Objective To investigate and evaluate the safety and efficacy of the aortic-mitral annular enlargement technique (double annular enlargement) in patients with small-size valve prostheses after prior valve surgery. MethodsThe clinical data of patients who underwent double valve annular enlargement in Wuhan Asia Heart Hospital from April 2020 to April 2022 were retrospectively analyzed. Results A total of 30 patients were collected, including 2 males and 28 females aged 9-78 (52.71±3.53) years. All patients had previous heart valve surgery, including 1 patient receiving the third heart surgery. All patients were operated on successfully and there were no postoperative in-hospital deaths. There was no postoperative bleeding which needed a secondary open-chest hemostasis, and one patient underwent permanent pacemaker implantation due to postoperative sick sinus syndrome. The mean diameter of the implanted prosthetic aortic valve was 24.23±1.60 mm, which was significantly larger than that of the preoperative aortic valve (21.03±1.90 mm, P＜0.001). The mean diameter of the implanted prosthetic mitral valve was 28.33±1.21 mm, which was significantly larger than that of the preoperative mitral valve (25.43±0.84 mm, P＜0.001). The mean peak gradient difference across the prosthetic aortic valve on postoperative echocardiography was 18.17±6.44 mm Hg, which was significantly lower than that of the preoperative aortic valve (82.57±24.48 mm Hg, P＜0.001). The mean peak gradient difference of the postoperative prosthetic mitral valve was 12.73±5.45 mm Hg, which was significantly lower than that of the preoperative mitral valve (19.43±8.97 mm Hg, P=0.003). Conclusion The double annular enlargement technique is safe and effective for reoperation in patients with a history of valve surgery with a small aortic root to obtain both a larger size prosthetic valve for a larger orifice area and stability of the mitral-aortic valve union, resulting in good postoperative hemodynamic characteristics and clinical outcomes.