A minimally invasive method of placing a delivery device substantially adjacent to vascular tissue and a device for use with such a method are disclosed. The delivery device may be a flexible biological construct with a flexible tethering means. The delivery device may be percutaneously inserted near vascular tissue such as, for example, peritoneal tissue. When the delivery device has been inserted, the tether may be used to pull the delivery device toward the vascular tissue and secure the device thereto. Contact between the front surface of the delivery device and the vascular tissue may be maintained by making and keeping the tether substantially taut. The delivery device may serve accomplish sustained delivery of active agents.