[1] James Cook Univ Hosp, Dept Cardiothorac Surg, Middlesbrough, Cleveland, England
[2] James Cook Univ Hosp, Dept Cardiol, Middlesbrough, Cleveland, England
[3] N Staffordshire Hosp, Dept Cardiothorac Surg, Stoke On Trent, Staffs, England
[4] World Trade Ctr, Cardiothorac Surg Network, CTSNet, Baltimore, MD USA
[5] Wythenshawe Hosp, Dept Cardiothorac Anaesthesia, Manchester M23 9LT, Lancs, England