In some examples, a catheter includes an elongated body configured for navigation through vasculature of a patient, the elongated body having an inner wall that defines a lumen extending from a proximal portion to a distal portion. The elongated body is configured to pass a fluid through the lumen and out a distal end of the elongated body. At the distal portion, the inner wall defines a convergent-divergent region such that a diameter of the lumen while moving distally within the elongated body converges from a first lumen diameter to a second lumen diameter and then diverges from the second lumen diameter to a third lumen diameter. The convergent-divergent region is configured to cause a fluid flowing through the lumen to cavitate as the fluid flows through the convergent-divergent region.