Feasibility study of the RenalGuard™ balanced hydration system: A novel strategy for the prevention of contrast-induced nephropathy in high risk patients

Early detection of oliguric events in critically ill patients in the ICU with a novel continuous urine flow measurement device: results of an initial validation study

OBJECTIVES

Urine output is used to evaluate fluid status and is an important marker for acute kidney injury (AKI). Our primary aim was to validate a new automatic urine output monitoring device by comparison to the current practice - the standard urometer.

METHODS

We conducted a prospective observational study in three ICUs. Urine flow measurements by Serenno Medical Automatic urine output measuring device (Serenno Medical, Yokneam, Israel) were compared to standard urometer readings taken automatically at 5-minutes intervals by a camera, and to hourly urometer readings by the nurses, both over 1 to 7 days. Our primary outcome was the difference between urine flow assessed by the Serenno device and reference camera-derived measurements (Camera). Our secondary outcome was the difference between urine flow assessed by the Serenno device and hourly nursing assessments (Nurse), and detection of oliguria.

RESULTS

Thirty-seven patients completed the study, with 1,306 h of recording and a median of 25 measurement hours per patient. Bland and Altman analysis comparing the study device to camera measurements demonstrated good agreement, with a bias of -0.4 ml/h and 95% confidence intervals ranging from - 28 to 27ml/h. Concordance was 92%. The correlation between Camera and hourly nursing assessment of urine output was distinctly worse with a bias of 7.2 ml and limits of agreement extending from - 75 to + 107 ml. Severe oliguria (urine output < 0.3 ml/kg/h) lasting 2 h or more was common and observed in 8 (21%) of patients. Among the severe oliguric events lasting more than 3 consecutive hours, 6 (41%) were not detected or documented by the nursing staff. There were no device-related complications.

CONCLUSION

The Serenno Medical Automatic urine output measuring device required minimal supervision, little ICU nursing staff attention, and is sufficiently accurate and precise. In addition to providing continuous assessments of urine output, it was considerably more accurate than hourly nursing assessments.

Transcatheter Aortic Valve Replacement-Associated Acute Kidney Injury: An Update

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is a relatively novel minimally invasive procedure for the treatment of symptomatic patients with severe aortic stenosis. Although it has been proven effective in improving mortality and quality of life, TAVR is associated with serious complications, such as acute kidney injury (AKI).

SUMMARY

TAVR-associated AKI is likely due to several factors such as sustained hypotension, transapical approach, volume of contrast use, and baseline low GFR. This narrative review aims to present an overview of the latest literature and evidence regarding the definition of TAVR-associated AKI, its risk factors, and its impact on morbidity and mortality. The review used a systematic search strategy with multiple health-focused databases (Medline, EMBASE) and identified 8 clinical trials and 27 observational studies concerning TAVR-associated AKI. Results showed that TAVR-associated AKI is linked to several modifiable and nonmodifiable risk factors and is associated with higher mortality. A variety of diagnostic imaging modalities have the potential to identify patients at high risk for development of TAVR-AKI; however, there are no existing consensus recommendations regarding their use as of this time. The implications of these findings highlight the importance of identifying high-risk patients for which preventive measures may play a crucial role, and should be maximized.

KEY MESSAGE

This study reviews the current understanding of TAVR-associated AKI including its pathophysiology, risk factors, diagnostic modalities, and preventative management for patients.

Closed-Loop Controlled Fluid Administration Systems: A Comprehensive Scoping Review

Physiological Closed-Loop Controlled systems continue to take a growing part in clinical practice, offering possibilities of providing more accurate, goal-directed care while reducing clinicians’ cognitive and task load. These systems also provide a standardized approach for the clinical management of the patient, leading to a reduction in care variability across multiple dimensions. For fluid management and administration, the advantages of closed-loop technology are clear, especially in conditions that require precise care to improve outcomes, such as peri-operative care, trauma, and acute burn care. Controller design varies from simplistic to complex designs, based on detailed physiological models and adaptive properties that account for inter-patient and intra-patient variability; their maturity level ranges from theoretical models tested in silico to commercially available, FDA-approved products. This comprehensive scoping review was conducted in order to assess the current technological landscape of this field, describe the systems currently available or under development, and suggest further advancements that may unfold in the coming years. Ten distinct systems were identified and discussed.

Contrast Induced Nephropathy: Efficacy of matched hydration and forced diuresis for prevention in patients with impaired renal function undergoing coronary procedures–CINEMA trial

Background

Matched hydration and forced diuresis (MHFD) using the RenalGuard device has been shown to reduce contrast induced nephropathy (CIN) following coronary interventions.

Aim

To evaluate the potential benefits of a non-automated MHFD protocol compared to current hydration protocol in prevention of CIN in patients with CKD.

Methods

A total of 1,205 patients were randomized to either non-automated MHFD group (n = 799) or intravenous hydration control group (n = 406). The MHFD group received 250 ml IV normal saline over 30 min before the coronary procedure followed by 0.5 mg/kg IV furosemide. Hydration infusion rate was manually adjusted to replace the patient's urine output. When urine output rate reached > 300 ml/h, patients underwent coronary procedure. Matched fluid replacement was maintained during the procedure and for 4-hour post-treatment. CIN was defined conventionally as ≥ 25% or ≥ 0.5 mg/dl rise in serum creatinine over baseline.

Results

CIN occurred in 121 of 1,205 (10.0%) patients in our study. With respect to the primary outcome, 64 (8.01%) of the MHFD patients developed CIN compared with 57 (14.04%) of the control group (p < 0.001).

Conclusions

A non-automated MHFD protocol is an effective and safe method for the prevention of CIN in patients with CKD.

The Pathophysiology and the Management of Radiocontrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is an impairment of renal function that occurs after the administration of an iodinated contrast medium (CM). Kidney dysfunction in CIN is considered transient and reversible in most cases. However, it is the third most common cause of hospital-acquired acute kidney injury and is associated with increased morbidity and mortality, especially in high-risk patients. Diagnostic and interventional procedures that require intravascular CM are being used with increasing frequency, especially among the elderly, who can be particularly susceptible to CIN due to multiple comorbidities. Therefore, identifying the exact mechanisms of CIN and its associated risk factors is crucial not only to provide optimal preventive management for at-risk patients, but also to increase the feasibility of diagnostic and interventional procedure that use CM. CM induces kidney injury by impairing renal hemodynamics and increasing the generation of reactive oxygen species, in addition to direct cytotoxicity. Periprocedural hydration is the most widely accepted preventive strategy to date. Here, we review the latest research results on the pathophysiology and management of CIN.

Left Ventricular End-Diastolic Pressure Versus Urine Flow Rate-Guided Hydration in Preventing Contrast-Associated Acute Kidney Injury

OBJECTIVES

This study compared left ventricular end-diastolic pressure (LVEDP)-guided and urine flow rate (UFR)-guided hydration.

BACKGROUND

Tailored hydration regimens improve the prevention of contrast-associated acute kidney injury (CA-AKI).

METHODS

Between July 15, 2015, and June 6, 2019, patients at high risk for CA-AKI scheduled for coronary and peripheral procedures were randomized to 2 groups: 1) normal saline infusion rate adjusted according to the LVEDP (LVEDP-guided group); and 2) hydration controlled by the RenalGuard System in order to reach UFR ≥300 ml/h (UFR-guided group). The primary endpoint was the composite of CA-AKI (i.e., serum creatinine increase ≥25% or ≥0.5 mg/dl at 48 h) and acute pulmonary edema (PE). Major adverse events (all-cause death, renal failure requiring dialysis, PE, and sustained kidney injury) at 1 month were assessed.

RESULTS

The primary endpoint occurred in 20 of 351 (5.7%) patients in the UFR-guided group and in 36 of 351 (10.3%) patients in the LVEDP-guided group (relative risk [RR]: 0.560; 95% confidence interval [CI]: 0.390 to 0.790; p = 0.036). CA-AKI and PE rates in the UFR-guided group and LVEDP-guided group were 5.7% and 10.0% (RR: 0.570; 95% CI: 0.300 to 0.960; p = 0.048), and, respectively, 0.3% and 2.0% (RR: 0.070; 95% CI: 0.020 to 1.160; p = 0.069). Three patients in the UFR-guided group experienced complications related to the Foley catheter. Hypokalemia rate was 6.2% in the UFR-guided group and 2.3% in the LVEDP-guided group (p = 0.013). The 1-month major adverse events rate was 7.1% in the UFR-guided group and 12.0% in the LVEDP-guided group (p = 0.030).

CONCLUSIONS

The study demonstrates that UFR-guided hydration is superior to LVEDP-guided hydration to prevent the composite of CA-AKI and PE.

RenalGuard system and conventional hydration for preventing contrast-associated acute kidney injury in patients undergoing cardiac interventional procedures: A systematic review and meta-analysis

BACKGROUND

Contrast-associated acute kidney injury (CA-AKI) can increase the mortality of patients undergoing transcatheter aortic valve replacement (TAVR) or percutaneous coronary intervention (PCI). The purpose of this paper was to compare the efficacy of the RenalGuard System and conventional hydration regimen in preventing CA-AKI in patients with TAVR or PCI.

METHODS

We searched PubMed, Embase, Web of Science, and the Cochrane Central Register of Clinical Trials (last updated July 11, 2020) for suitable reports. The primary outcome was the occurrence of CA-AKI. The secondary outcomes were renal replacement therapy (RRT), major cardiovascular events (MACEs), and other adverse complications.

RESULTS

The search strategy yielded 270 studies (with data for 2067 participants). In the subgroup of PCI, low incidence of CA-AKI (6.7% vs 15.7%; 95%CI: 0.27 to 0.54; I² = 8%; P < 0.00001) associate with RenalGuard group (RG) rather than control group (CG). Similarly, in the subgroup of TAVR, a low incidence of CA-AKI (15.6% vs 26.9%; 95%CI: 0.35 to 0.82; I² = 88%; P = 0.004) relates to RG. However, this result is highly heterogeneous. Compare with conventional hydration, RenalGuard significantly reduce the incidence of pulmonary edema (1.5%vs4.1%; 95%CI: 0.18 to 0.72; I² = 0%; P = 0.004).

CONCLUSIONS

RenalGuard System can lessen the risk of CA-AKI and RRT in patients undergoing PCI. But for patients experiencing TAVR, due to unique hemodynamic effects, the role of RenalGuard remains questionable. RenalGuard is more secure than conventional hydration. Future work should elucidate the feasibility and safety of this prophylactic intervention in cardiac interventional therapy.

Contrast-associated acute kidney injury: An update of risk factors, risk factor scores, and preventive measures

As lifespans lengthen, age-related diseases such as cardiovascular disease and diabetes are becoming more prevalent. Correspondingly, the use of contrast agents for medical imaging is also becoming more common, and there is increasing awareness of contrast-associated acute kidney injury (CA-AKI). There is no specific treatment for CA-AKI, and clinicians currently focus on prevention, interventions that alter its pathogenesis, and identification of risk factors. Although the incidence of CA-AKI is low in the general population, the risk of CA-AKI can reach 20% to 30% in patients with multiple risk factors. Many models have been applied in the clinic to assess the risk factors for CA-AKI, enable identification of high-risk groups, and improve clinical management. Hypotonic or isotonic contrast media are recommended to prevent CA-AKI in high-risk patients. Patients with risk factors should avoid using contrast media multiple times within a short period of time. All nephrotoxic drugs should be stopped at least 24 h before the administration of contrast media in high-risk populations, and adequate hydration is recommended for all patients. This review summarizes the pathophysiology of CA-AKI and the progress in diagnosis and differential diagnosis; updates the risk factors and risk factor scoring systems; reviews the latest advances related to prevention and treatment; discusses current problems in epidemiological studies; and highlights the importance of identifying high-risk subjects to control modifiable risk factors and use of a rating scale to estimate the risk and implement appropriate prevention strategies.

Bioimpedance Analysis–Guided Volume Expansion for the Prevention of Contrast-Induced Acute Kidney Injury (the BELIEVE Pilot Randomized Controlled Trial)

Introduction

Peri-procedural i.v. fluid administration is important for the prevention of contrast-induced acute kidney injury (CI-AKI). However, standardized fluid management protocols may not be suitable for all patients. We therefore wished to determine whether an individualized fluid administration protocol guided by measuring extracellular water (ECW) using bioimpedance analysis (BIA) would be safe and would reduce the incidence CI-AKI compared to a standardized fluid administration prescription.

Methods

In this pilot, randomized, parallel-group, single-blind, controlled trial, we compared the effect of BIA-guided isotonic bicarbonate administration according to the ratio of ECW to total body water (ECW/TBW) to our standard isotonic bicarbonate protocol in regard to the safety and efficacy of preventing CI-AKI in chronic kidney disease patients undergoing elective cardiac angiography. Our primary outcome was the incidence of CI-AKI, which was defined as a ≥0.3 mg/dl or 150% increase in serum creatinine concentration within 48 to 72 hours after cardiac angiography.

Results

We studied 61 patients, 30 in the bioimpedance group and 31 in the control group. Age was similar (72.5 ± 7 vs. 71.4 ± 7.9 years), as were body mass index (25.5 vs. 25.8 kg/m²) and baseline serum creatinine (1.3 ± 0.3 vs. 1.4 ± 0.4 mg/dl). The peri-procedural fluid volume administered was significantly greater in the BIA-guided hydration group (899.0 ± 252.7 ml vs. 594.4 ± 125.9 ml, P < .01). The incidence of CI-AKI was 3.3% in BIA-guided hydration group and 6.5% in the control group (relative risk = 0.52, 95% confidence interval = 0.05−5.40, P = 1.00). Adverse events reported were comparable between groups (6.7% vs. 6.5%, P = 1.00).

Conclusions

The overall incidence of CI-AKI after cardiac angiography in our patients with mild-to-moderate renal insufficiency was lower than anticipated. Isotonic bicarbonate administration guided by bioimpedance measurements was safe, and probably led to a lower incidence of CI-AKI, although this not reach statistical significance.

[Contrast medium-induced renal failure : Useful protective measures prior to contrast medium administration]

BACKGROUND

Iodinated contrast is essential for diagnosis and treatment in contemporary interventional cardiology. An important complication of percutaneous intervention is contrast-induced nephropathy, which is associated with increased morbidity and mortality, while prolonged hospitalization is responsible for economic consequences.

OBJECTIVES

This article reviews the definition of contrast-induced nephropathy, the role of biomarkers in early diagnosis to identify high-risk patients and potential therapeutic options for preventing acute nephropathy.

CURRENT DATA

The optimization of patients' circulating volume remains the main aspect for preventing contrast-induced nephropathy, as recent studies confirm. Several medications are known to be nephrotoxic, whereas several are nephroprotective and the subject of recent research.

CONCLUSION

Interventions to improve outcomes of established acute kidney injury have not been developed as yet. Prevention and early diagnosis are relevant factors in clinical management. It is important to identify patients at risk and to treat them preemptively.

Prevention of contrast-induced nephropathy by adequate hydration combined with isosorbide dinitrate for patients with renal insufficiency and congestive heart failure

BACKGROUND

Adequate hydration remains the mainstay of contrast-induced nephropathy prevention, and nitrates could reduce cardiac preload.

HYPOTHESIS

This study aimed to explore the adequate hydration with nitrates for patients with chronic kidney disease (CKD) and congestive heart failure (CHF) to reduce the risk of contrast-induced nephropathy (CIN) and at the same time avoid the acute heart failure.

METHODS

Three hundred and ninty-four consecutive patients with CKD and CHF undergoing coronary procedures were randomized to either adequate hydration with nitrates (n = 196) or to routine hydration (control group; n = 198). The adequate hydration group received continuous intravenous infusion of isosorbide dinitrate combined with intravenous infusion of isotonic saline at a rate of 1.5 mL/kg/h during perioperative period. The definition of CIN was a 25% or 0.5 mg/dL rise in serum creatinine over baseline. This trial is registered with www.clinicaltrials.gov, number NCT02718521.

RESULTS

Baseline characteristics were well-matched between the two groups. CIN occurred less frequently in adequate hydration group than the control group (12.8% vs 21.2%; P = 0.018). The incidence of acute heart failure did not differ between the two groups (8 [4.08%] vs 6[3.03%]; P = 0.599). Cumulative major adverse events (death, myocardial infarction, stoke, hospitalization for acute heart failure) during the 90-day follow-up were lower in the adequate hydration with nitrates group (P = 0.002).

CONCLUSIONS

Adequate hydration with nitrates can safely and effectively reduce the risk of CIN in patients with CKD and CHF.

Methods for Reducing Contrast Use and Avoiding Acute Kidney Injury During Endovascular Procedures

Iodinated Contrast Media (CM) has a plethora of applications in routine non-invasive or percutaneous invasive imaging examinations and therapeutic interventions. Unfortunately, the use of CM is not without complications, with contrast-induced acute kidney injury (CI-AKI) being among the most severe. CI-AKI is a syndrome defined as a rapid development of renal impairment after a few days of CM endovascular injection, without the presence of any other underlying related pathologies. Although mostly transient and reversible, for a subgroup of patients with comorbidities related to renal failure, CI-AKI is directly leading to longer hospitalization, elevated rates of morbidity and mortality, as well as the increased cost of funding. Thus, a need for classification in accordance with clinical and peri-procedural criteria is emerged. This would be very useful for CI-AKI patients in order to predict the ones who would have the greatest advantage from the application of preventive strategies. This article provides a practical review of the recent evidence concerning CI-AKI incidence, diagnosis, and sheds light on prevention methods for reducing contrast use and avoiding AKI during endovascular procedures. In conclusion, despite the lack of a specific treatment protocol, cautious screening, assessment, identification of the high-risk patients, and thus the application of simple interventions -concerning modifiable risk factors- can significantly reduce CI-AKI risk.

Effectiveness of contrast-associated acute kidney injury prevention methods; a systematic review and network meta-analysis

BACKGROUND

Different methods to prevent contrast-associated acute kidney injury (CA-AKI) have been proposed in recent years. We performed a mixed treatment comparison to evaluate and rank suggested interventions.

METHODS

A comprehensive Systematic review and a Bayesian network meta-analysis of randomised controlled trials was completed. Results were tabulated and graphically represented using a network diagram; forest plots and league tables were shown to rank treatments by the surface under the cumulative ranking curve (SUCRA). A stacked bar chart rankogram was generated. We performed main analysis with 200 RCTs and three analyses according to contrast media and high or normal baseline renal profile that includes 173, 112 & 60 RCTs respectively.

RESULTS

We have included 200 trials with 42,273 patients and 44 interventions. The primary outcome was CI-AKI, defined as ≥25% relative increase or ≥ 0.5 mg/dl increase from baseline creatinine one to 5 days post contrast exposure. The top ranked interventions through different analyses were Allopurinol, Prostaglandin E1 (PGE1) & Oxygen (0.9647, 0.7809 & 0.7527 in the main analysis). Comparatively, reference treatment intravenous hydration was ranked lower but better than Placebo (0.3124 VS 0.2694 in the main analysis).

CONCLUSION

Multiple CA-AKI preventive interventions have been tested in RCTs. This network evaluates data for all the explored options. The results suggest that some options (particularly allopurinol, PGE1 & Oxygen) deserve further evaluation in a larger well-designed RCTs.

Prevention of postcontrast acute kidney injury after percutaneous transluminal angioplasty by inducing RenalGuard controlled furosemide forced diuresis with matched hydration: study protocol for a randomised controlled trial

INTRODUCTION

Percutaneous transluminal angioplasty (PTA) is often complicated due to postcontrast acute kidney injury (PC-AKI) in patients diagnosed with chronic kidney disease (CKD). Hydration therapy is the cornerstone in the prevention of PC-AKI. Furosemide forced diuresis with matched hydration using the RenalGuard system enables a steady balance between diuresis and hydration. A randomised controlled trial will be performed in order to investigate whether furosemide forced diuresis with matched hydration in combination with the RenalGuard system decreases incidence of PC-AKI in patients with CKD receiving a PTA of the lower extremities. Furthermore, we will investigate whether sampling of urine biomarkers 4 hours after intervention can detect PC-AKI in an earlier stage compared with the golden standard, serum creatinine 48-72 hours postintervention.

METHODS AND ANALYSIS

A single-centre randomised controlled trial will be conducted. Patients >18 years in need of a PTA of the lower extremities and diagnosed with CKD will be randomly assigned to receive either standard of care prehydration and posthydration or furosemide forced diuresis with matched hydration periprocedural using the RenalGuard system. Four hours postintervention, a urine sample will be collected of all participating patients. Serum creatinine will be sampled within 10 days prior to intervention as well as 1, 3 and 30 days postintervention. The primary endpoint is incidence of PC-AKI post-PTA. Secondary endpoint is the rise of urine biomarkers 4 hours postintervention.

ETHICS AND DISSEMINATION

Study protocol is approved by the research ethics committee and institutional review board (reference number 16 T-201 and NL59809.096.16). Study results will be disseminated by oral presentation at conferences and will be submitted to a peer-reviewed journal. It is anticipated that study results will offer a solution to contrast-induced nephropathy in patients with CKD receiving a PTA of the lower extremities.

TRIAL REGISTRATION NUMBER

NTR6236; Pre-results.

EUDRACT NUMBER

2016-005072-10.

High-volume forced diuresis with matched hydration using the RenalGuard System to prevent contrast-induced nephropathy: A meta-analysis of randomized trials

BACKGROUND

Contrast-induced nephropathy (CIN) is a well-recognized complication of coronary angiography that is associated with poor outcomes. Several small randomized controlled trials (RCTs) have recently shown that in patients with chronic kidney disease (CKD), furosemide-induced forced diuresis with matched hydration using the RenalGuard system can prevent its occurrence. However, individual studies have been underpowered and thus cannot show significant differences in major clinical endpoints.

HYPOTHESIS

Forced diuresis with matched hydration using the RenalGuard system improves clinical outcomes in patients undergoing coronary angiography.

METHODS

Scientific databases and websites were searched for relevant RCTs. The pooled risk ratios were calculated using random-effects models. The primary endpoint was CIN, and the secondary endpoints were major adverse clinical events (MACEs) and the need for renal replacement therapy.

RESULTS

Data from 3 trials including 586 patients were analyzed. High-volume forced diuresis with matched hydration using the RenalGuard system decreased risk of CIN by 60% (risk ratio: 0.40, 95% confidence interval: 0.25 to 0.65, P < 0.001), MACE rate by 59%, and the need for renal replacement therapy by 78%, compared with the standard of care.

CONCLUSIONS

In patients with CKD undergoing coronary angiography, high-volume forced diuresis with matched hydration using the RenalGuard system significantly reduces the risk of CIN, MACE rate, and the need for renal replacement therapy. Larger RCTs with sufficient power are needed to confirm these findings.

Contrast-induced nephropathy: Basic concepts, pathophysiological implications and prevention strategies

Contrast-induced nephropathy (CIN) is reversible acute renal failure observed following administration of iodinated contrast media (CM) during angiographic or other medical procedures such as urography. There are various mechanisms through which CM develop their nephrotoxic effects, including oxidative stress and apoptosis. CIN is a real-life, albeit not very rare, entity. Exact pathophysiology remains obscure and no standard diagnostic criteria apply. The Acute Kidney Injury Network criteria was recently employed but its incidence/clinical significance warrants further clarification based on recent methodological advancements, because most published studies to date were contaminated by bias. The current study is a comprehensive review conducted to provide an overview of the basic concepts of CIN and summarize recent knowledge on its pathophysiology and the evidence supporting potential prevention strategies. CIN is expected to increase morbidity, hospital stay and mortality, while all patients scheduled to receive CM should undergo risk assessment for CIN and high-risk patients may be considered candidates for prevention strategies. The value of using compounds with antioxidant properties other than sodium bicarbonate, remains controversial, warranting further clinical investigation.

Prevention of Contrast-Induced Acute Kidney Injury by Furosemide With Matched Hydration in Patients Undergoing Interventional Procedures: A Systematic Review and Meta-Analysis of Randomized Trials

OBJECTIVES

The objective of this meta-analysis of randomized trials was to evaluate if the administration of furosemide with matched hydration using the RenalGuard System reduces contrast-induced acute kidney injury (CI-AKI) in patients undergoing interventional procedures.

BACKGROUND

CI-AKI is a serious complication following angiographic procedures and a powerful predictor of unfavorable early and long-term outcomes.

METHODS

Online databases were searched up to October 1, 2016, for randomized controlled trials. The primary outcome was the incidence of CI-AKI, and the secondary outcomes were need for renal replacement therapy, mortality, stroke, and adverse events.

RESULTS

A total of four trials (n = 698) published between 2011 and 2016 were included in the analysis and included patients undergoing percutaneous coronary procedures and transcatheter aortic valve replacement. RenalGuard therapy was associated with a lower incidence of CI-AKI compared with control treatment (27 of 348 [7.76%] patients vs. 75 of 350 [21.43%] patients; odds ratio [OR]: 0.31; 95% confidence interval [CI]: 0.19 to 0.50; I2 = 4%; p < 0.00001) and with a lower need for renal replacement therapy (2 of 346 [0.58%] patients vs. 12 of 348 [3.45%] patients; OR: 0.19; 95% CI: 0.05 to 0.76; I2 = 0%; p = 0.02). No major adverse events occurred in patients undergoing RenalGuard therapy.

CONCLUSIONS

The main finding of this meta-analysis is that furosemide with matched hydration by the RenalGuard System may reduce the incidence of CI-AKI in high-risk patients undergoing percutaneous coronary intervention or transcatheter aortic valve replacement. However, further independent high-quality randomized trials should elucidate the effectiveness and safety of this prophylactic intervention in interventional cardiology.

Automated Fluid Management for Treatment of Rhabdomyolysis

Purpose. Fluid therapy aimed at increasing urine output is a commonly employed strategy to prevent acute kidney injury (AKI) in critically ill patients with rhabdomyolysis. Automated fluid management has the potential to optimise urine output while avoiding fluid accumulation in rhabdomyolysis patients. Methods. In a single centre clinical service evaluation we compared a convenience sample of critically ill adults with rhabdomyolysis treated with automated fluid management using the RenalGuard® device to patients managed with manual fluid adjustment following our standard rhabdomyolysis protocol. Primary outcome was number of hours with urine output >2 mL/kg during first 48 h of therapy. Results. Eight patients treated with RenalGuard were compared to 28 patients treated with manual fluid management. Number of hours of target urine output was greater in the RenalGuard versus the Standard group (176/312 (56.4%) versus 534/1305 (40.9%); p < 0.01). Urine output was significantly higher in the first 24 h in the RenalGuard group (median (IQR) 4033 mL (3682–7363) versus 2913 mL (2263–4188 mL); p < 0.01). Fluid balance, electrolyte, diuretics, and bicarbonate use were comparable between groups. Conclusions. Automated fluid management resulted in a higher urine output more quickly in the treatment of rhabdomyolysis. Further research is needed to analyse the effect of diuresis-matched hydration for the prevention of AKI in rhabdomyolysis.

RenalGuard system in high-risk patients for contrast-induced acute kidney injury

BACKGROUND

High urine flow rate (UFR) has been suggested as a target for effective prevention of contrast-induced acute kidney injury (CI-AKI). The RenalGuard therapy (saline infusion plus furosemide controlled by the RenalGuard system) facilitates the achievement of this target.

METHODS

Four hundred consecutive patients with an estimated glomerular filtration rate ≤30 mL/min per 1.73 m(2) and/or a high predicted risk (according to the Mehran score ≥11 and/or the Gurm score >7%) treated by the RenalGuard therapy were analyzed. The primary end points were (1) the relationship between CI-AKI and UFR during preprocedural, intraprocedural, and postprocedural phases of the RenalGuard therapy and (2) the rate of acute pulmonary edema and impairment in electrolytes balance.

RESULTS

Urine flow rate was significantly lower in the patients with CI-AKI in the preprocedural phase (208 ± 117 vs 283 ± 160 mL/h, P < .001) and in the intraprocedural phase (389 ± 198 vs 483 ± 225 mL/h, P = .009). The best threshold for CI-AKI prevention was a mean intraprocedural phase UFR ≥450 mL/h (area under curve 0.62, P = .009, sensitivity 80%, specificity 46%). Performance of percutaneous coronary intervention (hazard ratio [HR] 4.13, 95% CI 1.81-9.10, P < .001), the intraprocedural phase UFR <450 mL/h (HR 2.27, 95% CI 1.05-2.01, P = .012), and total furosemide dose >0.32 mg/kg (HR 5.03, 95% CI 2.33-10.87, P < .001) were independent predictors of CI-AKI. Pulmonary edema occurred in 4 patients (1%). Potassium replacement was required in 16 patients (4%). No patients developed severe hypomagnesemia, hyponatremia, or hypernatremia.

CONCLUSIONS

RenalGuard therapy is safe and effective in reaching high UFR. Mean intraprocedural UFR ≥450 mL/h should be the target for optimal CI-AKI prevention.

Contrast Medium-Induced Acute Kidney Injury

Contrast medium-induced acute kidney injury (CI-AKI) is a predominant cause of hospital-acquired renal insufficiency. With an increasing number of contrast medium-enhanced radiological procedures being performed in a rapidly increasing ageing population in the Western world, it is imperative that more attention is given to understand the aetiology of CI-AKI to devise novel diagnostic methods and to formulate effective prophylactic and therapeutic regimens to reduce its incidence and its associated morbidity and mortality. This article presents high-yield information on the above-mentioned aspects of CI-AKI, primarily based on results of randomised controlled trials, meta-analyses, systematic reviews and international consensus guidelines.

The Prevention of Contrast-Induced Nephropathy

Objective: Contrast-induced nephropathy (CIN) is a complication which may develop after exposure to iodinated contrast media. The resulting acute kidney injury (AKI) is associated with an increase in both short- and long-term morbidity and mortality, increased hospital length of stay, and greater health care costs. The pathophysiological mechanism associated with the development of CIN remains unknown. This narrative review summarizes the pathophysiology, risk factors, and current evidence for the prevention of CIN. Data Sources: A MEDLINE literature search (2004-May 2014) was performed using search terms contrast-induced nephropathy and prevention. Additional references were identified from literature citations, review articles, and meta-analyses. Study Selection and Data Extraction: Abstracts of English-language human clinical trials that examined therapies for the prevention of CIN were evaluated. Studies that did not investigate a preventative intervention for CIN were excluded. Emphasis was placed on recent publications. Data Synthesis: A multitude of therapies focused on the prevention of CIN have been investigated. Unfortunately, many of these studies have produced negative and/or inconsistent results. There is a paucity of adequately designed clinical studies evaluating strategies for the prevention of CIN. However, the best data supports use of preprocedural hydration with isotonic solution as the standard of care for prophylaxis. Conclusion: Given the poor prognosis associated with CIN, there is need for improved methods to prevent it. At present, the best tools to protect patients from unnecessary risk for CIN are careful assessment of renal function, judicious use of procedures that utilize contrast media, and adequate hydration with isotonic solution.