Renal Resistive Index Research Articles

Gross morphological and ultrasonographic dimensions of normal feline kidney with reference to resistive index

Ultrasonography with color Doppler is the most quantitative analysis method for intra-renal parameters. There is a wide variation between authors in the measurement site and referencing the inter-lobar resistivity index (RI) in felines. Our objective is to morphometrically and ultrasonographically investigate the normal renal dimensions and vasculatures and draw up a normal reference value for the renal inter-lobar artery resistivity index (RI) using a Pulsed wave-Doppler ultrasonography. A total of twelve adult domestic cats were sedated and treated according to IACUC regulation guidelines to be examined using Doppler ultrasound. The same cats were used for morphometric investigation and divided into three groups regarding the used technique. The size difference between the right and left kidneys is slight, measuring 17 g (weight), 3.65 ± 0.06 cm (length), 2.54 ± 0.08 cm (width), and 2.21 ± 0.03 cm (thickness) for the right kidney, and about 15 g, 3.42 ± 0.06 cm, 2.32 ± 0.05 cm, and 2.13 ± 0.03 cm for the left one, respectively. There are three patterns of renal arteries’ point of origin. The mean RI values of both kidneys were 0.57 ± 0.08 (0.50–0.67) in the right kidney and 0.60 ± 0.08 (0.51–0.69) in the left kidney. The gross examination and ultrasonography measurements did not have a statistically different effect on the actual renal dimensions. Moreover, 0.69 is considered the standard resistivity index (RI) threshold of the feline inter-lobar artery with no correlation to the animal’s body weight.

Using Doppler duplex ultrasound to determine hemodynamic alterations in renal vasculature: Crucial pathophysiological event preceding renal dysfunction in decompensated cirrhosis

BackgroundRenal dysfunction is a watershed event in cirrhosis, often preceded by renal vasoconstriction. However, our reliability on elevated serum creatinine often delays interventions. Measurement of Renal Resistive Index (RI) and Renal Venous Stasis Index (RVSI) by Doppler ultrasound offers insight into renal vasoconstriction. MethodsFifty participants with decompensated cirrhosis with ascites and normal serum creatinine underwent renal Doppler ultrasound for the measurement of RI and RVSI. All patients were compliant with a salt-restricted diet. Individuals aged <18 years, hepatocellular carcinoma, non-cirrhosis-related ascites, pre-existing renal disease, obstructive uropathy, or history of nephrotoxic medication use were excluded. Statistical analyses, including Pearson correlation, regression analysis, and Chi-square/Fisher’s exact tests, were performed to assess the statistical significance between RI, RVSI, and renal parameters. Additionally, the association of RI with the model for end-stage liver disease sodium (MELD-Na) and Child-Turcotte-Pugh (CTP) scores was also assessed. ResultsMajority were males (88%), average CTP score was 11.7, mean MELD-Na score was 20.92, and mean serum creatinine was 1.05 mg/dL. Renal parameters had varying RI values among renal arteries, with the main right and left arteries at 0.615 [standard deviation (SD): 0.089] and 0.638 (SD: 0.083), respectively. RI and RVSI are significantly correlated with serum creatinine. Further, significant correlation between, RI, RVSI values noted with MELD-Na score even when serum creatinine values are normal. ConclusionStrong correlations between serum creatinine, RI, and MELD-Na scores hints at predictive clinical potential. Future research with larger cohorts and extended follow-up is required to gauge clinical utility and its impact on outcomes.

Association of mid-regional pro-adrenomedullin with office and 24-h ambulatory blood pressure in a Swiss general population sample.

Adrenomedullin (ADM) is a potent vasodilator. The association between plasma ADM levels and blood pressure (BP) remains unclear. We assessed the association between mid-regional-pro-ADM (MR-proADM) and BP in a multicenter population- and family-based cohort. We used data from the Swiss Kidney Project on Genes in Hypertension (SKIPOGH). We included participants present at both baseline and 3-year follow-up (N = 843). We examined the association of baseline MR-proADM with baseline office and 24 h ambulatory BP as well as the 3-year change in office BP. In secondary analyses, we studied the association between baseline MR-proADM and 3-year changes in pulse wave velocity (PWV), renal resistive index (RRI) and augmentation index (AI). Mixed-effects linear regression models were used. In cross-sectional analyses, MR-proADM was negatively associated with office, 24-h and daytime diastolic BP (DBP). MR-proADM was positively associated with nighttime systolic BP (SBP). In longitudinal analyses, baseline MR-proADM was associated with an increase in office SBP and pulse pressure (PP) over 3 years [β (95% CI): 8.2 (0.4, 15.9) and β (95% CI): 6.4 (0.3, 12.4), respectively] but not with changes in PWV, RRI and AI. The cross-sectional negative association of MR-proADM with DBP is in line with known vasodilatory properties of ADM. The positive association between MR-proADM and nighttime SBP at baseline may reflect endothelial dysfunction believed to be part of the pathogenesis of nocturnal hypertension. The association of higher baseline MR-proADM levels with increased SBP and PP at 3-year follow-up suggests that ADM levels could be a marker of cardiovascular risk.

PASS: A scoring system to evaluate persistent kidney injury in critically ill ICU adult patients

Background We evaluated if the course of recovery from sepsis-induced acute kidney injury (AKI) can be predicted using variables collected at admission. Methods A total of 63 patients admitted for sepsis-induced AKI in our Mangalore ICU were evaluated and baseline demographic and clinical/laboratory parameters, including serum creatinine (SCr), base excess (BE), Plethysmographic Variability Index (PVI), Caval Index, R wave variability index (RVI), mean arterial pressure (MAP) and renal resistivity index (RI) using renal doppler and need for inotropes were assessed on admission. Patients were managed as per standard protocol. After six hours of fluid resuscitation, patients were classified as volume responders or non-responders. Re-assessment was done at 24 hours and 72 hours after admission. Primary outcome was persistent AKI after 72 hours. Secondary outcome was initiation of dialysis or death within 15 days of admission. Results A total of 34 subjects recovered from AKI, of whom 32 patients were volume responders and 31 were non-responders. Response to fluid, MAP at admission and six hours, BE at admission, inotrope requirement, and PVI at admission did not correlate with recovery. Multiple logistic regression showed that SCr &lt; 2.36 mg%, RVI &gt; 14.45 and RI &lt; 0.8 on admission correlated with recovery and they were evaluated further to model AKI recovery and develop PASS. PASS score = (SCr points × 5.4) + (RVI points × 4.0) + (RI points × 6.2). One point each was allotted if SCr was &lt; 2.36, RVI was &gt; 14.45 and RI was &lt;0.8, and 0 otherwise. A score &gt; 7.8 predicted recovery with a sensitivity of 79.4%, specificity of 72.4%, PPV 81.8%, NPV 76.7% and AuROC of 0.85. Conclusions The PASS score can be used to identify salvageable cases of sepsis-AKI, guiding fluid resuscitation and aiding early referral from rural to tertiary care centers for better management.

Role of endogenous GLP-1 on arterial stiffness and renal haemodynamics following bariatric surgery.

Cardiovascular trials have revealed the positive impact of GLP-1 receptor agonists (GLP-1 RAs) on cardiovascular outcomes in type 2 diabetes (T2D). However, the specific effects of endogenous GLP-1 on arterial stiffness and renal function remain understudied. This study aimed to explore the influence of endogenous GLP-1 response post-bariatric surgery on arterial stiffness and renal haemodynamic. Thirty individuals with morbid obesity and without T2D, scheduled for Roux-en-Y Gastric Bypass (RYGB), were included. Clinical parameters, 3-hour oral glucose tolerance test (OGTT) with serial sampling for glycaemia, GLP-1 and insulin, carotid-femoral pulse wave velocity (cf-PWV), carotid distensibility coefficient (carotid-DC) and renal resistive index (RRI) measurements were conducted pre-surgery and 1-year post-surgery. Participants were categorized into high-response and low-response groups based on their post-surgery increase in GLP-1 (median increase of 104% and 1%, respectively, pre- vs. post-surgery). Post-surgery, high-response group demonstrated a greater reduction in cf-PWV (p = .033) and a greater increase (p = .043) in carotid DC compared to low-response group. These enhancements were observed independently of weight loss or blood pressure changes. High-response group exhibited a reduction in RRI (p = .034), although this association was influenced by improvement in pulse pressure. Finally, a multivariate stepwise regression analysis indicated that the percentage increase of GLP1, Δ-GLP1(AUC)%, was the best predictor of percentage decrease in cf-PWV (p = .014). Elevated endogenous GLP-1 response following RYGB was associated with improved arterial stiffness and renal resistances, suggesting potential cardio-renal benefits. The findings underscore the potential role of endogenous GLP-1 in influencing vascular and renal haemodynamics independent of traditional weight loss.

Comprehensive evaluation of fetal renal ultrasound parameters for fetal growth restriction

ObjectiveThis study aims to investigate variances in renal ultrasound parameters between fetuses experiencing fetal growth restriction (FGR) and those with normal intrauterine development, with the intent to offer actionable insights for clinical management. MethodForty-five pregnant women diagnosed with FGR between 28 and 36 weeks of gestation, who underwent examination at Wenzhou People's Hospital from September 2021 to June 2023, constituted the FGR group. Concurrently, 65 pregnant women with normal intrauterine development at matching gestational weeks formed the control group. Renal ultrasound parameters, encompassing renal artery peak systolic velocity (PSV), end diastolic velocity (EDV), time averaged maximum velocity (TAMX), resistive indices (S/D, PI, RI), ratios of renal volume to gestational age (RV/WEEK) and estimated fetal weight (RV/EFW), vascular indices (VI, FI, VFI), were compared between the two groups. All parameters represented the mean values of bilateral kidneys. ResultIn the FGR group, fetal renal artery PSV (37.71 ± 9.93 cm/s), EDV (6.19 ± 1.50 cm/s), TAMX (15.10 ± 3.83 cm/s), RV/WEEK (0.45 ± 0.12), RV/EFW (7.53 ± 3.24), VI (22.19 ± 15.00), and VFI (5.53 ± 3.63) were significantly lower compared to the control group (PSV: 47.11 ± 11.24 cm/s, EDV: 7.13 ± 2.00 cm/s, TAMX: 17.85 ± 3.85 cm/s, RV/WEEK: 0.66 ± 0.19, RV/EFW:9.20 ± 3.17, VI: 28.67 ± 14.72, VFI: 7.40 ± 3.68). Conversely, fetal renal artery resistive indices (S/D: 9.09 ± 2.58, PI: 2.71 ± 0.56, RI: 0.92 ± 0.04) in the FGR group were notably higher than those in the control group (S/D: 6.22 ± 1.93, PI: 2.20 ± 0.73, RI: 0.87 ± 0.04), with statistical significance (P < 0.05). No significant difference was found in renal FI between the FGR group (26.78 ± 6.59) and the control group (26.89 ± 5.82) (P > 0.05). Receiver operating characteristic (ROC) curve analysis revealed higher diagnostic efficacy for RV/WEEK and RI among individual indicators, while combined parameter application yielded the highest diagnostic efficiency. ConclusionUtilizing a comprehensive evaluation of fetal kidney ultrasound parameters with multiple indices facilitates early screening and diagnosis of FGR fetuses, thereby aiding clinical decision-making and enhancing newborn birth outcomes.

Application value of ultrasonic contrast imaging and ultrasonic parameters in post-transplant renal surgery.

Utilize VUEBOX quantitative analysis software to perform quantitative analysis dynamic ultrasound contrast images of post-transplant renal patients were assessed quantitatively five parameters of ultrasonic contrast and two-dimensional ultrasound are examined to explore their six value in Diagnosing Renal Graft Dysfunction. A retrospective analysis was conducted on 73 post-transplant renal patients who underwent ultrasound contrast examinations at Yiyang Central Hospital from July 2022 to December 2023, They were diagnosed clinically and pathologically. Based on pathological and clinical diagnostic results, the patients were divided into three groups: 47 cases in the stable renal function group, 18 cases in the acute rejection (AR) group, and 8 cases in the delayed graft function (DGF) group. All patients underwent routine ultrasound and ultrasound contrast examinations post-transplantation. By comprehensively assessing renal function test results, clinical course, and pathological findings, differences in ultrasonic contrast quantitative parameters were analyzed. Additionally, ROC curves were constructed to evaluate the diagnostic efficacy of ultrasound contrast in discriminating between transplant renal rejection reactions and delayed renal function recovery. Statistically significant differences in characteristics, such as renal segmental artery resistance index, were observed among the stable renal function group, AR group, and DGF group (all P < 0.05), while peak systolic velocity showed no statistical significance (P > 0.05). Differences in cortical time to peak (TTP), medullary time to peak(TTP), main renal artery rise time (RT), main renal artery(TTP), and main renal artery fall time (FT) were statistically significant among the stable renal function group, AR group, and DGF group (P < 0.05). ROC curve analysis demonstrated that the accuracy of quantitative parameters for the DGF group and AR group was as follows: Renal artery TTP = Renal artery RT > Renal artery FT > Medulla TTP > Cortex TTP (with respective area under the curve values of 0.828, 0.828, 0.758, 0.742, 0.719). Among these, Renal artery TTP and Renal artery RT exhibited larger AUC values, with sensitivities of 87.5% each and specificities of 81.2 and 87.5%, respectively. There are discernible differences in VUEBOX quantitative parameters between post-transplant AR and DGF cases, thereby providing imaging references for diagnosing of acute rejection and functional impairment following renal transplantation.

Influence of Bridging Stent Graft Implantation into the Renal Artery during Complex Endovascular Aortic Procedures on the Renal Resistance Index.

Comparative sonographic examination of the renal resistance index (RRI) can provide evidence of renal artery stenosis. The extent to which the RRI is changed after stent graft implantation is not known. The aim of this study was to investigate the influence of stent graft implantation into non-diseased renal arteries during endovascular treatment of pararenal aortic aneurysms on the RRI. Sonographic examinations of the kidneys were conducted using a GE ultrasound system. The evaluation was performed according to the European Society for Vascular Surgery (ESVS) 2D standard criteria. RRI values were determined in consecutive patients on the day before and after stent graft implantation and compared for each kidney. A total of 32 consecutive patients (73.9 ± 8.2 years, 5 females, 27 males) were treated with a fenestrated or branched aortic stent graft including bridging stent graft implantations into both renal arteries and received pre- and postinterventional examinations. Sonomorphologically, the examined kidneys were inconspicuous. The arborisation of the renal perfusion was preserved pre- and post-implantation. The RRI did not differ (0.66 ± 0.06 versus 0.67 ± 0.07; p = ns). Successful stent graft implantation into non-stenosed renal arteries did not lead to a relevant change in RRI. Therefore, the RRI is a suitable tool for assessing renal perfusion after fenestrated or branched endovascular aortic therapy.

Predictive value of renal resistive index combined with plasma biomarkers of endothelial cell activation for persistent acute kidney injury in patients with septic shock

AbstractObjectiveTo assess the predictive abilities of Doppler‐based resistive index and plasma biomarkers of endothelial cell activation in identifying persistent acute kidney injury (pAKI) among patients with septic shock.MethodPatients diagnosed with septic shock were categorized into none AKI (n = 25), transient AKI (tAKI, n = 47), and pAKI (n = 48) groups. Kidney function parameters (urine output, serum creatinine, and serum urea) were measured within the initial 24 h upon intensive care unit (ICU) admission. The Doppler‐based resistive index, and the plasma biomarkers [fractalkine, soluble E‐Selectin (sE‐Selectin), and soluble intercellular adhesion molecule‐1 (sICAM‐1)] were evaluated upon admission to the ICU.ResultsThe predictive capacity of Doppler‐based resistive index for distinguishing pAKI at day 3 from none AKI/tAKI in septic shock patients was moderate, with sensitivity of 47.92% and specificity of 76.39%. Fractalkine levels displayed significant differences across groups and exhibited a favorable predictive ability for pAKI at day 3 (AUC = 0.800), while sE‐Selectin and sICAM‐1 showed moderate predictive abilities (AUC = 0.636 and 0.634, respectively). Comparative analysis of predictive models demonstrated that incorporating kidney function parameters, Doppler‐based resistive index, and plasma biomarkers yielded the highest AUC of 0.903, followed closely by the model utilizing serum creatinine, urine output, and plasma fractalkine, with an AUC of 0.896.ConclusionIntegrating kidney function parameters, along with Doppler‐based resistive index and plasma biomarkers of endothelial cell activation, yielded the strongest predictive model for pAKI. Additionally, the combination of serum creatinine, urine output, and plasma fractalkine shows promise in risk assessment and management strategies for pAKI.

Renal arterial resistance index before and after vericiguat administration: Should it be considered the fantastic five?

BackgroundHeart failure (HF) is a chronic-progressive disease. Once established, it is almost impossible to obtain a restitutio ad integrum of the cardiac function, but current strategies aim at slowing down the progression towards the terminal stages of the disease, which inevitably lead to the exitus. On the basis of these considerations, it appears clear that pharmacological interventions applied in this clinical condition should prevent first the development of the disease, by controlling the risk factors for HF thus reducing the onset of the disease, second slowing the disease evolution towards the terminal phases thus containing clinical symptoms and reducing the number of hospitalizations. In this scenario, the add-on therapy with vericiguat seems promising as reported in the VICTORIA study without affecting renal function. Several evidence indicates that renal arterial resistance index (RRI) seems to better reflect cardiovascular damage also in HF patients, thus affecting patients prognosis MethodsIn the present study we have analyzed the effect of vericiguat administration in 27 HF patients specifically evaluating RRI. ResultsVericiguat signicantly reduces RRI. ConclusionsThe findings of the present study seems to indicate that vericiguat, beyond its primary mechanism of action, might offer an additional advantage in HF patients.

Value of Renal Artery Resistive Index in Nonazotaemic Cirrhotic Patients with Ascites

Background: Renal dysfunction is a common complication in patients with liver cirrhosis, with hepatorenal syndrome (HRS) being the most severe form. HRS is characterized by disturbances in both circulatory and kidney functions and is diagnosed by excluding other causes of renal failure. Objective: This study aimed to measure the renal artery resistive index (RI) in non-azotaemic cirrhotic patients with ascites to predict early renal haemodynamic dysfunction. Methodology: A prospective study was conducted involving 30 cirrhotic patients with ascites and 15 healthy controls. Renal artery RI was measured using Duplex Doppler ultrasonography. Inclusion criteria for patients included normal renal function, as indicated by serum creatinine ≤ 1.2 mg/dl and creatinine clearance rate ≥ 50 ml/min. Results: The mean renal artery RI was significantly higher in cirrhotic patients with ascites (70% had RI ≥ 0.70) compared to controls (all had RI &lt; 0.70). Significant differences were observed in serum bilirubin, SGPT, SGOT, and prothrombin time between cases and controls (p &lt; 0.05). Conclusion: Renal Doppler ultrasonography is a valuable noninvasive method for detecting early renal haemodynamic dysfunction in cirrhotic patients with ascites. Elevated renal artery RI can serve as an indicator of renal dysfunction, aiding in early diagnosis and management.

Analysis of risk factors for changes of renal artery resistance indexes in gout patients by ultrasound colour Doppler.

Gout may disturb renal hemodynamics by promoting uric acid deposition; however, this relationship has not been elucidated with adequate clinical evidence. In this study, we measured the renal artery resistance index (ARI) in patients with gout to identify the risk factors and establish predictive models for elevated renal ARI in these patients. Renal artery ultrasound examination was performed in 235 primary gout patients and 50 healthy controls (HCs); subsequently, their renal interlobar ARI (RIARI), renal segmental ARI (RSARI) and overall intrarenal ARI (OIARI) were recorded. Each ARI > 0.7 was considered elevated. RIARI, RSARI and OIARI were higher in patients with gout than in HCs (all P < 0.001). Nineteen (8.1%), 24 (10.2%) and 18 (7.7%) patients had elevated RIARI, RSARI and OIARI scores, respectively. Multivariate logistic regression analyses disclosed that: age ≥ 60 years (P = 0.000), abnormal beta2 microglobulin (β2MG) (P = 0.028), and abnormal high-density lipoprotein cholesterol (HDLC) (P = 0.030) were independently associated with elevated RIARI; age ≥ 60 years (P = 0.000), and abnormal β2MG (P = 0.013) were independently related to elevated RSARI; abnormal total protein (TP) (P = 0.014) were independently linked with elevated OIARI in gout patients. Consequently, predictive models for elevated ARI were established using nomograms based on the aforementioned independent risk factors, which showed a satisfactory value for estimating elevated RIARI [area under the curve (AUC):0.929], RSARI (AUC: 0.926) and OIARI (AUC: 0.660) in patients with gout, as validated by receiver operating characteristic curves. Renal ARI were elevated in patients with gout, whose independent risk factors included older age and abnormal β2MG, HDLC and TP levels.

Kidney Blood Flow and Renin-Angiotensin-Aldosterone System Measurements Associated With Kidney and Cardiovascular Dysfunction in Pediatric Shock.

Pediatric acute kidney injury (AKI) is a prevalent and morbid complication of shock. Its pathogenesis and early identification remain elusive. We aim to determine whether renal blood flow (RBF) measurements by point-of-care ultrasound (POCUS) and renin-angiotensin-aldosterone system (RAAS) hormones in pediatric shock associate with vasoactive requirements and AKI. This is a single-center prospective, noninterventional observational cohort study in one tertiary PICU in North American from 2020 to 2022 that enrolled children younger than 18 years with shock without preexisting end-stage renal disease. RBF was measured by POCUS on hospital days 1 and 3 and plasma RAAS hormone levels were measured on day 1. The primary outcome was the presence of AKI by Kidney Disease Improving Global Outcomes criteria at first ultrasound with key secondary outcomes of creatinine, blood urea nitrogen (BUN), Vasoactive-Inotrope Score (VIS), and norepinephrine equivalent dosing (NED) 48 hours after first ultrasound. Fifty patients were recruited (20 with AKI, mean age 10.5 yr, 48% female). POCUS RBF showed lower qualitative blood flow (power Doppler ultrasound [PDU] score) and higher regional vascular resistance (renal resistive index [RRI]) in children with AKI (p = 0.017 and p = 0.0007). Renin and aldosterone levels were higher in the AKI cohort (p = 0.003 and p = 0.007). Admission RRI and PDU associated with higher day 3 VIS and NED after adjusting for age, day 1 VIS, and RAAS hormones. Admission renin associated with higher day 3 creatinine and BUN after adjusting for age, day 1 VIS, and the ultrasound parameters. In pediatric shock, kidney blood flow was abnormal and renin and aldosterone were elevated in those with AKI. Kidney blood flow abnormalities are independently associated with future cardiovascular dysfunction; renin elevations are independently associated with future kidney dysfunction. Kidney blood flow by POCUS may identify children who will have persistent as opposed to resolving AKI. RAAS perturbations may drive AKI in pediatric shock.

Can Combination Therapy with Endothelin Receptor Antagonist and PDE5 Inhibitors Prevent Echocardiographic Findings Suspicious for Pulmonary Arterial Hypertension? Description of a Real-Life Case Series.

To retrospectively evaluate the incidence rate (IR) of elevated echocardiographic estimated systolic pulmonary artery pressure (sPAP), suspected for pulmonary hypertension (PH), in systemic sclerosis (SSc) patients after the introduction of a combination therapy with bosentan and sildenafil for treatment or prevention of digital ulcers. Patients attending the Scleroderma Unit of the Universital Hospital of Careggi from July 2010 to July 2023 were enrolled. Patients older than 18 years old with a history of digital ulcers, treated with bosentan and sildenafil in combination for at least 12 months, were included. Patients with a diagnosis of PH preceding the introduction of the therapy were excluded. Demographical data, disease duration, laboratoristic, and instrumental data (pulmonary function tests, echocardiographic estimation of sPAP, and ultrasonographic value of renal resistive index) were collected. The IR of echocardiographic signs suspected of pulmonary hypertension and their 95% confidence interval were calculated in events/1000 patients-years. Thirty-five patients were enrolled; the mean disease duration was 12.82 years (SD 5.92). The mean duration of the combination treatment was 81.03 (SD 43.1.3) months, and the total at-risk time was 2674 months. Two patients (5.7%) presented echocardiographic signs of PH (sPAP 50 mmHg and 40 mmHg); the IR was calculated to be 9/1000 patients-years (95% CI 7.95-10.12). In one of the two patients, right heart catheterism (RHC) excluded PAH, while the other patient refused to undergo RHC, and PAH could not be confirmed/excluded. The stability of PFTs and echocardiographic sPAP was observed during the observation time. The results of this retrospective study suggest that combination therapy with endothelin receptor antagonists and phosphodiesterase-5 (PDE5) inhibitors could help in preventing PAH in SSc; prospective case-control studies on a larger population are needed to improve knowledge in this field.

Toll-like receptor 4 mutation mitigates gut microbiota-mediated hypertensive kidney injury

Hypertension-associated dysbiosis is linked to several clinical complications, including inflammation and possible kidney dysfunction. Inflammation and TLR4 activation during hypertension result from gut dysbiosis-related impairment of intestinal integrity. However, the contribution of TLR4 in kidney dysfunction during hypertension-induced gut dysbiosis is unclear. We designed this study to address this knowledge gap by utilizing TLR4 normal (TLR4N) and TLR4 mutant (TLR4M) mice. These mice were infused with high doses of Angiotensin-II for four weeks to induce hypertension. Results suggest that Ang-II significantly increased renal arterial resistive index (RI), decreased renal vascularity, and renal function (GFR) in TLR4N mice compared to TLR4M. 16 S rRNA sequencing analysis of gut microbiome revealed that Ang-II-induced hypertension resulted in alteration of Firmicutes: Bacteroidetes ratio in the gut of both TLR4N and TLR4M mice; however, it was not comparably rather differentially. Additionally, Ang-II-hypertension decreased the expression of tight junction proteins and increased gut permeability, which were more prominent in TLR4N mice than in TLR4M mice. Concomitant with gut hyperpermeability, an increased bacterial component translocation to the kidney was observed in TLR4N mice treated with Ang-II compared to TLR4N plus saline. Interestingly, microbiota translocation was mitigated in Ang-II-hypertensive TLR4M mice. Furthermore, Ang-II altered the expression of inflammatory (IL-1β, IL-6) and anti-inflammatory IL-10) markers, and extracellular matrix proteins, including MMP-2, −9, −14, and TIMP-2 in the kidney of TLR4N mice, which were blunted in TLR4M mice. Our data demonstrate that ablation of TLR4 attenuates hypertension-induced gut dysbiosis resulting in preventing gut hyperpermeability, bacterial translocation, mitigation of renal inflammation and alleviation of kidney dysfunction.

Renal and Genitourinary Ultrasound Evaluation in Emergency and Critical Care: An Overview.

Renal and genitourinary ultrasound are fundamental resources employed by emergency and critical care healthcare providers to make prompt diagnoses and perform ultrasound-guided procedures. At the bedside, ultrasound can aid in the diagnosis of relevant pathologies, such as post-renal obstruction or kidney stones, and life-threatening conditions such as aortic dissection or hemoperitoneum. A narrative overview was performed, providing an updated review of renal and genitourinary ultrasound for emergency and critical care healthcare providers, emphasizing its advantages and the latest advances in the field. A thorough summary that can be utilized as a guide for emergency and critical care healthcare providers is presented. The daily hemodynamic management of critically ill patients involves the implementation of new protocols, such as VexUS or the evaluation of the renal resistance index. The role of ultrasound in managing acute nephropathy and genitourinary issues is increasingly crucial given its bedside availability, thus this imaging modality not only facilitates the initiation of therapeutic interventions but also provides swift prognostic insights that are vital to provide tailored patient care. As further advances in ultrasound will arise, it is important for healthcare providers to foster the use of these technologies capable of improving patient outcomes.

Evaluation of renal resistive index and new biomarkers in post-hepatitis C cirrhosis patients for developing kidney injury

Background In liver cirrhosis, hemodynamic changes in splanchnic and systemic circulations are involved. Indeed, no established laboratory markers for altered renal hemodynamics in cirrhosis were implicated. The duplex Doppler waveform analysis of intrarenal arteriolar vessels is considered a noninvasive estimate of renovascular impedance and renal arterial vasoconstriction. In particular, the renal resistive index (RRI) is considered as the best reliable indicator of renal blood flow in patients with different diseases. The study aimed to evaluate RRI, serum and urinary cystatin C, beta-trace protein, liver fatty acid protein, and kidney injury molecule-I as noninvasive indicators of altered renal hemodynamics in patients with cirrhosis with normal urea and creatinine. Patients and methods A case–control study included 60 patients with post-hepatitis C virus (HCV) cirrhosis and 40 healthy controls. Serum and urinary biomarkers were measured. Renal color Doppler duplex was used to evaluate RRI. Results Mean serum and urinary biomarkers in HCV patients were significantly higher than controls. Moreover, the RRI was higher in patients than in controls with P value less than 0.001. Rising levels of urea, high direct bilirubin, and hypoprothrombinemia with high serum kidney injury molecule 1 and RRI were significant independent predictors for subsequent kidney injury. Conclusion Urinary kidney injury molecule 1 is a reliable, sensitive, and specific biomarker for the prediction of kidney injury among HCV cirrhotic patients with an obvious superior test performance and specificity to e other biomarkers. An increase in serum kidney injury molecule 1 and RRI were associated with poor prognosis.

Renal Resistive Index and Estimated Glomerular Filtration Rate in Nondiabetic Chronic Kidney Disease Stage 3: A Cross-Sectional Analytical Study

Renal Resistive Index and Estimated Glomerular Filtration Rate in Nondiabetic Chronic Kidney Disease Stage 3: A Cross-Sectional Analytical Study

Renal resistive index measurements by ultrasound in patients with liver cirrhosis: Magnitude and associations with renal dysfunction

BACKGROUND The hemodynamic alterations seen in liver cirrhosis lead to renal vasoconstriction, ultimately causing acute kidney injury (AKI). The renal resistive index (RRI) is the most common Doppler ultrasound variable for measuring intrarenal vascular resistance. AIM To evaluate the association of the RRI with AKI in patients with liver cirrhosis and to identify risk factors for high RRI. METHODS This was a prospective observational study, where RRI was measured using Doppler ultrasound in 200 consecutive hospitalized patients with cirrhosis. The association of RRI with AKI was studied. The receiver operating characteristic (ROC) curve analysis was utilized to determine discriminatory cut-offs of RRI for various AKI phenotypes. Multivariate analysis was conducted to determine the predictors of high RRI. RESULTS The mean patient age was 49.08 ± 11.68 years, with the majority (79.5%) being male; the predominant etiology of cirrhosis was alcohol (39%). The mean RRI for the study cohort was 0.68 ± 0.09, showing a progressive increase with higher Child-Pugh class of cirrhosis. Overall, AKI was present in 129 (64.5%) patients. The mean RRI was significantly higher in patients with AKI compared to those without it (0.72 ± 0.06 vs 0.60 ± 0.08; P &lt; 0.001). A total of 82 patients (41%) had hepatorenal syndrome (HRS)-AKI, 29 (22.4%) had prerenal AKI (PRA), and 18 (13.9%) had acute tubular necrosis (ATN)-AKI. The mean RRI was significantly higher in the ATN-AKI (0.80 ± 0.02) and HRS-AKI (0.73 ± 0.03) groups than in the PRA (0.63 ± 0.07) and non-AKI (0.60 ± 0.07) groups. RRI demonstrated excellent discriminatory ability in distinguishing ATN-AKI from non-ATN-AKI (area under ROC curve: 93.9%). AKI emerged as an independent predictor of high RRI (adjusted odds ratio [OR]: 11.52), and high RRI independently predicted mortality among AKI patients (adjusted OR: 3.18). CONCLUSION In cirrhosis patients, RRI exhibited a significant association with AKI, effectively differentiated between AKI phenotypes, and predicted AKI mortality.

Impact of Norepinephrine and Dopamine Infusion on Renal Arterial Resistive Index during Pre-Emptive Living Donor Kidney Transplantation: Propensity Score Matching Analysis.

Background: Living donor kidney transplantation (LDKT) is a crucial treatment for end-stage renal disease, with pre-emptive LDKT (transplantation before dialysis initiation) offering significant benefits in graft function and patient survival. The selection of a vasopressor during LDKT, particularly between norepinephrine and dopamine, and its impact on renal arterial hemodynamics measured using the renal arterial resistive index (RARI) is poorly understood. Methods: This retrospective observational cohort study enrolled 347 eligible pre-emptive LDKT recipients from the Seoul St. Mary's Hospital between January 2019 and June 2023. Utilizing propensity score matching (PSM), the patients were categorized into dopamine and norepinephrine groups to compare the effects of these vasopressors on the intraoperative RARI, postoperative estimated glomerular filtration rate (eGFR), and hourly urine output. The RARI was measured via the Doppler ultrasonography of the renal hilum and parenchyma post-graft vascular and ureteral anastomoses. Results: The preoperative differences in the recipients' and donors' characteristics were mitigated following PSM. The dopamine group exhibited higher intraoperative RARI values at the renal hilum (0.77 ± 0.11 vs. 0.66 ± 0.13, p < 0.001) and parenchyma (0.71 ± 0.1 vs. 0.6 ± 0.1, p < 0.001) compared to those of the norepinephrine group. However, these differences were not statistically significant on postoperative day 7. The norepinephrine infusion adjusted for the propensity scores was associated with significantly lower odds of an RARI > 0.8 (hilum: OR = 0.214, 95% CI = 0.12-0.382, p < 0.001; parenchyma: OR = 0.1, 95% CI = 0.029-0.348, p < 0.001). The early postoperative outcomes showed a higher eGFR (day 1: 30.0 ± 13.3 vs. 25.1 ± 17.4 mL/min/1.73 m2, p = 0.004) and hourly urine output (day 1: 41.8 ± 16.9 vs. 36.5 ± 14.4 mL/kg/h, p = 0.002) in the norepinephrine group. Furthermore, the long-term outcomes were comparable between the groups. Conclusions: Norepinephrine infusion during pre-emptive LDKT is associated with more favorable intraoperative renal arterial hemodynamics, as evidenced by a lower RARI and improved early postoperative renal function compared to those of dopamine. These findings suggest a potential preferential role for norepinephrine in optimizing perioperative management and early graft functions in LDKT recipients. Given the retrospective nature of this study, further prospective studies are needed to confirm these observations. Additionally, the study limitations include the potential for unmeasured confounding factors and the inability to determine causality due to its observational design.