The analysis of left ventricular ejection fraction after minimally invasive surgery for primary mitral valve regurgitation

Although minimally invasive mitral valve surgery (MIMVS) has become the first choice for primary mitral regurgitation (MR) in recent years, clinical evidence in this field is yet limited. The main focus of this study was the analysis of preoperative (Pre), postoperative (Post), and 1‐year follow‐up (Fu) data in our series of MIMVS to identify factors that have an impact on the left ventricular ejection fraction (LVEF) evolution after MIMVS.

disease. Asymptomatic primary severe MR has been classified according to LVEF, LVESD, and atrial fibrillation (AF) and the presence or absence of pulmonary hypertension (PH). 2 According to these recommendations, LVEF represents one of the essential preoperative factors in the process of decision finding for surgical indication. Surgery is recommended when LVEF is reduced below 60% but yet greater than 30%. On the contrary, the recommendation for surgery is remarkably restricted in case of normal LVEF or severely depressed LVEF of less than 30%. 2 However, preoperative ejection fraction (EF) (PreEF) in the presence of severe MR may be technically overestimated, and a case in which follow-up LVEF (FuEF) occasionally deteriorates after surgery despite good PreEF is observed, whereas frequently improved FuEF is observed in clinical practice after successful MV repair. We conclude that the prediction of how LVEF will develop postoperatively (i.e, LVEF evolution = FuEF − PreEF) is cumbersome, particularly when PreEF is considered primarily. Current evidence with this respect is quite scarce, and it remains unclear which factors contribute to an improvement or a deterioration of FuEF.
Here, we analyzed our 436 consecutive patients who underwent isolated or combined minimally invasive mitral valve surgery (MIMVS) to evaluate (1) How does LVEF change after MIMVS for primary MR which was performed according to the guideline? (2) According to the results of Question

| Surgical indication and procedure
The indication of MV and TV operation was determined by based on EACTS guideline. 2 All patients received a minimally invasive surgical approach via right anterolateral mini-thoracotomy with peripheral vascular cannulation for extracorporeal circulation via femoral vessels or subclavian artery as described in detail before. [3][4][5]

| Echocardiographic evaluation
All patients underwent transthoracic echocardiographic evaluation preoperatively and at 1 year postoperatively. Echocardiography was performed as part of the institutional routine procedure. 6 We mea-

| Baseline characteristics
The baseline characteristics of the analyzed patients are presented in Table 1. A total of 221 (50.7%) men and 215 (49.3%) women were assigned with a mean age of 64.0 ± 12.9 years. TV repair was performed in 98 patients (22.5%). As part of the institutional policy, MV repair was favored over MVR whenever deemed feasible and durable, but MVR was also performed in 77 patients (17.3%) with a consideration of age, pathophysiology of MR and concomitant diseases.

| LV function analysis
The LV function is presented in Figure 1. In all groups, we identified that mean LVEF has declined over time. The statistical analysis of the correlation between PreEF and EF evolution is presented in Figure 2. Overall, we found a significant    LVEF. 16 Forward LVEF less than 35% has been demonstrated as a cut off value to predict higher short-term mortality after MV surgery. 17 Therefore, forward LVEF may be a superior parameter to the "total"

| Multivariable analysis
LVEF and may be employed to predict LV dysfunction after MV surgery. 18 On the other hand, it has been shown that a postoperative In past studies, some authors have noted that smaller LVESD, younger age, and sinus rhythms represent important preoperative determinants for preserved postoperative EF. [10][11][12] Our study could not provide the same results. However, these factors can also be a prognostic factor for overall favorable outcome, and hence, it seems necessary to consider them as postoperative predictive factors.
With the emerging notion of limitations adherent to LVEF other parameters have been discussed as alternative measures for assessment of cardiac function and particularly functional reserve. One of the alternative ordinal indicators of cardiac function is CI. Before this study, we speculated that CI might be a predictive factor for estimating cardiac deterioration after surgery. All patients preoperatively subjected to diagnostic workup at our cardiovascular center and referred to surgery for MR receive a right heart catheterization with a determination of cardiac output and CI. To evaluate our hypothesis on the value of CI, we analyzed data from patients without TR. Against our assumption, there was no correlation between preoperative CI and EF evolution. This "unexpected" result has caught our attention as it indicates that CI maybe even less critical than PreEF in the context of preoperative evaluation and risk assessment for patients with severe MR. However, CI was not routinely measured in every patient and datasets were available in a minority of patients.
There are several limitations to this study. First, our study was a nonrandomized series from a single center with retrospective analysis. Second, we did not analyze long-term prognosis, as our institutional standard procedure encounters for 1-year follow-up only. A long-term follow-up may add some insight into the progressive remodeling of LV and the evolution of LVEF.
Third, due to incomplete datasets, our study could not conclude the analysis of all echocardiographic parameters. Further studies are certainly warranted for comparative evaluation of these diagnostic values.

| CONCLUSION
Patients with greater PreEF are at higher risk for decreased LVEF at