Here is a model of a patient specific popliteal artery prepared using starccm+. It features a hexahedral mesh with prism boundary layer and fluid volume elements. Starccm+ does advanced Computation Fluid Dynamics and Fluid Structure Interaction simulations. It made quick work of this medical imaging data in STL format (with a little help from Meshlab).
The hexahedral mesh in the fluid volume can be appreciated in this cross section of the inlet face. The six-sided elements extend axially along the vessel and this elongated shape in the direction of the flow leads to more effecient numerical simulations. The prism transition elements permit a refinement of the mesh density at the vessel wall to capture realistic flow dynamics.