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Arterial hypertension in children after kidney transplantation is an important risk factor for graft loss and cardiovascular morbidity and mortality.
Ambulatory blood pressure monitoring (ABPM) is the gold standard for diagnosing hypertension in children, but the logistical demands and associated discomfort pose significant challenges.
Central systolic blood pressure (cSBP) more strongly reflects vascular changes than peripheral blood pressure (BP). Oscillometric devices, such as Mobil-o-Graph are attractive alternatives that provide reliable results and have specific pediatric reference values.
The aim of the present study was to analyze the prevalence of arterial hypertension using ABPM and cSBP and left ventricular hypertrophy (LVH) in pediatric kidney transplant patients
This was a retrospective, observational, cross-sectional, study. Between October 2021 and June 2023 we performed ABPM and cSBP evaluation in 46 children and adolescents who had previously received kidney transplant .
All of them had a functioning graft with GFR higher than 30 mL/min/1.73 m2, and had been stable for at least 6 months prior to study enrollment.
We used SpaceLabs 90217 monitor (SpaceLabs Healthcare, Issaquah, WA) for all ABPM studies and Mobil-O-Graph (IEM: GmbH, Stollberg) for measurement of central blood pressure. Wall thickness and dimensions of the left ventricle were measured using M-mode.
Left Ventricular Hypertrophy (LVH) was defined as left ventricular mass indexed (LVMI) to height 2.7 ≥95th percentile for gender and age. We examined the association between various BP parameters measured and presence or absence of LVHI.
Patient characteristics are described in table 1.
Based on values ≥95th percentile for cSBP and ABPM measurements and the use of antihypertensive medications, we grouped patients as normotensive, hypertensive, or with controlled hypertension (Figure 1).
Regarding ABPM, the percentage of patients who had mean arterial pressure (MAP) ≥ 95th percentile in the different time periods was: 9% for 24-hour global MAP, 11% for diurnal and 13% for nocturnal .
Patients identified with hypertension based on ABPM exhibited an increased likelihood of abnormal cSBP results in the multivariate analysis, with adjustments made for height z score and sex (OR: 1.06; 95%CI: 1.007- 1.14, p=0.03). cSBP showed an AUC =0.72 (95% CI 0.57–0.87). The best cutoff was 110 mmHg with sensitivity of 0.75, and specificity of 0.65.
Dimensions of the left ventricle were evaluated in 42 children, LVH was found in 13 (30%). All of them were hypertensive, 4 have abnormal ABPM and 6 abnormal cSBP, the remaining hypertensive children with LVH had controlled hypertension.
Normotensive patients by ABMP and cBPS had lower LVMI than hypertensive patients (uncontrolled + controlled): 28 vs 36 g/m(2.7) (p =0,02).
Measurement of blood pressure by cSBP is an easy and simple method to be performed as part of the routine examination in the kidney transplantation clinic. Regular monitoring and trends over time might help identify changes in cardiovascular health and guide adjustments to medications.