Left atrial stiffness index as a marker of early target organ damage in hypertension

This study aimed to evaluate left atrial (LA) mechanics using two-dimensional speckle-tracking echocardiography (2DSTE) and investigate their correlations with measures of target organ damage (TOD) in hypertension. We enrolled 42 healthy controls (Group I) and 286 hypertension patients: Group II (n = 79) had an LA volume index (LAVI) <28 ml/m2; Group III (n = 92) had an LAVI ≥28 ml/m2; and Group IV (n = 115) had hypertension with left ventricular hypertrophy (LVH). We measured the following parameters: LA reservoir strain and strain rate (LAS-S, LASR-S), LA conduit strain and strain rate (LAS-E and LASR-E), and LA booster strain and strain rate (LAS-A and LASR-A). The LA stiffness index (LASI) was defined as the ratio of early diastolic transmitral flow velocity/lateral mitral annulus myocardial velocity (E/e') to LAS-S. We performed correlation and regression analyses of individual TOD with LA phasic functions, the LASI, and cardiovascular risk factors. Our findings showed that there was a trend toward a gradual increase in the LASI from controls to normal LA and enlarged LA patients and finally to hypertrophic LV patients. The LASI was significantly higher in Group III [0.28 (0.20, 0.38)] than in Group I [0.20 (0.16, 0.23)] and Group II [0.22 (0.18, 0.27)] and was the highest in Group IV [0.33 (0.26, 0.43)]. The LA reservoir and conduit function gradually decreased from Group I to Group IV. Multivariate regression analysis revealed that the LASI was independently correlated with individual TOD. In conclusion, abnormal LA mechanics precede LA enlargement and LVH, and an increased LASI can be used as a marker of early TOD in hypertension.