Renal resistive index and cardiovascular organ damage in a large population of hypertensive patients

Abstract

We evaluated the relationship between renal resistive index (RRI) of the intrarenal vasculature and cardiovascular (CV) organ damage such as left ventricular hypertrophy (LVH), diastolic dysfunction and carotid atherosclerosis in a large sample of hypertensive patients. 566 hypertensive patients underwent echocardiography with conventional Doppler and Doppler tissue imaging (DTI), carotid and renal ultrasonography. In addition, lipids profile, creatinine in serum, and urinary albumin concentrations were determined. The patients were divided according to their RRI values in 2 groups: o70 and X70. Subjects with high RRI were older, had higher systolic and pulse pressure (PP) and more years of hypertension, compared to those with low RRI (Po0.0001). Patients with the higher RRI showed an increased left ventricular mass index (LVMI) and carotid intima-media thickness (IMT) with a higher prevalence of LVH, carotid plaques and microalbuminuria (Po0.001). There were differences in overall diastolic parameters, in particular when evaluated by DTI (Po0.001). A positive correlation was found between RRI and age, PP, carotid IMT, LVMI, SBP and a negative correlation was found with DTI diastolic parameters (Po0.001). Age, PP, carotid IMT and LVMI were independently related to RRI. While, RRI was independently related to IMT and IVRT. RRI, especially the higher values, are positively correlated with target organ damage in hypertensive patients, indicating that renal vascular resistance is related to morphologic and hemodynamic alteration of the CV system. The evaluation of RRI could predict the presence of early CV damage and provide an accurate estimate of overall risk.

Renal resistive index and low-grade inflammation in patients with essential hypertension

“…33,36 A relationship between RRI and IMT was also reported. 8,21,34,35 In our study, the correlation between RRI, RV/RRI and hsCRP persisted even after adjustment for age, IMT and PP, which are all related to systemic atherosclerosis and arterial stiffness. The high RRI and low RV/RRI values observed in our patients could mainly detect intrarenal tubulo-interstitial and arteriolar inflammatory damage associated with systemic low-grade inflammation, whilst 'extrarenal' RRI and RV/RRI determinants seem to have a minor role.…”

“…In fact, elevations in hsCRP have been associated with reduced arterial elasticity 27 and increased arterial stiffness measured by pulse wave velocity (PWV), 28,29 and the relationship between hsCRP and IMT as an early marker of atherosclerosis was shown. 30,31 Moreover, a strict dependence of RRI from arterial stiffness was demonstrated in experimental studies, 8,26 and an association was confirmed between RRI and PP, 21,[32][33][34][35] and between RRI and PWV. 33,36 A relationship between RRI and IMT was also reported.…”

Intra-renal hemodynamics and carotid intima-media thickness in the metabolic syndrome

“…Studies in subjects with kidney diseases showed an association between renal resistance indices and local renal impairment, demonstrating their ability to predict kidney diseases. Few studies investigated the association between intra-renal hemodynamic indices and carotid IMT exclusively in subjects with hypertension [9,27,31], with chronic kidney diseases [32] or kidney transplanted [33]. A major limitation of these studies, though, was their rather small sample sizes [9,27,32].…”

Impairment of skin blood flow during post-occlusive reactive hyperhemy assessed by laser Doppler flowmetry correlates with renal resistive index

“…Indeed, it has recently been suggested that RI might be a marker of the cardiovascular risk in the hypertensive. 14 We suggest that this could be accounted for by its relations with both the micro-and the macrocirculations.…”

“…The existence, in hypertensive patients, of a significant correlation between RI and impairments of target organs (urinary albumin/creatinine ratio, the index of left ventricular mass and intima media thickness 14,33 ) points to RI being a marker of cardiovascular risk. 33 Our results are consistent with this view by showing that RI is an integral compound index of both micro-and macrovascular impairments.…”