Vascular valve systems for treating calcified vascular vessel valves by delivery of one or more calcium chelating agents are described. The vascular valve system includes an expandable stent; a valve with a plurality of leaflets, and a hydrogel layer disposed on an outer surface of the stent. The hydrogel layer includes a hydrogel, and a calcium-chelating agent and an acidifying agent disposed within the hydrogel. The calcium-chelating agent and the acidifying agent are covalently bonded to the hydrogel. The hydrogel layer is configured to capture loosened calcium deposits to form a calcium-chelating agent complex covalently bonded to the hydrogel layer. Methods of making the vascular valve systems are also described.