Mitral valve interventions in heart failure

Abstract

Secondary mitral regurgitation (MR) results from left ventricular dilatation and dysfunction. Quantification of secondary MR is challenging because of the underlying myocardial disease. Clinical and echocardiographic evaluation requires a multi-parametric approach. Severe secondary MR occurs in up to one-fourth of patients with heart failure with reduced ejection fraction, which is associated with a mortality rate of 40% to 50% in 3 years. Percutaneous edge-to-edge mitral valve repair (MitraClip) has emerged as an alternative to surgical valve repair to improve symptoms, functional capacity, heart failure hospitalizations, and cardiac haemodynamics. Further new transcatheter strategies addressing MR are evolving. The Carillion, Cardioband, and Mitralign devices were designed to reduce the annulus dilatation, which is a frequent and important determinant of secondary MR. Several transcatheter mitral valve replacement systems (Tendyne, CardiAQ-Edwards, Neovasc, Tiara, Intrepid, Caisson, HighLife, MValve System, and NCSI NaviGate Mitral) are emerging because valve replacement might be more durable compared with valve repair. In small studies, these interventional therapies demonstrated feasibility and efficiency to reduce MR and to improve heart failure symptoms. However, neither transcatheter nor surgical mitral valve repair or replacement has been proven to impact on the prognosis of heart failure patients with severe MR, which remains high with a mortality rate of 14-20% at 1 year. To date, the primary indication for treatment of secondary severe MR is the amelioration of symptoms, reinforcing the value of a Heart Team discussion. Randomized studies to investigate the treatment effect and long-term outcome for any transcatheter or surgical mitral valve intervention compared with optimized medical treatment are urgently needed and underway.

Keywords: Heart failure; Hemodynamic; Secondary mitral regurgitation; Surgical mitral vale repair; Transcatheter mitral valve repair.

Figure 1

Pathophysiology of secondary mitral regurgitation (MR). Scheme of a dilated left ventricle (LV), leading to papillary muscle displacement and increased tethering forces on the mitral leaflets. Closing forces are reduced because of impaired LV contractility. Annulus dilatation occurs frequently, either due to LV or left atrial (LA) dilatation, or both. The imbalance between closing and tethering forces causes secondary MR. Ao, aorta.

Figure 2

Echocardiography of secondary mitral regurgitation (MR). (A) Echocardiographic four‐chamber view demonstrates the mechanism of secondary MR. Mitral valve leaflet tethering can be visualized as the ‘tenting’ sign, i.e. apical displaced leaflet coaptation. The yellow line simulates the virtual mitral annulus, the yellow arrow the tenting high. (B) Apical four‐chamber colour Doppler visualizes the central regurgitant flow of secondary MR. However, colour Doppler evaluation is not sufficient to quantify MR. (C) Parasternal short axis colour Doppler view of the mitral valve demonstrates a typical elliptical orifice area of MR along the entire leaflet coaptation line.

Figure 3

Haemodynamic changes during percutaneous edge‐to‐edge repair. (A) Transoesophageal echocardiography (TEE) two‐chamber colour Doppler view visualizes severe mitral regurgitation at baseline before transcatheter mitral valve repair (TMVR). (B) Pulsed‐wave (PW) Doppler shows blunted systolic antegrade pulmonary vein flow with late‐systole flow reversal at baseline. (C) Left atrial (bottom) and peripheral arterial (top) pressure tracings before TMVR. Left atrial pressure is elevated with a prominent v‐wave. (D) Two‐chamber colour Doppler view shows minimal residual mitral regurgitation after implantation of two MitraClips. (E) PW Doppler demonstrates similar systolic and diastolic antegrade flow in the pulmonary veins after TMVR. (F) Left atrial pressure (bottom) is reduced after successful TMVR despite higher arterial blood pressure (top). The latter might result from increased forward stroke volume but is also affected by the rate of vasopressor administration due to general anaesthesia during TMVR.

Figure 4

Pressure–volume relationship before and after transcatheter mitral valve repair. Schematic pressure–volume relationship derived from non‐invasive single‐beat analysis in patients with secondary mitral regurgitation before (blue) and after (red) transcatheter mitral valve repair (TMVR) with MitraClip implantation. The dotted lines represent the end‐systolic pressure–volume relationship whose slope, the end‐systolic elastance, is a marker of left ventricular contractility. The grey lines represent a normal, non‐failing heart. Modified according to Lavall et al.17