Vascular prostheses currently used in aortic replacement surgery do not have the same mechanical properties as human arteries. In vivo studies have revealed that aortic grafts augment heart load and alter blood pressure and flow waveforms. A one-dimensional model of the arterial tree was developed in order to analyze the different mechanisms by which grafts placed in the ascending aorta (proximal) and descending aorta (distal) affect hemodynamics. Graft compliance and properties were based on in vitro tests