improved methods of treatment of diseased or occluded vascular grafts in patients having undergone coronary artery bypass or other bypass surgery are disclosed . deployment of a conduit in the myocardium at a site distal to the site of attachment of the coronary artery bypass graft allows oxygenated blood to flow from a chamber in the heart directly into the coronary artery , bypassing blockages in the coronary artery and the graft originally used to bypass the coronary artery . to ensure proper positioning , the conduit is delivered through the graft to the myocardium . a new lining for the existing vein graft and methods of delivery are also disclosed .