Intrarenal Arterial Resistive Index Research Articles

Intrarenal Artery Resistive Index – An Invaluable Tool In Detecting Obstructive Uropathy

Intrarenal Artery Resistive Index – An Invaluable Tool In Detecting Obstructive Uropathy

Abstract #1405590: Resistive Index (RI) on Renal Doppler as an Early Marker for Detecting Diabetic Nephropathy (DN)

This study was carried out to find out Resistive Index (RI) on Renal Doppler as an early marker for detecting DN and also to find out sensitivity of RI for early detection of Diabetic nephropathy. It’s a case control study of 100 patients age >18 years Study group included 50 diabetic patients with microalbuminuria and 50 diabetic patients without microalbuminuria constituted controls. Detailed clinical history and microvascular complications were recorded. All patients underwent Renal Doppler by single operator on ultrasound GE Voluson E8 with 3.5 Htz probe and RI was assessed. Proportion of patients with RI >0.7 was significantly higher in Study group as compared to controls. Mean ± SD of RI in study group was 0.72 ± 0.06, which was significantly higher as compared to control (0.61 ± 0.04). (p value <0.0001). The patients who had diabetic nephropathy, 70.00% of patients had resistive index >0.7. If resistive index was >0.7, then there was 100.00% probability of diabetic nephropathy and if resistive index< =0.7, then there were 76.92% chances of absence of diabetic nephropathy. Significant positive correlation was seen between resistive index with urine albuminuria (mg/dL) having correlation coefficient of 0.414. The present study points to significant increase in intrarenal arterial RI on renal doppler among diabetic nephropathy patients, when compared to diabetics without nephropathy. So, RI on renal doppler can be used as early, sensitive marker for detection of diabetic nephropathy.

Hyponatremia and Renal Venous Congestion in Heart Failure Patients.

Objective The interrelationship between the heart and kidneys has a great importance in the homeostasis of the cardiovascular system. Heart failure patients present intrarenal arterial hypoperfusion and intrarenal venous congestion due to reduced left ventricle ejection fraction, which triggers numerous neurohormonal factors. The aim of this study was to investigate intrarenal vascularization (arterial and venous), as well as the links between it and systemic congestion and, on the other side, with the mortality in patients with heart failure. Material and Methods. This cross-sectional study was performed on a group of 44 patients with heart failure in different stages of evolution and 44 healthy subjects, matched for age and gender, as controls. Serum natremia, NT-proBNP, and creatinine analyses were performed in all patients and controls. Renal and cardiac ultrasonography was done in all patients and controls, recording intrarenal arterial resistive index (RRI), intrarenal venous flow (IRVF) pattern, renal venous stasis index (RVSI), and left ventricular ejection fraction (LVEF). Data are recorded and presented as mean ± standard deviation. Statistical analyses were performed using the Student t-test, ANOVA test, and the Pearson correlation. Differences were considered statistically significant at the value of p < 0.05. Results Hyponatremia was identified in 47.72% of the HF patients. This study revealed correlations between serum natremia and LVEF, NT-proBNP, serum creatinine, interlobar venous RVSI (p < 0.00001), and interlobar artery RRI (p ≤ 0.002). Hyponatremia and renal venous congestion represent negative prognostic factors in HF patients. Conclusion In HF patients, hyponatremia was correlated with cardiac dysfunction and intrarenal venous congestion. Hyponatremia and renal venous congestion represented negative prognostic factors in HF patients.

Early Sonographic Evaluation of Intrarenal Arterial Resistive Index and Long-term Renal Function in Renal Transplant Recipients in South Western Nigeria.

Background:Color Doppler ultrasonography of intrarenal arterial Resistive Index (RI), performed early after kidney transplant, has proven to reliably predict short-term allograft function. The aim of this study was to assess whether early Doppler assessment could correlate with long-term renal function.Methods:This was a retrospective study of intrarenal RI using ultrasound in 41 stable kidney transplant patients who underwent RI assessment within 1 month after the transplant. Color Doppler ultrasonography was done to calculate the intrarenal RI within the first 4 weeks after transplant. The mean values of the intrarenal RI of the interlobar arteries of the allograft kidneys were measured and recorded. The data were analyzed with the aid of computer-based SPSS 20.0 software for windows (IBM, International Business Machines Corporation, Company, Armonk, New York, USA).Results:Older recipient age, active smoking, and proteinuria were associated with a higher intrarenal RI. Multivariate analyses showed that renal RI and donor age were independent predictors of allograft outcome. Kaplan–Meier estimates of cumulative graft survival were significantly worse in patients who had the values of the RI of 0.7 or more than they were in patients who had the values of the RI of <0.7.Conclusion:This study reveals that renal RI determined within the 1st month after renal transplant correlates with long-term allograft function in kidney transplant recipients.

A comparative ultrasonographic evaluation of intrarenal artery resistive index among hypertensive and normotensive adults in a black African population compared to a European population.

BackgroundHypertensive nephropathy is an important medical problem among the black African population. Early detection of renovascular changes using ultrasonography can provide opportunity for immediate intervention towards preventing or at least delaying the irreversible hypertensive nephropathy.PurposeTo compare intrarenal resistive index (RI) in healthy normotensive and hypertensive adults in Kano, Nigeria.Material and MethodsA prospective comparative study of intrarenal RI using ultrasound in 150 hypertensives and 150 normotensive controls. The mean renal RI of the interlobar arteries of both kidneys were measured and recorded. The data were analyzed with the aid of computer-based SPSS 16.0 software for Windows.ResultsThe age range of the study participants was 35–70 years. The mean interlobar artery RI values were 0.59 ± 0.04 and 0.59 ± 0.03 on the right and left sides, respectively, in normotensive control individuals while those of hypertensive individuals were 0.73 ± 0.03 and 0.73 ± 0.03 for the mean interlobar artery RI values on the right and left sides, respectively.ConclusionThe intrarenal RIs were lower in normotensives when compared with the hypertensive participants, which were statistically significant. These showed that hypertension has significant effects on the kidneys, and with early detection and intervention, irreversible renal damage may be prevented.

A comparative ultrasonographic evaluation of intrarenal artery resistive index among hypertensive and normotensive adults in north-western Nigeria

Introduction: Hypertension is a sustained systolic blood pressure equal to or above 140 mmHg or diastolic blood pressure equal to or above 90 mmHg. The kidneys play a central role in the control of high blood pressure through the renin–angiotensin system. Thus, renovascular changes of myointimal hyperplasia in the intrarenal arteries may cause an increase in renal arterial impedance and eventually irreversible hypertensive nephropathy.The early detection of these renovascular changes using ultrasonography can provide opportunity for immediate intervention toward preventing or at least delaying the irreversible hypertensive nephropathy.Aims and Objectives: The objective of this study is to determine and compare intra-renal resistive index (RRI) in normotensive and hypertensive adults within the age range of 35–70 years at Aminu Kano Teaching Hospital, Kano, Nigeria.Materials and Methods: A prospective case–control study of intra-RRI using ultrasound in 150 hypertensive patients and 150 normotensive controls. The mean RRI of the interlobar arteries of both kidneys was measured and recorded. The data were analyzed with the aid of computer-based SPSS 16.0 software for windows.Results: The ages of the study participants ranged between 35 and 70 years. The age difference was not statistically significant (P = 0.88). The mean interlobar artery resistive index (RI) values were 0.59 ±Â 0.04 and 0.59 ±Â 0.03 on the right and left sides, respectively, in normotensive controls while those of hypertensive patients were 0.73 ±Â 0.03 and 0.73 ±Â 0.03 for the mean interlobar artery RI values on the right and left sides, respectively, and both were statistically significant.Conclusion: The intra-RRIs were lower in normotensive participants when compared with the hypertensive patients which were statistically significant. These showed that hypertension has significant effects on the kidneys, and with early detection and intervention, irreversible renal damage may be prevented.

Pediatric En Bloc Kidney Transplants: Clinical and Immediate Postoperative US Factors Associated with Vascular Thrombosis.

Purpose To evaluate clinical and immediate postoperative ultrasonographic (US) risk factors associated with vascular thrombosis of pediatric en bloc kidney grafts. Materials and Methods This institutional review board-approved HIPAA-compliant retrospective study consisted of 195 recipients of pediatric en bloc kidney grafts throughout a 10-year period. The average recipient and donor age was 45 years (range, 7-74 years) and 9 months (range, 0-84 months), respectively. Clinical factors and immediate postoperative US findings were assessed. Categorical variables were evaluated by using the Fisher exact test and linear models with generalized estimating equations. Results Seventeen patients (23 kidneys) experienced thrombotic events. In six patients (eight kidneys), thrombosis occurred intraoperatively. The remaining 11 patients (15 kidneys) received a diagnosis of thrombosis on postoperative days 1-13. Recipients more than 40 years old had a higher incidence of arterial thrombosis than did younger recipients (eight of 62 vs three of 133, respectively; P < .01). Recipients were more likely to develop thrombosis with donor weight less than 5 kg (10 of 52 vs seven of 140 with donor weight of ≥ 5 kg; P < .01), with intraoperative perfusional concern (10 of 21 vs seven of 174 without; P < .01), or with right-sided allograft placement (10 of 64 vs seven of 131 left sided; P = .03). At US of the 15 postoperative thrombotic events, the incidence of thrombosis was greater when donor arterial velocity was less than 100 cm/sec (seven of 56 vs four of 126 with velocity ≥ 100 cm/sec; P = .04). An intrarenal arterial resistive index of less than 0.6 was associated with higher incidence of arterial thrombosis (nine of 123 vs zero of 217, respectively; P = .01). A resistive index greater than 0.8 was associated with a higher incidence of venous thrombosis (four of 13 vs one of 217, respectively; P = .04). Conclusion Clinical factors and immediate US findings can help stratify patients receiving pediatric en bloc kidneys into risk categories for vascular thrombosis that, if proven in prospective studies, could affect immediate postoperative treatment. (©) RSNA, 2015.

Abstract 231: Hydrogen Sulfide Promotes Macrophage Polarization to Reduce Renal Inflammation in Angiotensin-II Induced Hypertension

Ageing is associated with structural and functional changes in the kidney and the presence of hypertension in this population further contributes to renal complications leading to renovascular sclerosis. Emerging evidence suggests that hydrogen sulfide (H 2 S) pathway participates in the pathogenesis of hypertension. Furthermore, chronic inflammation is known to play a critical role in ageing and development of hypertension. In this study, we hypothesized that angiotensin-II (Ang-II)-induced hypertension causes renal fibrosis by sustained activation of pro-inflammatory M1 macrophage promoting the release of inflammatory cytokines and treatment with H 2 S attenuates renal injury and fibrosis by promoting alternate activation of anti-inflammatory M2 macrophage. C57BL/6J (wild type, WT) mice, aged 18 months, were infused with Ang-II (1000ng/Kg/min) or saline using osmotic pumps for 4 weeks and treated without or with H 2 S in drinking water (30μM/L). Animal groups were 1) Saline, 2) Saline + H 2 S, 3) Ang-II, 4) Ang-II + H 2 S. Blood pressure was measured weekly and renal ultrasound was done to measure hemodynamic parameters. Systolic and diastolic blood pressure was increased in mice receiving Ang-II (160.73 ± 4.5 and 129.10 ± 4.9 respectively) and treatment with H 2 S showed significant reduction (134.5 ± 4.8 and 101.1 ± 4.5 respectively). Ultrasound revealed increased renal artery and intra-renal cortical artery resistive index in Ang-II mice (0.73 ± 0.03) which was significantly decreased following H2S treatment (0.61 ± 0.2). Ang-II increased the protein expression and mRNA levels of pro-inflammatory M1 macrophage marker, CD40, and TNF-α and MCP-1, whereas, H2S treatment increased the expression of anti-inflammatory M2 macrophage marker, CD206, and IL-10. Fluorescent probe H2DCF-DA showed increased intracellular reactive oxygen species with Ang-II treatment which was abrogated with H2S treatment. Our data suggests that H 2 S treatment in Ang-II-induced hypertension attenuates inflammation and hypertension by reducing classical activation of inflammatory M1 macrophage and promotes alternate activation of anti-inflammatory M2 macrophage.

Intrarenal arterial resistance is associated with microvascular complications in Chinese type 2 diabetic patients

Increased renal arterial resistance is associated with various types of chronic renal parenchymal diseases. A resistance index (RI) > 0.8 predicts deterioration in renal function in diabetic subjects. However, the association between renal RI and other diabetic complications has not been investigated. In this study, we examined the association between intrarenal arterial RI and diabetic complications in Chinese type 2 diabetic subjects. Three hundred and eighty-seven Chinese type 2 diabetic patients were recruited from a structured assessment programme to evaluate their risk factors and complications as a part of the quality improvement programme at the Prince of Wales Hospital. All subjects underwent ultrasound examinations for the assessment of intrarenal arterial RI of both kidneys. Clinical and biochemical parameters, including diabetes-related microvascular complications (nephropathy, retinopathy and sensory neuropathy) and macrovascular diseases, were examined. The mean RI of patients with any microvascular complications (0.70 ± 0.09 versus 0.65 ± 0.06) such as nephropathy (0.71 ± 0.09 versus 0.66 ± 0.06), retinopathy (0.71 ± 0.08 versus 0.67 ± 0.08) and sensory neuropathy (0.75 ± 0.07 versus 0.68 ± 0.08) and with any macrovascular complications (0.71 ± 0.09 versus 0.68 ± 0.08) was higher than those without (P < 0.05). On multivariate analysis, after controlling for confounding variables, an RI ≥0.75 was associated with microvascular complications, nephropathy, retinopathy and sensory neuropathy, with odds ratio of 4.02 [95% confidence interval (CI) 1.72-9.4], 4.99 (2.61-9.56), 2.78 (1.52-5.09) and 5.74 (1.8-18.3), respectively. The association of RI with macrovascular complications was not significant in multivariate analysis. Increased intrarenal arterial resistance was independently associated with an increased risk of microvascular complications including diabetic nephropathy, diabetic retinopathy and diabetic sensory neuropathy in Chinese type 2 diabetic patients.

Correlation of ultrasonographic measurement of intrarenal arterial resistance index with microalbuminuria in nonhypertensive, nondiabetic obese patients

To determine whether intrarenal arterial resistance index (RI) value is related to increased urinary albumin excretion and whether RI value is an independent good indicator to evaluate early renal damage in nonhypertensive, nondiabetic obese subjects. Sixty-four nonhypertensive, nondiabetic obese patients (OB) and 35 age- and sex-matched normal healthy subjects were involved in this study. Clinical characteristics and blood biochemistry of all the subjects were measured. Urinary albumin/creatinine ratio (ACR) and sonographic evaluation of renal blood flow were determined. ACR and interlobar arterial RI were significantly higher in obese patients than those of normal healthy subjects. Interlobar arterial RI value was higher in patients with microalbuminuria than those with normoalbuminuria. Correlation analysis showed interlobar artery RI value had a positive correlation with ACR (r = 0.615, p < 0.01) and plasma free fatty acids (FFAs, r = 0.407, p < 0.01). ACR had a positive correlation with BMI (r = 0.380, p < 0.01), waist circumference (r = 0.414, p < 0.01), plasma FFAs (r = 0.537, p < 0.01). Multivariate regression analyses showed that ACR was best predicted by interlobar artery RI value even when body mass index, waist circumference, FFAs, and high-sensitive C reaction protein were added in the statistical analysis. Interlobar arterial RI may be an independent predictor of microalbuminuria in nonhypertensive, nondiabetic obese patients, and interlobar arterial RI could be a useful tool for assessment early renal damage in obese patients.

Prognostic impact of renal arterial resistance index upon renal allograft survival: the time point matters

The renal arterial resistance index (RI) is reported to be a significant predictive parameter for renal allograft failure or death. The influence of the time point after renal transplantation on its predictive power has not been sufficiently evaluated. We performed a retrospective analysis of RI and its power to predict renal allograft failure or death with special emphasis on the time point of RI measurement. The present analysis is based on ultrasonographically recorded intrarenal arterial RI measurements, routinely obtained in our outpatient department, over a period of 13 years. Altogether, 88 patients with an RI measurement 0-3, 3-6 and 12-18 months after transplantation were included and retrospectively stratified into two groups according to the RI: those with an index >0.75 and those with an index of ≤0.75. Twenty patients (23%) reached the combined end point, i.e. allograft failure with a return to dialysis or death. The RI measured early after transplantation (0-3 and 3-6 months) did not predict the end point, whereas the RI obtained between 12 and 18 months showed a significant predictive value for renal transplant failure or death in a univariate approach [Wald test, P = 0.0013, hazard ratio (HR) 4.787, 95% confidence interval (CI) 1.846-12.411]. At 12-18 months after transplantation, 14% (12 patients) of the study population had an RI >0.75. Seven (58%) of these patients reached the end point versus 13 of 76 patients (17%) with an RI ≤0.75. In a multivariate Cox model, the RI measured between 12 and 18 months after transplantation exhibited the highest hazard ratio (HR 6.191, 95% CI 2.288-16.756, P = 0.0003) for transplant failure or death. In our hands, the RI obtained during the first 6 months after transplantation failed to predict renal allograft failure or death, whereas the RI measured 12-18 months after transplantation appeared useful to predict long-term allograft outcomes.

Correlation between the Resistive Index Values of Renal and Orbital Arteries

Background: Resistive index (RI) is an indirect measurement of blood flow resistance that can be used to evaluate vascular damage. Aims: The purpose of this study is to evaluate the association between RI values of orbital and intrarenal arteries by means of Doppler ultrasonography (US). Methods: We evaluated 103 diabetic patients. As a control group, 30 subjects were examined. The patients were divided into two groups. Group 1 consisted of patients with urinary albumin excretion (UAE) <300 mg/day and estimated glomerular filtration rate (eGFR) levels >90 ml/min (n = 50); Group 2 had a UAE >300 mg/day and/or eGFR levels between 89 and 60 ml/min (n = 53). The association between RI values obtained with Doppler US of the ophthalmic artery, central retinal artery, posterior ciliary artery and intrarenal arteries were calculated. Results: Both orbital and intrarenal arterial RI values in Group 1 and Group 2 were higher than the control group (p = 0.001); furthermore, values were higher in Group 2 than in Group 1 (p = 0.0004/0.029/0.036, p = 0.016, respectively). A positive correlation was found between orbital and intrarenal arterial RI values in Group 2 (r = 0.475, 0.285, 0.363, p < 0.01, respectively). Conclusion: Both orbital and renal arterial RI values were shown to be higher than the control group. Further, a trend towards higher RI values was observed with renal disease. RI may be useful as one of the markers for early diagnosis and follow-up of diabetic nephropathy and retinopathy.

The Effect of Enalapril on Renal Resistive Index, Urine Electrolyte Levels and TGF-β1 Levels of Kidney Tissues in Rats with Unilateral Partial Ureteropelvic Junction Obstruction

This study aimed to investigate renal arterial resistive index measurements and urine electrolytes before and after enalapril therapy in a rat model of unilateral ureteropelvic obstruction. The transforming growth factor (TGF)-β1 response of the renal tissue was also investigated. 30 Wistar albino rats were randomly allocated into 5 groups (n=6). Group C rats served as controls. Group S rats had only laparotomy. Group E rats were only treated with enalapril. Rats in group UP and group UPE underwent laparotomy to create a left unilateral moderate partial obstruction. 2 weeks after establishing partial ureteropelvic junction obstruction, group UPE rats were treated with enalapril. Urine was collected over 24 h in all groups. Intrarenal arterial resistive index measurements were performed before and 2 weeks after surgery and after enalapril treatment in group UPE, and before and after enalapril treatment in group E. Rats were sacrificed by intracardiac puncture and left kidneys were harvested to evaluate levels of mRNA TGF-β1. There was no significant difference in ARI values in group E. In group UPE, the difference between ARI values before and after surgery was statistically significant; the difference between ARI values after surgery and after enalapril treatment was also statistically significant. There was no statistically significant intra-group difference in urine electrolyte levels for UP group or UPE group. There was no difference in renal mRNA TGF-β1 levels. Enalapril maintained renal blood flow by decreasing the arterial resistive index and maintained renal tubular function by protecting urine concentration and dilution ability in a rat model with unilateral ureteropelvic junction obstruction.

Renal function and severity of bright liver. Relationship with insulin resistance, intrarenal resistive index, and glomerular filtration rate

Relationships of renal function and liver disease are described in acute and chronic liver failure. The aim of the study is to investigate which relationship, if any, is present between severity of non-alcoholic fatty liver disease (NAFLD), assessed by bright liver score (BLS) versus mild-moderate renal insufficiency assessed by glomerular filtration rate (GFR) and by ultrasound intra-renal arterial resistive index (RRI). Moreover, which difference, if any, can be found in NAFLD patients with normal versus increased transaminases. The study enrolled 323 NAFLD and 176 non-NAFLD consecutive patients, comparable for age, gender distribution, GFR, and RRI referred to a university clinical day hospital after an ultrasound diagnosis of bright liver, for clinical-nutritional counselling. Personalized computerized mediterranean diet, physical activity increase, and smoking withdrawal integrated counselling were provided. In NAFLD patients, homoeostasis model (HOMA) has a significant correlation with BLS. According to the severity of BLS, grade II-III versus grade I patients have significantly higher values of HOMA, body mass index (BMI), triglycerides, and longitudinal right liver length. By odds ratio, more severe BLS, increased HOMA, and transaminases are associated with lower GFR. Increased transaminases are associated with higher grades of BLS, HOMA, and BMI. By multiple linear regression waist-to-hip ratio, RRI, and BLS, as significant independent factors (p<0.0001), explain significantly variance to GFR. This is not observed in normal control group, in which only RRI is a factor explaining GFR. Greater RRI, abdominal obesity, and greater BLS account for a lower GFR in NAFLD patients suggesting the hypothesis that inter-related factors can be operating early in the natural history of obesity-related kidney and liver disease.

Associations of intra-renal arterial resistance index with chronic kidney disease and carotid intima-media thickness in type 2 diabetes mellitus

Renal dysfunction can be evaluated by increased intra-renal arterial resistance index (RI). We evaluated 113 Chinese men with type 2 diabetes on their RI. Results suggest that RI is associated with chronic kidney disease and subclinical arteriosclerosis. RI may help monitoring the deterioration of intra-renal hemodynamics.

Association of visceral adiposity with increased intrarenal artery resistive index in HIV-1-infected patients receiving highly active antiretroviral therapy.

The aim of our study was to evaluate whether perirenal fat thickness (PRFT), a parameter of central obesity, is related to kidney function and intrarenal artery resistive index (IARI) in human immunodeficiency virus (HIV)-1-infected patients. We enrolled 102 consecutive HIV-1-infected patients receiving highly active antiretroviral therapy for more than 12 months in a prospective cohort study. Echographically, the PRFT and IARI were measured and the serum metabolic parameters were evaluated. PRFT and IARI were measured using a 3.75 MHz convex linear probe. The mean of PRFT and IARI in HIV-1-infected patients with visceral obesity was considerably higher than that in patients without it (P <0.001 and <0.01, respectively). Using the average IARI as the dependent variable, age (odds ratio, 1.07; 95% confidence interval [CI], 1.01-1.14; P < 0.5) and PRFT (odds ratio, 1.28; 95% CI, 1.08P-1.51; P<0.01) were independent factors associated with IARI. Our data indicate that ultrasonographic assessment of PRFT may have a potential to be a marker of increased endothelial damage with specific involvement of the renal vascular district in HIV-1-infected patients.

Association of visceral adiposity with increased intrarenal artery resistive index in HIV-1-infected patients receiving highly active antiretroviral therapy

Purpose:The aim of our study was to evaluate whether perirenal fat thickness (PRFT), a parameter of central obesity, is related to kidney function and intrarenal artery resistive index (IARI) in human immunodeficiency virus (HIV)-1-infected patients.Materials and Methods:We enrolled 102 consecutive HIV-1-infected patients receiving highly active antiretroviral therapy for more than 12 months in a prospective cohort study. Echographically, the PRFT and IARI were measured and the serum metabolic parameters were evaluated. PRFT and IARI were measured using a 3.75 MHz convex linear probe.Results:The mean of PRFT and IARI in HIV-1-infected patients with visceral obesity was considerably higher than that in patients without it (P <0.001 and <0.01, respectively). Using the average IARI as the dependent variable, age (odds ratio, 1.07; 95% confidence interval [CI], 1.01–1.14; P < 0.5) and PRFT (odds ratio, 1.28; 95% CI, 1.08P–1.51; P<0.01) were independent factors associated with IARI.Conclusion:Our data indicate that ultrasonographic assessment of PRFT may have a potential to be a marker of increased endothelial damage with specific involvement of the renal vascular district in HIV-1-infected patients.

Early Assessment of Renal Resistance Index and Long-Term Renal Function in Renal Transplant Recipients

Background. The effect of the intrarenal arterial resistance index (RI) on long-term renal functions is not well known. We examined the predictive value of intrarenal RI on long-term allograft outcomes. Methods. We retrospectively investigated 121 stable renal transplant recipients, followed for a mean of 63.21 ± 19.9 months after renal transplant. Patients with complications during the first six months after transplant were not included. Color Doppler ultrasonography was done to calculate the intrarenal RI within the first four weeks after transplant. Results. Older recipient age, high pulse pressure, active smoking, and proteinuria were associated with a higher intrarenal RI. Multivariate analyses revealed that renal RI and donor age were independent predictors of allograft outcome. Kaplan-Meier estimates of cumulative graft survival were significantly worse in patients who had an RI of 0.7 or more than they were in patients who had an RI of less than 0.7 (p = .005). Development of chronic allograft nephropathy (CAN) was significantly higher in patients who had an RI of 0.7 or more (p = .02). Conclusions. Renal RI determined within the first month after renal transplant predicts long-term allograft function and development of CAN in renal transplant recipients.

Measurement of the intrarenal arterial resistance index for the identification and prediction of diabetic nephropathy

Background and Aims High intrarenal resistance index (RI) predicts renal function in several conditions; its use in the prediction of diabetic nephropathy (DN) is little explored. We aimed (1) to compare RI in diabetic and non diabetic hypertensive patients, and (2) to evaluate whether high RI is associated with clinical signs of DN and its progression over time. Methods and Results Design: observational, prospective. Participants: 92 type 2 diabetic patients and 37 non-diabetic controls aged 40–70, with hypertension and normal renal function. We measured ultrasound RI and, among others, creatinine, estimated glomerular filtration rate and urinary albumin excretion rate (AER) at baseline and after 4.5 years follow-up. Progression of albuminuric state (i.e., transition from baseline normo-microalbuminuria to follow-up micro-macroalbuminuria) was evaluated. RI was significantly higher in diabetic than non-diabetic participants (0.69 ± 0.05 vs 0.59 ± 0.05, p < 0.001). Diabetic patients with RI ≥ 0.73, i.e., above the 80th percentile of the RI distribution, had significantly higher baseline AER and a more frequent progression of the albuminuric state compared to patients with RI < 0.73 (27.7 μg/mg [12.1–235.4] vs 15.1 μg/mg [8.6–33.4]; 52.9% vs 9.5%, respectively). AER increased significantly from baseline to follow-up in patients with RI ≥ 0.73 (from 27.7 μg/mg [12.1–235.4] to 265.0 μg/mg [23.8–1018.1], p < 0.01), but not in those with RI < 0.73 (from 15.1 μg/mg [8.6–33.4] to 16.1 μg/mg [10.7–67.2], ns). OR for progression of albuminuric state, adjusted for established predictors of DN, including baseline AER, was 5.01 (1.4–17.7, 95% CI) for patients with RI ≥ 0.73 vs <0.73. Findings were confirmed in patients with normoalbuminuria at baseline. Conclusions In diabetic patients, high RI (≥0.73) is associated with features of DN and its progression over time, independent of albuminuria.

The Predictive Value of Arterial Renal Blood Flow Parameters in Renal Graft Survival

Background Renal allograft survival depends on a number of factors, however, no reliable simple parameter has been shown to predict long-term outcome after transplantation. Ultrasound is recognized and relatively inexpensive, providing information about renal location, contour, and size. Doppler ultrasonography shows kidney morphology and hemodynamics. The aim of this study was the evaluation of whether Doppler ultrasound of renal arteries performed in the early stage after transplantation was a valuable predictor for long-term-outcomes. Material and Methods The study included 17 female and 24 male patients, aged 17–69 years with stable graft function. The Doppler ultrasound of renal flow was done on the 1st and 3rd day after transplantaion, and estimated glomerular filtration rate (eGFR) on the 20th day. The measured indices were as follows: maximum blood flow velocity (V max), minimum blood flow velocity (V min), resistive index (RI), and pulsatile index (PI). The creatinine concentration was evaluated, and eGFR calculated. Results Mean renal and intrarenal artery RI increased to day 3 after transplantation, and then reduced. The mean renal and intrarenal V max at day 3 correlated positively with eGFR ( r = 0.38; P = .015); ( r = 0.45; P = .003, respectively). Mean renal and intrarenal V min correlated positively with eGFR ( r = 0.50; P = .001; r = 0.41; P = .008, respectively). The mean renal and intrarenal V max and V min on day 1 did not correlate with eGFR. Conclusions Early Doppler Ultrasonography of renal graft hemodynamics may be a valuable predictor of graft survival and long-term outcomes. Blood flow velocity within renal arteries seemed to be an important factor.