A guide catheter includes a tubular section formed of a shape memory polymer that can transform dynamically between first and second states or conditions, or among three states or conditions, to provide a wide range of properties of the guide catheter as desired during delivery of the guide catheter through the vasculature to a target site, and removal of the guide catheter from the target site and vasculature. The states or conditions of the shape memory polymer be dynamically changed to vary properties of the tubular section such as stiffness, flexibility, shape, or biodegradability, which can be controlled by exposure of the shape memory polymer to temperature changes, electric fields, magnetic fields, wavelengths of light, and chemical solutions.