A method and associated device for constricting fluid flow in vasculature comprising inserting a device into vasculature of a patient. The device comprising a frame defining an inflow portion, an outflow portion, and a center portion between the inflow portion and outflow portion and a fluid impermeable membrane lining at least the center portion, wherein a minimum diameter of the center portion is at least about 33% less than a diameter of the inflow portion, and the patient has deep vein reflux (DVR), chronic venous insufficiency (CVI), or excess shunting through a fistula. The method may further include placing the device within a vein proximally to a refluxing deep vein in a valve free zone.