2.4. Study enrollment and data extraction
Two reviewers (Xiang Yang, Ze ran Yu) extracted data independently using a predefined data extraction form. Disagreements were resolved by discussion or consensus with a third reviewer. Microsoft Office Excel 2013 (Microsoft, Redmond, Washington) was used for data extraction. The data extracted included the study name; publication year, study design, country of publication, sample size and baseline characteristics (age, gender, prior surgical history, time from AMI to VSD, time to VSD closure, when to intervention, presence of CS, prior intra-aortic balloon pump (IABP), inotropes use and size of the defect), and procedural characteristics (successful device implantation, size of device, type of device, immediate shunt reduction), the adverse events and complications. For studies with insufficient information, the reviewers contacted the primary authors, when possible, to acquire and verify the data.