Flow control elements can be injectably delivered through a needle (e.g., a fine hypodermic needle) or other tube and deployed into a blood vessel, percutaneously or laparoscopically, to effect the directional blood flow within the vessel. The valve (or other blood flow or occlusion control element) is delivered from outside the blood vessel directly to the chosen site within the blood vessel. The flow control elements are minimally invasive, reducing pain, discomfort and risk to the patient, while reducing the time the procedure takes to perform. In addition, the accuracy of deployment of the valve or other flow control element can be very precisely controlled.