Stricter Blood Pressure Control Is Associated With Lower Left Ventricular Mass in Children After Kidney Transplantation: A Longitudinal Analysis of the 4C-T Study

Abstract

Background: We assessed the effect of blood pressure (BP) control on left ventricular mass index (LVMI) and left ventricular hypertrophy (LVH).

Methods: Ninety-six patients (64 males) ≥9 months post-kidney transplantation from the 4C-T (Cardiovascular Comorbidity in Children with Chronic Kidney Disease and Transplantation) study were analyzed longitudinally (mean follow-up, 2.6±1.3 years). Cumulative systolic blood pressure (SBP)/diastolic BP exposure was calculated as a time-averaged area under the curve and categorized: ≤50th, 50th to ≤75th, 75th to ≤90th, and >90th percentile (pct). We performed adjusted linear and logistic mixed models for LVMI and LVH, respectively.

Results: At baseline, LVMI was 49.7±12.7g/m^2.16 with 64% (n=61) kidney transplantation recipients displaying LVH. Compared with patients with cumulative SBP exposure >90th pct, patients with cumulative SBP of 50th to ≤75th showed a significant LVMI reduction of -5.24g/m^2.16 (P=0.007). A similar tendency was seen for cumulative SBP≤50th (β=-3.70 g/m^2.16; P=0.067), but patients with cumulative SBP of 75th to ≤90th pct showed no reduction. A post hoc analysis in patients with cumulative SBP≤75th revealed that median SBP exposure was at 57.5th pct. For cumulative diastolic BP, a significant LVMI reduction was seen in all 3 categories ≤90th pct compared with patients >90th pct. Patients with cumulative SBP of ≤50th or 50th to ≤75th pct showed 79% or 83% lower odds of developing LVH, respectively. Patients with cumulative diastolic BP ≤50th showed a tendency of 82% lower odds for LVH (95% CI, 0.03-1.07).

Conclusions: Stricter BP control led to regression of LVMI and LVH. Our data suggest a BP target below the 60th pct, which needs to be substantiated in a randomized controlled trial.

Keywords: cardiovascular disease; hypertension; hypertrophy, left ventricular; pediatric nephrology; prospective study.

Figure.

Blood pressure (BP) exposure and left ventricular structure. A, Proportion of patients exposed to the 4 different cumulative BP categories differentiated by the presence or absence of left ventricular hypertrophy (LVH). The data presented refers to the first follow-up visit (n=96, 1.1 ± 0.4 years after baseline) and is presented for systolic BP (SBP) and diastolic BP (DBP) separately. B, Simulation of changes in left ventricular mass index (LVMI) according to the categories of either cumulative SBP or DBP exposure. The LVMI at baseline was set as 49 g/m^2.16. The LVMI after a cumulative exposure of either SBP or DBP at the follow-up visit was calculated based on the respective linear mixed model of LVMI (Tables 2 and 3). The other covariates were held fixed according to mean baseline values: sex=male, time since baseline=2 y, age=15 y, body mass index z-score=0, estimated glomerular filtration rate=65 mL/min/1.73 m². The red line at 45 g/m^2.16 indicates the cutoff value, above which patients are considered to suffer from LVH. pct indicates percentile.