US Patent 9456898 Heart valve prosthesis with open stent

A prosthetic apparatus is disclosed including: a tubular stent disposed about a longitudinal axis and extending from a proximal end to a distal end, the stent defining a tubular passage between the ends. The tubular stent has a proximal portion, a distal portion, and a middle portion located between the proximal and distal portions. The proximal and distal portions each comprise a mesh of support struts forming at least one ring of open elements disposed about the longitudinal axis. The middle portion features open regions which reduce or eliminate blockage of sensitive anatomical features at an implantation site.