1. University Hospital of Salamanca, Salamanca, Spain;
2. Hospital 12 de Octubre, Madrid, Spain;
3. Hospital Germans Trials i Pujol, Badalona, Spain;
4. Hospital Clinico de Valencia, Valencia, Spain;
5. Hospital de Donostia, San Sebastian, Spain;
6. Hospital Virgen de la Concha, Zamora, Spain;
7. Hospital Clinico San Carlos, Madrid, Spain;
8. Hospital Morales Messeguer, Murcia, Spain;
9. Hospital Lozano Blesa, Zaragoza, Spain;
10. Hospital General de Segovia, Segovia, Spain;
11. Hospital Santa Creu i Sant Pau, Barcelona, Spain;
12. Hospital Sont Llatzer, Palma de Mallorca, Spain;
13. Fundación Hospital de Alcorcón, Madrid, Spain;
14. Hospital San Pedro de Alcántara, Cáceres, Spain; and
15. Hospital Clinic i Provincial, Barcelona, Spain