The prognostic value of left atrial strain in patients with low-flow, low-gradient aortic stenosis

Abstract

Abstract Background Left atrial (LA) function is known to be an independent prognostic parameter in patients undergoing transcatheter aortic valve replacement (TAVR). However, the impact of LA function on postinterventional outcomes in patients with severe low-flow, low-gradient aortic stenosis (LFLG AS) is unknown. Objectives We aimed to evaluate postinterventional changes and prognostic value of LA strain in patients with LFLG AS who underwent TAVR. Methods We retrospectively included 88 patients (79.66 ± 6.33, 37.5% female) with symptomatic LFLG AS who underwent TAVR at the Heart Center Bonn. LA global function and strain were comprehensively assessed by the postprocessing left atrial phasic strain analysis – LA reservoir strain, LA conduit strain, and LA contractile strain ­– using a commercially available postprocessing software at baseline and three years after the procedure. The apical four-, two-, and three-chamber views with sufficient image quality were used for strain analysis. Results Baseline LA strain was found to be impaired in all patients (reservoir: 13.17 ± 7.62 %; conduit: 6.7 ± 6.4 %; contractile: -1.7 ±1.5 %). All-cause mortality was 41 % three years after the procedure. In the overall collective, LA reservoir strain was increased at follow-up (13.17 ± 7.62 % to 15.21 ± 10.13 %, p= 0.049), whereas conduit and contractile strain remained unchanged (p > 0.05). According to the survival at follow-up, we divided the cohort into survivors and non-survivors. Baseline reservoir (14.55 ± 8.14 % vs 9.59 ± 5.23 %, p= 0.002) and conduit (7.66 ± 7.14 % vs 4.44 ± 4.1 %, p= 0.017) strain were significantly higher in survivors. All LA strain parameters were significantly improved in survivors at follow-up. In contrast, non-survivors showed no relevant changes in LA strain parameters. In comparison of ROC curves, reservoir strain was found to be the best predictor for postinterventional survival after TAVR (reservoir AUC: 0.677, cutoff: 10 %, p = 0.007; conduit AUC: 0.642, cutoff: 3.7 %, p = 0.037; contractile AUC: 0.672, cutoff: -1,3 %, p = 0.008). Concordantly, we found that all LA strain parameters are independent predictors for three-year all-cause mortality after TAVR in cox regression analysis (reservoir OR: 0.89, p=0.005; conduit OR: 0.90, p=0.03, contractile OR: 0.71, p=0.029) in cox regression analysis. According to multivariate analysis, reservoir strain (OR: 0.91, p=0.05) and conduit strain (OR: 0.94, p=0.04) were found to be independent predictors for postinterventional survival. According to log-rank analysis, patients with a baseline reservoir strain < 10 % and a baseline conduit strain < 4 %) showed significantly higher mortality (p = 0.048). Conclusion Using LA strain parameters might optimize risk stratification and better decision-making with sufficient patient selection in this vulnerable cohort.