An endovascular treatment system includes a delivery sleeve that is insertable into an intravascular catheter. A therapeutic device is housed coaxially within the delivery sleeve and both are advanced within the catheter in combination. An advancement mechanism is connected to the therapeutic device to advance the therapeutic device out of the delivery sleeve and into a patient. The delivery sleeve includes a stop positioned on the proximal end. The stop contacts the proximal end of the catheter, limiting the distance the delivery sleeve is inserted into a catheter.