Corrigendum to 'A comparison of early redo surgery rates in Mosaic porcine and Perimount bovine pericardial valves' [Eur J Cardiothorac Surg 2018; doi:10.1093/ejcts/ezy113]. (17th May 2018) - Webb, Jessica; Parkin, Denise; Tøndel, Kristin; Simitsis, Panagiotis; Roxburgh, James; Chambers, John B