In certain embodiments, a device is configured to be compressed and inserted into the distal end of an endoscope. The delivery device can be configured to deliver the delivery catheter to the site of one or more fistulas in the wall of a body cavity or lumen within a patient. The delivery catheter is configured to deliver the device to the site of the one or more fistulas. The device is configured to expand at the site of the one or more fistulas and substantially seal the fistula in one or more directions. In some embodiments, at least a portion of the device is coated with and/or constructed of biocompatible material. In some configurations, the device is configured to be implanted for an extended period of time or even permanently. In some embodiments, at least a portion of the device is constructed of biodegradable, dissolvable and/or bioabsorbable material.