This disclosure is related to devices and related methods for isolating a treatment region in a human body from fluid pressure. In various embodiments, an implantable device for isolating a treatment region in a human body from fluid pressure comprises a first elongated segment, and a second elongated segment, and one or more branch segments in fluid communication with one of the first elongated segment and the second elongated segment. The elongated segments have a combined cross section that is substantially conformable to an intraluminal cross section of a body lumen into which they are implanted. A method of installing an implantable medical device into the body of a patient comprises deploying a first elongated segment, deploying a second elongated segment, and deploying one or more branch segments in a target region of a vasculature.
