Figure 1:

Inclusion and Exclusion Diagram: Graphical representation of the patients included in the present analysis. 155,297 index admissions were found with a total of 619,720 total readmissions. After excluding readmissions that took place longer than 1 year after the index admission, this left 112,113 readmissions which were then linked to their corresponding index admissions. The index admission data were then excluded if patients failed to be categorized by the algorithm to identify ACHD lesion, if a full 12-month follow-up period before and after index admission was not available, if patients died during index admission, if records were missing information required for analysis, and to remove outliers. This resulted in a final tally of 64,420 index admissions which were then used for analysis.