An enhanced cross stream mechanical thrombectomy catheter with backloading manifold having a distal end with outflow and inflow orifices at one side for producing concentrated cross stream jet flow for selective and concentrated thrombus ablation during thrombectomy procedures. The invention provides for suitable distancing of high powered ablation or suction forces from the near walls of the vasculature. Cross stream flow emanating from the one side of the distal end of the catheter resultantly urges the distal end of the catheter and thus the opposing non-orificed side of the distal end of the catheter toward and against the vascular wall to inhibit contact of the inflow orifice with the vascular wall. Features of the invention include a geometrically configured insert to facilitate the backloading or exchange of guidewires.