Association of E/E' and NT-proBNP with Renal Function in Patients with Essential Hypertension

Objectives: To evaluate the association of left ventricular (LV) diastolic function and N-terminal pro-brain natriuretic peptide (NT-proBNP) with renal function in essential hypertension. Methods: LV diastolic function was estimated by the ratio of early diastolic velocities (E) from transmitral inflow to early diastolic velocities (E') of tissue Doppler at mitral annulus (septal corner); NT-proBNP was measured in 207 hypertensive patients (mean age 56 +/- 14 years). The subjects were classified into 3 groups: E/E'<= 10 group (n = 48), 10<E/E'<= 15 group (n = 109) and E/E'>15 group (n = 50). The renal function was estimated by glomerular filtration rate (GFR) with Tc-99m-DTPA. GFR from 30 to 59 ml/min/1.73 m(2) was defined as Stage 3 chronic kidney disease (CKD). GFR was also estimated using the modified MDRD equation. Albuminuria was defined by urinary albumin/creatinine ratio (UACR). Results: GFR was lower and UACR was higher in E/E'>15 group than in 10<E/E' <= 15 group or E/E' <= 10 group (p<0.0001), GFR was significantly negative and UACR was positive correlated with E/E' and NT-proBNP (p<0.0001). In multivariate stepwise linear analysis, GFR had significant correlation with age (p = 0.001), gender (p = 0.003), E/E' (p = 0.03), lgNT-proBNP (p = 0.001) and lgUACR (p = 0.01), while eGFR had no significant correlation with E/E' or lgNT-proBNP. Multivariate logistic regression analysis, adjusted for potential confounding factors, showed that participants in E/E'>15 group were more likely to have Stage 3 CKD compared with those in E/E'<= 10 group with an adjusted odds ratio of 8.31 (p = 0.0036). Conclusions: LV diastolic function, assessed with E/E' and NT-proBNP is associated with renal function in essential hypertension.