Renal resistive index in patients supported with a durable continuous flow left ventricular assist device.

BACKGROUND: The impact of continuous flow resulting from contemporary left ventricular assist devices (LVAD) on renal vascular physiology is unknown. Renal resistive index (RRI) reflects arterial compliance, as well as renal vascular resistance, contributed by afferent and efferent arteriolar tone, the renal interstitium as well as renal venous pressures. METHODS: Prospective, single center study with renal Doppler evaluation at baseline (pre-implant) and at 3-months support. Outcomes assessed include need for post-operative renal replacement therapy (RRT), worsening renal function (WRF) defined as persistent increase from pre-implant KDIGO chronic kidney disease stage, right ventricular (RV) failure, and survival to transplantation. RESULTS: Pre-implant RRI did not predict cardiorenal outcomes including right heart failure, need for renal replacement therapy or worsening renal function. Post-implant RRI was significantly lower than pre-implant RRI, with a distinct Doppler waveform characteristic of continuous flow. Post-implant renal end-diastolic velocity, but not RRI, correlated strongly with LVAD flow (Spearman rho -0.99, p < 0.001), with trend toward correlation with mean arterial pressure (Spearman's rho 0.63, p = 0.129). There was a negative correlation between post-implant RRI and mean pulmonary artery pressure (Spearman's rho -0.81, p = 0.049), likely driven by elevated pulmonary capillary wedge pressure (Spearman's rho -0.83, p = 0.058). CONCLUSION: The hemodynamic contributors to RRI in LVAD supported patients are complex. Higher mean pulmonary artery and pulmonary capillary wedge pressures seen in lower RRI may reflect a smaller difference in systolic and diastolic flow. Future simultaneous Doppler assessment of the LVAD outflow graft and RRI may help understand the hemodynamic interactions contributing to this index.

The intratesticular artery resistive index as a predictor of spermatogenesis: A prospective study.

INTRODUCTION: With the objective to assess the correlation between the resistive index of intratesticular artery as predictor of spermatogenesis this case control study was conducted. METHODS: A Prospective study conducted during period April 2021 to March 2023. Total 50 patients, with oligoasthenozoospermia taken as cases and other 50 men with normal sperm count taken as controls. History taken & clinical examination, Semen analysis, hormonal evaluation & Color Doppler ultrasonography of scrotum done. Resistive Index of testicular arteries was obtained. Cases and controls were compared. RESULTS: The age of the study group ranged between 21 and 40 years. Among the cases maximum patients 23 out of 50 and among controls with maximum number 21 out of 50 patients were belonged to age group 26-30 years.The mean semen volume for the cases & controls was 2.76 ± 0.44 ml and 3.32 ± 0.54 ml respectively. The Mean sperm concentration in the cases & controls was 14.33 million/ml & 84.8 million/ml. Mean Type A sperm motility was 20.82% ± 7.86 in cases and 54.96% ± 5.41 in controls. The mean testicular volume in cases was 18.36 ± 0.75 & in controls was 18.39 ± 0.62 ml. Hormonal evaluation done in both cases and controls and mean value of FSH in cases and controls was 7.57 ± 2.34 and 6.27 ± 3.55 respectively (p-value = 0.036). Mean value of Resistive Index (PSV - EDV)/PSV) in cases and controls were found 0.63 ± 0.32 and 0.53 ± 0.37 respectively (p-value = 0.001). CONCLUSION: The intratesticular artery resistive index can be utilized as valuable predictive marker to indicate spermatogenesis.

Role of Uterine Artery Doppler Study Between 11 and 14 Weeks as a Predictor of Preeclampsia.

Introduction Preeclampsia is a serious complication marked by antepartum hemorrhage, resulting in severe maternal and fetal complications. Predicting this condition using placental dysfunction assessments, such as uterine artery Doppler ultrasound, is challenging due to the placenta's evolving structural and biochemical characteristics throughout different stages of pregnancy. Objectives To determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the uterine artery Doppler Pulsatility Index (PI) and Resistive Index (RI) in predicting preeclampsia. To compare the Doppler ultrasound measurements between normal pregnancies and those that develop preeclampsia. To assess the diagnostic accuracy of uterine artery Doppler ultrasound in predicting gestational hypertension in addition to preeclampsia. Methodology Conducted as a prospective study, 116 antenatal mothers with computed gestational ages and scan gestational ages between 11 and 14 weeks, and a previous history of preeclampsia were included. Subjects with chronic hypertension or multiple gestations were excluded. Participants underwent uterine artery Doppler screening, during which the PI and RI were measured upon obtaining three consecutive similar waveforms, and the mean PI of the left and right arteries was calculated. The outcomes of patients with normal pregnancies and those who developed preeclampsia were compared. Data were entered into Microsoft Excel (Microsoft® Corp., Redmond, WA, USA) and analyzed using IBM SPSS Statistics for Windows, Version 23 (Released 2015; IBM Corp., Armonk, NY, USA). Results The mean PI among participants was 1.75 (±0.38), with a range from 1 to 2.75. The mean RI was 0.58 (±0.08), ranging from 0.45 to 0.8. The cutoff for the mean PI in predicting preeclampsia was 2.27, which showed a sensitivity of 92.9%, specificity of 97.1%, PPV of 81.47%, NPV of 99.01%, and a diagnostic accuracy of 96.59% (area under the curve (AUC): 0.982). The cutoff for the mean RI for predicting preeclampsia was 0.695, with a sensitivity of 85.7%, specificity of 98%, PPV of 85.47%, NPV of 98.04%, and diagnostic accuracy of 96.52% (AUC: 0.965). In predicting gestational hypertension, the cutoff for the mean PI was 1.975, with a sensitivity of 80%, specificity of 82.9%, PPV of 17.41%, NPV of 98.92%, and diagnostic accuracy of 82.78% (AUC: 0.848). The cutoff for the mean RI in predicting gestational hypertension was 0.615, showing a sensitivity of 80%, specificity of 80.2%, PPV of 15.4%, NPV of 98.89%, and diagnostic accuracy of 80.19% (AUC: 0.767). Conclusion The research demonstrated that aberrant readings in uterine Doppler ultrasound, specifically in the PI and RI, possess strong overall validity in forecasting the occurrence of preeclampsia.

Renal arterial resistive index as a prognostic marker in lupus nephritis patients.

INTRODUCTION: Lupus nephritis (LN) is known to be one of the most serious complications of SLE and it is a major predictor of poor prognosis. Despite the improvement in understanding the pathophysiology of lupus nephritis and greater improvement in diagnostic approaches, lupus nephritis patients have poorer outcomes. OBJECTIVES: Study the relation between renal resistive index (RRI) and renal function and histopathological parameters in lupus nephritis (LN) patients. Also to investigate the usefulness of RRI in predicting response to treatment. PATIENTS AND METHODS: This study included 126 patients who were split into two groups (group 1: 101 LN patients and group 2: 25 SLE patients without renal affection); and 100 healthy controls (group 3). The RRI was measured for all participants through a colored Doppler ultrasound examination. LN patients underwent renal biopsy and received their therapy and were followed up for 6 months. RESULTS: The RRI was significantly greater in the LN group (mean±SD; 0.64±0.07) than in SLE patients without nephritis (0.5884±0.04) (P<0.0001). The RRI was greater in LN class IV (P<0.0001). RRI significantly correlated with the chronicity index (r=0.704, P<0.0001), activity index (r=0.310, P=0.002), and serum creatinine (r=0.607, P<0.0001) and negatively correlated with eGFR (r=-0.719, P<0.0001). Almost eighty-five percent (84.8%) of LN patients responded to induction therapy. RRI was significantly greater in the nonresponder group (mean±SD, 0.73±0.02) than that in the responder group (0.63±.07) (P<0.0001). All non-responders to induction therapy while only 29.8% of responders had an RRI of ˃0.7. RRI, according to regression analysis was a significant predictor of response to treatment in LN patients. CONCLUSION: RRI was significantly greater in the LN group and significantly correlated with kidney function and histopathological parameters. RRI can predict response to induction therapy in LN patients.

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.

Assessment of renal transplant dysfunction by doppler sonography: A systematic review and meta-analysis.

Background: Doppler sonography parameters, particularly the resistive index (RI), have been identified as an essential tool for assessing renal transplant dysfunction (RTD). However, there is some ambiguity in the findings of previous research studies on this matter. Therefore, the objective of our study is to examine the relationship between changes in RI subsequent to RTD. Methods: This was a systematic review and meta-analysis study. We searched three electronic databases PubMed, Web of Science, and Scopus, from the year 2000 to 10 May 2022. The main effect size was considered as the mean RI differences of cases with RTD confirmed by biopsy with control patients with no RTD. We used random effect models to pool the effect size. Results: Thirteen studies were included in our review. The pooled mean (95% CI) for the control group was calculated to be 0.71 (0.67, 0.75) and for patients with renal transplant dysfunction was 0.73 (0.68, 0.78), under a random effect model with high heterogeneity for both analyses (I2=98% and 97%, respectively). The pooled mean was significantly different between the control group and patients with RTD (P= 0.05), based on a t-test of pooled effect sizes. Conclusions: Based on the result of our study, we showed that there is a significant difference between RI in patients with kidney transplant dysfunction and the control group. However, RI cannot substitute kidney biopsy in the management and diagnosis of RTD.

Role of Shear Wave Elastography for Assessment of Renal-Allograft Fibrosis and its Correlation With Histopathology.

OBJECTIVES: To investigate whether shear wave elastography (SWE) can accurately identify interstitial fibrosis and tubular atrophy (IFTA) in chronic renal allograft injury (CRAI) and whether it can differentiate between different grades of IFTA. MATERIALS AND METHODS: Prospective observational study on renal transplant recipients who presented with CRAI. Patient selection was done on the basis of clinical presentation, serum creatinine, and eGFR levels. Biopsy and SWE were performed and SWE values were correlated with histopathological findings according to Banff schema. Receiver operating characteristic (ROC) was also analyzed to assess the diagnostic efficacy of SWE. RESULTS: Sxity-one patients were evaluated. Ten patients had no IFTA, 33 patients had mild IFTA, 16 patients had moderate IFTA, and 2 patients had severe IFTA. Mean parenchymal stiffness values in no IFTA, mild IFTA, moderate IFTA and severe IFTA were 39.86 ± 2.17 kPa (3.64 ± 0.09 m/s), 41.59 ± 3.36 kPa (3.71 ± 0.15 m/s), 47.59 ± 3.34 kPa (3.98 ± 0.14 m/s), and 53.83 ± 1.41 kPa (4.25 ± 0.03 m/s), respectively. SWE values of parenchymal stiffness reached statistical significance to differentiate between mild, moderate, and severe IFTA. ROC analysis revealed cut-off values of 45.09 kPa (3.89 m/s) to differentiate between mild IFTA and moderate IFTA, 52.06 kPa (4.18 m/s) to differentiate between moderate IFTA and severe IFTA with acceptable sensitivity and specificity. CONCLUSION: SWE is a non-invasive and cost-effective imaging tool to evaluate the disease status of renal allografts affected by CRAI. Thus, it can be of paramount importance if added to the regular follow-up imaging protocol of renal allograft along with grayscale and Doppler imaging.

The Relationship between Renal Resistive Index and Complexity of Coronary Lesions in Patients with Stable Coronary Artery Diseases.

Background: The most common cause of coronary artery diseases (CAD) is atherosclerosis. The synergy between percutaneous coronary intervention with TAXUS™ and cardiac surgery (SYNTAX) score was used to assess complex CAD lesions. The renal resistive index (RRI) is a Doppler ultrasound parameter calculated to assess renal haemodynamics. The direct relationship between CAD complexity and RRI was not yet investigated. The aim of our study was to investigate this relationship between RRI and SYNTAX score in stable CAD patients. Methods: This study included 214 patients with stable CAD and subsequent coronary angiography done at our institution. Regarding CAD complexity, these patients were classified into 166 patients with low SYNTAX score (SYNTAX ≤ 22), and 48 patients with high SYNTAX score (SYNTAX > 22). The demographic, laboratory, clinical, echocardiographic data and renal Doppler parameters; including RRI, were recorded. Results: Multivariate logistic regression analysis demonstrated that RRI (odds ratio, OR = 4.440, 95% (confidence interval) CI: 1.418-13.903, p = 0.010) was a novel independent predictor of high SYNTAX score in patients with stable CAD, in addition to other traditional predictors as diabetes mellitus (OR = 4.401, 95% CI: 1.081-17.923, p = 0.04), low-density lipoprotein cholesterol (LDL-C) (OR = 2.957, 95% CI: 1.920-8.995, p = 0.027), multi-vessel CAD (OR = 2.113, 95% CI: 1.241-2.280, p = 0.001) and Gensini score (OR = 6.539, 95% CI: 1.977-21.626, p = 0.002). Receiver operator characteristic curve analysis showed that RRI > 0.655 (sensitivity of 80%, specificity of 73.6%) was the best cut-off value for predicting high SYNTAX score. Conclusions: The non-invasively measured RRI is closely associated with high SYNTAX score in stable CAD patients.

Kidney Doppler ultrasonography in critical care nephrology.

Color pulsed-wave Doppler ultrasound (CPWD-US) emerges as a pivotal tool in intensive care units (ICUs) for diagnosing acute kidney injury (AKI) swiftly and non-invasively. Its bedside accessibility allows for rapid assessments, making it a primary imaging modality for AKI characterization. Furthermore, CPWD-US serves as a guiding instrument for key diagnostic-interventional procedures such as renal needle biopsy and percutaneous nephrostomy, while also facilitating therapy response monitoring and AKI progression tracking. This review shifts focus towards the integration of renal ultrasound into ICU workflows, offering contemporary insights into its utilization through a diagnostic standard-oriented approach. By presenting a flow chart, this review aims to provide practical guidance on the appropriate use of point-of-care ultrasound in critical care scenarios, enhancing diagnostic precision, patient management and safety, albeit amidst a backdrop of limited evidence regarding long-term outcomes.

Renal resistive index by point of care ultrasound to predict sepsis associated acute kidney injury in critically ill children.

BACKGROUND: Sepsis associated acute kidney injury (AKI) is linked with adverse outcomes in the PICU. Doppler-based renal resistive index (RRI) has shown promising results in adults for prediction of AKI. We aimed to explore the performance of RRI in children with sepsis. METHODS: This prospective observational study (March - November 2022) included children aged 1-12 years with sepsis admitted to the PICU. RRI and urine neutrophil gelatinase associated lipocalin (NGAL) were measured within 12 h of admission. Children were followed up for 3 days. AKI (new and persistent) was defined as any child with KDIGO stage 2 or 3 AKI on day 3. RESULTS: We enrolled 90 children but included 79 in final analysis. Two thirds (n = 53, 67%) had septic shock. Median (IQR) age was 6.2 years (4.1-9.2). RRI decreased with increasing age. Twenty-six (33%) children had AKI on day 3. Mean (SD) RRI was higher in the AKI group [0.72 (0.08) vs. 0.65 (0.07), p < 0.001].The area under ROC curve for RRI to detect AKI among the 1-4 year old group was 0.75 (95% CI:0.51, 0.98; p = 0.05) and among the 5-12 year old group was 0.76 (0.62, 0.89; p = 0.001). An RRI 0.71 predicted AKI with 100% sensitivity and 46.2% specificity among the 1-4-year-old group and RRI 0.69 predicted it with 70% sensitivity and 77.5% specificity in the 5-12-year-old group. RRI and eGFR at admission were independent predictors of AKI on multivariable analysis. Urine NGAL 94.8 ng/ml predicted AKI with 76.9% sensitivity and 77.4% specificity and AUROC was 0.74 (0.62, 0.86) among the 1-12-year-old group. CONCLUSIONS: RRI values varied with age. RRI showed good diagnostic accuracy to detect new/persistent AKI on day 3 in children with sepsis; however, it was less precise as an independent predictor.

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

BACKGROUND: 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. METHODS: 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). RESULTS: 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). CONCLUSIONS: 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.

Doppler Ultrasound and Resistive Indices in the Diagnosis of Ureteropelvic Junction Obstruction in the Pediatric Population.

OBJECTIVES: Mercapto acetyl tri-glycine renogram (MAG3) scan has been the gold standard assessment of pediatric ureteropelvic junction obstruction (UPJO) but requires intravenous access and radiation exposure. While Doppler ultrasound measurements of resistive indices (RI) of the arcuate arteries have been proposed as an alternative assessment of obstruction, they have not been widely adopted in the pediatric population. We hypothesized that RI of the main renal artery (RA) is more strongly correlated with MAG3 findings than arcuate RI. METHODS: Pediatric patients with unilateral Society for Fetal Urology grade 3-4 hydronephrosis undergoing concomitant RUS and MAG3 were recruited. Doppler ultrasound peak systolic velocity (PSV); RI of bilateral RA at the origin, middle, and hilum; and RI of the superior, middle, and lower pole arcuate arteries were obtained. MAG3 differential renal function (DRF) and T½ were recorded. Differences in RI measurements (DRI) between the affected and normal kidney were calculated and compared with DRF and T½. RESULTS: 31 patients (median 4.6-month-old) were enrolled. Only RA RI at the origin differed between affected and normal kidneys (p < .001). DRI RA at the origin showed weak evidence for an association with MAG3 DRF < 40% (p .07). DRI was not associated with T½ > 20 minutes. CONCLUSION: There was weak evidence for an association between RA DRI at the origin and DRF but not with T½. These findings suggest that RA DRI may provide additional data in the evaluation of patients with UPJO to tailor the use of MAG3 and associated risk of radiation exposure to those patients most at risk for concomitant renal function impairment.

Testicular Vascularization after Pediatric Inguinal Hernia Repair: A Systematic Review and Meta-Analysis.

BACKGROUND: The effect of pediatric inguinal hernia repair (IHR) on testicular vascularization remains unclear. Manipulating the spermatic cord during surgery may reduce blood flow due to edema and vasoconstriction. This can lead to testicular atrophy. The study aims to review current knowledge of testicular vascular impairment following IHR in children. METHODS: A systematic literature search was conducted in PubMed/Medline, Embase, Cochrane Library, and Web of Science. Methodological quality was assessed using validated tools. Data were extracted, and a pooled data analysis was performed. RESULTS: Ten studies were included in the systematic review. Six of these studies were eligible for meta-analysis. This revealed a significant decrease in testicular vascularization during the short-term follow-up (1 day-1 week) after IHR using the open surgical approach. This decrease was not present after laparoscopic intervention. There was no more increased resistance in the vessels at long-term follow-up (1 month-6 months), suggesting that the impaired vascularity is only temporary. CONCLUSIONS: There seems to be a short-term transient vascular impairment of the testis after open IHR in children. This might be of clinical relevance to prefer the laparoscopic approach for IHR in children, even though the open approach is the gold standard, in contrast to adult IHR. The impact on testicular function and sperm quality later in life remains unclear. Comparative studies of both techniques are needed to determine if there is a significant difference in testicular vascularity. Long-term studies are necessary to assess the impact of transiently reduced vascularity on sperm quality and fertility later in life.

Efficacy of drug-coated balloon catheters for patients with short-term recurrent dysfunction of arteriovenous fistula.

BACKGROUND: In this study, we aimed at clarifying the usefulness of drug-coated balloon catheters (DCBs) for arteriovenous fistulas (AVFs) that repeatedly undergo restenosis over a short period and to examine the factors that influence the patency period after DCB use. METHODS: This retrospective observational study was conducted using IN.PACT AV in 29 cases of AVFs with repeated restenosis within approximately 3 months, and temporary patency before and after DCB use in the same patients was compared. For target participants, the flow volume, resistive index (RI), and vascular diameter of the brachial artery were measured using an ultrasound diagnostic device. Stenosis diameter, reference vessel diameter, and stenosis length of the lesion were measured before and after DCB dilatation using digital subtraction angiography. RESULTS: Before DCB angioplasty, the postintervention primary patency at 3 months was 66%, and the average interval was 92 ± 21 days (mean ± standard deviation). After DCB angioplasty, the postintervention primary patency rates at 3 and 6 months were 92% and 36%, respectively. The postintervention primary patency was significantly higher after than before DCB angioplasty (p < 0.0001). A sub-analysis was performed on 25 patients who were followed up for 4 months or more after DCB. The RI values before and after dilatation with DCB significantly differed between the patency group 4 or more months after DCB and the patency group less than 4 months after DCB. CONCLUSION: For AVFs that require frequent PTA over a short period of time, DCB improved the patency rate 3 months after PTA, but the improvement effect at 6 months was limited. The effect of DCB on prolonging the patency rate of AVFs that require frequent PTA over a short period of time may be correlated with the RI value before and after PTA.

Evaluation of Renal Function with Urinary NGAL and Doppler Ultrasonography in ICU Patients: A 1-Year Observational Pilot Study.

BACKGROUND: We estimated the diagnostic accuracy of urinary NGAL for the diagnosis of AKI. METHODS: Urinary NGAL and Creatinine were measured daily for up to 3 days. Doppler ultrasonography was performed within 24 h of admission and for the following 3 days. RESULTS: Of the 21 patients, 44% had AKI during their ICU stay. The AKI group presented with higher values of serum Creatinine, renal length, MDRD as well as SAPS II already at admission. Urinary NGAL was significantly higher among patients with AKI and patients AKI-no at T0 (p < 0.0001) and increased steadily on T1 and T2. Urinary NGAL seemed to be a notable diagnostic marker for AKI from the first measurement (T0) with an area under the ROC of 0.93 (95% CI = 0.78-0.99) with a sensitivity of 99%. RRI levels were slightly higher in the AKI group at each time and increased gradually from T0 to T2 but reached statistical significance only at T2 (p = 0.02). Renal length and SAPS II at T0 showed high AuRoc and sensitivity. CONCLUSIONS: Urinary NGAL is a valuable marker for AKI in intensive care settings. It seemed that a pre-existing chronic renal disease, the SAPS II and the NGAL at admission represented the principal predictors of AKI.

Comparison of resistive index and shear-wave elastography in the evaluation of chronic kidney allograft dysfunction.

BACKGROUND: Detection of early chronic changes in the kidney allograft is important for timely intervention and long-term survival. Conventional and novel ultrasound-based investigations are being increasingly used for this purpose with variable results. AIM: To compare the diagnostic performance of resistive index (RI) and shear wave elastography (SWE) in the diagnosis of chronic fibrosing changes of kidney allograft with histopathological results. METHODS: This is a cross-sectional and comparative study. A total of 154 kidney transplant recipients were included in this study, which was conducted at the Departments of Transplantation and Radiology, Sindh Institute of Urology and Transplan tation, Karachi, Pakistan, from August 2022 to February 2023. All consecutive patients with increased serum creatinine levels and reduced glomerular filtration rate (GFR) after three months of transplantation were enrolled in this study. SWE and RI were performed and the findings of these were evaluated against the kidney allograft biopsy results to determine their diagnostic utility. RESULTS: The mean age of all patients was 35.32 ± 11.08 years. Among these, 126 (81.8%) were males and 28 (18.2%) were females. The mean serum creatinine in all patients was 2.86 ± 1.68 mg/dL and the mean estimated GFR was 35.38 ± 17.27 mL/min/1.73 m2. Kidney allograft biopsy results showed chronic changes in 55 (37.66%) biopsies. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of SWE for the detection of chronic allograft damage were 93.10%, 96.87%%, 94.73%, and 95.87%, respectively, and the diagnostic accuracy was 95.45%. For RI, the sensitivity, specificity, PPV, and NPV were 76.92%, 83.33%, 70.17%, and 87.62%, respectively, and the diagnostic accuracy was 81.16%. CONCLUSION: The results from this study show that SWE is more sensitive and specific as compared to RI in the evaluation of chronic allograft damage. It can be of great help during the routine follow-up of kidney transplant recipients for screening and early detection of chronic changes and selecting patients for allograft biopsy.

Renal arterial resistive index versus novel biomarkers for the early prediction of sepsis-associated acute kidney injury.

Acute kidney injury (AKI) is a critical complication of sepsis. There is a continuous need to identify and validate biomarkers for early detection. Serum and urinary biomarkers have been investigated, such as neutrophil gelatinase associated lipocalin (NGAL) and cystatin C (Cys C), but their reliability in the intensive care unit (ICU) remains unknown. Renal hemodynamics can be investigated by measuring the renal resistive index (RRI). This study aimed to compare the performance of RRI, serum NGAL (sNGAL), urinary NGAL (uNGAL), and serum Cys C levels as early predictors of the diagnosis and persistence of sepsis-associated AKI. A total of 166 adult patients with sepsis syndrome were enrolled immediately after ICU admission. Biomarkers were measured directly (T1) and on day 3 (T3). RRI was measured directly (T1) and 24 h later (T2). Patients were categorized (according to the occurrence and persistence of AKI within the first 7 days) into three groups: no AKI, transient AKI, and persistent AKI. The incidence rate of sepsis-associated AKI was 60.2%. Sixty-six patients were categorized as in the no AKI group, while another 61 were in transient AKI and only 39 were in persistent AKI. The RRI value (T1 ≥ 0.72) was the best tool for predicting AKI diagnosis (area under the receiver operating characteristic curve, AUROC = 0.905). Cys C (T1 ≥ 15.1 mg/l) was the best tool to predict the persistence of AKI (AUROC = 0.977). RRI (T1) was the best predictive tool for sepsis-associated AKI, while Cys C was the best predictor of its persistence and 28-day mortality.

Sequential carotid Doppler study in acute stroke and its clinical correlation: A prospective study.

Objectives: Resistive index (RI) and pulsatility index (PI) assessed on carotid Doppler assess the hemodynamic status of cranial vasculature. They are related to the severity of stroke and help determine the overall outcome. This study was done to compare the hospital stay and stroke severity with RI and PI of both internal carotid arteries. Materials and Methods: Patients >18 years of age presenting within 48 h of anterior circulation stroke (either ischemic or hemorrhagic) were included. They were divided into two groups based on their length of stay (LOS). They were assessed clinically on days 1, 3, and 5, and underwent a carotid Doppler study on the same days. The Doppler parameters were correlated with the LOS and stroke severity for possible associations. Results: One hundred and one patients were included. Forty-seven patients had a favorable outcome based on LOS. In this group, significant decrease in RI and PI scores was seen from days 1 to 3. In patients with unfavorable outcome, there was a significant increase in PI on days 1-3 and days 1-5. The National Institutes of Health Stroke Scale decreased significantly from days 1 to 5 in favorable group. Conclusion: For those with an unfavorable outcome and prolonged LOS, PI continues to increase suggesting a failure of autoregulation. Carotid Doppler can be a simple bedside tool to predict outcome in patients with acute stroke.

Renal sinus fat is associated with intrarenal hemodynamic abnormalities independent of visceral fat in patients with chronic kidney disease.

OBJECTIVE: Obesity is a risk factor of chronic kidney disease (CKD), contributing to the rising incidence of cardiometabolic diseases. Renal sinus fat (RSF) is an ectopic fat depot located at the renal cavity that could impair renal function and hemodynamic through compression of renal structures. The major purpose of this study was to explore the relationship between RSF accumulation and renal dysfunction in CKD patients. METHODS: We evaluated the associations between computed tomography measured RSF volume and key clinical and histologic parameters involved in renal function and hemodynamics in 132 well-characterized CKD patients who underwent renal biopsy (median age: 62 years; 63.6% men). RESULTS: RSF volume normalized by renal volume (RSF%) positively correlated with obesity-related traits such body mass index and visceral fat volume (VFV) (all P < 0.001) whereas it negatively correlated with estimated glomerular filtration rate (eGFR) (ρ = -0.42, P < 0.001) and 24-h urinary creatinine clearance (CCr) (ρ = -0.34, P < 0.001). Notably, we found robust positive correlations between RSF% and renal resistive index (RRI) measured by the Doppler ultrasound (ρ = 0.40, P < 0.001), and the histological severity of global glomerular sclerosis (ρ = 0.48, P < 0.001) and interstitial fibrosis and tubular atrophy (IFTA) (ρ = 0.35, P < 0.001). In the multivariate linear regression models, after accounting for potential confounders including VFV, RSF% remained significantly associated with CCr (ß = -0.26, P < 0.001), RRI (ß = 0.17, P = 0.022), global glomerular sclerosis (ß = 0.21, P = 0.002), and IFTA (ß = 0.17, P = 0.012). CONCLUSION: RSF accumulation is associated with renal dysfunction and hemodynamic abnormalities independent of visceral adiposity. Our results suggest that RSF may have a potential unique role in the pathogenesis of CKD.

Does central venous stenosis affects the brachial artery flow volume and peripheral vascular resistive index in patients on maintenance hemodialysis? A retrospective study.

BACKGROUND: A well-functioning vascular access (VA) is crucial for the patients on maintenance hemodialysis (HD). Central venous stenosis (CVS) is a common, yet, overlooked complication of VA as its diagnosis is challenging. Moreover, its effect on the flow volume (FV) and the peripheral resistive index (RI) was not well discussed before. Despite the availability of doppler ultrasound (DUS) in most centers, direct visualization of central veins using DUS is quite difficult. METHODS: This is a retrospective single-center self-controlled cohort study that was conducted in a specialized vascular access management tertiary center in Japan and included all patients with CVS who underwent percutaneous transluminal angiography (PTA) with or without vascular stenting in the period from January 2014 to September 2022. The patients were divided according to their VA type into arteriovenous fistula (AVF), and arteriovenous graft (AVG) groups, then subdivided, according to the type of stenosis, into two subgroups: CVS, and mixed central and peripheral venous stenosis (MVS) groups. The FV and RI of the feeding artery were compared in the same procedure before and after PTA to assess the impact of the procedure itself. RESULTS: Data of 485 percutaneous transluminal angiography procedures (PTA), performed in 95 patients during the period from January 2014 to September 2022, were collected. FV and RI were significantly affected in the patients with MVS than patients with CVS. After PTA, both FV and RI were significantly improved. The improvement rate of FV and RI after PTA were significantly higher in patients with MVS than patients with CVS. However, it was difficult to determine the cut-off value to diagnose or to assess the improvement of CVS. CONCLUSION: Our findings suggest that FV and RI measurement by DUS are good tools, along with the clinical findings for assessment of CVS in certain situations.