BACKGROUND: Composite outcome measures aim to provide a more holistic view when determining the effectiveness and safety of surgical interventions. Recently, 'Ideal Outcome' (IO) harmonized the European and American composite outcome of pancreatic surgery. The rate of IO after pancreatoduodenectomy was 54% but is unknown after left pancreatectomy(LP). METHODS: This transatlantic analysis included patients after LP from the audits in North America (NSQIP), Germany (StuDoQ), the Netherlands (DPCA), and Sweden (SNPPCR) (2014 - 2020). IO is obtained in the absence of (1)in-hospital mortality, (2)severe complications (Clavien-Dindo≥3), (3)postoperative pancreatic fistula (ISGPS grade B/C), (4)reoperation, (5)hospital stay exceeding the 75th-percentile, and (6)readmission. Clinical predictors of IO were identified using a multivariable logistic regression. RESULTS: Overall, 20,126 patients after LP were included (37.8% minimally invasive). The rate of IO after LP was 59.1%. The rate of IO varied among the four audits: North America 58.5%, Germany 53.4%, the Netherlands 56.9%, and Sweden 61.7% (P<
0.001). Among all variables, the rate of postoperative pancreatic fistula differed the most: North America 9.8%, Germany 23.9%, the Netherlands 20.5%, and Sweden 10.6% (P<
0.001). Minimally invasive LP was associated with higher rates of IO (65.4% vs 53.3%, P<
0.001) compared to open LP. No difference in the IO was observed between robot-assisted and laparoscopic LP. CONCLUSION: The new composite outcome measure IO was reached in 59% patients after LP and varied between four transatlantic audits. Minimally invasive LP was associated with higher rates of IO. IO can be used for evaluating, comparing, and improving patient outcomes between the four audits, especially regarding postoperative pancreatic fistula.