Ambulatory arterial stiffness index in children after kidney transplantation

Assessing masked hypertension and ambulatory arterial stiffness index in children congenital kidney malformations

BACKGROUND

Patients diagnosed with congenital kidney malformations are at an increased risk of developing hypertension, proteinuria, and progressing to chronic kidney disease (CKD). The present study aimed to determine the frequency of masked hypertension and ambulatory arterial stiffness index (AASI) in patients with congenital kidney malformations.

METHODS

The study included 174 patients with congenital kidney malformations (48 patients with unilateral renal agenesis (URA), 40 patients with ectopic kidney (EK), 36 patients with horseshoe kidney (HK), 31 patients with multicystic dysplastic kidney (MCDK), 19 patients with unilateral renal hypoplasia (URH), and 45 healthy controls.

RESULTS

The mean age was 12.9 ± 2.9 years, and the male-to-female ratio was 1.5. No significant differences were observed between the congenital kidney malformations groups concerning age, sex, follow-up period, proteinuria, or estimated glomerular filtration rate (eGFR) (P > 0.05). Nevertheless, the prevalence of masked hypertension exhibited a statistically significant increase in the congenital kidney malformations groups (except the URH group) compared to the control group (P < 0.05). The AASI was significantly greater in the congenital kidney malformations groups than in the control group (P < 0.05). The nighttime diastolic blood pressure (DBP), mean arterial pressure (MAP), and DBP index were significantly different between the congenital kidney malformations groups (P < 0.05). However, there were no significant differences in nondipping pattern, proteinuria, or masked hypertension between the congenital kidney malformations groups.

CONCLUSIONS

Patients with congenital kidney malformations should be periodically evaluated throughout life for BP. Based on the present findings, we strongly recommend ABPM for the diagnosis of masked hypertension and outcomes, including AASI score.

Follow-Up of Blood Pressure, Arterial Stiffness, and GFR in Pediatric Kidney Transplant Recipients

Pediatric renal transplant recipients (RTx) were studied for longitudinal changes in blood pressure (BP), arterial stiffness by pulse wave velocity (PWV), and graft function.

Patients and Methods: 52 RTx patients (22 males) were included; office BP (OBP) and 24 h BP monitoring (ABPM) as well as PWV were assessed together with glycemic and lipid parameters and glomerular filtration rate (GFR) at 2.4[1.0–4.7] (T₁) and 9.3[6.3–11.8] years (T₂) after transplantation (median [range]).

Results: Hypertension was present in 67 and 75% of patients at T₁ and T₂, respectively. Controlled hypertension was documented in 37 and 44% by OBP and 40 and 43% by ABPM. Nocturnal hypertension was present in 35 and 30% at T₁ and T₂; 24 and 32% of the patients had masked hypertension, while white coat hypertension was present in 16 and 21% at T₁ and T₂, respectively. Blood pressure by ABPM correlated significantly with GFR and PWV at T₂, while PWV also correlated significantly with T₂ cholesterol levels. Patients with uncontrolled hypertension by ABPM had a significant decrease in GFR, although not significant with OBP. Anemia and increased HOMAi were present in ~20% of patients at T₁ and T₂.

Conclusion: Pediatric RTx patients harbor risk factors that may affect their cardiovascular health. While we were unable to predict the evolution of renal function based on PWV and ABPM at T₁, these risk factors correlated closely with GFR at follow-up suggesting that control of hypertension may have an impact on the evolution of GFR.

Clinical value of ambulatory blood pressure in pediatric patients after renal transplantation

Hypertension is a highly prevalent co-morbidity in pediatric kidney transplant recipients. Undertreated hypertension is associated with cardiovascular complications and negatively impacts renal graft survival. Thus, the accurate measurement of blood pressure is of the utmost importance for the correct diagnosis and subsequent management of post-renal transplant hypertension. Data derived from the general population, and to a lesser extent from the pediatric population, indicates that ambulatory blood pressure monitoring (ABPM) is superior to blood pressure measurements taken in the clinical setting for the evaluation of true mean blood pressure, identification of patients requiring antihypertensive treatment, and in the prediction of cardiovascular outcome. This Educational Review will discuss the clinical value of ABPM in the identification of individual blood pressure phenotypes, i.e., normotension, new-onset hypertension, white-coat hypertension, masked hypertension, controlled blood pressure, and undertreated/uncontrolled hypertension in pediatric kidney transplant recipients. Finally, we examine the utility of performing repeated ABPM for treatment monitoring of post-renal transplant hypertension and on surrogate markers related to relevant clinical cardiovascular outcomes. Taken together, our review highlights the clinical value of the routine use of ABPM as a tool for identifying and monitoring hypertension in pediatric kidney transplant recipients.