Blood pressure control and left ventricular mass in children with chronic kidney disease

Abstract

Background and objectives: Heart disease is a major cause of death in young adults with chronic kidney disease (CKD). Left ventricular hypertrophy (LVH) is common and is associated with hypertension. The aims of this study were to evaluate whether there is a relationship between LVH and BP in children with CKD and whether current targets for BP control are appropriate.

Design, setting, participants, & measurements: In this single-center cross-sectional study, 49 nonhypertensive children, (12.6 ± 3.0 years, mean GFR 26.1 ± 12.9 ml/min per 1.73 m²) underwent echocardiographic evaluation and clinic and 24-hour ambulatory BP monitoring. LVH was defined using age-specific reference intervals for left ventricular mass index (LVMI). Biochemical data and clinic BP for 18 months preceding study entry were also analyzed.

Results: The mean LVMI was 37.8 ± 9.1 g/m²·⁷, with 24 children (49%) exhibiting LVH. Clinic BP values were stable over the 18 months preceding echocardiography. Patients with LVH had consistently higher BP values than those without, although none were overtly hypertensive (> 95th percentile). Multiple linear regression demonstrated a strong relationship between systolic BP and LVMI. Clinic systolic BP showed a stronger relationship than ambulatory measures. Of the confounders evaluated, only elemental calcium intake yielded a consistent, positive relationship with LVMI.

Conclusions: LVMI was associated with systolic BP in the absence of overt hypertension, suggesting that current targets for BP control should be re-evaluated. The association of LVMI with elemental calcium intake questions the appropriateness of calcium-based phosphate binders in this population.

Figure 1.

(a) Relationship of clinic SBP z-score with indexed LVM in all patients. (b) Relationship of clinic SBP z-score with LVM for height-specific z-scores (20) in all patients.

Figure 2.

Clinic SBP z-scores in children with CKD stage 3 to 5 with and without LVH. LVH was defined using age-specific reference intervals for normal children (19). Interrupted lines at the 90th and 95th percentile denote the clinical definition of prehypertension and hypertension, respectively (15). Data are shown as mean ± SEM. (b) Clinic DBP z-scores in CKD stage 3 to 5 patients with and without LVH. LVH was defined using age-specific reference intervals for normal children (19). Interrupted lines at the 90th and 95th percentile denote the clinical definition of prehypertension and hypertension, respectively (15). Data are shown as mean ± SEM.