A catheter device and methods useable to extract material from a body conduit, e.g., a blood vessel, are provided. The catheter comprises a flexible catheter advanceable into the body conduit, an opening in a wall of the catheter in fluid communication with a material collection chamber, and a controllably arcuate segment near the distal tip of the catheter and the opening. The catheter may include a sliding member, located within a lumen of the catheter, used to move the material entering the catheter through the arcuate segment opening, into the material collection chamber and away from said opening. The catheter may include a single mechanism utilized to both generate a vacuum to cause material to enter the catheter at the arcuate segment opening and also cause the sliding member to travel, inside the catheter, moving material away from the opening and into the material collection chamber.