A device for accessing a vessel, duct or lumen, comprising a guidewire having a proximal end and a distal end, and at least one projection that extends from said guidewire at or near the distal end of the guidewire. When the guidewire is placed into the vessel, duct or lumen containing a flowing fluid, the drag on the guidewire is greater when the fluid is flowing from the proximal to distal end of the guidewire than it is when it is flowing distally-to-proximally, thereby helping to direct the guidewire. The device is particularly useful in crossing a narrowing in the vessel, duct or lumen, such as may occur in blood vessels containing a stenosis, such as due to atherosclerosis.
