From macro-effective to microinvasive: what is the right balance?

Traditionally, mitral valve (MV) surgery has been performed through median sternotomy. In an attempt to reduce surgical trauma, minimally invasive surgical techniques and, recently, even less invasive MV repair techniques, without the support of cardiopulmonary bypass, have been developed.

The comparison between transapical and surgical MV repair by D’Onofrio etal. [1] is interesting as it provides valuable insights in the real-world performance of new technology (Neochord Inc., St. Louis Park, MN, USA) in MV repair. The authors report a high rate of recurrent regurgitation in the Neochord group. Even in the presence of the most favourable anatomy (isolated central posterior leaflet prolapse/flail; 80 patients from both groups were left for analysis after matching), freedom from moderate regurgitation was only 63.9% (95% confidence interval 44.4–91.8%) at 5 years, compared to 74.6% (95% confidence interval 58.7–94.8%) seen in the median sternotomy group. While the difference was statistically not significant, the difference would be significant with a higher number of patients included in the analysis or if the freedom from recurrent regurgitation was higher with conventional surgery (recently, freedom from recurrent regurgitation rate as high as 93% at 10 years after surgical MV repair for posterior leaflet prolapse was reported [2]). Recurrent regurgitation is not an innocent observation but is related to impaired outcomes [3]. A durable repair is the primary goal of therapy and it remains questionable if this is achievable without annular stabilization.

The question arises—how should we use this new technology and which patients will actually benefit? Should we perform these procedures in relatively young patients (the median age in the study was just above 60 years) or should they be preserved for patients who are considered high risk or unfit for surgery? Is the goal (i) a less invasive approach with subsequent surgical repair (based on the results, the probability of a reintervention within years after the initial procedure is very high) or (ii) a long-lasting surgical repair with a less invasive approach to treat eventual recurrent regurgitation? Combining Neochord technology with transcatheter annuloplasty might solve some of the problems but the question remains—what is the right balance?