A system for aspirating thrombus includes an aspiration catheter including a supply lumen and an aspiration lumen each extending within an elongate shaft, and an opening at or near the distal end of the supply lumen, the opening configured to allow the injection of pressurized fluid into the aspiration lumen at or near the distal end of the aspiration lumen when the pressurized fluid is pumped through the supply lumen, a tubing set including tubing and having a distal end configured to couple to the aspiration lumen of the aspiration catheter and a proximal end configured to couple to a vacuum source, a tubing compression element configured to externally engage the tubing of the tubing set, and an activation interface configured to activate the tubing compression element to compress the tubing at a location between the proximal end of the tubing set and the distal end of the tubing set.