A system for treating atherosclerotic cardiovascular disease and cardiac valve dysfunction comprises delivering one or more calcium chelating agents locally to a treatment site. One aspect of the invention provides a method including delivering a nano-particulate calcium chelating agent into a vascular wall. Another aspect of the invention provides a method and device for forming a sealed chamber around a cardiac valve, releasing one or more calcium chelating agents into the sealed chamber and decalcifying a cardiac valve in need thereof.