P4.17 ACUTE DIETARY SODIUM CHANGES IS A PHYSIOLOGICAL DETERMINANT OF AORTIC STIFFNESS

Abstract

Objective: Aortic stiffness evaluation is recommended in standard care as hypertension target organ damage. The main determinants of aortic stiffness are age and blood pressure. We aimed to evaluate the impact of short-term extracellular volume changes induced by dietetic and pharmacological interventions on aortic stiffness. Methods: 74 healthy male subjects, age (median [IQR]) 23,9 [5,7] years, non-smokers, were assigned to a low sodium/high potassium diet during seven days, followed by a high sodium/low potassium diet for 14 days, the last seven with concomitant administration of amiloride. Carotid-femoral pulse wave velocity (PWV) (SphygmoCor®) was measured at baseline, 7th, 15th and 21st days. Results: PWV was stable during the low sodium/high potassium diet, significantly decreased during the high sodium/low potassium diet (−0,4 m/s, CI 95% −0,7 to −0.2, p<0.001) (day 7 to 15), and came back to baseline after the concomitant administration of amiloride (day 15 to day 21). In a mixed model analysis, mean daytime blood pressure (MBP), age and visit day 15 were independent determinants of changes in PWV. For each increase of 10 mmHg on MBP, PWV increased by 0,3 m/s (CI 95% 0,1 to 0,5, p=0,006), for each increase of 10 years of age, PWV increased by 0,4 m/s (CI 95% 0,1 to 0,7, p=0,01), and at visit 15 (high salt diet), PWV decreased by 0.3 m/s (CI 95 %, −0,52 to −0,12, p=0,002). Conclusions: Short-time increase in extracellular volume is associated with a signification decrease in aortic stiffness in a blood pressure independent manner.