A system and/or apparatus for delivering a medical device into a body includes an elongate tubular member and a valve fitted within a proximal end thereof. The valve preferably includes a tubular body and a flap, wherein the tubular body is engaged within the proximal end of the tubular member and has an open end approximately aligned with a proximal termination of the proximal end of the tubular member. The flap of the valve preferably extends over a hole formed in an end wall of the tubular body opposite a side of the end wall that faces a passage of the tubular body, which passage extends between the open end and the end wall. The hole communicates with the passage and with the lumen of the tubular member, and the flap is movable away from the hole when the device is introduced through the passage and the hole.