Aspiration catheter systems and methods of use

An intravascular catheter advancement device for advancing a catheter within the neurovasculature, the catheter advancement device comprising:

• a flexible elongate body having a proximal end, a distal end, and a single lumen extending therebetween, the flexible elongate body comprising:
• a proximal segment, wherein the proximal segment comprises a hypotube coated with a polymer;
• an intermediate segment comprising an unreinforced polymer having a durometer of no more than 72 D;
• and
• a tip segment, wherein the tip segment is formed of a polymer different from the intermediate segment and has a durometer of no more than about 35 D and a length of at least 5 cm, wherein the tip segment has a tapered portion that tapers distally from a first outer diameter to a second outer diameter over a length of between 1 and 3 cm,
• wherein the catheter advancement device has a length configured to extend from outside a patient's body, through a femoral artery, and to a petrous portion of an internal carotid artery and an inner diameter less than 0.024 inches to accommodate a guidewire.