A deep learning image analysis method for renal perfusion estimation in pseudo-continuous arterial spin labelling MRI

Accurate segmentation of renal tissues is an essential step for renal perfusion estimation and postoperative assessment of the allograft. Images are usually manually labeled, which is tedious and prone to human error. We present an image analysis method for the automatic estimation of renal perfusion based on perfusion magnetic resonance imaging. Specifically, non-contrasted pseudo-continuous arterial spin labeling (PCASL) images are used for kidney transplant evaluation and perfusion estimation, as a biomarker of the status of the allograft. The proposed method uses machine/deep learning tools for the segmentation and classification of renal cortical and medullary tissues and automates the estimation of perfusion values. Data from 16 transplant patients has been used for the experiments. The automatic analysis of differentiated tissues within the kidney, such as cortex and medulla, is performed by employing the time-intensity-curves of non-contrasted T1-weighted MRI series. Specifically, using the Dice similarity coefficient as a figure of merit, results above 93%, 92% and 82% are obtained for whole kidney, cortex, and medulla, respectively. Besides, estimated cortical and medullary perfusion values are considered to be within the acceptable ranges within clinical practice.

Food Insecurity and Chronic Kidney Disease: Considerations for Practitioners

The coronavirus disease 2019 pandemic has exacerbated existing health disparities related to food security status. Emerging literature suggests individuals with Chronic Kidney Disease (CKD) who are also food insecure have a greater likelihood of disease progression compared to food secure individuals. However, the complex relationship between CKD and food insecurity (FI) is understudied relative to other chronic conditions. The purpose of this practical application article is to summarize the recent literature on the social-economic, nutritional, to care through which FI may negatively impact health outcomes in individuals with CKD. While several studies have reported on the cross-sectional prevalence of FI among persons with CKD, literature is lacking about the severity and duration of exposure to FI on CKD outcomes. Future research is needed to better understand how FI impairs CKD care, nutritional and structural barriers that impact disease prevention and disease progression, and effective strategies to support patients.

Association between Circulating Levels of 25-Hydroxyvitamin D3 and Matrix Metalloproteinase-10 (MMP-10) in Patients with Type 2 Diabetes

Background: Matrix metalloproteinase-10 (MMP-10) levels increase progressively starting from early diabetic kidney disease (DKD) stages. Vitamin D3 (vitD3) deficit is associated with a higher risk of diabetic microangiopathy. Reduced MMP-10 expression has been observed after exposure to vitD3. Aim: to assess how vitD3 status is related to MMP-10 levels in patients with Type 2 diabetes (T2D). Methods: 256 patients with T2D were included in this cross-sectional study. Demographic, clinical and serum MMP-10 and 25-hydroxyvitamin D3 (25(OH)D3) levels were collected from each patient. The association between MMP-10 and (25(OH)D3) levels was assessed using a correlation analysis and fitting a multivariate linear regression model. Results: Serum MMP-10 levels were inversely correlated with circulating 25(OH)D3 (rho = −0.25; p < 0.001). In the subgroup analysis this correlation was significant in patients with DKD (rho = −0.28; p = 0.001) and in subjects with vitD3 deficit (rho = −0.24; p = 0.005). In the regression model adjusted for kidney function, body adiposity, smoking and vitD supplementation MMP-10 levels were 68.7 pg/mL lower in patients with 25(OH)D3 > 20 ng/mL, with respect to ≤20 ng/mL (p = 0.006). Conclusions: vitD3 repletion status is an independent predictor of MMP-10 levels in T2D patients. Perhaps, high 25(OH)D3 values should be targeted in these patients in order to prevent vascular complications.

Anti-Spike antibodies three months after SARS-CoV-2 mRNA vaccine booster dose in patients on hemodialysis: the prospective SENCOVAC study

Introduction

Patients on hemodialysis are at high-risk for complications derived from coronavirus disease-19 (COVID-19). The present analysis evaluated the impact of a booster vaccine dose and breakthrough severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections on humoral immunity three months after the booster dose.

Methods

This is a multicentric and prospective study assessing IgG anti-Spike antibodies 6 and 9 months after initial SARS-CoV-2 vaccination in patients on hemodialysis that had also received a booster dose before the 6-month assessment (early booster) or between the 6- and 9-month assessments (late booster). The impact of breakthrough infections, type of vaccine, time from the booster and clinical variables were assessed.

Results

A total of 711 patients (67% male, 67 [20-89] years) were included. Of which, 545 (77%) received an early booster and the rest a late booster. At 6 months, 64 (9%) patients had negative anti-Spike antibody titers (3% of early booster and 29% of late booster patients, p = 0.001). At 9 months, 91% of patients with 6-month negative response had seroconverted and there were no differences in residual prevalence of negative humoral response between early and late booster patients (0.9% vs 0.6%, p = 0.693). During follow-up, 35 patients (5%) developed breakthrough SARS-CoV-2 infection. Antibody titers at 9 months were independently associated to mRNA-1273 booster (p = 0.001), lower time from booster (p = 0.043) and past breakthrough SARS-CoV-2 infection (p&lt;0.001).

Conclusions

In hemodialysis patients, higher titers of anti-Spike antibodies at 9 months were associated to mRNA-1273 booster, lower time from booster and past breakthrough SARS-CoV-2 infection.

FC 126: Association Between Circulating Levels of 25-Hydroxyvitamin D and Metalloproteinase-10 (MMP 10) in Patients With Type 2 Diabetes Mellitus. Cross-Sectional Study

BACKGROUND AND AIMS

Matrix metalloproteinases (MMP) play an important role in diabetic kidney disease (DKD) (1). MMP-10 levels have been shown to increase progressively starting from the early stages of DKD (2). Vitamin D (vitD) deficit is associated with a higher risk of microangiopathy in diabetes. In humans, vitD status correlates inversely with MMP-9 circulating levels and VitD supplementation is associated with a decrease in these levels (3). In vitro, studies demonstrated reduced expression of MMP-10 after an exposure to vitD (4). However, no studies have yet assessed how vitD status is related to MMP-10 circulating levels. We aimed (1) to evaluate the association between the serum levels of 25-hydroxyvitamin D [25(OH)D3] and MMP-10 in a cohort of type 2 diabetes (T2D) patients and (2) to study a potential effect of chronic kidney disease (CKD) stage or estimated glomerular filtration rate (eGFRcr) on this association.

METHOD

The cross-sectional association between MMP-10 and 25(OH)D3 levels (&gt;30 ng/mL, normal; 20–30 ng/mL, insufficiency; &lt;20 ng/mL,  deficiency; and relevant cut-offs 45 and 15 ng/mL) was investigated, by multivariate linear regression analysis after MMP-10 logarithm transformation, in 256 T2D patients recruited (2009–2016) in the Clinica Universidad de Navarra (Spain). Study protocol was approved by the Ethical Committee (2021.183TFG). Covariates were smoking habit, body adiposity percentage estimated by CUN-BAE formula, CKD stage and vitD3 supplement use. Age and sex were already included in the CKD-EPI formula. Interactions and collinearities were also analysed. Statistical analysis was performed using STATA software and two-tailed P-values &lt;0.05 were considered statistically significant.

RESULTS

Characteristics of patients are given in Table 1. VitD deficit was significantly (P &lt;0.001) more prevalent in patients with CKD (61%) compared with those without CKD (40%). MMP-10 showed a significant negative correlation with 25(OH)D3 (rho = –0.246; P &lt;0.001),  which remained significant including only CKD patients (rho = –0.283; P &lt;0.001) and stronger above 45 ng/mL (rho = –0.7308, P &lt;0.001) or moderate between 30 and 45 ng/mL (rho = –0.3290, P = 0.0045) (Fig. 1). In the fully adjusted model, MMP-10 was negatively associated (P = 0.019) with severe vitD deficiency [estimated coefficient –0.86 (–0.76 to –0.97)]. There was no interaction between covariates and 25(OH)D levels and collinearities were also discarded.

CONCLUSION

In T2D patients, circulating MMP-10 was inversely associated with serum 25(OH)D3 levels, especially in those patients with CKD and at the extremes of vitD level range. These results suggest that higher values of 25(OH)D3 should be targeted in these patients. The efficacy of vitD supplementation in reducing circulating MMP-10 levels should be further examined.

MO734CONTRIBUTION OF SOLUBLE ST2 TO THE EFFECT OF RIGHT VENTRICULAR DYSFUNCTION ON MORTALITY IN HEMODIALYSIS PATIENTS

Background and Aims

Right ventricular dysfunction (RVD) has been shown to predict mortality in patients with kidney failure. It has been proposed that RVD in these patients is mediated by inflammatory and fibrotic mechanisms, which may be enhanced by hemodialysis (HD). The present study aimed to investigate the potential associations between RVD and circulating biomarkers of myocardial inflammation and fibrosis with all-cause mortality in HD patients.

Method

We performed a retrospective single-centre cohort study of prevalent patients admitted in a chronic HD program for more than 3 months. Clinical characteristics and echocardiographic parameters were assessed in all patients. Pre-dialysis blood samples for measurement of inflammatory (e.g., C reactive protein, interleukin-1, interleukin-18) and fibrotic (e.g., soluble suppression of tumorigenesis-2 [sST2], galectin-3, C-terminal pro-peptide of procollagen type I and N-terminal pro-peptide of procollagen type III) biomarkers were collected. Right ventricular dysfunction (RVD) was defined using tricuspid annular plane systolic excursion (TAPSE) &lt;1.7 cm or pulsed Doppler peak annular velocity (S´) &lt;9.5 cm/s. The ability of sST2 to discriminate between mortality was assessed using AuROC curve.

Results

We enrolled 48 patients (mean age 74 [64–79] years, 62.5% males) followed over a period of 1.4 years. Mortality was higher 45.5% (log-rank, p=0.003) in patients with RVD as diagnosed by S' than in patients without RVD. No difference in mortality was observed for RVD defined by TAPSE. There were no differences in the morphology and function parameters of the left ventricle between patients with and without RVD. From all biomarkers measured only sST2 was associated with RVD. Indeed, an age- and sex-adjusted analyses showed that doubling of sST2 was inversely associated with a decreased in S´ (estimate=-2.03, 95% CI [-3.04 to -1.00] cm/s; P=0.002). Mortality was increased in patients with sST2 ≥40.45 ng/mL compared to patients with sST2 &lt;40.45 ng/mL (66.7% vs. 18.9%, log-rank; p=0.004). Crude analysis showed that patients presenting with S’ &lt;9.5 cm/s and sST2 ≥40.45 ng/mL exhibited higher mortality (log-rank; p=0.001) than patients with S’ &gt;9.5 cm/s and sST2 &lt;40.45pg/mL.

Conclusion

Albeit preliminary these findings suggest that an excess of sST2 may be involved in RVD and on its effect on mortality in HD patients. The myocardial pro-remodeling effect of sST2 among HD patients with RVD warrants further investigation.

Effect of exopolysaccharides produced by dairy starter cultures on biofilms formed on reverse osmosis membranes

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Not all EPS-producing starter cultures have an advantage in regard to their ability to form biofilm on membrane separation surfaces.

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Variations between different EPS modify adhesive behavior to reverse osmosis membranes.

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Cell hydrophobicity is critical for initial adhesion to RO membrane separation surface and thus biofilm formation.

Two different cheese starter cultures producing exopolysaccharides (EPS⁺: Streptococcus thermophilus strain ST3534 and Lactococcus lactis ssp. cremoris strain JFR+) and their isogenic EPS-negative (EPS⁻: S. thermophilus strain ST5842 and L. lactis ssp. cremoris strain JFR–) variants were used to study the attachment of bacterial cells in the absence of growth (at 4°C) and the resultant biofilm formation on reverse osmosis membranes (at 30 or 35°C). We used M17 broth and a 10% solution of whey protein concentrate (with 35% protein) as growth media for biofilm development under static conditions. As expected, ST3534 (EPS⁺) showed significantly greater cell counts within biofilms than ST5842 (EPS⁻). In the absence of growth, however, cells of these 2 isogenic Streptococcus strains attached to the membrane in similar numbers. In contrast, JFR+ counts were significantly lower than those of JFR– under all conditions. These findings indicate that the EPS produced by S. thermophilus may play a greater role in building up the 3-dimensional structure of the biofilm, rather than only assisting during initial attachment of the cells to the membrane, whereas the EPS produced by L. lactis ssp. cremoris hampered both initial attachment to the membrane and biofilm formation. Although no differences were observed in the surface charge of the cells between the 2 EPS-producing cultures, surface hydrophobicity was associated with the different adhesive properties of these microorganisms. In conclusion, our results exclude the hypothesis that all EPS-producing starter cultures have an advantage in regard to their ability to form biofilm on membrane separation surfaces. In contrast, variations between different EPS, with hydrophobicity being an important influencing feature, modify adhesive behavior to reverse osmosis membranes.

Population Genomic Analysis of Mycoplasma bovis Elucidates Geographical Variations and Genes associated with Host-Types

Among more than twenty species belonging to the class Mollecutes, Mycoplasma bovis is the most common cause of bovine mycoplasmosis in North America and Europe. Bovine mycoplasmosis causes significant economic loss in the cattle industry. The number of M. bovis positive herds recently has increased in North America and Europe. Since antibiotic treatment is ineffective and no efficient vaccine is available, M. bovis induced mycoplasmosis is primarily controlled by herd management measures such as the restriction of moving infected animals out of the herds and culling of infected or shedders of M. bovis. To better understand the population structure and genomic factors that may contribute to its transmission, we sequenced 147 M. bovis strains isolated from four different countries viz. USA (n = 121), Canada (n = 22), Israel (n = 3) and Lithuania (n = 1). All except two of the isolates (KRB1 and KRB8) were isolated from two host types i.e., bovine (n = 75) and bison (n = 70). We performed a large-scale comparative analysis of M. bovis genomes by integrating 103 publicly available genomes and our dataset (250 total genomes). Whole genome single nucleotide polymorphism (SNP) based phylogeny using M.agalactiae as an outgroup revealed that M. bovis population structure is composed of five different clades. USA isolates showed a high degree of genomic divergence in comparison to the Australian isolates. Based on host of origin, all the isolates in clade IV was of bovine origin, whereas majority of the isolates in clades III and V was of bison origin. Our comparative genome analysis also revealed that M. bovis has an open pangenome with a large breadth of unexplored diversity of genes. The function based analysis of autogenous vaccine candidates (n = 10) included in this study revealed that their functional diversity does not span the genomic diversity observed in all five clades identified in this study. Our study also found that M. bovis genome harbors a large number of IS elements and their number increases significantly (p = 7.8 × 10⁻⁶) as the genome size increases. Collectively, the genome data and the whole genome-based population analysis in this study may help to develop better understanding of M. bovis induced mycoplasmosis in cattle.

Optimization of pseudo-continuous arterial spin labeling for renal perfusion imaging

PURPOSE

To evaluate labeling efficiency of pseudo-continuous arterial spin labeling (PCASL) and to find the gradient parameters that increase PCASL robustness for renal perfusion measurements.

METHODS

Aortic blood flow was characterized in 3 groups: young healthy volunteers (YHV1), chronic kidney disease (CKD) patients (CKDP), and healthy controls (HCO). PCASL inversion efficiency was evaluated through numeric simulations considering the measured pulsatile flow velocity profiles and off-resonance effects for a wide range of gradient parameters, and the results were assessed in vivo. The most robust PCASL implementation was used to measure renal blood flow (RBF) in CKDP and HCO.

RESULTS

Aortic blood velocities reached peak values of 120 cm/s in YHV1, whereas for elderly subjects values were lower by approximately a factor of 2. Simulations and experiments showed that by reducing the gradient average (G_ave ) and the selective to average gradient ratio (G_max /G_ave ), labeling efficiency was maximized and PCASL robustness to off-resonance was improved. The study in CKDP and HCO showed significant differences in RBF between groups.

CONCLUSION

An efficient and robust PCASL scheme for renal applications requires a G_max /G_ave ratio of 6-7 and a G_ave value that depends on the aortic blood flow velocities (0.5 mT/m being appropriate for CKDP and HCO).

P1309RIGHT VENTRICULAR-PULMONARY ARTERIAL UNCOUPLING IN PATIENTS ON CHRONIC HEMODIALYSIS WITH SEVERE RIGHT VENTRICULAR REMODELING

Background and Aims

Patients on chronic hemodialysis (HD) may present right ventricular (RV) dysfunction and increased pulmonary artery pressure (PA). The aim of the current study is to describe the RV-PA coupling in chronic patients on HD.

Method

This study explored the adequacy of RV-PA coupling in 41 patients on HD. They underwent a comprehensive transthoracic Doppler echocardiography, and were stratified in accordance with the severity of RV remodeling defined by the presence of RV dilation (tricuspid annulus ≥40 mm) and RV systolic dysfunction (tricuspid annulus systolic excursion plane [TAPSE] &lt;17 mm). RV-PA coupling was estimated by the TAPSE to PA systolic pressure (TAPSE:PASP) ratio.

Results

Three groups of patients were identified: No RV remodeling (Group 1, n=26), mild-to-moderate RV remodeling (Group 2, n=11) and severe RV remodeling (Group 3, n=4). Compared to patients from Groups 1 and 2, patients from Group 3 exhibited significant lower TAPSE values (p&lt;0.001), a tendency to higher PASP values (p=0.054) and significant lower TAPSE:PASP ratio values (p=0.012). C-reactive protein levels and were directly correlated with PASP (r=0.405, p=0.017) and inversely with TAPSE (r=-0.311, p=0.041) and the TAPSE:PASP ratio (r= -0.392, p=0.015) in all patients. These echocardiographic parameters were not correlated with other biochemical, hemodynamic or anthropometric parameters.

Conclusion

These findings suggest that RV-PA coupling is markedly decreased in HD patients with severe RV remodeling. The role of systemic inflammation in RV remodeling and RV-PA uncoupling in HD patients warrants further studies.

Magnetic resonance imaging biomarkers for chronic kidney disease: a position paper from the European Cooperation in Science and Technology Action PARENCHIMA

Functional renal magnetic resonance imaging (MRI) has seen a number of recent advances, and techniques are now available that can generate quantitative imaging biomarkers with the potential to improve the management of kidney disease. Such biomarkers are sensitive to changes in renal blood flow, tissue perfusion, oxygenation and microstructure (including inflammation and fibrosis), processes that are important in a range of renal diseases including chronic kidney disease. However, several challenges remain to move these techniques towards clinical adoption, from technical validation through biological and clinical validation, to demonstration of cost-effectiveness and regulatory qualification. To address these challenges, the European Cooperation in Science and Technology Action PARENCHIMA was initiated in early 2017. PARENCHIMA is a multidisciplinary pan-European network with an overarching aim of eliminating the main barriers to the broader evaluation, commercial exploitation and clinical use of renal MRI biomarkers. This position paper lays out PARENCHIMA's vision on key clinical questions that MRI must address to become more widely used in patients with kidney disease, first within research settings and ultimately in clinical practice. We then present a series of practical recommendations to accelerate the study and translation of these techniques.

Intra-Catheter Leukocyte Culture to Monitor Hemodialysis Catheter Colonization. a Prospective Study to Prevent Catheter-Related Bloodstream Infections

The most serious problem related to the use of tunneled catheters in hemodialysis is bacteremia. The aim of this study was to detect hemodialysis catheter colonization and, establish a preemptive therapy based on a catheter antibiotic lock in order to prevent development of catheter-related bloodstream infections. During a 24-month period, all patients with tunneled catheters in our hemodialysis unit were evaluated by extracting a through-catheter leukocyte culture every 15 days. There were 28 episodes of catheter colonization occurring in 13 patients (2.2 colonization episodes per 1000 catheter patient-days). At the time of colonization, catheters had been in place for a mean of 562 days (range: 16 to 1475 days). Coagulase negative staphylococci (CNS) were the most common microorganisms to be isolated. A preemptive therapy consisting in teicoplanin locks (10 mg/mL) for 21 days was able to eradicate catheter colonization in 89% of the cases when CNS were isolated. However, relapse of colonization occurred in 61.2% of these cases. The mean duration of catheter use was 239 days (range: 9 to 483 days) after treatment of a colonization episode. The incidence of catheter-related bloodstream infection in our population was 0.78 episodes per 1000 catheter patient-days (IC 95%: 0.374–1.434). This study shows the utility of intra-catheter leukocyte culture for early detection of hemodialysis catheter colonization. Moreover, it establishes that the eradication of biofilm-related CNS is possible without the removal of the catheter, thus enabling a longer catheter lifespan. (Int J Artif Organs 2008; 31: 820–6)

Improvement of drug prescribing in acute kidney injury with a nephrotoxic drug alert system

Objective

Electronic alert systems have shown their capacity for improving the detection of acute kidney injury (AKI). The aim of this study was to design and implement a clinical decision support system (CDSS) for improving drug selection and reducing nephrotoxic drug use in patients with AKI.

Methods

The study was designed as an intervention study comparing a pre and post cohort of patients admitted during April 2014 and April 2015, respectively (phase I and phase II). The intervention was a CDSS which provided kidney function and nephrotoxic drug information. Furthermore, an interruptive alert was designed to detect patients suffering an AKI event while taking a nephrotoxic drug and to see if the dose was then reduced or the drug was discontinued by the physicians.

Results

One-third of the inpatients were included in the analysis because they met the inclusion criteria (1004 and 1002 patients in phases I and II, respectively). 735 and 761 of them received at least one nephrotoxic alert (73% vs 76%; p=0.763). 65 and 88 patients suffered AKI during admission (6.5% vs 8.8%; p=0.051). In phase I, patients received 384 nephrotoxic alerts (55%) with 78 (20%) of them provoking a change or discontinuation of the nephrotoxic drug. In phase II this value increased to 154 out of 526 (29%) after implementation of the CDSS (p<0.01).

Conclusions

A CDSS with interruptive alerts that inform of the development of AKI in real time in patients with nephrotoxic drug prescription has a positive impact on the judicious use of these drugs.

Arterial spin labeling MRI is able to detect early hemodynamic changes in diabetic nephropathy

PURPOSE

To investigate whether arterial spin labeling (ASL) MRI could detect renal hemodynamic impairment in diabetes mellitus (DM) along different stages of chronic kidney disease (CKD).

MATERIALS AND METHODS

Three Tesla (3T) ASL-MRI was performed to evaluate renal blood flow (RBF) in 91 subjects (46 healthy volunteers and 45 type 2 diabetic patients). Patients were classified according to their estimated glomerular filtration rate (eGFR) as group I (eGFR > 60 mL/min/1.73 m² ), group II (60 ≥ eGFR>30 mL/min/1.73 m² ), or group III (eGFR ≤ 30 mL/min/1.73 m² ), to determine differences depending on renal function. Studies were performed at 3T using a 12-channel flexible body array combined with the spine array coil as receiver.

RESULTS

A 28% reduction in cortical RBF was seen in diabetics in comparison with healthy controls (185.79 [54.60] versus 258.83 [37.96] mL/min/100 g, P < 3 × 10^-6 ). Differences were also seen between controls and diabetic patients despite normal eGFR and absence of overt albuminuria (RBF [mL/min/100 g]: controls=258.83 [37.96], group I=208.89 [58.83], P = 0.0018; eGFR [mL/min/1.73 m² ]: controls = 95.50 [12.60], group I = 82.00 [20.76], P > 0.05; albumin-creatinine ratio [mg/g]: controls = 3.50 [4.45], group I = 17.50 [21.20], P > 0.05). A marked decrease in RBF was noted a long with progression of diabetic nephropathy (DN) through the five stages of CKD (χ²  = 43.58; P = 1.85 × 10^-9 ). Strong correlation (r = 0.62; P = 4 × 10^-10 ) was obtained between RBF and GFR estimated by cystatin C.

CONCLUSION

ASL-MRI is able to quantify early renal perfusion impairment in DM, as well as changes according to different CKD stages of DN. In addition, we demonstrated a correlation of RBF quantified by ASL and GFR estimated by cystatin C.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1810-1817.

Comparison of Intravenous and Oral Hydration in the Prevention of Contrast-Induced Acute Kidney Injury in Low-Risk Patients: A Randomized Trial

AIMS

Contrast-induced acute kidney injury (CI-AKI) is a common cause of renal failure. We evaluated the effectiveness of oral sodium citrate versus intravenous (IV) sodium bicarbonate for CI-AKI prophylaxis as well as their influence on kidney injury biomarkers.

MATERIAL AND METHODS

A randomized, controlled, single-center study including 130 hospitalized patients (62.3% men), who were randomized to receive sodium bicarbonate (1/6 men, 3 ml/kg/h for 1 h; n = 43), oral sodium citrate (75 ml/10 kg divided into 4 doses; n = 43) or nonspecific hydration (n = 44) before contrast administration, was conducted. Serum creatinine and kidney injury biomarkers (cystatin C, neutrophil gelatinase-associated lipocalin, interleukin-8, F2-isoprostanes and cardiotrophin-1 [CT-1]) were assessed.

RESULTS

Incidence of CI-AKI was 9.2% with no differences found between hydration groups: 7.0% in sodium bicarbonate group, 11.6% in oral sodium citrate group and 9.1% in the nonspecific hydration group. Urinary creatinine and urinary CT-1/creatinine ratio decreased 4 h after contrast infusion (p < 0.001), but none of the biomarkers assessed were affected by the treatments.

CONCLUSIONS

There were no differences in hydration with oral sodium citrate and IV sodium bicarbonate for the prophylaxis of CI-AKI. Therefore, oral hydration represents a safe, inexpensive and practical method for preventing CI-AKI in low-risk patients. No effect on biomarkers for kidney injury could be demonstrated.

Randomized clinical trial on acute effects of i.v. iron sucrose during haemodialysis

AIM

Haemodialysis induces endothelial dysfunction by oxidation and inflammation. Intravenous iron administration during haemodialysis could worsen endothelial dysfunction. The aim of this study was to ascertain if iron produces endothelial dysfunction and the possible neutralizing effect of N-acetylcysteine when infused before iron. The oxidative and inflammatory effects of iron during haemodialysis were also assessed.

METHODS

Forty patients undergoing haemodialysis were studied in a randomized and cross-over design with and without N-acetylcysteine infused before iron sucrose (50 or 100 mg). Plasma Von Willebrand factor (vWF), soluble intercellular adhesion molecule-1 (sICAM-1) levels, malondialdehyde, total antioxidant capacity, CD11b/CD18 expression in monocytes, interleukin (IL)-8 in monocytes and plasma IL-8 were studied at baseline and during haemodialysis.

RESULTS

Haemodialysis produced significant (P < 0.001) increase in plasma vWF, sICAM-1, malondialdehyde, IL-8 and CD11b/CD18 expression in monocytes, as well as decrease in total antioxidant capacity. Iron induced significant increase in plasma malondialdehyde and IL-8 in monocytes, but had no effect on total antioxidant capacity, CD11b/CD18 expression, plasma IL-8, vWF and sICAM-1. The addition of N-acetylcysteine to 50 mg of iron produced a significant (P = 0.040) decrease in malondialdehyde.

CONCLUSION

Standard (100 mg) and low (50 mg) doses of iron during haemodialysis had no effects on endothelium. Iron only had minor effects on inflammation and produced an increase in oxidative stress, which was neutralized by N-acetylcysteine at low iron dose. Haemodialysis caused a significant increase in oxidative stress, inflammation and endothelial dysfunction markers.

Cardiac-surgery associated acute kidney injury requiring renal replacement therapy. A Spanish retrospective case-cohort study

Background

Acute kidney injury is among the most serious complications after cardiac surgery and is associated with an impaired outcome. Multiple factors may concur in the development of this disease. Moreover, severe renal failure requiring renal replacement therapy (RRT) presents a high mortality rate. Consequently, we studied a Spanish cohort of patients to assess the risk factors for RRT in cardiac surgery-associated acute kidney injury (CSA-AKI).

Methods

A retrospective case-cohort study in 24 Spanish hospitals. All cases of RRT after cardiac surgery in 2007 were matched in a crude ratio of 1:4 consecutive patients based on age, sex, treated in the same year, at the same hospital and by the same group of surgeons.

Results

We analyzed the data from 864 patients enrolled in 2007. In multivariate analysis, severe acute kidney injury requiring postoperative RRT was significantly associated with the following variables: lower glomerular filtration rates, less basal haemoglobin, lower left ventricular ejection fraction, diabetes, prior diuretic treatment, urgent surgery, longer aortic cross clamp times, intraoperative administration of aprotinin, and increased number of packed red blood cells (PRBC) transfused. When we conducted a propensity analysis using best-matched of 137 available pairs of patients, prior diuretic treatment, longer aortic cross clamp times and number of PRBC transfused were significantly associated with CSA-AKI.

Patients requiring RRT needed longer hospital stays, and suffered higher mortality rates.

Conclusion

Cardiac-surgery associated acute kidney injury requiring RRT is associated with worse outcomes. For this reason, modifiable risk factors should be optimised and higher risk patients for acute kidney injury should be identified before undertaking cardiac surgery.