Transatlantic registries for minimally invasive liver surgery: towards harmonization

Background Several registries focus on patients undergoing minimally invasive liver surgery (MILS). This study compared transatlantic registries focusing on the variables collected and differences in baseline characteristics, indications, and treatment in patients undergoing MILS. Furthermore, key variables were identified. Methods The five registries for liver surgery from North America (ACS-NSQIP), Italy, Norway, the Netherlands, and Europe were compared. A set of key variables were established by consensus expert opinion and compared between the registries. Anonymized data of all MILS procedures were collected (January 2014–December 2019). To summarize differences for all patient characteristics, treatment, and outcome, the relative and absolute largest differences (RLD, ALD) between the smallest and largest outcome per variable among the registries are presented. Results In total, 13,571 patients after MILS were included. Both 30- and 90-day mortality after MILS were below 1.1% in all registries. The largest differences in baseline characteristics were seen in ASA grade 3–4 (RLD 3.0, ALD 46.1%) and the presence of liver cirrhosis (RLD 6.4, ALD 21.2%). The largest difference in treatment was the use of neoadjuvant chemotherapy (RLD 4.3, ALD 20.6%). The number of variables collected per registry varied from 28 to 303. From the 46 key variables, 34 were missing in at least one of the registries. Conclusion Despite considerable variation in baseline characteristics, indications, and treatment of patients undergoing MILS in the five transatlantic registries, overall mortality after MILS was consistently below 1.1%. The registries should be harmonized to facilitate future collaborative research on MILS for which the identified 46 key variables will be instrumental.