Decalcifying heart valve

1. A vascular valve system comprising:

an expandable stent comprising an outer surface and a lumen;

a valve comprising a plurality of leaflets, wherein the valve is disposed within the lumen of the expandable stent; and

a material layer adjacent to at least a portion of the valve and disposed on the outer surface of the expandable stent, the material layer comprising a hydrogel, a calcium-chelating agent, and an acidifying agent;

wherein the hydrogel comprises a network of electrospun fibers; and

wherein the acidifying agent is selected from the group consisting of ascorbic acid, acetic acid, lactic acid, and any combination thereof; and

wherein the acidifying agent is present in the hydrogel at from 0.5 percent to 15 percent by weight; and

wherein the acidifying agent is effective to decrease a local pH to initiate a conversion of insoluble calcium carbonate (CaCO 3 ) into soluble calcium bicarbonate.

2. The vascular valve system of claim 1 , wherein the valve comprises at least one of a tissue or a polymeric material.

3. The vascular valve system of claim 2 , wherein the tissue comprising porcine pericardium.

4. The vascular valve system of claim 1 , wherein the valve is attached to the expandable stent with a plurality of sutures.

5. The vascular valve system of claim 1 , wherein the material layer is disposed around a circumference of the valve.

6. The vascular valve system of claim 1 , wherein the material layer is disposed on a portion of the valve.

7. The vascular valve system of claim 1 , wherein the hydrogel is selected from the group consisting of oligo(amidoamine/(β-amino ester), gelatin, methyl cellulose, collagen, chitosan, hyaluronic acid, chondroitin sulfate, alginate, agar, agarose, fibrin, polyethylene glycol, polyethylene oxide, polyvinyl alcohol, poly(propylene fumarate), oligo(polyethylene glycol) fumarate, poly(N-isopropylacrylamide), polypropylene oxide, poly(aldehyde guluronate), polylactic acid, polyglycolic acid, poly(lactic-co-glycolic) acid, polyanhydride, combinations thereof, and copolymers thereof.

8. The vascular valve system of claim 1 , wherein the calcium-chelating agent is selected from the group consisting of ethylene diamine tetraacetic acid, phosphonates, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, N-hydroxyethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, and glycine.

9. The vascular valve system of claim 1 , wherein the calcium-chelating agent is covalently bound to the hydrogel.

10. The vascular valve system of claim 1 , wherein the acidifying agent is covalently bound to the hydrogel.

11. The vascular valve system of claim 1 , wherein the material layer spans a thickness of the valve along a longitudinal axis and is configured to fully cover a native valve when positioned between a body vessel and the vascular valve system.

12. The vascular valve system of claim 1 , further comprising one or more acidic functionalities that are different than the calcium-chelating agent, wherein the acidic functionalities are configured to be positioned at an ion-exchange/calcified plaque interface.