Ideal therapy for secondary mitral regurgitation: should we look under the annulus?

Secondary (aka ischaemic or Carpentier surgical classification Type IIIb) mitral regurgitation (MR) is a common complication of coronary artery disease and is associated with adverse prognosis.1 The fundamental mechanism of ischaemic MR relates to remodelling and distortion of the ischaemic left ventricle (LV). As viable myocardial cells are lost following infarction, the wall becomes thinner and bulges outward, a process that begins almost immediately and then progresses over weeks to months. As a result of ischaemic LV distortion and dilation, the  mitral leaflets become tethered towards the apex, restricting leaflet closure.2 Standard mitral valve repair for ischaemic MR at the time of revascularisation involves placing an undersized rigid mitral valve (MV) annuloplasty ring (restrictive mitral annuloplasty, RMA) to restore coaptation by correcting posterior annular dilatation. However, RMA does not eliminate the mechanistic problem in ischaemic MR, which is a subvalvular problem with altered geometry of the chordal apparatus due to ventricular dilation from coronary artery disease or cardiomyopathy. In their paper in Heart , Harmel and colleagues3 performed a meta-analysis of 1 prospective and 11 retrospective trials examining outcomes of the addition of one of several subannular procedures in addition to RMA for ischaemic MR and conclude that the addition of such procedure(s) is associated with a substantially lower rate of recurrent MR. Harmel and colleagues3 highlight an important unmet need in MV therapy, which is a need for a …