A device (10) for maintaining fluid flow through at least one passage in a human or animal body, the device comprising two end portions (12, 14) for anchoring the device in position, and an intermediate portion (16) which allows movement of the end portions relative to each another, wherein the end portions and intermediate portion together define a pathway for fluid flow through the device. The device is particularly suitable for use in the treatment of coronary heart disease by minimally invasive surgery, and the invention extends to a method for diverting fluid flow from one passage to another.