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

Navigating nephrotoxic waters: A comprehensive overview of contrast-induced acute kidney injury prevention

Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of acute kidney injury deriving from the intravascular administration of contrast media in diagnostic and therapeutic procedures and leading to longer in-hospital stay and increased short and long-term mortality. Its pathophysiology, although not well-established, revolves around medullary hypoxia paired with the direct toxicity of the substance to the kidney. Critically ill patients, as well as those with pre-existing renal disease and cardiovascular comorbidities, are more susceptible to CI-AKI. Despite the continuous research in the field of CI-AKI prevention, clinical practice is based mostly on periprocedural hydration. In this review, all the investigated methods of prevention are presented, with an emphasis on the latest evidence regarding the potential of RenalGuard and contrast removal systems for CI-AKI prevention in high-risk individuals.

Assessing the Role of Bioelectrical Impedance Vector Analysis in Prognosis and Prevention of Contrast-Associated Acute Kidney Injury After Percutaneous Coronary Intervention

This study evaluated the impact of Bioelectrical Impedance Vector Analysis (BIVA)-guided hydration therapy on contrast-associated acute kidney injury (CA-AKI) in patients undergoing percutaneous coronary intervention (PCI). From April 2022 to January 2023, this prospective study at the Eastern General Hospital of the Chinese People's Liberation Army involved 902 adults with stable coronary artery disease (CAD) scheduled for PCI. BIVA measurements were performed pre-contrast, followed by a standard hydration regimen. The study focused on the development of CA-AKI and major adverse cardiovascular events (MACE, including all-cause death, nonfatal myocardial infarction, and target vessel revascularization) within 1 year post-PCI. Among the 902 patients (average age: 60.8 years, 65.2% men), CA-AKI post-PCI was observed in 10.8%. Those with CA-AKI had more comorbidities and higher baseline creatinine levels. The contrast volume-to-estimated Glomerular Filtration Rate (eGFR) ratio was higher in CA-AKI patients, with a significantly increased resistance/height ratio (R/H). High R/H values correlated with a greater risk of MACE and all-cause mortality within a year. The study underscores the importance of BIVA-guided hydration therapy and R/H ratio in predicting CA-AKI in PCI patients with stable CAD. Incorporating R/H ratio assessments may enhance pre-procedural risk assessment and improve long-term outcomes (P = .0017).

Hydration to Prevent Contrast-Associated Acute Kidney Injury in Patients Undergoing Cardiac Angiography

Administration of fluid (oral and intravenous) is the cornerstone of prevention of contrast-associated acute kidney injury in the cardiac environment. Intravenous saline is the preferred fluid. The amount, timing, and duration of therapy are discussed. A key determinant of the benefit may be the rate of urine output stimulated by the therapy. Approaches using hemodynamic-guided rates of fluid administration and novel techniques to generate large urine outputs while maintaining fluid balance are highlighted.

Key Considerations regarding the Renal Risks of Iodinated Contrast Media: The Nephrologist's Role

BACKGROUND

The administration of iodinated contrast medium during diagnostic and therapeutic procedures has always been associated with the fear of causing acute kidney injury (AKI) or an exacerbation of chronic kidney disease. This has led, on the one hand, to the deterrence, when possible, of the use of contrast medium (preferring other imaging methods with the risk of loss of diagnostic power), and on the other hand, to the trialling of multiple prophylaxis protocols in an attempt to reduce the risk of kidney injury.

SUMMARY

A literature review on contrast-induced (CI)-AKI risk mitigation strategies was performed, focussing on the recognition of individual risk factors and on the most recent evidence regarding prophylaxis.

KEY MESSAGES

Nephrologists can contribute significantly in the CI-AKI context, from the early stages of the decision-making process to stratifying patients by risk, individualising prophylaxis measures based on the risk profile, and ensuring appropriate evaluation of kidney function and damage post-procedure to improve care.

Effect of Vigileo/FloTrac System-Guided Aggressive Hydration in Acute Myocardial Infarction Patients to Prevent Contrast-Induced Nephropathy After Urgent Percutaneous Coronary Intervention

Tailored hydration strategies appear to provide an effective solution for preventing contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI). The Vigileo/FloTrac system could predict the patients' fluid responsiveness and tolerance to hydration. This prospective multicenter, randomized controlled, open-label study evaluated the efficacy of aggressive hydration guided by the Vigileo/FloTrac system for CIN prevention in patients with acute myocardial infarction (AMI). This trial enrolled patients with AMI undergoing urgent PCI, and these patients were randomized (1:1) to receive either aggressive hydration guided by Vigileo/FloTrac system (intervention group) or general hydration (control group). Patients with AMI in the intervention group received a loading dose of saline, and the hydration speed was adjusted according to the change of Vigileo/FloTrac index. The primary end point is CIN, which was defined as a >25% or >0.5 mg/100 ml increase in serum creatinine compared with baseline during the first 72 hours after urgent PCI. This trial was registered in ClinicalTrials.gov (NCT04382313). A total of 344 patients with AMI were enrolled and randomized in our trial, and the baseline characteristics, including risk factors of CIN, of the Vigileo/FloTrac-guided hydration group (n = 173) and control group (n = 171) were well balanced (all p >0.05). The total hydration volume in Vigileo/FloTrac-guided hydration group was significantly much more than control group (1,910 ± 600 vs 440 ± 90 ml, p <0.001). The incidence of CIN in the Vigileo/FloTrac-guided hydration group was significantly decreased than that in the control group (12.1% [21/173] vs 22.2% [38/171], p = 0.013). There was not significantly different in the incidence of acute heart failure after PCI (9.2% [16/173] vs 7.6% [13/171], p = 0.583). The incidence of main adverse cardiovascular events in the Vigileo/FloTrac-guided hydration group was lower than that in the control group but without statistically difference (30 events [17.3%] vs 38 events [22.2%], p = 0.256). In conclusion, Vigileo/FloTrac system-guided aggressive hydration could effectively decrease the risk of CIN for patients with AMI undergoing urgent PCI and avoid attack of acute heart failure at the same time.

[Monocentric experience of the RenalGuard® system to limit post-contrast acute kidney injury in patients at high-risk undergoing interventional coronary procedures]

BACKGROUND

Despite an often favorable risk/benefit ratio, patients with severe chronic kidney disease are sometimes declined for interventional coronary procedures, due to the risk of acute kidney injury post-contrast (AKI-PC). A large preventive supply of intravenous fluid may be problematic in this population. The RenalGuard® system allows hyperhydration by maintaining a stable volemia through an enhanced diuresis.

METHODS AND RESULTS

This work reports the evaluation of the RenalGuard® system in 25 consecutive patients with chronic kidney disease (glomerular filtration rate < 40 mL/min/1.73 m²) requiring an interventional coronary procedure (coronary angiography and/or percutaneous coronary intervention) and at high risk of IRA-PC. An increase in serum creatinine ≥ 26.5 µmol/L at 48-72 hours (AKI-PC definition) was observed in 4 patients (16%). The mean glomerular filtration rate was 26 ± 8 mL/min/1.73 m² at 48-72 hours versus 25 ± 8 mL/min/1.73 m² at baseline. No patient presented with an increase in serum creatinine ≥ 1.5 from baseline, stage 2 or 3 AKI, or acute pulmonary edema. No renal replacement therapy was necessary. One death unrelated to AKI-PC occurred during hospital stay.

CONCLUSIONS

This single-center observational study suggests that the RenalGuard® system, allowing diuresis-adjusted hyperhydration, is safe and useful for patients at high risk of AKI-PC after an interventional coronary procedure.

New perspectives on contrast-induced nephropathy during coronary interventions

Tweetable abstract To reduce contrast-induced nephropathy as a complication of percutaneous coronary intervention, several thresholds have been proposed, including maximum contrast dose, contrast volume/estimated glomerular filtration rate, revised maximal contrast dose and zero-contrast percutaneous coronary intervention in select patients.

Contrast-Associated Acute Kidney Injury

Contrast-associated acute kidney injury (CA-AKI) is an impairment of renal function, which occurs within days of intravascular administration of iodinated contrast media. Taking into account that minimally invasive cardiac interventions are becoming increasingly popular, compared to traditional surgery, given their impact on prognosis and costs, CA-AKI remains a subject of increasing interest for patients and physicians. This review summarizes the epidemiology and risk stratification, diagnostic criteria, pathophysiology and clinical implications of CA-AKI, providing evidence for the most studied preventive strategies.

CONTRAST INDUCED ACUTE KIDNEY INJURY IS NOT A SITUATION TO BE AFRAID OF

Acute kidney injury (AKI), formerly called acute renal failure (ARF), is clinically manifested as a reversible acute increase in nitrogen waste products, as measured by blood urea nitrogen (BUN) and serum creatinine levels. Contrast induced acute kidney injury (CIAKI) is a potentially fatal complication of angiographic procedures caused by the use of contrast media (CM). It is the third most prevalent cause of hospital acquired acute renal damage, accounting for around up to 30% of cases. Contrast induced nephropathy (CIN) is defined as a greater than 25% or 0.5 mg/dl (44 μmol/l) increase in serum creatinine (Scr) from baseline within 3 days. More sensitive indicators of renal damage are sought, hence numerous tubular injury biomarkers are being studied. Multiple risk factors may lead to the development of CIN; these risk factors are classified as patient-related and procedure-related. Treatment of CIN Is primarily symptomatic and consist firstly of careful fluid and electrolyte management, although dialysis may be necessary in some cases. With available treatment options, prevention is the cornerstone of management.

CHIPS: Prevention of contrast-induced nephropathy before and after cardiac catheterization

ABSTRACT

Contrast-induced nephropathy is the leading cause of acute kidney injury in hospital settings. Practitioners must have a comprehensive understanding of preventive interventions. This article provides a mnemonic NPs can use to prevent contrast-induced nephropathy. The mnemonic, CHIPS, addresses Contrast minimizations, Hemofiltration, Iso-osmolar/low osmolar contrast, Pharmacologic interventions, and Saline I.V. hydration.

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.

Hydration: Intravenous and Oral: Approaches, Principals, and Differing Regimens: Is It What Goes in or What Comes Out That Is Important?

The literature (in English) was accessed to review the evidence that administration of fluids is protective of contrast-associated acute kidney injury (CA-AKI). The evidence was evaluated with the intent of understanding mechanisms of protection. Prospective randomized trials comparing oral versus intravenous fluid, sodium chloride versus no intravenous fluid, sodium bicarbonate versus sodium chloride, and forced matched hydration versus intravenous sodium chloride provided the data. In general, the more fluid administered, the lower the incidence of CA-AKI. However, understanding the mechanism of this beneficial effect suggests that it is the urine output that most directly affects the incidence of CA-AKI.

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.

RenalGuard system to prevent contrast-induced acute kidney injury in Japanese patients with renal dysfunction; RESPECT KIDNEY study

Increasing the urine flow rate (UFR) reduces the toxic effect of contrast media. Use of the RenalGuard system enables the achievement of a high UFR by maintaining intravascular volume and prevents the development of contrast-induced acute kidney injury (CI-AKI). However, the efficacy and safety of RenalGuard system have not yet been evaluated in Japan. This multicenter prospective study evaluated the efficacy and safety of the RenalGuard therapy in preventing CI-AKI development in 60 Japanese patients with renal dysfunction [estimated glomerular filtration rate (eGFR) < 45 mL/min/1.73 m²] undergoing catheter procedures. Baseline eGFR and Mehran's CIN (contrast-induced nephropathy) risk score were 35.1 ± 8.5 mL/min/1.73 m² and 11.7 ± 4.3, respectively. Regardless of this high-risk profile, the incidence of CI-AKI was 8.6% (5/58) compared with the 26.1% incidence estimated by the CIN risk score. Moreover, two-sided 95% (Fisher's) exact confidence interval was 2.9-19.0 and its upper limit (i.e., 19.0) was less than the prespecified threshold incidence of 25.0. Univariate logistic regression analysis demonstrated that the UFR during catheter procedure was one of the most important factor associated with CI-AKI (odds ratio 0.99, confidence interval 0.98-1.00, p = 0.03). In conclusion, RenalGuard therapy may prevent CI-AKI development in Japanese patients with renal dysfunction. Further large-scale prospective multicenter studies are necessary to confirm our findings.

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.

Remote ischemic preconditioning for prevention of contrast induced nephropathy-Insights from an Indian study

Objectives

To study if four cycles of remote ischemic preconditioning (RIPC) could offer protection against contrast induced nephropathy (CIN) and post procedural renal dysfunction in high risk patients undergoing percutaneous coronary intervention (PCI).

Methods

This was a prospective single blind randomized sham controlled trial where patients undergoing coronary angioplasty with stage III chronic kidney disease were randomized into sham preconditioning and remote ischemic preconditioning. The primary outcome was the reduction in the incidence of CIN. The secondary outcomes were the maximum improvement in eGFR, maximum reduction in serum creatinine and composite of requirement of hemodialysis, death and rehospitalization for heart failure up to 6 weeks after PCI.

Results

Eleven out of fifty patients in the study group developed CIN (22%) compared to eighteen out of the fifty control patients (36%) (p = 0.123). There was a statistically significant improvement in the post procedure creatinine values at 24 h (p = 0.013), 48 h (p = 0.015), 2 weeks (p = 0.003), 6 weeks (p = 0.003) and post procedure glomerular filtration rate (eGFR) values at 24 h (p = 0.026), 48 h (p = 0.044), 2 weeks (p = 0.015) and 6 weeks (p = 0.011) in study group compared to control group. The secondary outcome composite of requirement of hemodialysis, death and rehospitalization for heart failure was not statistically significant (p: 0.646).

Conclusion

RIPC does not result in significant reduction of CIN. However RIPC helps in the prevention of post procedural worsening in eGFR and serum creatinine even up to 6 weeks.

Contrast media-induced nephropathy: how has Italy contributed in the past 30 years? A systematic review

Background and objective

The use of contrast media in Italy has exponentially increased in the past 3 decades. However, it is unknown whether there has been an increase in clinical research evaluating the risks associated with contrast media usage, especially regarding contrast-induced nephropathy. To fill this gap in knowledge, we performed a systematic review.

Study eligibility criteria

Meta-analyses, observational studies, and clinical trials assessing contrast media-induced nephropathy as the safety outcome, in which at least one author was affiliated with an Italian university/health care structure, were eligble.

Data sources

Ovid MEDLINE, Ovid Embase, Cochrane Methodology Register, and Web of Science were screened.

Participants

Men and women exposed to contrast media.

Results

In total, 60 original articles were retrieved with an incremental trend between 1990 and 2017. Cohort studies were the most common study design represented. In total, 45 of 60 (75.0%) studies were monocenter studies and 41 of 60 (68.3%) received no funding. In all, 91.7% of studies disclosed no conflicts of interest and 81.7% had no external collaboration. Most of the studies provided a level of evidence of III-2 (32/60; 53.3%) and II (23/60; 38.3%). In total, 50 of 60 studies (83.3%) were published in a scientific journal ranked in the first quartile of their subject area.

Conclusion

There was an increased number of studies evaluating contrast-induced nephropathy in Italy during the last three decades. These studies covered procedures to prevent contrast-induced nephropathy or aimed to identify risk factors, biomarkers, and scores, and their related prognosis.

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.