[1] Manchester Univ Hosp NHS Fdn Trust, Wythenshawe Hosp, Dept Cardiothorac Surg, Southmoor Rd, Manchester M23 9LT, Lancs, England
[2] Univ Manchester, Manchester Univ Hosp NHS Fdn Trust, Div Cardiovasc Sci, ERC, Manchester, Lancs, England
[3] Liverpool Heart & Chest Hosp, Dept Cardiothorac Surg, Liverpool, Merseyside, England