Catheter Management of Mitral Regurgitation

Mitral regurgitation (MR) is one of the most common valvular abnormalities, second only to aortic valve stenosis. Treatment depends on the duration and severity of this condition. Acute severe MR, often caused by papillary muscle rupture or leaflet perforation from infective endocarditis, leads to significant hemodynamic instability, acute volume overload, and congestion—necessitating immediate surgical intervention.  Chronic MR can be categorized into 2 types: primary and secondary. Primary MR is caused by a primary abnormality of 1 or more components of the valve apparatus (leaflets, chordae tendineae, papillary muscles, annulus).In contrast, secondary MR is caused by alterations in left ventricular or left atrial function and shape. If mild and asymptomatic, chronic MR can be medically managed and monitored over time. However, patients with symptomatic chronic MR should undergo evaluation for potential surgical intervention. In cases of patients who are asymptomatic with chronic MR, surgical consideration may be warranted if they exhibit signs of depressed left ventricular function and dilatation, atrial fibrillation, or pulmonary hypertension. Transthoracic echocardiography (TTE) is the initial imaging modality for screening and evaluating mitral valve morphology and pathology and determining the mechanism of MR. TTE also helps quantify the severity of MR and assess left ventricular function and size, and left atrial size. Various parameters are used for qualitative and quantitative MR assessment, including a 2-dimensional analysis of mitral valve leaflet characteristics, motion, coaptation, MR jet to left atrial area ratio, vena contracta, effective regurgitant orifice area, regurgitant volume, regurgitant area, left ventricular ejection fraction, and left ventricular end-diastolic area. In cases where TTE images do not provide adequate information, transesophageal echocardiography (TEE) can offer a more detailed assessment. Three-dimensional TEE can provide an "enface" view of the MV, resembling a surgical inspection, which can greatly aid discussions and preprocedure planning (see Mitral Valve, En Face View). In situations where TEE is contraindicated, cardiac magnetic resonance imaging is an alternative option, providing highly accurate data for MR assessment and evaluation of left ventricle dimensions. Results from recent studies have shown percutaneous mitral valve repair as a viable alternative for high-surgical-risk patients suffering from severe symptomatic MR. This procedure has demonstrated low morbidity and mortality rates among many patients. The Endovascular Valve Edge-to-Edge Repair Study Trial (EVEREST) 1 laid the groundwork, demonstrating the safety and feasibility of the edge-to-edge repair technique. The subsequent EVEREST 2 randomized control trial compared percutaneous edge-to-edge repair with surgical mitral valve repair/replacement; this suggested the surgical approach's superiority in reducing MR but also supported the long-term safety of the edge-to-edge repair device and its durability in reducing MR.  The edge-to-edge leaflet repair device is a minimally invasive, catheter-based therapy based on the principle of the "Alfieri stitch," a surgical technique pioneered by Dr. Ottavio Alfieri, an Italian cardiothoracic surgeon. This technique involves bringing together the 2 flailing leaflets of the MV, resulting in reduced or eliminated regurgitation. Typically, this repair creates a double orifice based on the surgical edge-to-edge Alfieri repair. Many percutaneous options exist for patients with MR and multiple comorbidities, placing them at higher risk for surgical interventions. These percutaneous techniques can be classified based on the specific site of the mitral apparatus they target, such as the leaflets (edge-to-edge repair), annulus (indirect or direct annuloplasty), chordae (neo-chords, percutaneous chord implantation), or left ventricle (percutaneous left ventricle remodeling). This article discusses primary and secondary MR and noninvasive catheter management options, including their indications, contraindications, procedural techniques, and complications. The primary focus of the discussion will be on the United States Food and Drug Administration's approved edge-to-edge repair devices.