Renal resistive index in chronic kidney disease patients: Possible determinants and risk profile.

BACKGROUND: High ultrasound renal resistive index (RI) predicts poor cardiorenal outcomes in chronic kidney disease (CKD) and has recently emerged as a marker of nephroprotective drugs response. Thus, having a risk profile of CKD patients with abnormal RI may be relevant for the clinicians. METHODS: Consecutive patients referred to our non-dialysis CKD clinic from 01/01/2016 to 01/12/2016, were evaluated by clinical and ultrasound analysis. Inclusion criteria were age >18 years and presence of CKD defined as estimated glomerular filtration rate (eGFR)<60 mL/min/1.73m2 and/or proteinuria>0.150g/24h. Renal artery stenosis, solitary kidney, acute kidney injury were the main exclusion criteria. RI value was the mean of three measures in segmental arteries in each kidney. Univariate analysis was performed to evaluate associations between continuous RI and clinical variables. Multivariate linear regression analysis, based on stepwise method with an elimination criterion of p<0.10, was used to assess the independent correlates of RI as continuous variable. RESULTS: We studied 73 patients (69.9% men). Mean RI was 0.67±0.09. Frequencies of diabetes and cardiovascular disease (CVD) were 19.2% and 20.6% and median eGFR 54.1 [30.0-84.6] mL/min/1.73m2. From low (<0.65) to intermediate (0.65-0.70) to high (>0.70) RI categories, eGFR and haemoglobin levels were decreased while diabetes, cardiovascular disease (CVD), phosphate and smokers were higher. At univariate analysis, RI was significantly associated with age, presence of diabetes, CVD, serum phosphorus, eGFR, Urea and haemoglobin. Multi-adjusted stepwise regression analysis showed that lower eGFR levels (p<0.001), diabetes (p = 0.042), CVD (p = 0.009), smoking habit (p = 0.021) and higher serum phosphorus levels (p = 0.001) were associated with higher continuous RI. Serum phosphorus showed Area Under the Curves (AUC) values of 0.714 and 0.664 for discriminating RI cut-offs of 0.70 and 0.65. CONCLUSIONS: This analysis suggests that RI is higher in CKD patients with CVD, diabetes, smoking habit and higher serum phosphorus, regardless of eGFR. Further studies are needed to verify whether higher RI indicates more complex pathway of intrarenal damage, besides and beyond kidney function.

Successful Use of Aliskiren in a Case of IgA- Mesangial Glomerulonephritis Unresponsive to Conventional Therapies.

INTRODUCTION: The early suspension of Altitude trial in recent years has induced most nephrologists and cardiologists to abandon Aliskiren use. Consequently, the potential usefulness of the direct renin inhibition in IgA glomerulonephritis remained an under-investigated therapeutic option. CASE REPORT: We report the case of a 53 years old IgA GMN patient unresponsive to all conventional anti-angiotensin-2 agents, steroids and immunosuppressants, in which the administration of Aliskiren permitted to achieve and maintain a complete proteinuria remission in the absence of any adverse event. CONCLUSION: Aliskiren might represent a valid and safe therapeutic option in IgA GMN, although further investigations would be needed to confirm this conclusion.

Direct inhibition of plasmatic renin activity with aliskiren: a promising but under-investigated therapeutic option for non-diabetic glomerulonephritis.

Non-diabetic glomerulonephritis is a frequent cause of end-stage renal disease. The use of renin-angiotensin-aldosterone system blockers is a fundamental therapeutic approach. However, converting enzyme inhibitors (ACE-is) and angiotensin receptor blockers do not always achieve the desired target of proteinuria. The induction of the prorenin and renin up-regulation is a possible explanation. Aliskiren is the first drug acting as direct inhibitor of plasmatic renin activity, also able to interfere with the prorenin and renin profibrotic escape. We aimed at reviewing the literature for the assessment of potential efficacy and safety of aliskiren in the treatment of non-diabetic glomerulonephritis. The data on this topic are limited; however, we concluded for a possible usefulness of aliskiren. The renal safety profile appears potentially acceptable in non-diabetic patients although extreme carefulness, particularly with respect to long-term renal and cardiovascular tolerability, is recommended.

Can renal sonography be a reliable diagnostic tool in the assessment of chronic kidney disease?

OBJECTIVES: Kidney size has been found to be correlated with anthropometric features and kidney function. Therefore, we postulate that if the conventionally measured renal sonographic parameters (pole-to-pole length, width, and parenchymal thickness) are taken according to standardized rules and corrected for body height, their association with kidney function could be strengthened, thus helping validate renal sonographic information for a better assessment of chronic kidney disease (CKD) status. METHODS: This cross-sectional study included 72 stable adult patients with stage 1 to 4 CKD. Sonographic parameters were obtained from both kidneys and averaged, and the measurements obtained were further corrected for patients' body height. The glomerular filtration rate (GFR) was estimated by the Chronic Kidney Disease Epidemiology Collaboration equation. RESULTS: Parenchymal thickness and renal length showed the highest correlation level with the GFR. This significant correlation, however, was greatly ameliorated by the correction for patients' body height (r = 0.537; P < .001; r = 0.510; P < .001, respectively). Of note, the product of these two parameters corrected for body height showed the best degree of correlation with the GFR (r = 0.560; P < .001), as confirmed by analysis of variance after subdivision of the population into CKD stage groups according to the GFR. Receiver operating characteristic curve analysis for discrimination of a GFR of less than 60 mL/min indentified the combined parameter as the one with the highest area under the curve (0.78; 95% confidence interval, 0.66-0.89), followed renal length corrected for height (area under the curve, 0.77; 95% confidence interval, 0.66-0.88). CONCLUSIONS: Correction of renal sonographic parameters for body height strengthens the degree of the correlation of renal sonography with the GFR. The improved correlation with the GFR makes renal sonography a reliable tool for a more complete assessment of patients with CKD.