Perspective:

This large, retrospective study based on administrative data in France concludes that M-TEER for MR was associated with lower rates of CV mortality, ICD/pacemaker implantation, and stroke compared to isolated MV surgery; but the study has several limitations, many related to the retrospective analysis of administrative data. First, the ability to control for multiple differences in the M-TEER and MV surgery groups leaves open the possibility (if not the probability) of residual confounders—possibly demonstrated by higher non-CV death despite lower CV death in an M-TEER group that had far more comorbidities prior to propensity matching. Second, the presence of severe MR is assumed (based on the performance of a procedure and ‘MR’ as the principal diagnosis), but the presence of concomitant mitral stenosis cannot be excluded among patients who underwent MV surgery. Third, the study was not able to differentiate between either treatment for primary vs. secondary MR or for mitral valve repair vs. replacement. Fourth, the study does not address procedural success, and note is made that pulmonary edema hospitalization and VT/VF cardiac arrest rates were higher in the M-TEER group. Finally, median follow-up was only 0.4 years, but outcomes data are reported at 3 years (with only ~10% of subjects at risk). Although the conclusions are intriguing, it might be premature to conclude that M-TEER is superior to MV surgery for patients with isolated severe MR.