In some embodiments, a medical device may include one or more of the following features: (a) a metal fabric formed of braided metal strands, (b) the medical device having a collapsed configuration for delivery through a channel in a patient's body and having a generally dumbbell-shaped expanded configuration with two expanded diameter portions separated by a reduced diameter portion formed between opposed ends of the device and unsecured metal strand ends at the opposed ends, and (d) a thrombogenic agent located on the metal fabric.