To investigate whether salt sensitivity is associated with differences in left ventricular mass or geometry, salt sensitivity testing and Doppler echocardiography was performed in 30 essential hypertensive patients (7 women and 23 men) with mean age 43+/-9 years. Salt sensitivity was defined as a 10% increase or more in 24-h blood pressure (24hBP) when going from low to high dietary sodium intake based on a single test. Eight patients were characterized as salt sensitive and 22 as salt resistant. At baseline, there was no difference in casual blood pressure (156/103+/-17/9 vs 158/100+/-18/11 mmHg) or 24hBP (152/ 90+/-25/15 vs 159/89+/-19/8 mmHg), in duration of hypertension (5+/-4 vs 4+/-3 years), daily sodium excretion (144+/-68 vs 171+/-68 mmol), left ventricular mass (LVM) (212+/-45 vs 246+/-52 g) or left ventricular relative wall thickness (RWT) between the salt sensitive and salt resistant groups of patients. In the total study population, increased RWT was found in 17 patients, and increased LVM in 10 patients. In only 10 patients were both these variables normal. Left ventricular geometric pattern did not differ between the salt sensitive and salt resistant groups. LVM and RWT were significantly correlated with 24hBP (r = 0.57 and 0.51, respectively; both p < 0.01). Significant correlation was also found between LVM and casual blood pressure, blood volume, body surface area, serum creatinine and albuminuria (r = 0.53, 0.60, 0.54, 0.54 and 0.43, respectively; all p < 0.01). In multiple regression analysis, 24hBP and blood volume were identified as independent predictors of LVM (R = 0.51, p < 0.001).
Conclusions: increased RWT or LVM is common in both salt sensitive and salt resistant essential hypertensive patients. Salt sensitivity status based on a single test does not influence left ventricular hypertrophy or geometry. Twenty-four-hour blood pressure is related to increased RWT and LVM.