[1] Maasstad Hosp Rotterdam, Rotterdam, Netherlands
[2] Med Ctr Leeuwarden, Leeuwarden, Netherlands
[3] Hosp Univ Virgen Arrixaca, Murcia, Spain
[4] Hosp St Pau & Santa Creu, Barcelona, Spain
[5] Hosp & Univ Fribourg, Fribourg, Switzerland
[6] Onassis Cardiac Surg Ctr, Athens, Greece
[7] Complejo Hosp Univ Juan Canalejo, La Coruna, Spain
[8] Hosp Clin Univ Santiago de Compostela, Santiago De Compostela, Spain
[9] Kantonsspital Aarau, Aarau, Switzerland
[10] Onze Lieve Vrouw Hosp, Amsterdam, Netherlands
[11] Amphia Hosp Breda, Breda, NB, Canada