Effects of a Low-Salt and High-Potassium Diet on Arterial Stiffness and Left Ventricular Function in Indigenous Papuans

Abstract

Background A sodium-restricted diet represents a potential non-pharmacological strategy for improving blood pressure, arterial stiffness, and left ventricular (LV) diastolic function. We investigated age-related differences in LV structure and function and the relationship between LV function and central hemodynamics in an indigenous Papuan population, who maintain a traditional lifestyle, including a low-salt and high-potassium diet. Methods and Results We measured LV dimensions, transmitral blood flow, and mitral annular tissue velocities through echocardiography and Doppler imaging. Blood pressure and brachial-ankle pulse wave velocity were measured using an automatic device (Omron). Central blood pressure and wave reflection parameters were estimated via oscillometry (Mobil-O-Graph, using European calibrations). A total of 82 native Papuans (median age, 42 years; 38 women; no blood pressure treatment) were enrolled. Age-related difference in brachial systolic pressure was modest but significant, and brachial-ankle pulse wave velocity significantly increased with age; however, LV mass index remained unchanged. LV ejection fraction and global longitudinal strain were preserved; mitral A-wave velocity and average E/e´ increased; and e´ and E/A decreased with age. Brachial-ankle pulse wave velocity and spot urine Na/K were positively and independently correlated with E/e´. Age and heart rate were inversely associated with E/A. In conclusion, LV systolic function was preserved; however, LV diastolic function decreased with age in Papuans. Moreover, age-related arterial stiffening, but not wave reflections, was inversely related to LV diastolic function. Conclusions Our results suggest that arterial and LV stiffness may not be altered by sodium restriction. Longitudinal studies are warranted to elucidate the effects of diet on arterial and LV function.

Keywords: aging; arterial stiffness; left ventricular function; potassium; salt intake.

Figure 1

Correlations between brachial‐ankle pulse wave velocity and indices of left ventricular diastolic function. Correlation of baPWV with average e´ (A), E/e´ (B), mitral A‐wave velocity (C), and E/A (D). A indicates late diastolic mitral inflow; baPWV, brachial‐ankle pulse wave velocity; E, early diastolic mitral inflow; and e´, mitral annular early diastolic velocity.