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

Abstract

In essential hypertension, increased renal resistive index (RRI) is associated to a reduction of renal function and microalbuminuria, and to renal tubulo-interstitial damage. A tubulo-interstitial inflammatory infiltration was found in experimental models of hypertension, and serum high-sensitive C-reactive protein (hsCRP) levels correlated with urinary markers of tubulointerstitial damage in humans. We studied the relationship between RRI and serum hsCRP in hypertensives with preserved renal function, without microalbuminuria. We investigated hypertensive patients without diabetes, renal failure, microalbuminuria or major inflammatory disease. Serum levels of hsCRP were assayed. RRI was calculated by intrarenal Doppler ultrasound and considered pathologic when X0.70 or 495% of upper confidence limit expected for age decade. The renal volume-to-resistive index ratio (RV/RRI) was also calculated. We evaluated 85 patients (57 ± 14 years, 61 males). Patients with pathologic RRI (n ¼ 21) were older and had significantly higher hsCRP levels (4.70 ± 2.30 vs 2.93 ± 2.09 mg l À1 , Po0.01) compared with patients with normal RRI, as well as patients with decreased RV/RRI (n ¼ 43). HsCRP was directly related with RRI (r ¼ 0.41, Po0.001) and inversely with RV/RRI (r ¼ À0.35, Po0.001). HsCRP proved to be a significant predictor of both pathologic RRI and decreased RV/RRI, even after adjustment. In essential hypertension low-grade inflammation is associated with tubulo-interstitial damage evaluated by Doppler ultrasonography.

The evaluation of renal hemodynamics changes in Familial Mediterranean fever with color Doppler sonography

“…In HT patients, involvement of glomerular vascular structures is characterized by albumin excretion. 27,28 In their study, € Ozelsancak et al 27 reported higher levels of RRI in non-treated hypertensive patients compared to the control group. Again in the same study, a positive correlation between RRI and urinary albumin excretion, and a negative correlation between RRI and creatinine clearance was reported.…”

“…It has a critical role in evaluating blood flow in renal artery and vein pathology (such as stenosis, thrombosis, and trauma), acute and chronic renal inflammation, and parenchymal pathology. 8,19 RRIbased studies on patients with systemic lupus erythematosus (SLE), 20,21 scleroderma patients, 22,23 diabetic patients, [24][25][26] and hypertensive patients 27,28 are available in the literature. SLE is another autoimmune connective tissue disease that may cause kidney involvement.…”

Relationship between Aortic Arch Calcification, Detected by Chest X-Ray, and Renal Resistive Index in Patients with Hypertension

“…According to the study by Berni et al [10], the proportion of patients having RRI ≥0.70 was found to be about 25%. <precision/absolute error was kept at 5% and type 1 error was kept at 5%.…”

Resistive intrarenal index: myth or reality?

“…Increased intrarenal RI is considered a marker of intrarenal arterial stiffness and is associated with the worsening of renal function and tubulointerstitial damage related to the inflammatory status of the essential hypertension: in humans, high-sensitivity C-reactive protein (hs-CRP) serum levels correlate with urinary markers of tubulointerstitial damage, and in hypertensive patients, the hs-CRP value directly correlates with the RI. 21 The most common cause of renovascular hypertension is the renal artery stenosis (RAS) owing to atherosclerotic disease. In these patients, renal intraparenchymal RI has been proven to be higher than in the cases of RAS induced by Takayasu's arteritis or fibromuscular dysplasia, because, in atherosclerotic patients, arteriosclerosis, intrarenal arteriolosclerosis and glomerular sclerosis are associated with an increase in vascular stiffness, a reduction in arterial compliance and inward remodelling of the RA.…”