Valve mechanism for flow regulation in a shunt

An apparatus for shunting blood, the apparatus comprising:

• a flow-indication chamber shaped to define an entry port and an exit port;
• one or more moveable objects disposed within the flow-indication chamber and configured to move in response to a flowing of the blood from the entry port to the exit port,
• at least a portion of a wall of the flow-indication chamber being transparent so as to expose the moveable objects to sight;
• a pullable element passing through a wall of the flow-indication chamber and configured to cover a port selected from the group consisting of:
• the entry port and the exit port, upon being pulled;
• and
• a spring coupled to the pullable element and to an inner wall of the flow-indication chamber, and configured to inhibit the pullable element from covering the port in an absence of any pulling force applied to the pullable element.

A method, comprising:

• coupling an upstream end of a first conduit to a source blood vessel of a subject and a downstream end of the first conduit to an entry port of a shunt;
• coupling an upstream end of a second conduit to an exit port of the shunt and a downstream end of the second conduit to a sink blood vessel of the subject, such that blood flows from the source blood vessel to the sink blood vessel via the shunt, thus causing movement of one or more moveable objects disposed within the shunt, the movement being visible through a wall of the shunt;
• and
• slowing or stopping the flow of the blood by pushing or pulling an element passing through a wall of the flow-indication chamber, thereby causing the element to cover a port selected from the group consisting of:
• the entry port and the exit port.