Yana Valerieva1, Ivan Lutakov1, Branimir Golemanov1, Georgi Jelev2, Borislav Vladimirov1
1Clinical Center of Gastroenterology, University Hospital “Queen Joanna-ISUL” Sofia, Medical University Sofia, Bulgaria
2Clinical Center of Gastroenterology, Department of Surgery, University Hospital “Queen Joanna-ISUL” Sofia, Medical University Sofia, Bulgaria