A cannulation system for perfusing a patients circulatory system, includes an inflow cannula having a first end adapted to be connected to said circulatory system and a second end adapted to be connected to a blood pump, an outflow cannula having a first end adapted to be connected to the blood pump and a second end adapted to be connected to said circulatory system at a location downstream of the first end of the inflow cannula. The flow of blood from the pump is in series with the normal blood flow of the circulatory system of the patient and creates a localized region of hypertension.