Sonographic Evaluation of Renal Parameters in Individuals with Essential Hypertension and Correlation with Normotensives

Abstract

Background: Hypertension can secondarily involve the kidneys, and renal sonographic parameters can be used to indirectly assess renal function or status. Ultrasound is an inexpensive and safe modality for evaluating the kidneys. The purpose of this study was to sonographically assess renal parameters in patients with essential hypertension to determine the parameters that may indicate increased risk of renal damage. Materials and Methods: One hundred and fifty individuals (96 females and 54 males) with essential hypertension attending consultant outpatient clinic in University of Benin Teaching Hospital were evaluated. An equal number of nonhypertensive volunteers comprising of 80 females and 70 males were studied as controls. For individuals and controls, the renal length, width, anteroposterior diameters, renal parenchymal volume, cortical thickness, and echogenicity were assessed. Serum creatinine was also obtained. Statistical Package for the Social Sciences (SPSS version 17.0) was used in data analysis. Results: The mean renal parenchymal volume and cortical thickness were 99.1 ± 25.8 cm³ and 1.0 ± 0.2 cm on the right and 113.8 ± 35.8 cm³ and 1.0 ± 0.2 cm on the left for the hypertensive individuals. The values for the normotensives were 100.5 ± 19.8 cm³ and 1.2 ± 0.2 cm on the right and 118.7 ± 27.4 cm³ and 1.3 ± 0.2 cm on the left. The difference in cortical thickness between the two groups was statistically significant. No significant difference was noted between renal parenchymal volume of the right and left kidneys in the individuals and controls. The variation in cortical echogenicity between the hypertensives and controls was statistically significant; 74.0% and 75.3% of hypertensives and 28.0% and 26.0% of normotensives had increased cortical echogenicity on the right and left kidneys, respectively. The serum creatinine value was significantly higher in the hypertensive group. Conclusion: Cortical echogenicity grading was significantly higher among hypertensives than normotensives while renal parenchymal volume and cortical thickness were lower among hypertensives. In the hypertensives and normotensives, renal parenchymal volume, cortical thickness, and renal length were higher in males compared to the females and in the left kidney compared to the right. Hypertension seems to have more effect in the renal cortex than the medulla.

Keywords: Cortical thickness, essential hypertension, renal parenchyma, ultrasound