Current Insights into Renal Resistive Index Significance in Kidney and Cardiovascular Disease

Abstract

Initially, renal resistive index (RRI) was investigated to improve diagnosis in kidney diseases, but failed to meet this goal. Recently many papers highlighted the prognostic significance of RRI in chronic kidney disease, in the estimation of revascularization success of renal artery stenoses or the evolution of the graft and recipients in renal transplantation. Moreover, RRI gained importance in prediction of acute kidney injury in critically ill patients. Along with RRI study in renal pathology have been revealed correlations of this index with parameters of systemic circulation. The theoretical and experimental premises of this connection were reconsidered, and studies for analyzing the link between RRI and arterial stiffness, central and peripheral pressure or left ventricular flow were conducted with this purpose. A high amount of data is currently indicating that RRI is influenced more by pulse pressure and vascular compliance than by renal vascular resistance – assuming that RRI reflects the complex interplay between systemic circulation and renal microcirculation and should be considered as a marker of systemic cardiovascular risk beyond its prognostic relevance for kidney disease. In this review we will go through clinical research that revealed the implications of RRI in renal and cardiovascular disease.

Understanding Doppler Renal Resistive Index: An Exploration of Clinical and Theoretical Determinants

“…However, a plethora of studies over the last decade have identify RRI as a useful prognostic indicator for a range of comorbidities in patients who are acutely unwell. RRI more accurately reflects the complex combined effects of systemic circulation and renal microcirculation and is now rightly understood to be a marker of systemic cardiovascular risk rather than an isolated prognostic indicator for renal recovery [30]. However, high RRI (≥ 0.7) compares favourably with conventional markers (albuminuria and low eGFR) as an early indicator of diabetic kidney disease, and as a potential marker for sub-clinical acute kidney injury (AKI) and post procedural AKI risk [7,[31][32][33][34][35][36].…”