A 64-year-old woman had a mitral valve repair 10 years previously and subsequently had her mitral valve replaced for recurrence of severe mitral regurgitation with a 29-mm St Jude's bileaflet mechanical prosthesis at another institution 5 years ago. She presented to our department following a recent transient ischaemic attack and an echogenic lesion was picked up on the sewing ring of her mitral prosthesis (figure 1A, see online supplementary video 1).