Dr. Mark C. Mattar

Gastroenterologist Mouen Khashab specializes in therapeutic endoscopy, and he oversees this group of practitioners across the Johns Hopkins enterprise. Nationally and internationally known in the field of interventional endoscopy, Dr. Khashab has contributed immensely to the field’s advancement as a minimally invasive means to treat gastrointestinal and pancreaticobiliary disorders. Dr. Khashab earned his medical degree from the American University of Beirut Faculty of Medicine, and subsequently completed a residency in internal medicine and a fellowship in gastroenterology at Indiana University. He then completed a two-year fellowship at The Johns Hopkins Hospital before joining the faculty in 2011. A busy researcher, Dr. Khashab has published more than 600 papers in peer-reviewed journals. In 2013, he described the procedure called gastric peroral endoscopic myotomy (known as G-POEM) and was able to disseminate and teach it all over the world. Other procedures that he expanded include peroral endoscopic myotomy (POEM), peroral endoscopic myotomy with fundoplication (POEM-F), Zenker’s peroral endoscopic myotomy (Z-POEM) and full thickness resection. In 2022, he received the Master Endoscopist Award from the American Society for Gastrointestinal Endoscopy (ASGE) for his numerous contributions to the field. His procedural expertise includes endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasound (EUS), interventional EUS, submucosal endoscopy, POEM/achalasia, endoscopic mucosal resection, endoscopic submucosal dissection, luminal stenting, large polyp resection and Barrett’s therapy, among others. Dr. Khashab is involved with multiple gastrointestinal societies and has served on many committees, including the ASGE Standards of Practice Committee, which is in charge of formulating guidelines for the practice of endoscopy. He has also served as an associate editor for the journal Endoscopy, a premier journal in the field. Khashab is a highly sought-after speaker at national and international conferences, and he has participated in multiple live endoscopy conferences. Outside of academic medicine, Dr. Khashab is an entrepreneur. His major interest is in new technology and medical devices, and his goal is to disrupt the field by introducing technology that makes endoscopic procedures safer, easier, efficient and more scalable. Dr. Khashab is highly rated in 52 conditions, according to our data. His clinical expertise encompasses Achalasia, Pancreatic Pseudocyst, Bile Duct Obstruction, Endoscopy, and Gastric Bypass. Dr. Khashab is board certified in American Board Of Internal Medicine. Dr. Khashab is currently accepting new patients.

Theo Heller is a Gastroenterologist practicing medicine in Bethesda, Maryland. Dr. Heller is highly rated in 20 conditions, according to our data. His clinical expertise encompasses Hepatitis D, Hepatitis, Portal Hypertension, Gastrectomy, and Endoscopy.

Saleh Alqahtani is a Gastroenterologist practicing medicine in Washington, Washington, D.c.. Dr. Alqahtani is highly rated in 14 conditions, according to our data. His clinical expertise encompasses Non-Alcoholic Fatty Liver Disease, Obesity, Hepatitis, Liver Transplant, and Hepato-Pancreato-Biliary Surgery. Dr. Alqahtani is currently accepting new patients.