Impact of left atrial stiffness on the prognosis of patients treated with transcatheter aortic valve implantation

Introduction and Objectives The Atrial Stiffness Index (ASI), estimated by echocardiography as the ratio between E/e’ and atrial reservoir strain, is a novel parameter of atrial function that has shown prognostic value in settings such as heart failure (HF) and ischemic heart disease. The aim of this study is to evaluate the association of the ASI with the occurrence of cardiovascular events in patients with severe aortic stenosis (AS) treated with transcatheter aortic valve implantation (TAVI). Methods A retrospective analysis was conducted on a prospective and consecutive cohort of patients treated with TAVI at a tertiary hospital between 2009 and 2023. The association between baseline left atrial (LA) function before TAVI implantation and the incidence of cardiovascular events during follow-up was assessed. Results The median age of the patients included in the study (n=1280) was 83 years (interquartile range [IQR] 79–86), 54.4% (n=696) were women, and 35.5% had a history of atrial fibrillation. The median EuroSCORE II was 3.3 (IQR 2.1–5.9). Regarding echocardiographic parameters, median left ventricular ejection fraction (LVEF) was 60% (IQR 53–66), mean indexed LA volume was 48.6 ml/m² (SD 27), mean LA reservoir strain was 15.3% (SD 9), and mean ASI was 1.6 (SD 2.5). A total of 78% of patients met criteria for increased ASI (≥0.55). During a median follow-up of 31 months (IQR 18–52), 19.9% of patients were hospitalized for heart failure, and 39% died. The association between different LA function parameters and clinical events is shown in the Table. An elevated ASI (≥0.55) was significantly associated with higher incidence of heart failure hospitalization (HR 1.90), mortality (HR 1.45), and the combined endpoint of cardiovascular death and heart failure hospitalization (HR 1.82) (Figure). Furthermore, increased ASI was associated with a higher risk of persistent moderate or severe mitral or tricuspid regurgitation one year after TAVI. Conclusions In our cohort of patients with severe AS treated with TAVI, increased ASI was significantly associated with a higher risk of heart failure hospitalization and mortality, as well as with persistent significant mitral and tricuspid regurgitation following TAVI. These findings support the prognostic value of atrial stiffness index as a useful tool for risk stratification in this patient population.