gms | German Medical Science

Background: Accessing the mitral valve for MitraClip implantation requires creation of an atrial septum defect (ASD). MC itself is considered being a palliation only as mitral insufficiency remains. A proportion of patients after MitraClip require consecutive surgical measures because of technical failure or inappropriate clinical improvement. The recent studies report an immediate relief of the left atrial pressure (LAP) and also a mid- and long-term increase in LAP due to iASD.

We hypothesize that the ASD in combination with the remaining mitral insufficiency plays a role in altering the postinterventional course of the patients. Thus, we analyzed those patients receiving consecutive surgery after MC regarding necessary measures for consequences of right heart burden.

Methods: 26 patients were retrospectively analyzed after Mitral valve replacement following MitraClip (MC) between 2010 and 2016. In a matched pair analysis 26 patients with corresponding demographic data and risk profile from the same period receiving primary mitral valve repair (MVP) were collected. Development of pulmonary hypertension as well as necessity of tricuspid repair (TR) and iASD closure (iASDC) was analyzed. Statistical analysis was performed using SPSS®.

Results: Mean age was 70 ±12.4 years in both groups, mean log. EuroSCORE was 22.24% ± 15.95 in MC and 22.09% ± 15.7 in MVP group. Mean left ventricular ejection fraction was 43% preoperatively, and 48% postoperatively in both groups. Postoperatively, an improvement of around I classes was observed in both groups. Compared with the MVP group, an increase in mean pulmonary artery pressure, a dilatation of the left atrium, and increased tricuspid regurgitation were observed in MC group. Thirty day mortality was 26.92% in MC whereas it was 11.54% in MVP. The overall survival was 50% in MC and 84.61% in MVP (Wilcoxon: p=0.015, Log Rank p=0.009).

Conclusions: Patients who required surgical MVR after previous MC fared worse than a matched cohort receiving primary MVP. It was indeed shown that patients after MC developed significantly higher PAP and required significantly more TR and iASDC than MVP patients. It can be speculated that in contrast to current believe the ASD as well as the remaining mitral insufficiency lead to right heart burden and pulmonary hypertension thereby resulting in an increase of tricuspid insufficiency.

In view of the obviously adverse influence on the right heart primary indication for MitraClip should not be too liberally made.