Severe functional ischaemic mitral regurgitation: is functional a misnomer for a dysfunctional valve? A case report

Background: Mitral regurgitation (MR) in the context of left ventricular systolic dysfunction is often designated as functional, with emphasis on the underlying cardiomyopathy leading to malcoaptation of the 'otherwise normal valve'. Case summary: A 63-year-old male with ischaemic cardiomyopathy (left ventricular ejection fraction 20%) presented with intractable heart failure in need of inotropic support and could not be stepped down from an ICU hospital setting. Functional MR, graded as moderate on transthoracic echocardiography, was initially not considered as pertinent to the clinical condition and options discussed included initiation of dialysis for volume management, chronic inotropic support, and palliative measures. However, a re-examination of the mitral valve by transoesophageal echo revealed severe regurgitation from annular dilatation and restricted mobility during systole. Transcatheter edge to edge repair utilizing the PASCAL device resulted in marked reduction of MR followed by an abrupt clinical improvement, weaning off inotropes and discharge home 4 days later. At four-year follow-up, the patient is stable on optimal heart failure therapy. Discussion: For many patients with heart failure and underlying cardiomyopathy, the presence of significant functional MR, instead of a 'bystander' disease, actually becomes the dominant driver of symptoms and compounds the low cardiac output state. In these patients, the term 'functional' MR becomes a misnomer, as in fact the so called 'otherwise normal' mitral valve is actually a severely dysfunctional valve with a wide malcoaptation zone. Transcatheter edge to edge repair is an effective bailout procedure for patients with low cardiac output and disproportionate severe functional MR.