Born with a solitary kidney: at risk of hypertension

Abstract

Background Subjects with a congenital solitary kidney (CSK) are believed to be at risk of hypertension due to their low number of nephrons. However, as CSK is a congenital abnormality of the kidney or urinary tract (CAKUT), subtle dysplastic changes contributing to hypertension cannot be excluded. Methods We retrospectively compared office blood pressure (OBP) and ambulatory blood pressure monitoring (ABPM) between two groups of children with CAKUT, aged 6-18 years: Group A with a CSK and Group B with two kidneys. All had normal renal parenchyma on scintigraphy and normal renal function. OBP and mean systolic and diastolic 24-h, daytime and nighttime ambulatory BP records were analyzed. The distribution of OBP and APBM as continuous values and the prevalence of hypertension (ambulatory/severe ambulatory or masked hypertension) in the two groups were compared. Results There were 81 patients in Group A and 45 in Group B. Median OBP standard deviation scores were normal in both groups, without significant differences. Median ABPM standard deviation scores, although normal, were significantly higher in Group A and the prevalence of hypertension was higher (ambulatory/severe ambulatory or masked) (33.3 vs. 13.3%, p = 0.019), mainly because of the greater occurrence of masked hypertension. Conclusions Our data show that a CSK per se can be associated with an increased risk of hypertension from the pediatric age. Therefore, ABPM, which has proved valuable in the screening of hypertension, is warranted in children with a CSK, even if laboratory and imaging assessment is otherwise normal.

Physiology and Pathophysiology of Compensatory Adaptations of a Solitary Functioning Kidney

“…Similarly, La Scola et al (2016) observed that in a cohort of 146 children with a congenital SFK, only 5% of patients had hypertension at a mean age of 12 years and only 4% presented with proteinuria at a mean age of 6 years. However, a more recent study by La Scola et al (2020) found that 33% of SFK patients were hypertensive. This was based on ambulatory blood pressure measurement, which did show many cases of masked hypertension, similar to the KIMONO study ( Westland et al, 2014 ; La Scola et al, 2020 ).…”

“…However, a more recent study by La Scola et al (2020) found that 33% of SFK patients were hypertensive. This was based on ambulatory blood pressure measurement, which did show many cases of masked hypertension, similar to the KIMONO study ( Westland et al, 2014 ; La Scola et al, 2020 ). The inconsistencies in cardiovascular and renal outcomes observed between studies may therefore reflect differences in study parameters such as inclusion criteria, selection bias, age of follow-up, and methods used to determine blood pressure, GFR and proteinuria.…”

Risk stratification for children with a solitary functioning kidney

“…Patient characteristics such as sex and ethnicity could be involved. Most studies showed no association between sex and risk for kidney injury in SFK patients [4,6,[8][9][10][11][12]. One notable exception is the study by Alfandary et al in which male adolescents with SFK had a threefold higher risk of kidney injury compared to female patients [11].…”

Cardiovascular risk assessment in children and adolescents with congenital solitary kidneys

“…[1][2][3] Patients with CSK maintained better GFR levels by developing better adaptation mechanisms 5 ; however, HT risk was higher or similar to those with ASK in different studies. 2,5,6 The risk of ambulatory or masked HT (AHT and MHT, respectively) is increased in cases with CSK (4). Arterial stiffness, which shows subclinical end-organ damage, is increased in cases with AHT and MHT, and may lead to increased central BP (cBP).…”