Retrieval of material from vessel lumens can be improved by use of a distal element comprising an expandable mesh. a treatment device includes an elongated member having a proximal portion and a distal portion configured to be positioned within a blood vessel at a treatment site at or near a thrombus. A distal element comprising an expandable mesh is coupled to the distal portion of the elongated member via a connection assembly. In an expanded state, at least a portion of the mesh is configured to be in apposition with the blood vessel wall at the treatment site to anchor or stabilize the elongated member with respect to the blood vessel. The distal element can be electrically coupled to an extracorporeal current generator.