Transcatheter mitral valve repair with clip for treatment of secondary or functional mitral insufficiency. Literature review

Abstract

Mitral insufficiency is one of the most common acquired heart valve diseases and a common cause of heart failure, often in response to mitral annulus dilation. In such cases, the condition is referred to as functional or secondary and may be associated with ischemic heart disease or other dilated cardiomyopathies of varying etiology. Mitral valve insufficiency is common among older patients or individuals with several comorbidities, who are often not eligible for conventional mitral valve surgery due to high risk of intraoperative death and complications. Surgical outcomes (valve repair or replacement) may also be limited, particularly in patients with functional mitral insufficiency (class IIb indication according to most international guidelines). Several less invasive clip-based transcatheter mitral valve repair techniques have been developed. These have been addressed in several randomized trials in the last few years, such as the EVEREST-II, the MITRA-FR and the COAPT trials. Positive COAPT trial outcomes supported the indication of mitral clip procedures in functional mitral regurgitation patients with favorable anatomy, who remain symptomatic despite optimal medical treatment. Patients with "disproportionate" mitral insufficiency (i.e., large degree of mitral regurgitation relative to ventricular dysfunction) are those who benefit most from the intervention, with lower rates of hospital readmission and death. These outcomes prompted the incorporation of novel technologies (MitraClip® NTR, MitraClip® XTR and Pascal). Major features of these devices, such as longer clip arms, capability of independent grasping of anterior and posterior leaflets, and wider arm width range are reviewed in detail in this article.