Introduction Non-immune haemolysis following native mitral regurgitation is extremely rare. Typically, mechanical complications are directly associated with non-immune haemolysis in cases of native mitral regurgitation. We present a case of primary native mitral regurgitation complicated by non-immune haemolysis.

Case Presentation We report a case of a 30-year-old woman with history of primary mitral regurgitation due to chronic rheumatic heart disease for the past 10 years. Over the last two years, she had a decline in functional status and developed unexplained iron deficiency anaemia. In 2021, she underwent mitral valve repair with neo chord implantation. Intraoperatively, the A/3 was redundant and prolapse with ruptured primary chordae, and a small vegetation attached to it. 2 × CV4 neo chordae were placed at A2 and A3. A size 30 Medtronic CG Future was implanted. Despite this, she continued to suffer from recurrent, unexplained iron deficiency anaemia, requiring multiple episodes of intravenous iron supplementation to maintain her haemoglobin levels. Her baseline haemoglobin prior to the repair was 7.4 g/dL, which dropped to 5.5 g/dL, with hypochromic microcytic anaemia and very low serum ferritin levels, consistent with iron deficiency anaemia. Serum haptoglobin reduced and LDH elevated. A repeat echocardiogram revealed severe mitral regurgitation with an effective regurgitant orifice (ERO) of 0.3 cm² and a maximum velocity of 6 m/s. Transoesophageal echocardiography showed a very tight neo chord with non-coapting of the mitral leaflets. Redo mitral valve replacement done. Intraoperatively, dense adhesion at anterior surface of the heart. The AMVL was thickened and retracted at A3 with no coaptation of P3. Post operatively, patient had significant clinical improvement with restoration of baseline haemoglobin.

Discussion Non-immune mechanical haemolysis is related to shear stress on red blood cells as they pass through the valve, leading to crenation. In cases of native mitral regurgitation, this phenomenon is often related to multiple factors that contribute to the high amplitude, velocity, and magnitude of the regurgitant jet, resulting in haemolysis. In this case, the persistent anaemia is key point to the diagnosis. The IDA is caused by mechanical haemolysis. It is due to neo chord implantation in restricted way, and over time, its elongation lead to a recurrence of the prolapse. Ultimately, this patient experienced a recurrence of mitral regurgitation, necessitating mitral valve replacement.

Conclusion Non-immune haemolysis following mitral valve repair warrants further investigation focused on the mitral valve apparatus to better understand and address the underlying mechanical issues.