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 < 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.

Renal Arterial and Venous Doppler in Cardiorenal Syndrome: Pathophysiological and Clinical Insights.

In recent decades, there has been considerable effort in investigating the clinical utility of renal Doppler measurements in both cardiovascular and renal disorders. In particular, a measure of renal arterial resistance, the renal resistive index (RRI), has been demonstrated to predict chronic kidney disease progression and acute kidney injury in different clinical settings. Furthermore, it is linked to a poorer prognosis in individuals suffering from chronic heart failure. Examining the renal venous flow through pulsed Doppler can offer additional insights into renal congestion and cardiovascular outcomes for these patients. This review seeks to summarize the existing data concerning the clinical significance of arterial and venous renal Doppler measurements across various cardiovascular and renal disease contexts.

Changes in renal microcirculation in patients with nephrotic and nephritic syndrome: The role of resistive index.

BACKGROUND: Renal Resistive Index (RRI) is an important and non-invasive parameter of renal damage and it is associated with abnormal microcirculation or to a parenchymal injury. The aim of our study was to compare the RRI in a cohort of patients with renal diseases categorized in three groups: nephrotic syndrome (NS), acute nephritic syndrome (ANS) and patients with urinary abnormalities (UA). METHODS: Four hundred eighty-two patients with median age of 48 years (IQR 34-62) with indications for kidney disease were included in the study. Biochemical analyses, clinical assessment with detection of NS, ANS and UA and comorbidities were reported. Renal Doppler ultrasound with RRI was evaluated in all patients at the time of enrolment. RESULTS: NS was present in 81 (16.8 %) patients while ANS in 81 (16.8 %) and UA in 228 (47.3 %) patients. Patients with ANS showed significant higher RRI compared to both patients with NS [0.71 (IQR 0.67-0.78) vs 0.68 (0.63-0.73), p < 0.001] and UA [0.71 (0.67-0.78) vs 0.65 (0.61-0.71), p < 0.001]; RRI was higher in NS patients than in patients with UA [0.68 (0.63-0.73) vs 0.65 (0.61-0.71), p < 0.001]. Patients with ANS had significantly lower median estimated glomerular filtration rate (eGFR) compared respectively to NS and UA patients [19.7 ml/min vs 54.8 ml/min and vs 72.3 ml/min, p < 0.001], while renal length was significantly higher in patients with NS compared to both patients with ANS and UA [111.88 mm vs 101.98 mm and vs 106.15, p < 0.001]. Patients with ANS had more frequently hematuria and RRI ≥ 0.70 (p < 0.001) compared to both patients with NS and patients with UA. The multiple regression analysis, weighted for age, showed that RRI inversely correlates with eGFR (ß coefficient = -0.430, p < 0.001). CONCLUSIONS: Higher and pathological RRI were found in ANS than NS and UA. Renal resistive index in ANS reflects changes in intrarenal perfusion and microvascular dysfunction related to disease characteristics.

Resistive index as predictor of acute kidney injury in patients with non-ST-segment elevation myocardial infarction.

BACKGROUND: Acute kidney injury (AKI) is common in patients with non-ST-segment elevation myocardial infarction (NSTEMI). Early detection of AKI is likely to speed diagnosis and implementation of measures to preserve renal function. To evaluate if renal Doppler resistive index (RI) would predict AKI in patients with NSTEMI on presentation in the emergency department. METHODS: Patients with NSTEMI at the emergency department were included. The renal Doppler RI was measured. Baseline demographic data and clinical characteristics of patients at admittance were recorded. Based on discharge diagnosis, the patients were divided into AKI group and no-AKI group. Multiple logistic regression analysis was performed to determine predictor variables significantly associated with AKI. RESULTS: A total of 293 patients were included in the analysis; 44 (15.0%) developed AKI without need for dialysis. There were statistical differences in the age, incidence of diabetes mellitus and cerebrovascular disease, beta-receptor blockers, serum creatinine and renal index between the two groups. Using multivariate logistic regression analysis, age [OR 1.87; 95% confidence interval (CI) 1.595-2.585; p = 0.027], diabetes mellitus (OR 2.007, 95% CI: 1.489-2.793; p = 0.014), serum creatinine (OR 1.817, 95% CI: 1.568-2.319; p = 0.013), and RI (OR 2.168, 95% CI: 1.994-4.019; p = 0.003) predicted AKI in patients with NSTEMI. According to receiver operating characteristic (ROC) analysis, RI showed a significantly increased area under the curve (AUC) compared to serum creatitine (AUC: 0.891 vs 0.679; p < 0.001). CONCLUSIONS: Renal Doppler RI may be a useful predictor of AKI in patients with NSTEMI in the emergency department.

"Tardus-parvus waveform" the only initial clue to mid-aortic syndrome- a rare cause of youth onset hypertension: A case report and a comprehensive review.

Middle aortic syndrome (MAS), an uncommon cause of secondary hypertension, is defined by obstructive narrowing of the abdominal aorta and ostia of its major branches like the renal and splanchnic arteries. Most of the cases of MAS are categorized as idiopathic; however, genetic disorders like Williams syndrome, mucopolysaccharidosis, neurofibromatosis type 1 (NF1), and Alagille syndrome, and acquired inflammatory diseases such as Takayasu arteritis and other nonspecific arteritis can also lead to MAS. MAS is commonly seen in children and young adults presenting with severe hypertension, congestive heart failure, renal failure, or severe leg claudication. The diagnosis of MAS on CT, MR, and conventional angiography is fairly straightforward. However, the spectrum of sonographic findings in MAS can be varied. Since ultrasound is frequently utilized as a first-line investigation for secondary causes of hypertension, it is especially crucial to understand the sonographic features of MAS. Here, we report a case of a young female who presented to our hospital with severe hypertension. On the Renal Doppler scan, the only clue of the renovascular etiology of her secondary hypertension was the "tardus-parvus waveform'' in the intrarenal arteries.

Renal Transplant Artery Stenosis and Kinking: An Unusual Association.

Renal artery stenosis of the kidney allograft associated with kinking is not a frequent finding. As a correctable cause of graft dysfunction, it is important to diagnose it as soon as possible to avoid further graft damage and improve graft and patient survival. As pulsed wave Doppler ultrasound mapping of the graft's renal arteries is essential to diagnose possible alterations, point of care ultrasound (POCUS) is a highly useful tool for early diagnosis. We present a case in which nephrologists performed this examination promptly allowing a timely diagnosis and treatment plan.

Phenotyping congestion in acute heart failure by renal flow and right heart to pulmonary circulation coupling.

AIMS: In acute heart failure (AHF), kidney congestion is basic to treatment and prognosis. Its aetiology is manifold and quite unexplored in details mainly regarding the right heart to pulmonary circulation (Pc) coupling. We investigated the right heart to kidney interrelationship by Doppler renal flow pattern, right atrial dynamics, and right ventricular (RV) function to Pc coupling in AHF. METHODS AND RESULTS: In 119 AHF patients, echocardiographic and renal Doppler data were analysed. Univariate and multivariate regression models were performed to define the determinants of a quantitative parameter of renal congestion, the renal venous stasis index (RVSI). When grouped according to different intra-renal venous flow patterns, no differences were observed in haemodynamics and baseline renal function. Nonetheless, patients with renal Doppler evidence of congestion showed a reduced RV function [tricuspid annular plane systolic excursion (TAPSE), S'-wave velocity, and fractional area change], impaired RV to Pc coupling [TAPSE/pulmonary artery systolic pressure (PASP) ratio], and right atrial peak longitudinal strain (RAPLS), along with signs of volume overload [increased inferior vena cava (IVC) diameters and estimated right atrial pressure]. Univariate and multivariate regression analyses confirmed TAPSE/PASP, RAPLS, and IVC diameter as independent determinants of the RVSI. RVSI was the only variable predicting the composite outcome (cardiac death, heart failure hospitalization, and haemodialysis). An easy-to-use echo-derived right heart score of four variables provided good accuracy in identifying kidney congestion. CONCLUSIONS: In AHF, the renal venous flow pattern combined with a right heart study phenotypes congestion and clinical evolution. Keys to renal flow disruption are an impaired right atrial dynamics and RV-Pc uncoupling. Integration of four right heart echocardiographic variables may be an effective tool for scoring the renal congestive phenotype in AHF.

Renal Doppler ultrasonography for predicting non-diabetic kidney disease in patients with diabetes.

PURPOSE: This study was conducted to assess the role of renal Doppler ultrasonography (US) in predicting non-diabetic kidney disease (NDKD) in patients with diabetes, using histologic findings as the reference standard. METHODS: Fifty-nine consecutive patients with diabetes who underwent renal Doppler US and native kidney biopsy were included in this retrospective, single-institutional study. Based on histologic findings, patients were classified as having diabetic nephropathy (DN) or NDKD. Renal Doppler US findings, including cortical echogenicity, corticomedullary differentiation, and the resistive index (RI), were compared between DN and NDKD. A subgroup analysis according to chronic kidney disease (CKD) status was also performed. RESULTS: Cortical echogenicity and corticomedullary differentiation showed no significant differences between DN and NDKD (P=0.887 and P>0.99, respectively), whereas the RI was significantly higher in patients with DN than in those with NDKD (P=0.032). The subgroup analysis revealed a significant difference in the RI between DN and NDKD in patients with diabetes and CKD (P=0.010), but a significant difference was not found in those without CKD (P=0.713). When limited to patients with diabetes and CKD, the RI had an area under the curve value of 0.759, sensitivity of 57.1%, specificity of 81.0%, positive likelihood ratio of 3.0, and negative LR of 0.5 for predicting NDKD, using a cutoff value of ≤0.69. CONCLUSION: Renal Doppler US may be useful in predicting NDKD in patients with diabetes and CKD.

Clinical relevance and prognostic value of renal Doppler in acute decompensated precapillary pulmonary hypertension.

AIMS: We aim to evaluate the clinical relevance and the prognostic value of arterial and venous renal Doppler in acute decompensated precapillary pulmonary hypertension (PH). METHODS AND RESULTS: The renal resistance index (RRI) and the Doppler-derived renal venous stasis index (RVSI) were monitored at admission and on Day 3 in a prospective cohort of precapillary PH patients managed in intensive care unit for acute right heart failure (RHF). The primary composite endpoint included death, circulatory assistance, urgent transplantation, or rehospitalization for acute RHF within 90 days following inclusion. Ninety-one patients were enrolled (58% female, age 58 ± 16 years). The primary endpoint event occurred in 32 patients (33%). In univariate logistic regression analysis, variables associated with RRI higher than the median value were non-variable parameters (age and history of hypertension), congestion (right atrial pressure and renal pulse pressure), cardiac function [tricuspid annular plane systolic excursion (TAPSE) and left ventricular outflow tract- velocity time integral], systemic pressures and NT-proBNP. Variables associated with RVSI higher than the median value were congestion (high central venous pressure, right atrial pressure, and renal pulse pressure), right cardiac function (TAPSE), severe tricuspid regurgitation, and systemic pressures. Inotropic support was more frequently required in patients with high RRI (P = 0.01) or high RVSI (P = 0.003) at the time of admission. At Day 3, a RRI value <0.9 was associated with a better prognosis after adjusting to the estimated glomerular filtration rate. CONCLUSION: Renal Doppler provides additional information to assess the severity of patients admitted to the intensive care unit for acute decompensated precapillary PH.

Electrocardiographic Time-Intervals Waveforms as Potential Predictors for Severe Acute Kidney Injury in Critically Ill Patients.

Background: Acute kidney injury (AKI) is common in critically ill patients admitted to intensive care units (ICU) and is frequently associated with poorer outcomes. Hence, if an indicator is available for predicting severe AKI within the first few hours of admission, management strategies can be put into place to improve outcomes. Materials and methods: This was a prospective, observational study, involving 63 critically ill patients, that aimed to explore the diagnostic accuracy of different Doppler parameters in predicting AKI in critically ill patients from a mixed ICU. Participants were enrolled at ICU admission. All underwent ultrasonographic examinations and hemodynamic assessment. Renal Doppler resistive index (RDRI), venous impedance index (VII), arterial systolic time intervals (a-STI), and venous systolic time intervals (v-STI) were measured within 2 h from ICU admission. Results: Cox proportional hazards models, including a-STI, v-STI, VII, and RDRI as independent variables, returned a-STI as the only putative predictor for the development of AKI or severe AKI. An overall statistically significant difference (p < 0.001) was observed in the Kaplan−Meier plots for cumulative AKI events between patients with a-STI higher or equal than 0.37 and for cumulative severe AKI-3 between patients with a-STI higher or equal than 0.63. As assessed by the area under the receiver operating curves (ROC) curves, a-STI performed best in diagnosing any AKI and/or severe AKI-3. Positive correlations were found between a-STI and the N-terminal brain natriuretic peptide precursor (NT-pro BNP) (ρ = 0.442, p < 0.001), the sequential organ failure assessment (SOFA) score (ρ: 0.361, p = 0.004), and baseline serum creatinine (ρ: 0.529, p < 0.001). Conclusions: Critically ill patients who developed AKI had statistically significant different a-STI (on admission to ICU), v-STI, and VII than those who did not. Moreover, a-STI was associated with the development of AKI at day 5 and provided the best diagnostic accuracy for the diagnosis of any AKI or severe AKI compared with RDRI, VII, and v-STI.

Venous Doppler to Assess Congestion: A Comprehensive Review of Current Evidence and Nomenclature.

Organ congestion from venous hypertension is an important pathophysiological mechanism mediating organ injury in several clinical contexts including critical illness, congestive heart failure and end-stage chronic kidney disease. However, the practical evaluation of venous congestion is often challenging at the bedside because of the limitations of traditional methods. Point-of-care ultrasound (POCUS) enables the clinician to assess venous velocity profiles during the cardiac cycle using Doppler modalities. Venous Doppler profile abnormalities at multiple sites are detected when elevated venous pressure results in hemodynamic changes within the systemic venous circulation. The detection of these abnormal Doppler profiles may identify patients with clinically significant systemic venous congestion. These patients have been reported to be at increased risk of medical complications. Improving the evaluation of venous congestion may lead to individualized treatment and improved patient outcomes. In this review, we describe the physiologic principles necessary to understand venous Doppler assessment. We also propose a nomenclature for the description of venous Doppler profiles. Finally, we provide a narrative review of the current clinical evidence related to use of venous Doppler assessment in various clinical contexts.

Assessment of kidney involvement in systemic sclerosis: From scleroderma renal crisis to subclinical renal vasculopathy.

The spectrum of kidney involvement in systemic sclerosis (SSc) includes scleroderma renal crisis, widely recognized as the most severe renal-vascular complication, but also several forms of chronic renal vasculopathy and reduced renal function are complications of scleroderma. Scleroderma renal crisis, myeloperoxidase-antineutrophil cytoplasmic antibody associated glomerulonephritis, penicillamine-associated renal disease, abnormal urinalysis, alteration of vascular endothelial markers, scleroderma associated-vasculopathy with abnormal renal resistance indices and cardiorenal syndromes type 5 were also reported in SSc patients. A frequent form of renal involvement in SSc patients is a subclinical renal vasculopathy, characterized by vascular damage and normal renal function. Indeed, asymptomatic renal changes, expressed by increase of intrarenal stiffness, are often non-progressive in SSc patients but can lead to a reduction in renal functional reserve. The purpose of this review is to provide an assessment of kidney involvement in SSc, from SRC to subclinical renal vasculopathy.

Renal-Resistive Index and Acute Kidney Injury in Aortic Surgery: An Observational Pilot Study.

OBJECTIVE: Acute kidney injury (AKI) is a common perioperative complication in patients undergoing cardiovascular surgery, increasing mortality, morbidities, and costs. Recently, growing interest has risen in the use of the renal-resistive index (RRI) as a predictor of perioperative AKI. The aim of this study was to evaluate the role of RRI variation to identify postoperative AKI. DESIGN: An observational, prospective, pilot study. SETTING: Department of Vascular Surgery, University Hospital of Padova. PARTICIPANTS: The study authors included 53 consecutive patients undergoing aortic surgery from September 2018 to June 2019. MEASUREMENTS AND MAIN RESULTS: Basal and daily postoperative serum creatinine and urine output were assessed. RRI was measured preoperatively and on the first postoperative day. AKI was defined using Kidney Disease Improving Global Outcome criteria. Twelve patients out of 53 developed AKI. The RRI percentage increase (%RRI) was associated with the development of AKI by univariate regression (p = 0.01). The receiver operating characteristic curve showed an overall diagnostic accuracy of 0.75 (95% confidence interval [CI], 58.2-92.6). The cutoff of 7 percentage points in the %RRI resulted in early identification of AKI onset with 90% specificity (95% CI, 76.9-97.3). The net benefit of postoperative RRI-based management was 11%. CONCLUSIONS: RRI variation could be a useful tool to investigate kidney function in patients undergoing aortic surgery. The %RRI in the perioperative time seems to detect AKI onset early and potentially could enhance renal-protective management within 24 hours after surgery.

Elevated renal resistive index is independently predicted by older age, but not by the presence of chronic kidney disease: a retrospective cohort study.

BACKGROUND: Renal resistive index (RRI), which reflects intrarenal arterial impedance, is routinely measured when undertaking renal Doppler ultrasonography (RDU). Increased RRI has been suggested to reflect renal parenchymal disease and imply risk of kidney disease progression. But this has been disputed and extra-renal haemodynamic factors rather than intra-renal factors have been proposed to determine RRI. AIMS: To investigate the relationship between elevated RRI and presence of chronic kidney disease (CKD), and examine whether elevated RRI at baseline is associated with decline in estimated glomerular filtration rate (eGFR) on follow up. METHODS: This retrospective observational study examined the association of elevated RRI (>0.7) with the presence of CKD (eGFR < 60 mL/min for >3 months), demographic and clinical factors in multivariable models. We also examined the effect of elevated RRI on eGFR decline on follow up using mixed models. RESULTS: Of the 346 patients undergoing RDU (median age 69.7 years; 46.2% male), 180 had elevated RRI. There was a strong inverse association between RRI and eGFR at baseline, 1 and 2 years (rho = -0.53, -0.51, -0.53, all P < 001). Elevated RRI was independently predicted by older age (odds ratio 3.29; 95% confidence interval 2.25-4.8; P < 0.001) and diabetes (odds ratio 2.65; 95% confidence interval 1.21-5.80; P = 0.015), but not CKD using multivariate logistic regression. Decline of eGFR was not different between RRI categories on follow up. CONCLUSION: Elevated RRI was predicted by older age and diabetes, but not by the presence of CKD. Baseline RRI was not associated with eGFR decline.

Renal doppler indices and their correlation with laboratory indices of human immunodeficiency virus sero-positive adult individuals.

INTRODUCTION: Renal Doppler resistive index (RI) and pulsatility index (PI) values are potentially more sensitive at detecting renal abnormalities when compared to standard laboratory indices in patients with HIV/AIDS. To the best of our knowledge, there are no published research articles on renal Doppler indices and their correlation with laboratory indices of HIV sero-positive adult individuals. This study aimed to assess the renal function of HIV-sero-positive adults using RI and PI, and correlating these indices against laboratory values. METHODS: A prospective cross-sectional study was conducted from July 2019 to April 2020. A purposive sampling method was employed and included 396 HIV sero-positive adult individuals. Sampling for the renal RI and PI was performed at the level of the inter-lober arteries, in between the medullary pyramids. An RI value above 0.70 and a PI value above 1.56 were consider abnormal. Serum creatine and urea together with evidence of proteinuria were recorded at the time of scanning. RESULTS: Forty-three (10.9%) men had an abnormal RI, 32 (8.1%) had abnormal PI, five (2.5%) had abnormal creatinine, two (1%) abnormal urea and eight (4.1%) with proteinuria. In women, 29 (7.3%) had abnormal RI, 22 (5.6%) abnormal PI, four (2%) abnormal creatinine and urea and six (3%) had proteinuria. There was a statistically significant weak positive correlation between RI and PI and serum creatinine and urea (r > 0.2, P < 0.05). CONCLUSION: The proportion of patients with abnormal RI and PI was higher than the proportion of participants with abnormal serum urea, creatinine and proteinuria. Renal Doppler indices could be used be used in the early assessment of renal function in HIV sero-positive adults individuals. IMPLICATIONS FOR PRACTICE: Serum creatinine and urea are routinely used to evaluate renal function in patients with HIV/AIDS. Findings from this initial study show that RI and PI could be used detecting early renal abnormalities when compared to standard laboratory values.

Renal resistive index is associated with acute kidney injury in COVID-19 patients treated in the intensive care unit.

BACKGROUND: Renal resistive index (RRI) is a promising tool for the assessment of acute kidney injury (AKI) in critically ill patients in general, but its role and association to AKI among patients with Coronavirus disease 2019 (COVID-19) is not known. OBJECTIVE: The aim of this study was to describe the pattern of RRI in relation to AKI in patients with COVID-19 treated in the intensive care unit. METHODS: In this observational cohort study, RRI was measured in COVID-19 patients in six intensive care units at two sites of a Swedish University Hospital. AKI was defined by the creatinine criteria in the Kidney Disease Improving Global Outcomes classification. We investigated the association between RRI and AKI diagnosis, different AKI stages and urine output. RESULTS: RRI was measured in 51 patients, of which 23 patients (45%) had AKI at the time of measurement. Median RRI in patients with AKI was 0.80 (IQR 0.71-0.85) compared to 0.72 (IQR 0.67-0.78) in patients without AKI (p = 0.004). Compared to patients without AKI, RRI was higher in patients with AKI stage 3 (median 0.83, IQR 0.71-0.85, p = 0.006) but not in patients with AKI stage 1 (median 0.76, IQR 0.71-0.83, p = 0.347) or AKI stage 2 (median 0.79, min/max 0.79/0.80, n = 2, p = 0.134). RRI was higher in patients with an ongoing AKI episode compared to patients who never developed AKI (median 0.72, IQR 0.69-0.78, p = 0.015) or patients who developed AKI but had recovered at the time of measurement (median 0.68, IQR 0.67-0.81, p = 0.021). Oliguric patients had higher RRI (median 0.84, IQR 0.83-0.85) compared to non-oliguric patients (median 0.74, IQR 0.69-0.81) (p = 0.009). After multivariable adjustment, RRI was independently associated with AKI (OR for 0.01 increments of RRI 1.22, 95% CI 1.07-1.41). CONCLUSIONS: Critically ill COVID-19 patients with AKI have higher RRI compared to those without AKI, and elevated RRI may have a role in identifying severe and oliguric AKI at the bedside in these patients.

The Renal Resistive Index: A New Biomarker for the Follow-up of Vascular Modifications in Systemic Sclerosis.

OBJECTIVE: The aim of the present retrospective observational study was to evaluate the change of Renal Resistive Index (RRI) over time (ΔRRI) and under treatment in patients with systemic sclerosis (SSc) as well as to correlate these changes with disease complications. METHODS: Two hundred thirty patients [29 male, median age 57 (IQR 48-67) yrs] were enrolled. At baseline and follow-up (3.43, IQR 2.81-4.45 yrs), we collected the following data: disease variables, nailfold videocapillaroscopy (NVC) pattern, forced vital capacity (FVC), diffusing lung capacity for carbon monoxide (DLCO), systolic pulmonary arterial pressure (sPAP), presence of interstitial lung disease, RRI, evaluation of glomerular filtration rate, and new onset of pulmonary arterial hypertension (PAH). RESULTS: RRI value is high in SSc patients with digital ulcers and anticentromere antibodies, active and late NVC patterns, and limited cutaneous SSc. A significant correlation was observed between ΔRRI and ΔsPAP (R = 0.17, P = 0.02), with statistically higher ΔRRI (0.08 ± 0.02 vs 0.03 ± 0.05, P = 0.04) in patients complicated by PAH onset. No other new-onset complication was associated with ΔRRI. The receiver-operating characteristic curve analysis confirmed the predictive role of ΔRRI in development of new PAH (area under the curve 0.84, 95% CI 0.75-0.93, P = 0.02). In patients with SSc never exposed to sildenafil, ΔRRI was higher (0.04 ± 0.05) compared to both patients exposed to sildenafil during the study period (0.01 ± 0.05, P = 0.03) or in those exposed at the time of baseline evaluation (0.00 ± 0.05, P = 0.01). CONCLUSION: RRI and its variation in time are a reliable marker of SSc-related vasculopathy, both in renal and extrarenal compartments.

Prognostic Role of Measurement of Renal Resistive Index in Systemic Sclerosis.

OBJECTIVE: The spectrum of vascular involvement in systemic sclerosis (SSc) includes digital ulcers, gangrene, Raynaud's phenomenon, renovascular disease, and pulmonary hypertension (PH). Recognition of markers of subclinical vascular disease in SSc is an area of active research, but such studies are limited. This study assesses the role of measurement of the renal resistive index (RRI) as an early marker of renal and systemic vasculopathy. It is a step forward towards examining the possibility of a "unified vascular phenotype' in SSc. METHODS: In this single-centre prospective study, RRI was calculated for SSc patients >18 years age. Elevated RRI (>0.7) was correlated with renal function (eGFR and proteinuria) and systemic vasculopathy manifestations like digital ulcers, digital infarcts, and PH. RESULTS: A total of 73 patients with mean (SD) age 41.8(10.9) years were included. Mean (SD) RRI in the right and left renal artery was 0.65(0.08) and 0.66(0.07), respectively. 16 (21.9%) patients had elevated RRI (>0.7). A strong negative correlation was noted between elevated RRI and eGFR (r= -0.96, p=0.03). The percentage of patients with overt proteinuria was higher in the group with elevated RRI (20% versus 7%) (p=0.16). Similarly, digital ulcers (56% vs 33%) and digital pitting (50% vs 35%.) were numerically higher in the group with raised RRI, although statistical significance was not reached because of small numbers (p=0.09 and 0.28, respectively). No correlation of RRI with PH was identified. CONCLUSION: RRI correlates well with asymptomatic renal dysfunction and holds promise in the assessment of systemic vasculopathy. However, validation in studies with a larger sample size is needed.

Renal venous congestion following hemorrhagic shock due to traumatic liver injury.

A 78-year-old woman who sustained traumatic liver injury with hemorrhagic shock was hospitalized. She was admitted to the ICU after blood transfusion and emergent angiography. AKI was observed on the following day. Blood transfusion was continued because initial assessment was prerenal AKI due to hypovolemia. Despite transfusion of blood products and administration of diuretics, aggravated renal dysfunction, and low urine output continued, resulting in respiratory failure due to pulmonary edema. Renal venous congestion was suspected as the primary cause of AKI, since IVC compression from a hematoma with IVC injury was observed on CT imaging captured on admission, and renal Doppler ultrasonography demonstrated an intermittent biphasic pattern of renal venous flow. It was finally concluded that renal venous congestion resulted from IVC compression, since urine output increased remarkably after RRT without additional diuretics, and follow-up CT and renal Doppler ultrasonography revealed improvements in IVC compression and renal venous flow pattern, respectively. Renal venous congestion has been often reported to be associated with acute decompensated heart failure and, to our knowledge, this is the first report to describe trauma-induced renal venous congestion. Trauma patients are at risk for renal venous congestion due to massive blood transfusion after recovery from hemorrhagic shock; therefore, if they develop AKI that cannot be explained by other etiologies, physicians should consider the possibility of trauma-induced renal venous congestion and perform renal Doppler ultrasonography.

Renal doppler changes in patients with acute pancreatitis: A prospective study.

BACKGROUND: Renal Doppler to assess renal resistive index (RRI) is an attractive option to prognosticate acute kidney injury (AKI) in acute pancreatitis (AP) as it is feasible within scope of point-of-care ultrasound. However, RRI has been infrequently evaluated in AP. OBJECTIVE: Prospectively study diagnostic and prognostic performance of RRI in patients with AP. METHODOLOGY: 75 patients with AP were prospectively enrolled and followed till recovery/death. All patients were subjected to renal Doppler and RRI was compared between patients with and without AKI. RESULTS: Thirty six patients developed AKI and 39 patients did not develop AKI. AKI network stage 1, 2 and 3 AKI was seen in 7(19.4%), 12(33.3%) and 17 (47.2%) patients respectively. Prognostic scoring done at admission by SIRS, modified marshal score, and BISAP scores, as well as duration of hospitalization and mortality rates were significantly higher in patients with AKI. Mean peak systolic velocity and RRI at upper, middle and lower poles of bilateral kidneys were comparable between patients with and without AKI. The RRI was abnormal in 46 (66.6%) patients and it was <0.6 in 35/46 (76%) and >0.7 in 11/46 (24%) patients respectively. RRI <0.6 was observed in 16 (53.3%) and 19 (48.7%) patients with and without AKI respectively (p = 0.80). RRI >0.7 was observed in 4 (53.3%) and 7 (48.7%) patients with and without AKI respectively (p = 0.74). CONCLUSIONS: AKI is associated with poor prognosis in AP. RRI on renal Doppler at admission seems to have poor diagnostic as well as prognostic performance for AKI in patients with AP.