An aspiration catheter is provided including a proximal section and a distal section extendable through the proximal section. A vacuum transfer tool may be coupled to a proximal end of the proximal section. The vacuum transfer tool may include a proximal transfer tube and a distal transfer tube, each having an aspiration port in communication with a vacuum source. The proximal transfer tube may be removably received within a proximal end of the distal transfer tube. The distal section of the catheter may be inserted into the proximal section through the proximal transfer tube. The proximal transfer tube may maintain a vacuum around the proximal end of the distal section of the catheter such that when the distal section is removed by decoupling the proximal and distal transfer tubes, the vacuum within the distal transfer tube and proximal section of the catheter is maintained, preventing the escape of any clots.
