A device for improving the function of a heart valve comprised of valve tissue including an annulus and a plurality of leaflets for allowing and preventing blood flow is disclosed. The device comprises a support member being configured to abut one side of the valve and being arranged to conform to the shape of at least a part of the valve annulus, said support member having an inherent adaptation to a shape change such that an increased cross-section of at least part of the support member is associated with a shortened length of the support member, whereby the support member is susceptible to an expansion of a cross-section of the support member when the support member has conformed to the shape of at least part of the valve annulus such that the support member assumes a desired, altered shape.
