MitraClip and surgery should not compete

Current trend in treating valvular heart diseases is towards as less invasive as possible, especially in elderly patients. Among percutaneous therapies, MitraClip is the most frequently used to address severe mitral regurgitation (MR) and has proved to be quite innocuous [ 1 ]. However, there are more and more publications showing that MitraClip, although not detrimental, may be futile, especially in patients with ejection fraction less than 30% and high pulmonary pressures [ 1 ]. All these publications are mixing both functional and organic MR, which seems to be inadequate [ 2 ]. Even in the functional MR subgroup, ischaemic MR has a much worse prognosis than non-ischaemic MR. It is also striking that although well recognized, functional MR is not a valvular disease but a ventricular disease. Despite this agreed concept, everybody still treats the mitral valve (MV) as the main target although it is a surrogate end-point. Surgery, well before percutaneous techniques, has more or less failed to show its efficacy in this context as most surgeons have addressed the MV and not the left ventricle (LV). Surprisingly, interventional cardiology believes that by addressing the same end-point again and again but percutaneously, it will overcome the failures of the more invasive approaches. Everest 2 trial compares a surgical treatment, which includes an edge-to-edge technique and an annuloplasty, with the MitraClip, and concludes that MitraClip achieves similar results and therefore claims that it is a success. Surgery in well-selected patients, with not too dilated LV, mild/moderate pulmonary pressures and no right ventricular failure, has shown to be efficient. Otherwise, mitral repair is not widely accepted and some advocate MV replacement as a safer option [ 3 ]. It is, therefore, quite surprising that a surgical option with a failing efficacy may become all of a sudden an optimal treatment just because it is percutaneous. De Bonis et al. [ 4 ] present in a 6-year period a selected group of 85 patients who underwent MitraClips. Their selection has excluded all failures, which are defined by MR greater than 2+, deaths and associated procedures. They then have selected only 58 patients in between 1999 and 2006 (7-year period) who underwent edge-to-edge or Alfieri stich out of 65 patients who concomitantly received mitral annuloplasty. It is quite remarkable that coming from the promoting group of such technique, there were only 65 patients over 7 years, which means less than 10 patients per year. They have also stressed that edge-to-edge procedure without annuloplasty did not provide acceptable results, which was confirmed by others [ 5 ]. Along with these surgical results, one would expect that MitraClip alone would not be sufficient and that the addition of a percutaneous annuloplasty would make this therapeutical option more realistic. MitraClip, being less invasive and also strongly supported and driven by industry, has seen its numbers grow in less than 5 years up to 25 000 procedures. Despite this, many unanswered questions remain. Even if there are many flaws in this publication [ 4 ], especially concerning the methodology comparing at different era different therapeutical options applying to different MR aetiologies, the conclusion may still be a word of caution. In the hands of these experts, results are not those of the Everest 2 trial. Patients who underwent MitraClip did not show consistent results throughout time and surely not as good results as those who underwent surgery. If results are analysed more in depth, the most striking factor is that there was a significant decrease in left ventricular end-diastolic diameter (LVEDD) only in patients who underwent surgery and not in those who received a MitraClip. This matter might be the underlying triggering factor that explains why there is a higher MR recurrence rate in MitraClip as opposed to edge-to-edge. However, most publications refer to clinical status improvement, despite some degree of residual MR. It could be that MitraClip might relieve temporarily symptoms by decreasing MR grade without the initial insult of open heart surgery. But improving reverse remodelling requires to eradicate MR completely, which is not the case with many MitraClips. Improving survival cannot be achieved without improving LV function, which is directly linked to a decrease in both LVEDD and left ventricular end-systolic diameter. However, all surgeons know that the questionable results of mitral annuloplasty for ischaemic MR are directly linked to residual or recurrent MR. This fate does not seem to affect MitraClip patients, as those with residual MR 2+, are still considered as good results [ 6 ]. Therefore, these two therapeutical options are intended for different patients. The MitraClip, currently without the addition of a percutaneous ring, should be strictly used, as far as the functional MR is concerned, for patients with not too severe LV dysfunction and absolute contraindications for surgery or with a prohibitive risk because of severe comorbidities as suggested in the latest guidelines of the American Heart Association/American College of Cardiology (class 2b recommendations) for primary MR [ 7 ]. However, when surgery is possible, it remains clearly the best alternative.