1. Hospital 12 de Octubre, Madrid, Spain;
2. University Hospital, Groningen, The Netherlands;
3. Hospital Central de Asturias, Oviedo, Spain;
4. Hospital Universitario Virgen del Rocío, Sevilla, Spain;
5. Hospital General, Jerez de la Frontera, Spain;
6. Hospital Clinic, Barcelona, Spain;
7. Hospital San Pedro de Alcántara, Cáceres, Spain;
8. Fundaleu, Buenos Aires, Argentina;
9. Hospital Juan Canalejo, La Coruña, Spain;
10. Hospital General, Alicante, Spain;
11. Hospital Universitario, Salamanca, Spain;
12. Hospital Clínico Universitario, Valencia, Spain;
13. Hospital Clínico San Carlos, Madrid, Spain;
14. Hospital Insular, Las Palmas, Spain;
15. Hospital Carlos Haya, Málaga, Spain;
16. Hospital de Cruces, Baracaldo, Spain;
17. Hospital Sant Pau, Barcelona, Spain; and
18. Erasmus University Medical Center, Rotterdam, The Netherlands
19. Hospital Universitario La Fe, Valencia, Spain;