A thrombectomy is the excision of an abnormal or angerous thrombus (blood clot). It is performed intraluminally (meaning directly in the cavity of a vessel) using a balloon catheter. The thrombus is then either pressed against the walls in order to restore at least part of the natural lumen; or the balloon is 'opened' after the thrombus and then carefully moved retrogradely so that the clot can be drawn out of the vessel.