Through disease or age, the tissue that supports the heart valve's opening (the annulus) can weaken and lose its shape. To repair this condition, a device called an annuloplasty ring or band is sewn around the base of the heart valve to reshape it and give it support.An annuloplasty band or ring is made of durable plastic, metal, or fabric and may be flexible or rigid. These rings and bands are designed to hold the natural shape, motion, and flexibility of the annulus.