Left atrial volume predicts mortality in low-risk dialysis population on long-term low-salt diet

Echocardiography provides insight to the management of end-stage renal disease (ESRD) and might be valuable in assessing the prognosis. We evaluated the predictive value of echocardiography along with clinical findings in a low-risk hemodialysis (HD) population who had been treated with strict salt restriction strategy for blood pressure control.

Study population consisted of a cohort of 555 ESRD patients from 8 HD centers where the same strict volume control strategy applied for blood pressure control. Clinical findings and echocardiography were examined as predictors of mortality for a mean follow-up period of 3 years (29.6 +/- 11.6 months).

During the follow-up, 89 patients (16%) died. Left atrium (LA) volume index was the only independent echocardiographic predictor of mortality (hazard ratio 1.025, 95% CI 1.001-1.050, P = .042). The other predictors of mortality were age, pulse pressure, diabetes mellitus, and high-sensitivity C-reactive protein. However, when we added interdialytic weight gain (IDWG) ratio to the Cox model, it also appeared as an independent predictor of mortality, whereas LA volume index no longer was.

Increased LA volume index emerged as the only independent echocardiographic determinant of mortality in low-risk dialysis patients treated by strict volume control. Close relationship with IDWG ratio indicates the intermittent stretching of atrium between dialysis sessions leading to atrial remodeling. This index is not the result of a single factor such as age, hypervolemia, or left ventricular hypertrophy but reflects the combination of these contributing causes. Therefore, it might be considered as an overall echocardiographic sign of mortality in ESRD.