1. Endoscopy Unit, Department of Digestive Diseases, Hospital Universitari de Bellvitge-IDIBELL, Barcelona, Spain
2. Endoscopy Unit, Department of Digestive Diseases, Althaia Xarxa Hospitalaria de Manresa, Manresa, Spain
3. Endoscopy Unit, Department of Digestive Diseases, Hospital Universitari Mutua de Terrassa, CIBERehd, Spain