Surgical Strategy for Preserving Native Mitral Valves in Infants With Ventricular Septal Defects and Mitral Regurgitation

<b>Objectives:</b> Volume overload due to ventricular septal defect (VSD) can cause mitral valve dilation, resulting in mitral regurgitation (MR). We aimed to support the clinical decision-making on mitral valvuloplasty during VSD closure by reviewing patients with VSD and MR. <b>Methods:</b> Of the 1524 patients who underwent VSD closure from 2004-2024, 30 had moderate or worse MR. Among them, 14 underwent VSD closure-alone, while 16 underwent concomitant mitral valve repair. Primary outcome was long-term mitral valve-related events. Secondary outcome was serial valve function changes. The median follow-up period was 6.7 years. <b>Results:</b> The median age and weight at the time of surgery were 5.4 months and 5.6 kg. In the VSD closure-alone group; 13 patients had moderate MR and 1 patient had severe MR preoperatively. At follow-up, 12 patients had mild or less MR, one patient had moderate MR, and the outcome was unknown in one. No reoperations were required. In the VSD closure with mitral valvuloplasty group, 12 patients had moderate MR and 4 patients had severe MR preoperatively. At follow-up, ten patients had mild or less MR; three patients had moderate MR, two patients had severe MR, and the outcome was unknown in one. Three patients required mitral valve replacement. Freedom from reoperation at one, five, and ten years was 96.3%, 87.3%, and 87.3%, respectively. Preoperative MR severity and Carpentier type IIIa were risk factors for the progression of MR and reoperation. <b>Conclusions:</b> Ventricular septal defect closure-alone can reduce functional MR in most cases, but patients with structural MR are at higher risk for progressive MR and may eventually require mitral valve replacement. Decision-making should consider preoperative MR severity and structural valve abnormalities.