US Patent 7223280 Surgical implants and delivery systems therefor

A stent for occluding the human ductus arteriosus comprises a length of wire of shape memory effect or superelastic material which is expandable from a relatively straightened state for introduction into the patient to an occluding state wherein the wire defines an occluding anchor part and a spiral anchor part and a straight linking part connecting the two wherein the wire has a series of turns extending over the cross-sectional area of the occluding anchor part.