Abstract: Apparatus and methods are described for treating cardiovascular diseases with an embolization coil placement system utilizing an embolization coil and a pusher device. The embolization coil includes a releasable attachment assembly with a deformable ring-shaped member for connecting the embolization coil to a hydraulic pressure actuated coil release assembly on the pusher device. The coil release assembly includes a coil mounting wire with a bulbous distal portion that extends distally from a proximal tubular portion of the pusher device. A small inflatable balloon is mounted on the pusher device surrounding the coil mounting wire and fluidly connected to the proximal tubular portion. The embolization coil delivery system is prepared for use by crimping the deformable ring-shaped member around the deflated balloon member and the mounting wire. The bulbous distal portion of the mounting wire retains the crimped ring-shaped member on the pusher device.