Severe haemolytic anaemia and acute renal failure caused by pinhole perforation of native mitral valve: a case report.

Background: Mechanical haemolytic anaemia following mitral valve plasty or replacement is not uncommon. However, to our knowledge, there are no reports of haemolytic anaemia caused by native mitral valve regurgitation requiring surgical intervention. Case summary: A 70-year-old woman was admitted for acute decompensated heart failure with moderate mitral regurgitation and haemolytic anaemia. Although her heart failure responded promptly to medical therapy, her renal function progressively deteriorated, ultimately requiring haptoglobin supplementation. Haematologic conditions potentially causing haemolysis were excluded, and mitral regurgitation (MR) was suspected as the underlying cause. Cardiac magnetic resonance imaging and transoesophageal echocardiography identified an MR jet through a pinhole perforation of the A3 segment of the mitral valve, which was subsequently confirmed intraoperatively. The patient's haemolytic anaemia improved markedly following mitral valve replacement. We concluded that the mechanical haemolysis was due to MR through a pinhole perforation of the native mitral valve. Discussion: A prior study suggested the presence of subclinical intravascular haemolysis in patients with primary MR. In the present case, an accelerated MR jet through a pinhole perforation, in addition to a jet directed against the atrial wall, appears to have caused clinically significant haemolysis. This case highlights that native mitral valve perforation can induce mechanical haemolysis in a manner similar to that seen following mitral valve surgery.