Mechanical mitral valve endurance in children under 2 years

The management of mitral valve disease in young children is challenging. Mechanical mitral valves could provide long-term durability; however, the need for anticoagulation increases the risk profile of mechanical valves. We report our experience in mechanical mitral valve replacement (MVR) in children under 2 years of age and evaluate factors affecting the outcomes. The study included all patients younger than 2 years who underwent mechanical MVR between 2000 and 2023. The study outcomes were mitral valve reoperation, bleeding, valve-related thrombosis, and survival. Twenty-three patients were included, with a mean age of 10.2 ± 5.9 months. The mitral valve sizes ranged from 16 to 25 mm, and 6 (26%) were placed in the supra-annular position. Complete heart block occurred in seven patients (30%), and operative mortality occurred in three patients (13%). Postoperative warfarin was used in 17 patients (74%). After discharge, bleeding occurred in five patients (22%), four were managed conservatively, and one had intracranial hemorrhage treated with craniotomy. Nine patients (39%) had valve-related thrombosis; two underwent reoperation, while seven were treated with alteplase in 26 patients. Valve-related thrombosis was more common in patients with supra-annular valves (p < 0.001) and in those who were not on warfarin (p < 0.001). A total of seven patients (30%) underwent redo MVR, and redo was more common in young patients (p = 0.029) and in patients with supra-annular valves (p < 0.001). Survival of the whole cohort was 73% at 5 years. Among the annular position group, 5-year survival was 88%, while among the supra-annular position group, survival was 50% after 3 months and 25% after 14 months (p = 0.009). Mechanical MVR in children younger than 2 years is associated with high complication rates, including thrombosis and bleeding. The supra-annular valve position appears to be a risk factor for thrombosis and reoperation. Anticoagulation with warfarin remains challenging. However, further studies evaluating alternative options are needed.