An intravascular valve assembly having a valve case and a flexible pressure-actuated flow control valve. The valve case includes attached proximal and distal case portions that present respective spaced apart fluid ports and a fluid passageway extending between the ports. The flexible pressure-actuated flow control valve is disposed within the fluid passageway and includes a slitted central valve wall. The proximal case portion includes an axially-extending boss that projects distally, with a portion of a distal end of the boss contacting the flow control valve. The valve permits fluid flowing in a distal direction to pass through the slit. Fluid flowing in a proximal direction, however, causes the valve to compresses against the boss and the slit to close, thus restricting fluid flow in a proximal direction.
