A catheter assembly comprising an elongated tubular structure having a distal end and a proximal end a septum disposed within the interior of the tubular structure so as to define a first lumen and a second lumen, and a valve element disposed at the distal end of the tubular structure and configured to move longitudinally relative to the tubular structure between (i) a closed position in which the distal end of the tubular structure is closed off by the valve element, and (ii) an open position in which the distal end of the tubular structure is not closed off by the valve element wherein the tubular structure, septum and valve element are configured so as to provide fluid communication between the first and second lumen when the valve element is disposed in its closed position.
