Background 

While the role of left atrial mechanics and function has been increasingly recognized in the context of heart failure and valvular heart disease, few studies have investigated the impact of atrial function on outcome in transcatheter aortic valve replacement (TAVR) patients.  Different methods to evaluate the atrial function have been described previously, such as the assessment of the left atrial function index (LAFI). This rhythm-independent index, has been shown to be a predictor of cardiovascular events in patient with heart failure or a marker of improvement in patients with atrial fibrillation undergoing catheter ablation. However, the applicability of the LAFI to predict outcome in patients with severe aortic stenosis has not been elucidated so far.

Objectives 

In this retrospective multicenter study, we sought to investigate the impact of the left atrial function, as assessed with the LAFI, on outcome in patients undergoing TAVR.

Methods

In this retrospective multicenter study, we assessed baseline LAFI in 733 patients undergoing TAVR for severe aortic stenosis in two German high-volume centers between 2008 and 2019. Since neither normal values nor established cut-offs for the LAFI in patients with severe aortic stenosis exist, we generated receiver operating characteristics (ROC) curves for 1-year mortality to determine the optimum cut-off value of the LAFI in our patient population. In consideration of the Youden-Index, a LAFI <= 13.5 was used to discriminate between the patients and assessed for post-procedural outcome. To further evaluate the effect of TAVR on LAFI we performed a subgroup analysis including 598 patients with adequate echocardiography images at different times of follow-up (pre-TAVR, post-TAVR before discharge (early follow-up), after 3-, or 6 months (midterm follow-up), or after 12 months of follow-up (long-term follow-up).

Results

Mean age of our study population was 80.5 ±7.1 with a mean LAFI of 28.0 ± 20.0 (median LAFI of 23.0 (IQR 13.0-39.0). Patients with a LAFI £ 13.5 had significantly more often atrial fibrillation (p < 0.001), lower LVEF (p < 0.001) and higher levels of NT-proBNP (p < 0.001). After TAVR, a significant improvement in the LAFI as compared to baseline was observed at 12 months after the procedure (28.4 vs. 32.9; p = 0.001) (Figure 1).  Compared to patients with a LAFI > 13.5, those with a LAFI <= 13.5 showed significantly higher rate of one-year mortality (7.9% vs. 4.0%; p = 0.03) (Figure 2).

Conclusion

Poor atrial function, as evaluated by the LAFI is associated with higher mortality in TAVR patients. TAVR improves LAFI within 12 months after the procedure.

 
Figure 1


Figure 2