A gastric bypass device includes an occlusion device that is adapted to be deployed relative to a patient's pyloric sphincter, an anastomosis anchor that is adapted to be deployed relative to an anastomosis between the patient's stomach and their small intestine, and a tether that extends through the patient's small intestine between the occlusion device and the anastomosis anchor. A dynamic leash may be secured relative to the occlusion device and may work in conjunction with the tether to help hold the occlusion device in place.