Treatment of secondary mitral regurgitation by transcatheter edge-to-edge repair using MitraClip

Transcatheter edge-to-edge repair (TEER) is becoming the standard invasive treatment for ventricular functional mitral regurgitation (MR). It is necessary to determine the severity of MR before treatment with MitraClip; however, the severity of secondary MR is usually underestimated compared with that of primary MR and varies temporally. Therefore, to accurately determine the severity of MR, it is important to correctly use the algorithm of the guidelines for valvular heart disease and aggressively perform stress echocardiography. Before performing TEER, the difficulty of the procedure should be evaluated. First, morphological features that make TEER unsuitable, such as cleft of the mitral leaflet, mitral stenosis (MS), or perforation of the mitral leaflet, should be checked. The mitral valve orifice area, transmitral valve pressure gradient, coaptation depth, coaptation length, and posterior leaflet length should be measured to determine the difficulty of the procedure based on the inclusion criteria of Endovascular Valve Edge-to-Edge Repair Study II and the German consensus. After MitraClip implantation, in addition to assessing the severity of MS and residual MR, the pulmonary venous flow pattern and stroke volume should be evaluated to comprehensively assess whether TEER improves the hemodynamics. MitraClip has also been used to treat atrial functional MR, another type of secondary MR. Several reports suggest that MitraClip is effective for atrial functional MR; however, evidence is still being accumulated.