The device has a loop-shaped support (42) arranged to abut a side of a heart valve. A flange unit is connected to the loop-shaped support, where the flange unit is made of fabric material. The flange unit is provided to be arranged against an annulus when the loop shaped support abut the heart valve. Another loop-shaped support (44) is arranged to abut another side of the heart valve opposite to the former side, where a portion of the valve tissue is trapped between the supports (42, 44). Independent claims are also included for the following: (1) a kit of a medical device (2) a method for repairing a heart valve (3) a method for replacing a heart valve.