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Page 4 of 6 Pal et al. Vessel Plus 2019;3:39 I http://dx.doi.org/10.20517/2574-1209.2019.24

per center, but criteria for eligibility was not much different than MITRA-FR trial. Lastly, as previously
noted, the MITRA-FR authors do not deny that they may have included patients with heart failure too
[18]
advanced to derive benefit .
Intensive analysis of these two trials have led most practitioners to agree that the trials are “complimentary
[7]
[21]
rather than contradictory” (Tang et al. , Carabello et al. ). Whether the diagnosis is “disproportionate
[8]
[7]
[9]
MR” (Packer et al. , Praz et al. ) or “tertiary MR” , consensus appears to be that patients with the
combination of severe secondary MR (EROA > 0.3 cm ) with no more than moderate LV dilatation (LVEDVI
2
@
2
< 96 mL/m ) potentially will benefit from percutaneous edge-to-edge repair (MitraClip ) procedure after
optimal medical therapy, as shown in COAPT trail.
Furthermore, as pointed out by Praz et al. , these two trials lead to the following conclusions regarding
[9]
percutaneous therapy for secondary MR:
1. Extreme LV dilatation with less severe secondary MR (no benefit: MITRA-FR trial).
2. Moderate LV dilatation with more severe secondary MR (benefit: COAPT trial).
3. Extreme LV dilatation with more severe secondary MR (unknown benefit).

SURGICAL PERSPECTIVE
The American Association for Thoracic Surgery in 2016 revised their guideline recommendation for
[1]
severe secondary MR to MV replacement rather than repair for patients with LVEDD > 65 mm . Surgical
[4]
correction of secondary MR has been a topic of great interest and a matter of equipoise . The challenge
has been that surgical anatomic correction has not necessarily translated into a lasting clinical benefit .
[22]
Conceptually, the basis for surgical correction has been to produce a normal architecture, most often with
placement of a mitral annuloplasty ring. Edge-to-edge percutaneous technique without any reinforcement
[23]
with annular ring, seems unconvincing. Badhwar et al. posit that while MV replacement is best for
symptom resolution, valve repair still has its “niche” role in pathoanatomically suitable patients with
secondary MR. They suggest an entire pathoanatomic classification based on: (1) annular dilatation; (2)
ejection fraction; and (3) leaflet tethering. Based on this they suggest “low surgical risk patients” may
undergo CABG + mitral valve repair or replacement whereas “high surgical risk” may have catheter
based transmitral valve replacement or repair. As a caveat, this hypothesis has not been tested yet in
prospective randomized clinical trials. Definitive conclusions regarding the relative efficacy of other
[24]
techniques for secondary MR including percutaneous neo-chord, percutaneous annuloplasty ring , and
percutaneous MV replacement await appropriate clinical studies. In the light of these evolving techniques.
Future guidelines may increasingly rely on assessment of surgical risk, likelihood of successful anatomic
correction and clinical benefit and feasibility.

CONCLUSION AND FUTURE STUDIES
Percutaneous edge-to-edge mitral valve repair for mitral regurgitation has been practiced in Europe since
approved by the European Commission in 2008. It is estimated that 65% of percutaneous repair for MV in
Europe are for secondary MR. In contrast, in North America, the United States Food and Drug Association
approved this procedure in 2013 only for primary (degenerative) mitral regurgitation, consequently
about 80% of all MitraClip procedures in US are for primary MR. Thus, Europeans overall have a much
@
broader experience in MitraClip procedures. This may be reflected in the approach taken by the MITRA-
FR authors, namely that percutaneous MV repair would be more readily offered on a less stringent basis
compared to the more medically refractory subjects included in the COAPT. For certain, percutaneous
edge-to-edge repair is not for every patient with secondary MR. That said, there is one specific subset of
patients that did show benefit. Identification of these patients and successful percutaneous valve repair will
require meticulous medical optimization of heart failure, careful echocardiographic measurements and a