[1] Univ Duisburg Essen, Univ Hosp Essen, Dept Thorac & Cardiovasc Surg, West German Heart & Vasc Ctr Essen, D-45122 Essen, Germany
[2] Int Thorac & Cardiovasc Res Assoc ITCVR, D-26133 Oldenburg, Germany
[3] Univ Pernambuco, Dept Cardiovasc Surg Pronto Socorro Cardiol Perna, BR-74970240 Recife, PE, Brazil
[4] Imperial Coll London, Fac Med, Dept Med, London SW7 2AZ, England
[5] Univ Hosp Essen, Dept Cardiothorac Surg, Heart Ctr Essen Huttrop, D-45138 Essen, Germany
[6] Univ Med Ctr Tubingen, Dept Thorac & Cardiovasc Surg, D-72076 Tubingen, Germany