Background: There is mounting evidence at experienced centers that aortic annular enlargement (AAE) procedures are safe adjuncts to surgical aortic valve replacement (SAVR) that do not increase perioperative morbidity and mortality. This systematic review and meta-analysis aims to assess the impact of AAE procedures on mid-term outcomes after SAVR.Methods: OVID MEDLINE, OVID Embase, and Cochrane Library were searched comprehensively.Comparative studies examining adult patients undergoing SAVR with and without AAE were eligible for inclusion. Studies involving aortic root replacement, Ross procedures, and Ozaki procedures were excluded.The risk of bias was assessed according to Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I), and the quality of evidence was evaluated according to Grading of Recommendations Assessment, Development and Evaluation (GRADE). Random effects meta-analysis facilitated the quantitative synthesis.Results: A total of 2,765 records were retrieved. After full-text review, 15 eligible studies were identified for data extraction and synthesis. The dataset included a total of 216,654 patients (AAE: 7,967; no AAE: 208,687). Only mid-term outcomes were available. In unmatched and unadjusted studies, perioperative mortality was noted to be higher in the AAE group. However, this difference was not observed in studies with matching or adjusted outcomes. In both the unmatched and unadjusted studies, and the matched and adjusted studies, there were no statistically significant differences identified regarding perioperative stroke, myocardial infarction, or permanent pacemaker implantation. Similarly, there were no statistically significant differences identified in mid-term mortality [hazard ratio (HR), 1.03; 95% confidence interval (CI): 0.95 to 1.11; P=0.49; I 2 =20% (matched/adjusted studies)], aortic valve reintervention [HR, 0.98; 95% CI: 0.75 to 1.27;