Comparative sonographic evaluation of intra-renal resistive index among adult patients with essential hypertension and normotensives in a Nigerian tertiary institution

Abstract

The intra-renal resistive index is a Doppler parameter that is useful in predicting adult hypertensive patients who are likely to develop nephrosclerosis and to follow up hypertensive patients on reno-protective drugs to determine effects of drugs on renal function. This was a prospective cross-sectional comparative descriptive study conducted at the University of Benin Teaching Hospital (UBTH). It involved the use of Doppler ultrasound assessment of intra-renal resistive index in 50 hypertensive individuals and 50 “age-and-sex” matched normotensive controls. The data was analyzed using statistical package for social sciences(SPSS) version 20.0. Correlation tests were considered significant at p-value less than or equal to 0.05 at 95% confidence interval.The mean intra-renal resistive index in this study was 0.60 ± 0.05 with a range of 0.49 - 0.70 in the hypertensives and 0.57 ± 0.05 with a range of 0.47 - 0.70 for the normotensives. Among the hypertensive subjects a significant positive correlation was found between the intrarenal resistive index and the pulse pressure (r= 0.327, p= 0.018). The pulse pressure is also the only independent predictor of the intra-renal resistive index among hypertensive subjects. There was significantly higher intra-renal RI value among the hypertensive subjects compared to the normotensives. The intra-renal RI showed a positive correlation with the pulse pressure and it was only independent predictor of the resistive index.

Keywords: Resistivity index, resistive index, RI, intra-renal RI, hypertension