Increase In Renal Resistive Index Research Articles

P237 WORSENING OF RENAL FUNCTION AND INCREASE IN RENAL RESISTANCE INDEX AFTER CARDIAC SURGERY

Abstract Worsening of renal function (WRF) is frequently observed after cardiac surgery and it is associated with both short– and long–term worse outcome. Among the pathophysiological conditions favoring the occurrence of WRF, the abnormalities in renal blood flow could play a key role. The aim of this study was to evaluate the changes in renal resistance index (RRI), a parameter reflecting renal parenchymal and hemodynamic parameters, after cardiac surgery. Methods Thirty–one patients were enrolled (age 65±12 years, 29% males, mean left ventricular ejection fraction 55±5%, mean creatinine serum levels 0.89±0.18 mg/dl, mean eGFR 89±28 ml/min*1.73 m2). All patients underwent cardiac surgery. Before cardiac surgery, after 3 days and before discharge, RRI was evaluated according to Peurcelot’s formula by renal interlobular arteries pulsed Doppler. Worsening of renal function was defined as an increase in serum creatinine of > 0.3 mg/dl associated with a change > 25% or the need of renal replacement therapy due to severe acute kidney injury. Results As shown in the table 1, after cardiac surgery a significant increase in RRI was observed at 3 days after cardiac surgery but not before discharge. The significant increase in RRI was observed both in patients with and without WRF. However, in patients with WRF significant higher values of RRI were observed before as well as after cardiac surgery. Conclusions Among patients undergoing cardiac surgery a significant increase in RRI values is observed after surgery. Among patients with WRF a significant greater values of RRI are observed before as well as cardiac surgery thus suggesting that a critical increase in renal resistance could play a role in the cardiorenal syndrome worsening.

Renal Resistive Index: Revisited.

Introduction Chronic kidney disease (CKD) is universally considered a public health burden and the majority of cases are found to be diabetic at the time of diagnosis. Renal biopsy is the prime modality for the complete evaluation of renal injuriesbut is invasive. Duplex Doppler sonography can help to determine renal resistive index (RRI), which is an excellent marker for demonstrating dynamic or structural changes of intrarenal vessels. In this study, we evaluated the intrarenal hemodynamic abnormalities with RRI in diabetic and non-diabetic kidney disease patients. Also, RRI was correlated with the established parameters of renal dysfunction, i.e., estimated glomerular filtration rate (eGFR) and other biochemical parameters. Results There was a significant correlation of RRI with eGFR and serum creatinine indicating its role as a Doppler parameter, which can be used as complementary to biochemical parameters. A remarkable difference was noted in the RRI values between diabetic and non-diabetic groups in the early stages of CKD, revealing its ability to arrive at etiopathogenesis in the early stages. The renal resistive index increases in a sequential pattern and is an indicator of declining renal function. Conclusions The addition of sonographic parameters like renal resistive index could help in the complete evaluation of chronic kidney disease in diabetic and non-diabetic groups. A sequential increase in renal resistive index is a better indicator of the progressive worsening of renal function as opposed to an absolute cut-off value.

PS-C26-4: ASSOCIATIONS BETWEEN ARTERIAL STIFFNESS INDICES AND CHRONIC KIDNEY DISEASE CATEGORIES IN ESSENTIAL HYPERTENSIVE PATIENTS

Background: This study investigated the association between arterial stiffness indices and asymptomatic chronic kidney disease (CKD) risk categories in hypertensive patients by using oscillometric device. Methods: Arterial stiffness indices, including 24-hour brachial and aortic systolic blood pressure (SBP) and pulse wave velocity (PWV), were measured by an oscillometric Mobil-O-Graph device, brachial-ankle PWV (baPWV) by a volume-plethysmographic method, and renal resistive index (RI) by ultrasonography, in 184 essential hypertensive patients (66.0 ± 17.1 years, 47.3% male). CKD was categorized into 3 stages based on the Kidney Disease Improving Global Outcomes (KDIGO) criteria, using a combination of estimated glomerular filtration and albuminuria. Results: The 24-hour aortic PWV (aPWV), baPWV, and RI increased with worsening severity of CKD risk category (all P < 0.01 for trend). Multivariate logistic regression analysis found that a 1 SD increase of nighttime aortic SBP (odds ratio [OR] 1.52), PWV (OR 4.80), or RI (OR 1.75) was an independent predictor of high or very-high CKD stage (all P < 0.05). After adjustment for potential confounders, day-to-night change in brachial SBP as well as in aPWV differed among groups (P < 0.05, respectively). In a multivariate regression model, day-to-night changes in aortic SBP and PWV, and RI were independently associated with day-to-night brachial SBP change. Conclusions: In hypertension, circadian hemodynamics in high CKD stage are characterized by higher nighttime values of aortic SBP and PWV and disturbed intrarenal hemodynamics. Further, the blunted nocturnal BP reduction in these patients might be mediated via disturbed intrarenal hemodynamics and circadian hemodynamic variation in aortic SBP and arterial stiffness.

In essential hypertension, a change in the renal resistive index is associated with a change in the ratio of 24-hour diastolic to systolic blood pressure.

An increase in the renal resistive index (RRI) in patients with essential hypertension (EH) predicts deterioration in renal function. In patients with EH, changes in hemodynamic parameters significantly affect the RRI. This study aimed to define changes in Ambulatory Blood Pressure Monitoring (ABPM) parameters that are significantly associated with a change in RRI in patients with EH. We evaluated ABPM and the RRI in 96 patients with EH without organ extrarenal changes at baseline and after two years of follow-up. The relationships between changes in ABPM parameters and the RRI over the period were evaluated. After two years of follow-up, the increase in RRI was consequential. Simultaneously, 24-h systolic blood pressure increased significantly and 24-h diastolic blood pressure decreased. In the whole group and in the group with calculated cystatin C clearance (eGFRcyst) >/=90 ml/min/1.73 m2, the change in RRI significantly negatively correlated with the change in the ratio of 24-h diastolic to systolic blood pressure (D/S ratio), but also with the change in 24-h pulse blood pressure. However, in patients with eGFRcyst>90 ml/min/1.73 m2, only the change in the 24-h D/S ratio significantly correlated with the change in RRI. Based on the backward stepwise regression analysis, the change in RRI was significantly dependent only on the change in 24-h D/S ratio and not on the change in 24-h pulse pressure. A change in the ratio of diastolic to systolic pressure better reflects a change in RRI than a change in pulse pressure.

Intraoperative evaluation of renal resistive index with transesophageal echocardiography for the assessment of acute renal injury in patients undergoing coronary artery bypass grafting surgery: A prospective observational study.

Background:Acute kidney injury (AKI) is a common complication after on pump coronary artery bypass grafting (CABG) surgery and is associated with a poor prognosis. Postoperative AKI is associated with morbidity, mortality, and increase in length of intensive care unit (ICU) stay and increases the financial burden. Identifying individuals at risk for developing AKI in postoperative period is extremely important to optimize outcomes. The aim of the study is to evaluate the association between the intraoperative transesophageal echocardiography (TEE) derived renal resistive index (RRI) and AKI in patients undergoing on-pump CABG surgery.Methods:This prospective observational study was conducted in patients more than 18 years of age undergoing elective on pump CABG surgery between July 1, 2018, and December 31, 2019, at a tertiary care center. All preoperative, intraoperative, and postoperative parameters were recorded. TEE measurement was performed in hemodynamically stable patients before the sternum was opened. Postoperative AKI was diagnosed based on the serial measurement of serum creatinine and the monitoring of urine output.Results:A total of 115 patients were included in our study. Thirty-nine (33.91%) patients had RRI >0.7 while remaining seventy-six (66.08%) patients had RRI <0.7. AKI was diagnosed in 26% (30/115) patients. AKI rates were significantly higher in patients with RRI values exceeding 0.7 with 46.15% (18/39) compared to 15.75% (12/76) in RRI values of less than 0.7. Multivariate analysis revealed that AKI was associated with an increase in RRI and diabetes mellitus. The RRI assessed by receiver operating characteristic (ROC) curve and the area under the curve (AUC) to distinguish between non-AKI and AKI groups were 0.705 (95% CI: 0.588–0.826) for preoperative RRI. The most accurate cut-off value to distinguish non-AKI and AKI groups was a preoperative RRI of 0.68 with a sensitivity of 70% and specificity of 67%.Conclusions:An increased intraoperative RRI is an independent predictor of AKI in the postoperative period in patients undergoing CABG surgery. The cutoff value of TEE-derived RRI in the intraoperative period should be >0.68 to predict AKI in the postoperative period.

The relationship of renal resistive index and carotis intima media thickness in patients with diabetic microalbuminuria

ObjectivesDiabetes is a chronic disease with increasing morbidity and mortality. Microalbuminuria is seen in diabetic patients due to nephropathy. Patients with microalbuminuria are at high risk for atherosclerosis. It is thought that comparing the carotid artery, which is most frequently affected by atherosclerosis, by measuring and comparing the renal resistive index, may be beneficial for early diagnosis and treatment of diabetic complications. MethodsOur study included 108 patients with diabetic microalbuminuria. Carotid intima media thickness (CIMT) and renal resistive index (RRI) measured, who applied to Adana Numune Training and Research Hospital between January and November 2016. We aimed to evaluate the patients with normal-abnormal RRI and normal-abnormal CIMT. The patients' diabetes age, weight, height, fasting blood sugar, HbA1c, and creatinine parameters were compared. ResultsWe observed an increase in RRI in parallel with the increase in CIMT in diabetic microalbuminuric patients (p<0,001). There was also a positive correlation between the creatinine value and the RRI (p:0.021). The increase in creatinine was significantly associated with the increase in CIMT(p<0.001). However, we could not detect the similar correlation with body mass index (BMI) in terms of both RRI andCIMT. ConclusionRRI measurement can be performed together with CIMT measurement for early detection of atherosclerosis. Patients with microalbuminuria and prone to atherosclerosis that cannot be detected by measurement of CIMT can be detected by measurement of the RRI.

Increase of renal resistive index and mineral metabolism disorder in patients with acute coronary syndrome with preserved renal function.

Coronary artery disease is one of the first causes of death in the Western world; for this reason, it is essential to identify new, systemic, non-invasive and low-cost cardiovascular risk markers. The acute coronary syndrome includes ST-Elevation Myocardial Infarction (STEMI) and Non-ST-Elevation Myocardial Infarction (NSTEMI), based on ECG findings. We aimed to evaluate Renal Resistive Index (RRI) as a marker of cardiovascular risk and assess the associations with other cardiovascular risk factors (metabolic indexes, mineral metabolism disorders and endothelial dysfunction and atherosclerosis markers) in STEMI and NSTEMI patients. Clinical, laboratory and instrumental examinations as metabolic and inflammation indexes, markers of atherosclerosis and endothelial dysfunction (renal function, mineral metabolism disorders, inflammation indexes, Intima Media Thickness (IMT), Ankle Brachial Pressure Index, Left Ventricular Mass Index, Relative Wall Thickness) were performed. Eighty-one patients with STEMI and NSTEMI were enrolled. We showed a significant positive correlation between RRI and age (p<0.01), intact parathyroid hormone (p<0.01) and IMT (p<0.01), as well as a significant negative correlation between RRI and body surface area (BSA) (p=0.02), estimated Glomerular Filtration Rate (eGFR) (p<0.01), serum calcium (p<0.01) and 25-hydroxy-vitamin D (p=0.03). Moreover, we found a significant correlation between RRI and male patients (p<0.01), coronary artery disease history (CAD) (p=0.049), hypertension (p=0.025) and left ventricular eccentric hypertrophy (LVEH) (p=0.047). Our study showed an association between RRI and the main traditional and non-traditional cardiovascular risk factors involved in atherosclerosis pathogenesis, such as age, BSA, hypertension, male sex, CAD history, mineral metabolism disorders and LVEH, in patients with preserved renal function. Moreover, we found a significant correlation between RRI and eGFR, suggesting that RRI could be useful in the evaluation of both renal function and progression of renal damage, even in an early stage with a conserved or only slightly reduced kidney function. We also showed a significant correlation with some markers of systemic atherosclerosis such as IMT and LVEH. For a more precise assessment of prognosis and cardiovascular risk in patients with high cardiovascular mortality, we suggest performing a systematic RRI evaluation, considering the non-invasive nature of the procedure, its reproducibility, easy execution, and low costs.

Associations Between Arterial Stiffness Indices and Chronic Kidney Disease Categories in Essential Hypertensive Patients.

This study investigated the association between arterial stiffness indices and asymptomatic chronic kidney disease (CKD) risk categories in hypertensive patients. Arterial stiffness indices, including 24-hour brachial and aortic systolic blood pressure (SBP) and pulse wave velocity (PWV), were measured by an oscillometric Mobil-O-Graph device, brachial-ankle PWV (baPWV) by a volume-plethysmographic method, and renal resistive index (RI) by ultrasonography, in 184 essential hypertensive patients (66.0 ± 17.1 years, 47.3% male). CKD was categorized into 3 stages based on the Kidney Disease Improving Global Outcomes (KDIGO) criteria, using a combination of estimated glomerular filtration and albuminuria. The 24-hour aortic PWV (aPWV), baPWV, and RI increased with worsening severity of CKD risk category (all P < 0.01 for trend). Multivariate logistic regression analysis found that a 1 SD increase of nighttime aortic SBP (odds ratio [OR] 1.52), PWV (OR 4.80), or RI (OR 1.75) was an independent predictor of high or very-high CKD stage (all P < 0.05). After adjustment for potential confounders, day-to-night change in brachial SBP as well as in aPWV differed among groups (P < 0.05, respectively). In a multivariate regression model, day-to-night changes in aortic SBP and PWV, and RI were independently associated with day-to-night brachial SBP change. In hypertension, circadian hemodynamics in high CKD stage are characterized by higher nighttime values of aortic SBP and PWV and disturbed intrarenal hemodynamics. Further, the blunted nocturnal BP reduction in these patients might be mediated via disturbed intrarenal hemodynamics and circadian hemodynamic variation in aortic SBP and arterial stiffness.

Determinants of the serial changes in measurements of renal allograft Doppler resistive index in the first postoperative month.

Introduction:The role of single Doppler-derived renal resistive index (RI) in renal allograft management is still a controversial issue, however detection of changes in serial duplex scanning has been reported as more valuable. This study aimed to test the hypothesis that early change in RI following transplantation may be related to factors associated with delayed graft function (DGF).Material and methods:113 patients were included, in whom two RI measurements were performed within 30 days post-transplant. According to an RI change (equal to or more than 10%) in the second measurement, patients were assigned to decrease (Group I), no change (Group II), or increase (Group III) group.Results:30 subjects had a decrease, 55 had no change, and 28 had an increase in the second RI measurement. The donors were younger in Group III in comparison to Group II. In comparison to Group I, Group III had a higher frequency of deceased donor, DGF, and presence of tubular necrosis and tubular vacuolization in peri-implantation biopsies.Conclusion:the increase of RI during the first weeks of the postoperative period seems to be associated with DGF and with tubular necrosis / tubular vacuolization in peri-implantation biopsies, likely related to ischemia reperfusion injury.

Evaluation of acute kidney injury with oxidative stress biomarkers and Renal Resistive Index after cardiac surgery

Background We investigated whether cardiopulmonary bypass (CPB) related oxidative stress mediated glycocalyx degradation can cause an increase in renal resistive index (RRI) or postoperative AKI. Additionally, to evaluate whether RRI and early postoperative serum cystatin C levels could improve the prediction sensitivity of acute kidney injury (AKI). Methods Forty-two patients undergoing cardiac surgery were included in this prospective observational study. RRI was measured pre-operatively and in the cardiac intensive care unit. Blood samples were collected for analyzing of cellular injury biomarkers at preoperative and postoperative second hours. We determined areas under the receiver operating characteristic curve (AUC) and odds ratios for postoperative biomarkers and RRI to predict AKI. Results While postoperative cystatin C level (AUC: 0.902, 95% CI = 0.79–1.00, p < .001) and RRI (AUC: 0.748, 95% CI = 0.56–0.93, p = .023) have diagnostic and predictive value in the prediction of AKI, we could not identify any relation between products of oxidative stress and the glycocalyx degradation and AKI. Conclusion These data suggest that CPB leads to structural and oxidative changes at the protein level and the integrity of glycocalyx is disturbing, but these changes are not specific to kidney injury. Our data suggest that serum cystatin C level and RRI could be used as an early biomarker for postoperative AKI after cardiac surgery.

The renal resistive index as a new complementary tool to predict microvascular diabetic complications in children and adolescents: a groundbreaking finding.

The increasing prevalence of type 1 diabetes mellitus (DM) has made it necessary to have new markers for early detection of diabetic nephropathy. Renal resistive index (RI) by using renal Doppler can be a helpful tool in detecting functional alterations in renal hemodynamics. This study was conducted on 100 children and adolescents with type 1 DM. They were further subdivided into two equal subgroups: group 1 with type 1 DM and normo-albuminuria [urinary albumin excretion (UAE) <30 mg/24 hours], and group 2 with type 1 DM and hyper-albuminuria (increased UAE >30 mg/24 hours). There were 37 males (37%) and 63 females (63%); their mean ages were 13.6±2.53 (range, 10-19) years and mean disease duration was 8.867±2.260 (range, 5-13) years. Progressive increase in RI was significantly associated with increased disease duration more than 10 years, elevated serum HbA1c more than 7.5% and early pubertal stages. While not significantly related to sex, weight, height, blood pressure or serum lipid profile, diabetic micro-vascular complications (nephropathy and sensory neuropathy) were more prevalent among patients with RI more than 0.58. Renal RI could be a useful complementary test for the evaluation of functional alterations in renal hemodynamics in the early stages of diabetic nephropathy.

Determinants of Doppler-based renal resistive index in patients with septic shock: impact of hemodynamic parameters, acute kidney injury and predisposing factors

BackgroundIncreased renal resistive index (RI) measured by Doppler ultrasonography has been shown to be associated with acute kidney injury (AKI) in septic patients. However, its clinical use is limited by poor sensitivity and specificity which may be explained by its numerous determinants [in particular mean arterial pressure (MAP)]. We measured, in patients with septic shock, RI at different MAP levels over a short period of time on the admission day to ICU (D1) and every 3 days until day 10 (D10) to define the determinants of RI and study specifically the relationship between RI and MAP.ResultsConsecutive patients with septic shock without preexisting chronic renal dysfunction were included in this prospective cohort study in two ICUs. Sixty-five patients were included in the study. Thirty-three (50.8%) and 15 (23.1%) patients had a history of chronic hypertension or diabetes, respectively. At D3, 35 patients presented AKI with AKIN 2 or 3 criteria (severe AKI, AKIN2-3 group) and 30 presented no AKIN or AKIN 1 criteria (AKIN0-1 group). As previously described, RI at D1 was higher in the AKIN2-3 group than in the AKIN0-1 group (0.73 interquartile range [0.67; 0.78] vs. 0.67 [0.59; 0.72], p = 0.001). A linear mixed model for predicting RI from D1 to D10 showed that an increase in pulse pressure, presence of severe AKI and additional day of ICU hospitalization were associated with an increase in RI. An increase in MAP and recovery from severe AKI were associated with a decrease in RI. In the presence of chronic hypertension or diabetes, an increase in MAP resulted in a lower decrease in RI, than in the absence of such factors. Presence of AKI at D3 did not impact the relationship between MAP and RI.ConclusionsSevere AKI was associated with a reversible increase in RI without significant interaction with the relationship between MAP and RI. Conversely, the presence of chronic hypertension and/or diabetes interacted with this relationship.

Low systolic blood pressure values, renal resistive index measurement and glomerular filtration rate in a non-dialysis dependent chronic kidney disease population.

A longitudinal prospective case control study was organized to explore the relationships between glomerular filtration rate (GFR), renal resistive index (RRI) and blood pressure values in a non-dialysis dependent adult population affected by chronic kidney disease and exposed to low systolic blood pressure (SBP) values. The study sample (54 patients: 31 males and 23 females with an average age of 61.7 ± 19.2 years) was randomly selected from a population of adult non-dialysis dependent patients that scored a SBP < 100 mmHg at the medical examination. The patients were equally divided in two groups defined by the presence and absence of chronic kidney disease, (i.e. a GFR less or greater than 60 ml/min/1.73 m2, respectively). Patients were submitted to a full therapeutic and dietetic intervention to correct the hypotension until reaching a steady SBP > 100 mmHg. In the group with chronic renal disease, the comparison between the data recorded with SBP < 100 mmHg (t0) and those detected with SBP ≥ 100 mmHg (t1) showed a statistically significant decrease of serum creatinine as well as an increase of GFR (mean serum creatinine t0 - serum creatinine t1: 0.194 ± 0.35, p < 0.01; mean GFR t0 - GFR t1: -4.615 ± 8.8, p < 0.013). There was also a statistically significant reduction of the RRI (mean right kidney RRI t0 - mean right kidney RRI t1: + 0.082 ± 0.03, p < 0; mean left kidney RRI t0 - mean left kidney RRI t1: 0.076 ± 0.03, p < 0). We concluded that, in CKD, when aorta is stiffed, a decrease of SBP can limit the renal perfusion that, in this condition, is mostly dependent by stroke volume, causing an increase of RRI and a decrease of GFR that we suppose as reversible with the restoration of SBP.

Hypertension is Common in Patients with Newly Diagnosed Acromegaly and is Independently Associated with Renal Resistive Index.

There are conflicting results regarding the frequency of hypertension (HT) and values of related parameters in patients with acromegaly. We aimed to determine the frequency of HT and values of its associated parameters in patients with acromegaly. 57 patients with newly diagnosed acromegaly were included in this study. Renal ultrasonography (US) was performed in addition to routine evaluation of acromegaly. Renal resistive index (RRI), renal pulsatility index (RPI), and accelerated time were measured using Doppler US. Hypertension was detected in 16 patients (28.1%) with newly diagnosed acromegaly. Serum triglyceride, TSH, growth hormone, and insulin growth factor 1 levels were higher and HDL levels were lower in acromegaly patients with HT. RRI and RPI values were found to be higher in acromegaly patients with HT. In logistic regression analysis, only the RRI value was found to be independently related to the presence of HT. Based on this analysis, it was determined that the frequency of HT increases 2.99 times for each increase in RRI of 0.05 units. When ROC analysis was performed, it was found that the area under the ROC curve was 0.781. In the same analysis, when the cutoff value for RRI was taken to be 0.70, the development of HT in acromegaly patients was determined with 75% sensitivity and 78% specificity. In patients with newly diagnosed acromegaly, HT frequency was significantly increased and it was independently associated with the RRI value. Therefore, these patients should be closely monitored for HT-the most frequent and important cardiovascular risk factor-and treated before they develop target organ damage.

Clinical Impact of Hemorheology Assessed Using the Microchannel Array Flow Analyzer on Renal Resistive Index in Patients With Type 2 Diabetes Mellitus

Background: The renal resistive index (RRI) assessed using ultrasonography is reportedly associated with not only kidney function but also cardiovascular disease incidence. In contrast, hemorheology assessed using the microchannel array flow analyzer (MC-FAN) has demonstrated the significance of cardiovascular risk factors in recent clinical studies. This cross-sectional study aimed to clarify the clinical impact of hemorheology assessed using MC-FAN on RRI in patients with type 2 diabetes mellitus from the perspective of primary prevention of cardiovascular events. Methods: In total, 302 outpatients undergoing treatment for type 2 diabetes mellitus (121 males and 181 females; mean age ± standard deviation, 66 ± 12 years) with no history of cardiovascular diseases were enrolled. The whole blood passage time (WBPT) was assessed using MC-FAN as a marker of hemorheology, and the relationship between RRI and various clinical parameters including WBPT was examined. Results: A significant positive correlation was observed between WBPT and RRI (correlation coefficient = 0.48; P < 0.001). Furthermore, the multiple regression analysis demonstrated that WBPT was selected as an independent variable for RRI as a subordinate factor (? = 0.37; P < 0.001). Patients with high WBPT (? 70 s) and median WBPT (50.2 - 69.6 s) had a significantly higher risk (odds ratio (OR): 7.9; 95% confidence interval (CI): 2.4 - 19.6; P < 0.01 and OR: 2.1; 95% CI: 1.1 - 7.8; P < 0.05, respectively) of having a high RRI (? 0.70) than those with low WBPT (? 50.0 s). Conclusions: The results of this study indicate that hemorheology assessed using MC-FAN is an important determining factor for RRI in patients with type 2 diabetes mellitus. Furthermore, we suggest that an increase in RRI can be prevented by maintaining WBPT ? 50.0 s. Further investigation of a large number of prospective studies, including intervention therapies, will be required to confirm the results of this study. J Endocrinol Metab. 2017;7(5):146-152 doi: https://doi.org/10.14740/jem448w

Clinical Impact of Hemorheology Assessed Using the Microchannel Array Flow Analyzer on Renal Resistive Index in Patients With Type 2 Diabetes Mellitus

Background: The renal resistive index (RRI) assessed using ultrasonography is reportedly associated with not only kidney function but also cardiovascular disease incidence. In contrast, hemorheology assessed using the microchannel array flow analyzer (MC-FAN) has demonstrated the significance of cardiovascular risk factors in recent clinical studies. This cross-sectional study aimed to clarify the clinical impact of hemorheology assessed using MC-FAN on RRI in patients with type 2 diabetes mellitus from the perspective of primary prevention of cardiovascular events. Methods: In total, 302 outpatients undergoing treatment for type 2 diabetes mellitus (121 males and 181 females; mean age ± standard deviation, 66 ± 12 years) with no history of cardiovascular diseases were enrolled. The whole blood passage time (WBPT) was assessed using MC-FAN as a marker of hemorheology, and the relationship between RRI and various clinical parameters including WBPT was examined. Results: A significant positive correlation was observed between WBPT and RRI (correlation coefficient = 0.48; P &lt; 0.001). Furthermore, the multiple regression analysis demonstrated that WBPT was selected as an independent variable for RRI as a subordinate factor (beta = 0.37; P &lt; 0.001). Patients with high WBPT (&gt;= 70 s) and median WBPT (50.2 - 69.6 s) had a significantly higher risk (odds ratio (OR): 7.9; 95% confidence interval (CI): 2.4 - 19.6; P &lt; 0.01 and OR: 2.1; 95% CI: 1.1 - 7.8; P &lt; 0.05, respectively) of having a high RRI (&gt;= 0.70) than those with low WBPT (&lt;= 50.0 s). Conclusions: The results of this study indicate that hemorheology assessed using MC-FAN is an important determining factor for RRI in patients with type 2 diabetes mellitus. Furthermore, we suggest that an increase in RRI can be prevented by maintaining WBPT &lt;= 50.0 s. Further investigation of a large number of prospective studies, including intervention therapies, will be required to confirm the results of this study. J Endocrinol Metab. 2017;7(5):146-152 doi: https://doi.org/10.14740/jem448w

Renal Resistive Index as a Novel Indicator for Renal Complications in High-Fat Diet-Fed Mice

Background/Aims: The renal resistive index (RI) is a novel candidate as a renal injury prognostic indicator, but it remains unclear how renal RI levels correspond to renal injury in diabetic nephropathy. Methods: To examine this issue, we compared 8-week-old male C57BL/6 mice fed with high-fat diet (HFD) versus chow diet (CHD) for 16 weeks. At 8 and 12 weeks, the glomerular filtration rate (GFR), urinary albumin-to-creatinine ratio (UACR), and inflammatory factors (IL-1β, IL-6, TNFα, and MCP-1) were measured, along with the increase in renal RI. Results: Our study suggests RI values positively correlate with GFR for the first 12 weeks of HFD feeding. In contrast, the GFR of 16-week HFD feeding is lower than that of 12-week HFD feeding, whereas RI levels are significantly increased. Additionally, our study suggests RI values accurately indicate the renal fibrosis and renal injury in HFD-fed mice treated with lovastatin. Conclusion: This study seems to confirm the utility of a noninvasive and repeatable ultrasound parameter to rapidly evaluate renal fibrosis in a HFD-induced type 2 diabetic mouse model in vivo. This highly sensitive and comparable renal RI measurement could monitor the whole procedure of disease development in real-time. RI measurement of the renal artery is capable of differentiating responses to standard therapy with lovastatin in HFD-fed mice from the CHD group.

Renal Vasoconstriction Occurs Early During Shockwave Lithotripsy in Humans.

In animal models, pretreatment with low-energy shock waves and a pause decreased renal injury from shockwave lithotripsy (SWL). This is associated with an increase in perioperative renal resistive index (RI). A perioperative rise is not seen without the protective protocol, which suggests that renal vasoconstriction during SWL plays a role in protecting the kidney from injury. The purpose of our study was to investigate whether there is an increase in renal RI during SWL in humans. Subjects were prospectively recruited from two hospitals. All subjects received an initial 250 shocks at low setting, followed by a 2-minute pause. Treatment power was then increased. Measurements of the renal RI were taken before start of procedure, at 250, after 750, after 1500 shocks, and at the end of the procedure. A linear mixed-effects model was used to compare RIs at the different time points. Fifteen patients were enrolled. Average treatment time was 46 ± 8 minutes. Average RI at pretreatment, after 250, after 750, after 1500 shocks, and post-treatment was 0.67 ± 0.06, 0.69 ± 0.08, 0.71 ± 0.07, 0.73 ± 0.07, and 0.74 ± 0.06, respectively. In adjusted analyses, RI was significantly increased after 750 shocks compared with pretreatment (p = 0.05). Renal RI increases early during SWL in humans with the protective protocol. Monitoring for a rise in RI during SWL is feasible and may provide real-time feedback as to when the kidney is protected.

Response to Renal Resistive Index and Cardiovascular and Renal Outcomes in Essential Hypertension

We thank Dr Heine et al1 for their interest in our recent findings2,3 and for their crucial and constructive criticisms and comments concerning the renal resistive index (RI). In response, we classified the primary composite end points into cardiovascular events, including nonfatal congestive heart failure, stroke, myocardial infarction, aortic dissection, and death, and renal events, including end-stage renal failure requiring regular hemodialysis, and found that, in a univariate Cox proportional-hazard model, a 1-SD increase of RI was a significant predictor of cardiovascular events (hazard ratio [HR], 5.47; 95% confidence interval [CI], 4.55–6.96; P <0.01) and renal events (HR, 10.79; 95% CI, 4.84–40.82; P <0.01). Multivariate analysis could not be performed because of the low number of occurrences of each end point, and thus, further investigation will be …

Value of renal resistive index as an early marker of diabetic nephropathy in children with type-1 diabetes mellitus

Constant increase in the incidence of type-1 diabetes (T1-DM) has made it necessary to have new markers for the early detection of diabetic nephropathy (DN). One of the markers that could be helpful in detecting functional alterations in renal hemodynamics is assessment of the renal resistive index (RI) by using renal Doppler. We studied 25 patients with T1-DM (Group-A), which comprised of 15 females and 10 males, with a mean age of 10.8 ± 2.2 years and duration of diabetes of 5 ± 1.1 years. A control group (Group-B) comprising 20 healthy children, 12 females and eight males with mean age of 11.6 ± 2 years, was also studied. The following parameters were studied in the two groups: age, serum creatinine, albumin excretion rate (AER), glomerular filtration rate (GFR), glycosylated hemoglobin (HbA1c) and mean renal RI of both kidneys. We found an increase in the mean RI in diabetic patients versus healthy children; the mean RI in Group-A was 0.64 ± 0.55 while it was 0.58 ± 0.0.28 in Group-B (P <0.000). This increase in RI had a positive correlation with duration of the disease, GFR and HbA1c levels, but there was no correlation with serum creatinine or AER. We conclude that RI is increased early in TI-DM, and it can be a predictor of DN.