A system for removing an obstruction from a blood vessel. The system can include a catheter with a proximal section with a proximal section lumen diameter, a distal section with a distal section lumen diameter less than the proximal section lumen diameter, an intermediate section extended between proximal and distal sections. The system can include a clot retrieval device with a clot engaging element. The system can include a shaft being advanceable through the lumen of the catheter the obstruction of the blood vessel, the shaft can include a shaft proximal section; a shaft distal section attached to the clot engaging element and configured to cross the obstruction, a diameter of the shaft proximal section being greater than a diameter of the shaft distal section thereby inhibiting the shaft proximal section from distally advancing through the catheter distal section.