A medical device may include a device handle having a diverter block non-movably disposed within an interior cavity of the handle, the diverter block including at least one lumen extending longitudinally therethrough and a distal mounting portion. A delivery sheath may be coupled to the device handle. A catheter assembly may extend distally from the device handle within the delivery sheath. The catheter assembly may include a multi-lumen polymeric shaft coupled to the diverter block, and a metallic hypotube section disposed about and fixedly attached to a proximal end of the shaft. The hypotube section may releasably lock the shaft to the diverter block in fluid communication with the at least one lumen of the diverter block. The delivery sheath may be axially translatable relative to the device handle and the catheter assembly may be fixed in position relative to the device handle.