Longitudinal Changes in Left Atrial Stiffness Index Improve Risk Stratification in Patients with Hypertension

Background: Left atrial (LA) stiffness index is a non-invasive echocardiographic parameter reflecting left ventricular filling pressure; however, its prognostic significance in hypertension remains unclear. We aimed to assess the prognostic value of the longitudinal change in LA stiffness index in patients with hypertension. Methods: We analyzed 1,442 hypertensive patients from the STRATS-HHD registry who underwent echocardiography including LA and left ventricular (LV) strain at baseline and 6-18 months. Patients were categorized into four groups according to longitudinal changes in LA stiffness index: normal-normal, improved, aggravated, and persistently stiff. The primary outcome was a composite of hospitalization for heart failure (HHF) and cardiovascular death, and secondary outcomes included HHF and incident atrial fibrillation. Results: Among 1,442 patients, 996 (69.1%) were classified as normal-normal, 173 (12.0%) as improved, 91 (6.3%) as aggravated, and 182 (12.6%) as persistently stiff. Over 5 years, aggravated (adjusted hazard ratio [aHR] 2.175, 95% confidence interval [CI] 1.048-4.515, P=0.037) and persistently stiff (aHR 2.935, 95% CI 1.697-5.076, P<0.001) groups were associated with a higher risk of the primary outcome, whereas the improved group showed a similar risk to the normal-normal group. Similar trends were observed for HHF and for incident atrial fibrillation. Adding LA stiffness index into a model including clinical factors and LV mass index improved risk prediction for composite outcomes. Conclusions: LA stiffness index was associated with clinical outcomes in hypertensive patients, with longitudinal changes providing additional prognostic information. Assessment of its trajectory may further refine risk stratification in patients with hypertension.