Intraoperative echocardiographic assessment of mitral regurgitation after mitral clip implantation: literature review

Initially, percutaneous mitral clip emerges as an alternative to surgery in patients with severe mitral regurgitation (MR) and high surgical risk. Nonetheless, it is now also considered a first-line treatment in patients with left ventricular ejection fractions somewhere between 20% and 50%, end-systolic diameters < 70 mm, and pulmonary systolic pressures < 70 mmHg. Successful results depend on reducing the severity of MR. The common parameters used to evaluate native MR have not been properly validated in this context. Therefore, the parameters that should be used to quantify residual MR during intraprocedural transesophageal echocardiography are still under discussion. There is scarce evidence and no validation studies. Although these have limitations, color Doppler echocardiography, proximal isovelocity surface area (PISA) and its derived area, continuous-wave Doppler signal, transmitral flow, and regurgitant flow are not accurate parameters to quantify residual MR due to clip artifacts. On the other hand, the width of the vena contracta, the 3D-vena contracta area, and pulmonary venous flow are associated with a satisfactory approach. Using a comprehensive method is the most practical thing to do.