The present invention provides devices and methods for attachment of an implanted device, such as an artificial stoma device, a gastrointestinal sleeve device or an attachment cuff, within a patient's digestive tract for treatment of obesity. Special surgical fasteners provide a lasting and durable attachment to the gastrointestinal tissue without causing excessive pressure that could result in tissue erosion and detachment of the implanted device. Fastener delivery devices that facilitate peroral placement and deployment of fasteners and secondary devices are also provided. Also described are implantable devices and attachment means that avoid causing excessive pressure within the tissue by having compliance that is compatible with the gastrointestinal tissues where it is attached.