[Continuous ambulatory monitoring of blood pressure and the left ventricular mass index in children with kidney diseases].

INTRODUCTION: Numerous epidemiological studies have shown that blood pressure (BP) is positively related to cardiovascular morbidity and mortality. Although the relationship between BP and the incidence of morbid events is consistent and highly significant, it is difficult to predict the absolute risk. Several studies have shown that the organ damage associated with hypertension correlate to a greater degree with 24 h average BP than with clinic BP and the most of them evaluated left ventricular hypertrophy in these patients.

OBJECTIVE: To evaluate the correlation between left ventricular mass index (LVMi) and BP, BP variability, pulse pressure (PP), BP load and hyperbaric index (HBI).

DESIGN AND METHODS: Ambulatory blood pressure monitoring (ABPM) was performed in 30 children with renal disease aged 12.7 +/- 5.5 years. Ten of them had normal renal function, 3 had renal transplant and 17 of them had end-stage renal disease and were on chronic haemodialysis. All of the patients were submitted to an echocardiographic evaluation and LVMi was calculated according to Penn convention. Ambulatory blood pressure monitoring was performed during the 24 h period and average values of systolic and diastolic BP were evaluated. As an index of variability of BP values we used standard deviation (SD) of mean. Evaluation of average BP values has some disadvantages--it does not take into account the peaks of blood pressure and the values are lower if the circadian rhythm of BP is preserved--for this reason BP load and HBI were evaluated as well. BP load represented the percentage of BPs exceeding the upper limits of normal and HBI the integrated area under the ambulatory BP curve. For the upper limits of normal was used 95th percentile from the multicenter study of German authors.

RESULTS: There was no correlation between LVMi and evaluated parameters.

CONCLUSIONS: The response of myocardium to chronic increase of the afterload is highly individual, and probably the role of genetics in this is very important. Echocardiography (LVMi) could not be used with certainty for the evaluation of ventricular mass.