. Author manuscript; available in PMC: 2021 Feb 1.
Published in final edited form as: Gastroenterology. 2019 Dec 6;158(3):705–731.e5. doi: 10.1053/j.gastro.2019.12.001
This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/