A vascular plug for implantation into a patients vessel includes an inflatable balloon and a flow accelerator. The flow accelerator includes a conical portion and a tubular coupling element which couples the conical portion to an aperture to the interior of the inflatable balloon. The flow accelerator will concentrate and therefore accelerate fluid flow into the inflatable balloon. Flow accelerator will increase the pressure of fluid thereby to cause the inflatable balloon to inflate even within a pressurised blood vessel. The plug may include a sleeve which provides a chamber between the flow accelerator and the balloon, into which blood may pass from the inflatable balloon or the flow accelerator to create additional blood statis and as a result thrombosis and a second occlusive barrier.
