Dr. Mark 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 top areas of expertise are Achalasia, Pancreatic Pseudocyst, Bile Duct Obstruction, Endoscopy, and Gastric Bypass.

Theo Heller is a Gastroenterologist in Bethesda, Maryland. Dr. Heller is highly rated in 16 conditions, according to our data. His top areas of expertise are Hepatitis D, Hepatitis, Portal Hypertension, Gastrectomy, and Endoscopy.

Vikesh Singh is a gastroenterologist who specializes in pancreatology and pancreaticobiliary endoscopy. He evaluates and treats patients with inflammatory diseases of the pancreas, including acute and chronic pancreatitis and autoimmune pancreatitis as well as the complications of these diseases. After earning his medical degree from the Johns Hopkins University School of Medicine, Dr. Singh remained at Johns Hopkins to complete residency training in internal medicine. He pursued fellowship training in gastroenterology at Brigham and Women’s Hospital, and earned a master’s degree in epidemiology from the Harvard T. H. Chan School of Public Health. He then returned to Johns Hopkins, where he completed a two-year advanced endoscopy fellowship with a focus on pancreaticobiliary endoscopy. Dr. Singh has been on the faculty at Johns Hopkins since 2008, and rose to the rank of professor in 2021. His research interests include acute and chronic pancreatitis, autoimmune pancreatitis, exocrine pancreatic insufficiency, and novel methods to evaluate and treat abdominal pain. Dr. Singh is a member of the board of directors of the National Pancreas Foundation, chair of the Pancreatic Disorders Section of the American Gastroenterological Association, a councilor for the International Association of Pancreatology and a member of the inaugural medical advisory board for the Familial Chylomicronemia Syndrome Foundation. Dr. Singh is highly rated in 27 conditions, according to our data. His top areas of expertise are Exocrine Pancreatic Insufficiency, Hereditary Pancreatitis, Acute Pancreatitis, Pancreatectomy, and Endoscopy.