A vascular occluder (10) includes first and second baffle members (14, 16) which are formed of an expansion device such as a stent (18, 20) across which extends an impermeable membrane (22, 24). The baffle members (14, 16) are held at a given separation by spacer elements (28, 30). The separation creates a chamber (26) between the baffle members (14, 16) in which the blood is able to stagnate, thereby creating a second occlusion barrier. One of the baffle members (16) may have an aperture within its membrane (24) for receiving a delivery catheter for delivery of thrombogenic agent into the chamber (26). The occluder (10) has a given length, thereby making it suitable for implantation in difficult vessel sections and is also able to avoid problems of recanalization of the vessel which can occur with prior art occluders.
