LEFT VENTRICULAR REMODELING IN RELATION TO INTERACTION BETWEEN BLOOD PRESSURE AND SODIUM RENAL HANDLING AND INTAKE IN UNTREATED CHINESE PATIENTS

Abstract

Objective: Whether or not renal sodium handling was associated with left ventricular remodeling independent of blood pressure (BP) is uncertain. Design and method: Consecutive untreated patients referred for ambulatory BP monitoring were recruited. Two-dimensional echocardiography was performed to measure left ventricular properties. Fractional excretion of lithium (FELi) and fractional distal reabsorption rate of sodium (FDRNa) were calculated as markers of proximal and distal sodium handling, respectively. Results: The 952 untreated patients (51.0% women; mean age, 50.8 years) included 614 (64.5%) ambulatory hypertension and 138 (14.5%) with left ventricular hypertrophy. FELi and FDRNa averaged 21.5% and 95.9%, respectively. In multivariable-adjusted analyses, per 1-SD increment in systolic/diastolic BP (+12.4/9.0 mm Hg) and reduction in FELi (-11.3%) and FDRNa (-2.4%) were associated with 0.19/0.19 and 0.19/0.20 mm higher interventricular septal wall thickness (IVS), respectively, 0.10/0.12 and 0.18/0.22 mm higher left ventricular posterior wall thickness (LVPW), respectively, and 2.99/2.68 and 2.17/1.95 g/m2 higher left ventricular mass index (LVMI), respectively. Associations of IVS and LVPW with FELi and FDRNa were tighter than with BP (P<0.001), whereas the opposite trend was observed for LVMI (P<0.001). There was significant (P<0.045) interaction between urinary sodium excretion and FELi in relation to LVPW and LVMI. Only in tertile 1 of FELi, LVPW and LVMI were positively associated with urinary sodium excretion (P<0.040). The interaction between urinary sodium excretion and FDRNa in relation to left ventricular structure was nonsignificant (P>0.25). Conclusions: Renal sodium handling as assessed by FELi and FDRNa, were independently associated with left ventricular remodeling, particularly with ventricular wall thickening.