A comparative ultrasonographic evaluation of intrarenal artery resistive index among hypertensive and normotensive adults in north-western Nigeria

Introduction: Hypertension is a sustained systolic blood pressure equal to or above 140 mmHg or diastolic blood pressure equal to or above 90 mmHg. The kidneys play a central role in the control of high blood pressure through the renin–angiotensin system. Thus, renovascular changes of myointimal hyperplasia in the intrarenal arteries may cause an increase in renal arterial impedance and eventually irreversible hypertensive nephropathy. The early detection of these renovascular changes using ultrasonography can provide opportunity for immediate intervention toward preventing or at least delaying the irreversible hypertensive nephropathy. Aims and Objectives: The objective of this study is to determine and compare intra-renal resistive index (RRI) in normotensive and hypertensive adults within the age range of 35–70 years at Aminu Kano Teaching Hospital, Kano, Nigeria. Materials and Methods: A prospective case–control study of intra-RRI using ultrasound in 150 hypertensive patients and 150 normotensive controls. The mean RRI of the interlobar arteries of both kidneys was measured and recorded. The data were analyzed with the aid of computer-based SPSS 16.0 software for windows. Results: The ages of the study participants ranged between 35 and 70 years. The age difference was not statistically significant (P = 0.88). The mean interlobar artery resistive index (RI) values were 0.59 ± 0.04 and 0.59 ± 0.03 on the right and left sides, respectively, in normotensive controls while those of hypertensive patients were 0.73 ± 0.03 and 0.73 ± 0.03 for the mean interlobar artery RI values on the right and left sides, respectively, and both were statistically significant. Conclusion: The intra-RRIs were lower in normotensive participants when compared with the hypertensive patients which were statistically significant. These showed that hypertension has significant effects on the kidneys, and with early detection and intervention, irreversible renal damage may be prevented.