1. Department of Medicine, Pulmonary Medicine, Prince Sultan Medical City, Riyadh, Saudi Arabia
2. Department of Surgery, Thoracic Section, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
3. Department of Medicine, Gastroenterology, Prince Sultan Medical City, Riyadh, Saudi Arabia
4. Department of Surgery, Thoracic Section, Prince Sultan Medical City, Riyadh, Saudi Arabia