Percutaneous “edge-to-edge” leaflet repair in patients with secondary mitral valve regurgitation

Functional or secondary mitral regurgitation (MR) is a heterogeneous entity afflicting patients with heart failure both with reduced or preserved left ventricular ejection fraction. It results from an imbalance between closing forces and tethering or pushing strengths acting on the valve in the absence of structural alterations of mitral valve (MV) apparatus. According to previous studies, more than 20% of patients with heart failure and reduced left ventricular ejection fraction have severe MR, even though the definition of the severity of the MV disease in this setting remains a debated issue due to the poor reproducibility of quantitative measurements and its dynamic nature, highly dependent on left ventricular loading conditions and performance in relation to optimization of medical treatment. Furthermore, it is still unclear whether MR is a direct contributor to a worse prognosis or merely a marker of severity of the disease affecting the left ventricle. Isolated MV surgery in these patients is burdened by significant operative mortality, high rates of recurrent MR and absence of proven survival benefit. In recent years, percutaneous treatment of functional MR arose as a viable and safe alternative to conventional surgery, proving capable of reducing symptoms and recurrent hospitalization rates for heart failure, and even improving prognosis in selected patients. In this review we will discuss the percutaneous treatment of functional MR through transcatheter “edge-to-edge” leaflet repair performed with the two systems currently available: the MitraClip System and the PASCAL Repair System, from available evidence to technical practice.