Methods and systems for treatment of acute ischemic stroke

A method of performing a medical procedure at a treatment site in a cerebral vessel of a patient, the method comprising:

• positioning a system of devices into an advancement configuration, the system of devices comprising:
• a catheter having a catheter lumen, an inner diameter and a distal end;
• and
• an inner member sized and shaped to slide within the catheter lumen, wherein the inner member defines a single lumen and has a distal portion, the distal portion having a first outer diameter that tapers distally to a second outer diameter that is smaller than the first outer diameter, wherein the inner member transitions in flexibility from a proximal end of the inner member to a distal end of the inner member, the distal end of the inner member being more flexible than the distal end of the catheter, and
• wherein, when positioned in the advancement configuration, the inner member extends coaxially through the catheter lumen until the distal portion of the inner member is positioned distal to the distal end of the catheter and the inner member is held fixed relative to the catheter;
• and
• concurrently advancing the catheter and the flexible inner member distal to a petrous portion of an internal carotid artery while the system of devices is positioned in the advancement configuration.