Considerations in the development of the International Multicenter Pediatric Portal Hypertension Registry.

Portal hypertension, a common sequela of chronic liver disease, is complicated by variceal hemorrhage, one of its most serious complications. Evidence-based approaches to managing variceal hemorrhage are limited by the scarcity of data related to this rare entity. Multicenter international registries are increasingly utilized to garner critical information about rare diseases. The International Multicenter Pediatric Portal Hypertension Registry (IMPPHR) was developed to acquire pediatric data about the mortality of first variceal hemorrhage and approaches to primary and second prophylaxis of variceal hemorrhage with a goal of improving outcomes in children with portal hypertension. IMPPHR evolved from pediatric portal hypertension symposia at the Baveno V and VI meetings in 2010 and 2015, with a formal executive committee initiating the development of IMPPHR in 2019. The registry opened in 2020, with data closure in 2024, including information from 44 centers and >700 subjects. The complexities and approaches to developing IMPPHR are described.