In essential hypertension, a change in the renal resistive index is associated with a change in the ratio of 24-hour diastolic to systolic blood pressure

Abstract

An increase in the renal resistive index (RRI) in patients with essential hypertension (EH) predicts deterioration in renal function. In patients with EH, changes in hemodynamic parameters significantly affect the RRI. This study aimed to define changes in Ambulatory Blood Pressure Monitoring (ABPM) parameters that are significantly associated with a change in RRI in patients with EH. We evaluated ABPM and the RRI in 96 patients with EH without organ extrarenal changes at baseline and after two years of follow-up. The relationships between changes in ABPM parameters and the RRI over the period were evaluated. After two years of follow-up, the increase in RRI was consequential. Simultaneously, 24-h systolic blood pressure increased significantly and 24-h diastolic blood pressure decreased. In the whole group and in the group with calculated cystatin C clearance (eGFRcyst) ≥90 ml/min/1.73 m2, the change in RRI significantly negatively correlated with the change in the ratio of 24-h diastolic to systolic blood pressure (D/S ratio), but also with the change in 24-h pulse blood pressure. However, in patients with eGFRcyst˂90 ml/min/1.73 m2, only the change in the 24-h D/S ratio significantly correlated with the change in RRI. Based on the backward stepwise regression analysis, the change in RRI was significantly dependent only on the change in 24-h D/S ratio and not on the change in 24-h pulse pressure. A change in the ratio of diastolic to systolic pressure better reflects a change in RRI than a change in pulse pressure.

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

“…RRI assess renal microcirculation in response to several pathologies [89]. In addition, various hemodynamic renal and extrarenal factors influence RRI quantification [89].…”

“…RRI assess renal microcirculation in response to several pathologies [89]. In addition, various hemodynamic renal and extrarenal factors influence RRI quantification [89]. Among renal factors, the most important are capillary wedge pressure, interstitial and venous pressure, while arterial vascular compliance, cardiac function, and systolic and diastolic blood pressure have significant extrarenal value [89].…”

“…In addition, various hemodynamic renal and extrarenal factors influence RRI quantification [89]. Among renal factors, the most important are capillary wedge pressure, interstitial and venous pressure, while arterial vascular compliance, cardiac function, and systolic and diastolic blood pressure have significant extrarenal value [89]. Moreover, heart rate variability influences RRI values independently from other hemodynamic parameters [28].…”

“…Accordingly, high systemic arterial stiffness and pulse pressure are associated with increased RRI, even in physiological conditions, such as aging [90]. Mediated by increased blood pulsatility in a renal vascular bed with low impedance, pulse wave velocity or central pulse pressure, markers of aortic stiffness and atherosclerosis, have strong correlations with RRI, independent of intrinsic renal function [28,[89][90][91]. Moreover, Calabia et al identified a value of RRI more than 0.69 that correlates with increased arterial stiffness and atherosclerotic cardiovascular events [28].…”

“…Moreover, RRI prove its efficacy in early diagnosis and prognostic of renal complications in arterial hypertension [90]. Thus, a high RRI is associated with a faster renal function decrease, even when GFR is still normal [89]. In untreated hypertensive patients, RRI associates with albuminuria; a RRI greater than 0.7 predicts urinary protein excretion [90].…”