Percutaneous methods and apparatuses for forming a venous valve from autologous tissue. A catheter having a retractable dissecting system received therein is delivered to a target location where a new venous valve is to be created. A distal balloon or other radially-expandable component mounted on the catheter is expanded against the vein wall, and the dissecting system is proximally retracted to deploy one or more dissecting components that dissect a subintimal layer of the vein wall. Radial expansion of the dissecting component(s) within the vein wall creates one or more leaflets and corresponding pocket/sinuses in the vein that collectively act as a venous valve, and/or the radially-expandable component of the catheter is subsequently collapsed such that the dissecting component(s) each pull a flap of the dissected tissue towards the vein lumen to create one or more leaflet(s) and corresponding pocket/sinuses in the vein.