Assessment of salt sensitivity in essential hypertension by 24-h ambulatory blood pressure monitoring

• Published in: American journal of hypertension Vol. 8; no. 10 Pt 1; p. 970
• Main Authors: de la Sierra, A, Lluch, M M, Coca, A, Aguilera, M T, Sánchez, M, Sierra, C, Urbano-Márquez, A
• Format: Journal Article
• Language: English
• Published: United States 01-10-1995
• Subjects: Adult; Aged; Blood Pressure - drug effects; Blood Pressure Monitoring, Ambulatory; Circadian Rhythm; Diet, Sodium-Restricted; Drug Resistance; Female; Humans; Hypertension - physiopathology; Male; Middle Aged; Sodium Chloride - pharmacology
• ISSN: 0895-7061
• DOI: 10.1016/0895-7061(95)00225-1

We used ambulatory blood pressure monitoring (ABPM) in the assessment of salt sensitivity in 40 essential hypertensive patients, comparing 24-h mean blood pressure during 7 days of low salt (20 mmol NaCl/day) and high salt (260 mmol NaCl/day) intake. Salt sensitivity was diagnosed in 18 essential hypertensive patients (45%), each of them showing a significant increase in mean blood pressure (P < .05) from low to high salt diet. Salt-sensitive patients exhibited a high-salt-dependent increase in all blood pressure parameters including 24-h systolic, mean, diastolic blood pressure, blood pressure load, area under the curve, and awake and asleep blood pressure values. These patients exhibited a nondipper profile on both low-salt and high-salt diets. Salt-resistant patients (55%) showed a decrease in awake, and an increase in asleep blood pressure values after high salt intake, thus tending to flatten the circadian blood pressure profile. We conclude that ABPM is a useful method to assess salt sensitivity. In salt-resistant patients high salt intake induces a significant increase in asleep blood pressure with no significant changes in 24-h blood pressure, promoting a flattened blood pressure curve and tending to transform a dipper into a nondipper profile, which could have important implications in end-organ damage.