LAUSR

We thank Dr. Imamura for taking interest in our study “Prognosis of Functional Mitral Regurgitation after Aortic Valve Replacement for Pure Severe Aortic Stenosis” and thank the editors of the Journal of Cardiac Surgery for the opportunity to discuss the concerns raised in his letter to the editor. First, the author enquires about the timing of echocardiographic follow‐up in patients undergoing isolated aortic valve replacement (AVR) and double valve procedure. This timing varied greatly between patients, as some benefited from nearly 10 years of echocardiographic follow‐up, while others only benefited from a few days of follow‐up because of perioperative mortality. Excluding perioperative mortality, the mean echocardiographic follow‐up for patients in all groups was 2.4 years and the median was 2.1 years. Including perioperative mortality, mean follow‐ up was 1.8 years and median follow‐up was 1.5 years. What is apparent from studying figure 4 is that the negative impact of significant residual mitral regurgitation (MR) on survival in patients undergoing isolated AVR seems to appear within the first few months to a year following surgery. This suggests that patients with severe aortic stenosis (AS) and significant functional MR undergoing isolated AVR should be monitored closely with echocardiograms during the first months following surgery, and that a staged correction of residual MR should be considered rapidly in those whose MR persists at this early follow‐up. Second, Dr. Imamura suggests that expanding the analysis of predictors of postoperative MR improvement following isolated AVR beyond echocardiographic parameters would be helpful in considering the best therapeutic strategy for patients. Given the small size of our population, it was impossible to conduct subgroup analyses. We agree that including demographic characteristics, past medical history, laboratory data and hemodynamic characteristics in such an analysis would be of great use and could be the basis for future larger, prospective studies with greater statistical power than ours. Finally, Dr. Imamura enquires about whether any specific interventions, including percutaneous mitral valve repair, were performed in patients with significant residual MR following isolated AVR. While this was not the focus of our study, we agree that studying the feasibility, safety and effectiveness of a stagedMR correction in such patients would be of great interest. A study published byWitberg et al. in 2021 provides an interesting basis for future studies. Similarly to our findings, this retrospective study of 7303 patients with severe AS and concomitant MR undergoing transcatheter aortic valve replacement (TAVR) found that significant MR persists in 44.1% of patients with significant preoperative significant MR, and that significant residual MR was associated with significantly greater 4‐year mortality (43.8% vs. 35.1% 4‐year mortality; p= .0008). In a subsection of this study, 182 patients with significant residual MR after TAVR were paired using a propensity‐matched score and divided into two groups based on whether they underwent subsequent percutaneous mitral valve repair (transcatheter mitral valve repair [TMVR]) or not. Results showed a significantly better functional class at 1‐year follow‐up for patients undergoing TMVR (82.4% vs. 33.4% New York Heart Association Class I or II; p< .001), as well as a nonstatistically significant trend in 4‐year mortality favouring patients undergoing TMVR (37.5% vs. 64.6% 4‐year mortality; p= .097). While they should be validated in a larger prospective study, these results suggest that patients with significant residual MR following TAVR could safely and effectively undergo subsequent TMVR.