and define pulsatility enhancing windows of the implantable frame. The corner structures may comprise plurality of neighboring longitudinal struts that extend in a longitudinal direction of the blood vessel when placed to form the vessel wall to a substantially polygonal cross-section and distribute pressure loading of the corner structure among the plurality of neighboring longitudinal struts to improve biocompatibility. The corner structures also allow increased forming of the vessel wall and can provide stretching of the vessel wall to enhance pulsatility of the vessel wall.
