Kidney volume and ambulatory blood pressure in children

Abstract

Low nephron number has been shown to be a risk factor for hypertension (HTN) in adulthood. Kidney volume may serve as a surrogate marker for nephron mass. The relationship between kidney volume and ambulatory blood pressure (BP) in the pediatric population is not known. A retrospective chart review of children younger than 21 years who were evaluated for HTN was performed. Twenty-four-hour BP and ultrasonography data were obtained. Multiple regression was used to examine associations between BP and kidney volume. Of 84 children (mean age 13.87 years, 72.6% males), 54 had HTN. Systolic BP index during the awake, sleep, and 24-hour periods (all P≤.05) was found to be positively correlated with total kidney volume. Greater total kidney volume was found to be a positive predictor of 24-hour and sleep systolic index (P≤.05). It failed to serve as a predictor of HTN, pre-HTN, or white-coat HTN. Contrary to expectation, total kidney volume was positively associated with systolic BP indices. | INTRODUCTIONBy the 36th week of gestation, nephron development is usually complete in humans, with approximately 60% of development occurring during the third trimester.1 Upon completion of nephrogenesis, no new nephrons are formed. 1,2 Birth weight has been shown to be a strong determinant of nephron mass in the kidneys. 2,3 Previous literature has described a direct relationship between nephron number and birth weight. Manalich and colleagues 4 found that infants with low birth weight had a 20% reduction in nephron number compared with normal controls. 4 They also noted an inverse relationship between glomeruli number and glomerular volume, suggesting that low birth weight results in fewer, larger glomeruli. 4Reduced nephron endowment has been ascribed to be a risk factor for primary hypertension (HTN) and cardiovascular disease in adulthood as well as progressive renal disease. | MATERIAL AND METHODSChildren younger than 21 years followed by the pediatric nephrology division in a single tertiary center were examined in a retrospective chart review. Patients who were evaluated for HTN between the years of 2010 and 2014 were selected for review. Data were retrieved from 24-hour ambulatory BP monitoring (ABPM) and kidney ultrasounds that were previously performed as part of the patient's clinical care.A renal ultrasound was performed in all patients who were studied

Renal size and cardiovascular risk in prepubertal children

“…However, Gurusinghe et al . 18 showed that total kidney volume was positively associated with SBP indices in children below 21 years (n = 84) diagnosed with primary hypertension, contrary to which they were expecting since hypertensive patients are found to have fewer glomeruli than their normotensive counterparts 28 . They claimed that low birth weight may have a greater impact on BP with increasing age 29 .…”

Primary Pediatric Hypertension: Current Understanding and Emerging Concepts

“…Kidney volume has been used as a surrogate indicator for nephron number. However, kidney volume is positively, rather than negatively, correlated with SBP in children 4–20 years of age [24•]. Furthermore, decreased capillary sprouting increases vascular resistance, leading to increased BP.…”

Cyst-to-kidney volume ratio in the sonographic diagnosis of unilateral multicystic dysplastic kidney in children

“…The thickness (T) of the kidneys and the APD of the renal pelvis were measured at mid-transverse sonograms [13,15]. We used the ellipsoid formula to calculate the volumes of MCDKs and grade IV hydronephrotic kidneys: π/6×L×W×T in which π/6 was accepted as 0.523 [16,17]. For practical purposes and to reduce the burden of calculation, we used the simplified form of prolate ellipsoid formula to obtain the volumes of the renal pelvises as follows: π/6 x D x (APD)² [18].…”