Ambulatory blood pressure monitoring in heart failure and serum sodium levels

Aims: To determine whether there are differences in blood pressure profile on dynamic assessment by ambulatory blood pressure monitoring (ABPM) according to serum sodium levels in stable heart failure patients.

Methods: Data were collected from the Spanish National Registry on Ambulatory Blood Pressure Monitoring in Heart Failure (DICUMAP). Patients underwent ABPM by the oscillometric principle using a Spacelabs 90121 monitor. The sample was divided into three groups according to sodium levels and their clinical and laboratory data and echocardiographic findings were analyzed. Robust statistical methods were used to compare the groups in univariate and multivariate models.

Results: A total of 175 patients (44.57% male) were analyzed. We found a predominance of anomalous circadian blood pressure profiles in all three groups, with a significantly higher percentage of risers in the lowest serum sodium group (p=0.05). In addition, in this group there were significant differences in mean 24-hour systolic blood pressure (SBP) (24-h SBP, p=0.05) and in mean daytime SBP (dSBP, p=0.008), with significant differences in nocturnal fall in SBP (p=0.05) and in diastolic blood pressure (p=0.005). In multivariate analysis a significant relationship was found between sodium levels and 24-h SBP (OR 0.97, 95% CI 0.95-0.99, p=0.01) and dSBP (OR 0.96, 95% CI 0.94-0.99, p=0.004).

Conclusion: A relationship was found between lower sodium levels and lower systolic blood pressure, especially during waking hours, with a lower decline between daytime and night-time blood pressure.