Study Evaluating the Use of RenalGuard to Protect Patients at High Risk of AKI

Tailored hydration for the prevention of contrast-induced acute kidney injury after coronary angiogram or PCI: A systematic review and meta-analysis

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is a frequent complication of coronary interventions associated with an increased risk of mortality and morbidity. The optimal intravenous hydration strategy to prevent CI-AKI is not well-established. The primary objective is to determine if a tailored hydration strategy reduces the risk of CI-AKI and of major adverse cardiovascular events (MACE) in patients undergoing coronary angiography compared with a nontailored hydration strategy.

METHODS

A study-level meta-analysis of randomized controlled trials comparing tailored versus nontailored hydration strategies for the prevention of CI-AKI (primary outcome) and of MACE (main secondary outcome) in patients undergoing coronary angiography for any indication was performed. Tailored hydration was defined as the administration of intravenous fluids based on patient-specific parameters other than weight only.

RESULTS

A total of 13 studies were included (n = 4,458 participants). The overall risk of bias was moderate. A tailored strategy was associated with a significant reduction in the risk of CI-AKI (RR = 0.56, 95% CI, [0.46-0.69], P < .00001; I2 = 26%), and of MACE (RR = 0.57, 95% CI, [0.42-0.78], P = .0005; I2 = 12%). A tailored hydration strategy was not associated with a significant reduction in the other prespecified secondary outcomes, except for all-cause mortality (RR = 0.57, 95% CI, [0.35, 0.94], P = .03; I2 = 0%). The impact of a tailored strategy on the primary outcome was consistent in sensitivity analyses.

CONCLUSION

These results suggest that tailored hydration is superior to nontailored hydration in reducing the risk of CI-AKI and MACE in patients undergoing coronary angiography. Future trials are required to identify the optimal tailored hydration strategy.

Efficacy of the Renal-guard system in the prevention of contrast-induced nephropathy following cardiac interventions among patients with chronic kidney disease

Background

Contrast-induced nephropathy (CIN), also called as contrast associated-acute kidney injury (CA-AKI) is a common complication following cardiac procedures. KDIGO guidelines define CIN as a ≥25% increase in serum creatinine or an absolute increase of at least 0.5 mg/dl 48-72 h post-contrast administration. The single most effective measure in preventing CIN is peri-procedural intravascular hydration typically from 12 h before to 24 h after contrast media exposure but has limitations. Recently, the RenalGuard (RG) system has emerged as a new tool, demonstrating safer and more efficient hydration and reducing the incidence of AKI caused by CIN.

Aims

We conducted this meta-analysis on the effectiveness of the RG system in preventing CIN in patients undergoing cardiac interventions.

Methods

A comprehensive literature search of PubMed (MEDLINE), Science Direct, and Embase was conducted from its inception until February 2024 for randomized controlled trials (RCTs) including patients aged >18 years undergoing cardiac procedures with underlying chronic kidney disease (CKD), estimated glomerular filtration rate (eGFR) 20-60 ml/min/1.73 m2 and left ventricular ejection fraction (LVEF) >50%. The outcomes of interest were risk of CIN, risk of renal replacement therapy (RRT), in-hospital mortality and 30-day mortality, major adverse cardiovascular events (MACE), changes in serum creatinine (sCr) levels, and incidence of pulmonary edema. A random-effects meta-analysis was performed using Review Manager (RevMan) [Computer Program] Version 5.4 Cochrane Collaboration.

Results

A total of 9 RCTs including 3,215 patients with CKD undergoing cardiac procedures on volume expansion strategies were included with 1,802 patients on the RG system and 1,413 patients using alternate volume expansion techniques. Pooled analysis of 9 RCTs reported a significantly lower risk of CIN in patients using the RG system vs. control [OR 0.51 (0.35, 0.74), P = 0.0004; I2 = 55%]. There was no significant difference in the risks of RRT, in-hospital mortality, 30-day MACE, pulmonary edema, or change in sCr levels.

Conclusion

This meta-analysis indicates the beneficial utilization of the RG system in populations with moderate-to-high risk and underlying CKD undergoing cardiac interventions in preventing CIN. However, it did not demonstrate a notable impact on mortality, RRT, MACE, pulmonary edema, and sCr levels when compared to the control group.

Diuretics for preventing and treating acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is a well-known complication of critical illnesses, significantly affecting morbidity and the risk of death. Diuretics are widely used to ameliorate excess fluid accumulation and oliguria associated with AKI. Their popularity stems from their ability to reduce the energy demands of renal tubular cells by inhibiting transporters and flushing out intratubular casts. Numerous studies have assessed the effects of diuretics in the context of AKI prevention and treatment. However, a comprehensive systematic review addressing this topic has yet to be conducted.

OBJECTIVES

This review aimed to explore the benefits and harms of diuretics for both the prevention and treatment of AKI.

SEARCH METHODS

The Cochrane Kidney and Transplant Register of Studies was searched up to May 2024 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) and quasi-RCTs in which diuretics were used to prevent or treat AKI.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data using standardised data extraction forms. Dichotomous outcomes were expressed as risk ratios (RR) with 95% confidence intervals (CI). Where continuous scales of measurement were used to assess the effects of treatment, the standardised mean difference (SMD) was used. The primary review outcomes for AKI prevention studies were the incidence of AKI and any use of kidney replacement therapy (KRT). For treatment studies, the primary outcome was any use of KRT. The certainty of evidence was assessed per outcome using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 64 studies (83 reports, 9871 participants): 53 prevention studies (8078 participants) and 11 treatment studies (1793 participants). Studies were conducted in the following World Health Organization regions: the Americas (15), Eastern Mediterranean (9), Europe (25), South-East Asia (2), and the Western Pacific (13). Thirty-six studies were single-centre studies, 19 were multicentre, and the setting was unclear in nine studies. Diuretics were compared to placebo, no treatment or conventional therapy, saline solutions (isotonic or hypotonic), 5% dextrose, 5% glucose, Hartmann's solution, and Ringer's acetate. Overall, the risk of bias was low in one study, high in 19 studies, and of some concern in 41 studies. Three studies could not be assessed because they did not report any outcomes of interest. For AKI prevention, compared to control, diuretics may reduce the risk of AKI (38 studies, 5540 participants: RR 0.75, 95%, CI 0.61 to 0.92; I2 = 77%; low-certainty evidence) and probably reduce any use of KRT (32 studies, 4658 participants: RR 0.63, 95% CI 0.43 to 0.91; I2 = 0%, moderate-certainty evidence) and death (33 studies, 6447 participants: RR 0.73, 95% CI 0.59 to 0.92; I2 = 0%; moderate-certainty evidence). The use of diuretics may result in little or no difference in the need for permanent dialysis (2 studies, 956 participants: RR 0.52, 95% CI 0.08 to 3.47; I2 = 21%; low-certainty evidence), hypotension (7 studies, 775 participants: RR 1.27, 95% CI 0.87 to 1.86; I2 = 0%; low-certainty evidence) and hypokalaemia (6 studies, 1383 participants: RR 1.20, 95% CI 0.88 to 1.73; I2 = 43%; low-certainty evidence), and had uncertain effects on arrhythmias (13 studies, 3375 participants: RR 0.77, 95% CI 0.57 to 1.04; I2 = 53%; very-low certainty evidence). Diuretics may make little or no difference to changes in SCr within 30 days (8 studies, 646 participants: SMD 0.41, 95% CI -0.01, to 0.83; I2 = 82%; low-certainty evidence) but it was uncertain whether diuretics increased urinary output (8 studies, 1155 participants: SMD 1.87, 95% CI -0.20 to 3.95; I2 = 99%; very low-certainty evidence). For AKI treatment, diuretics may make little or no difference to any use of KRT (8 studies, 1275 participants: RR 0.93, 95% CI 0.83 to 1.04; I2 = 2%; low-certainty evidence) or death (14 studies, 2052 participants: RR 1.08, 95% CI 0.96 to 1.22; I2 = 0%; low-certainty evidence). Diuretics may increase hypotension (2 studies, 720 participants: RR 1.99, 95% CI 1.16 to 3.41; I2 = 90%; low-certainty evidence) and probably increase arrhythmias (6 studies, 1011 participants: RR 1.62, 95% CI 1.12 to 2.33; I2 = 0%; moderate-certainty evidence). Diuretics may result in little or no difference in hypokalaemia (3 studies, 478 participants: RR 1.52, 95% CI 0.70 to 3.31; I2 = 0%; low-certainty evidence). It was uncertain whether diuretics increased urinary output (3 studies, 329 participants: SMD 4.40, 95% CI -0.94 to 9.74; I2 = 99%; very low-certainty evidence). The need for permanent dialysis and changes in serum creatinine were not reported.

AUTHORS' CONCLUSIONS

When used for the prevention of AKI, diuretics may reduce the risk of AKI. However, our confidence in the effect estimate is limited. Diuretics probably reduce the incidence of KRT use, and we are moderately confident in the effect estimate. When used for the treatment of AKI, diuretics may make little or no difference to any use of KRT, and our confidence in the effect estimate is limited. More RCTs are needed to explore the role of diuretics for treating established AKI.

Kidney protection strategy lowers the risk of contrast-associated acute kidney injury

We developed a comprehensive kidney protection strategy (KPS), which comprises left ventricular end-diastolic pressure-guided saline hydration, ultralow contrast coronary angiography, and a staged coronary revascularization procedure under suitable conditions. This study aimed to investigate KPS's effect on the risk of developing contrast-associated acute kidney injury (CA-AKI) among persons with moderate-to-advanced kidney insufficiency (KI). Seventy patients who had undergone cardiac catheterization with an estimated glomerular filtration rate (eGFR) of 15-45 mL/min/1.73 m2 were investigated retrospectively. Among these, 19 patients who had received KPS and 51 who had undergone cardiac catheterization with usual care (UC) were enrolled. CA-AKI was defined as a 0.3-mg/dL increase in serum creatinine levels or dialysis initiation within 72 h after contrast exposure. The inverse probability of treatment weighting (IPTW)-adjusted cohort was analyzed according to the Mehran 2 risk categories. Patients' mean age was 73.3 ± 9.6 years; mean eGFR was 29.8 ± 8.5 mL/min/1.73 m2; and median of Mehran 2 risk score, 8. Most patients presented with acute myocardial infarction (AMI) or heart failure, and one-fifth of the administered cardiac catheterizations were emergency procedures. After the IPTW adjustment, the KPS group showed a significantly lower CA-AKI risk than the UC group (4% vs. 20.4%; odds ratio 0.19, 95% confidence interval 0.05-0.66). This effect was consistent across various subgroups according to different variables, including old age, AMI, advanced KI, high-risk category, left ventricular systolic dysfunction, and multivessel disease. Conclusively, KPS may reduce the CA-AKI risk in high-risk patients with moderate-to-advanced KI who have undergone cardiac catheterization.

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.

Effect of periprocedural furosemide-induced diuresis with matched isotonic intravenous hydration in patients with chronic kidney disease undergoing transcatheter aortic valve implantation

BACKGROUND

Acute kidney injury (AKI) after transcatheter aortic valve implantation (TAVI) is a serious complication which is associated with increased mortality. The RenalGuard system was developed to reduce the risk of AKI after contrast media exposition by furosemide-induced diuresis with matched isotonic intravenous hydration. The aim of this study was to examine the effect of the RenalGuard system on the occurrence of AKI after TAVI in patients with chronic kidney disease.

METHODS

The present study is a single-center randomized trial including patients with severe aortic valve stenosis undergoing TAVI. Overall, a total of 100 patients treated by TAVI between January 2017 and August 2018 were randomly assigned to a periprocedural treatment with the RenalGuard system or standard treatment by pre- and postprocedural intravenous hydration. Primary endpoint was the occurrence of AKI after TAVI, and secondary endpoints were assessed according to valve academic research consortium 2 criteria.

RESULTS

Overall, the prevalence of AKI was 18.4% (n = 18). The majority of these patients developed mild AKI according to stage 1. Comparing RenalGuard to standard therapy, no significant differences were observed in the occurrence of AKI (RenalGuard: 21.3%; control group: 15.7%; p = 0.651). In addition, there were no differences between the groups with regard to 30-day and 12-month mortality and procedure-associated complication rates.

CONCLUSION

In this randomized trial, we did not detect a reduction in AKI after TAVI by using the RenalGuard system. A substantial number of patients with chronic kidney disease developed AKI after TAVI, whereas the majority presented with mild AKI according to stage 1 (ClinicalTrials.gov number NCT04537325).

In-hospital outcomes of transcatheter aortic valve replacement in patients with chronic and end-stage renal disease: a nationwide database study

BACKGROUND

Chronic kidney disease (CKD) and end-stage renal disease (ESRD) have been associated with worse outcomes after transcatheter aortic valve replacement (TAVR). With TAVR indications extending to a wider range of patient populations, it is important to understand the current implications of chronic renal insufficiency on clinical outcomes. We aim to determine the impact of CKD and ESRD on in-hospital outcomes after TAVR.

METHODS

We queried the National Inpatient Sample for TAVR performed between 2016 and 2020 using International Classification of Diseases-10th Revision codes. We compared in-hospital mortality and clinical outcomes between three groups: normal renal function, CKD and ESRD. The association between CKD/ESRD and outcomes was tested with multivariable logistic regression analyses, using normal renal function as baseline.

RESULTS

In the five-year study period, 279,195 patients underwent TAVR (mean age 78.9 ± 8.5 years, 44.4% female). Of all patients, 67.1% had normal renal function, 29.2% had CKD, and 3.7% had ESRD. There were significant differences in age, sex, and prevalence of comorbidities across groups. In-hospital mortality was 1.3%. Compared to patients with normal renal function, patients with renal insufficiency had higher in-hospital mortality, with the highest risk found in patients with ESRD (adjusted odds ratio: 1.4 [95% confidence interval: 1.2-1.7] for CKD; adjusted odds ratio: 2.4 [95% confidence interval: 1.8-3.3] for ESRD). Patients with CKD or ESRD had a higher risk of cardiogenic shock, need for mechanical circulatory support, and vascular access complications, compared to those with normal renal function. In addition, patients with ESRD had a higher risk of cardiac arrest and periprocedural acute myocardial infarction. The incidence of conversion to open heart surgery was 0.3% and did not differ between groups. Post-procedural infectious and respiratory complications were more common among patients with CKD or ESRD.

CONCLUSION

Patients with CKD and ESRD are at higher risk of in-hospital mortality, cardiovascular, and non-cardiovascular complications after TAVR. The risk of complications is highest in patients with ESRD and does not result in more frequent conversion to open heart surgery. These results emphasize the importance of individualized patient selection for TAVR and procedural planning among patients with chronic renal insufficiency.

Diuresis-matched versus standard hydration in patients undergoing percutaneous cardiovascular procedures: meta-analysis of randomized clinical trials

INTRODUCTION AND OBJECTIVES

Contrast-associated acute kidney injury (CA-AKI) is a potential complication of procedures requiring administration of iodinated contrast medium. RenalGuard, which provides real-time matching of intravenous hydration with furosemide-induced diuresis, is an alternative to standard periprocedural hydration strategies. The evidence on RenalGuard in patients undergoing percutaneous cardiovascular procedures is sparse. We used a Bayesian framework to perform a meta-analysis of RenalGuard as a CA-AKI preventive strategy.

METHODS

We searched Medline, Cochrane Library and Web of Science for randomized trials of RenalGuard vs standard periprocedural hydration strategies. The primary outcome was CA-AKI. Secondary outcomes were all-cause death, cardiogenic shock, acute pulmonary edema, and renal failure requiring renal replacement therapy. A Bayesian random-effect risk ratio (RR) with corresponding 95% credibility interval (95%CrI) was calculated for each outcome. PROSPERO database number CRD42022378489.

RESULTS

Six studies were included. RenalGuard was associated with a significant relative reduction in CA-AKI (median RR, 0.54; 95%CrI, 0.31-0.86) and acute pulmonary edema (median RR, 0.35; 95%CrI, 0.12-0.87). No significant differences were observed for the other secondary endpoints [all-cause death (RR, 0.49; 95%CrI, 0.13-1.08), cardiogenic shock (RR, 0.06; 95%CrI, 0.00-1.91), and renal replacement therapy (RR, 0.52; 95%CrI, 0.18-1.18)]. The Bayesian analysis also showed that RenalGuard had a high probability of ranking first for all the secondary outcomes. These results were consistent in multiple sensitivity analyses.

CONCLUSIONS

In patients undergoing percutaneous cardiovascular procedures, RenalGuard was associated with a reduced risk of CA-AKI and acute pulmonary edema compared with standard periprocedural hydration strategies.

Simplified Rapid Hydration Prevents Contrast-Associated Acute Kidney Injury Among CKD Patients Undergoing Coronary Angiography

BACKGROUND

Patients with chronic kidney disease (CKD) undergoing coronary angiography (CAG) are at high risk of contrast-associated acute kidney injury (CA-AKI) and mortality. Therefore, there is a clinical need to explore safe, convenient, and effective strategies for preventing CA-AKI.

OBJECTIVES

This study sought to assess whether simplified rapid hydration is noninferior to standard hydration for CA-AKI prevention in patients with CKD.

METHODS

This multicenter, open-label, randomized controlled study was conducted across 21 teaching hospitals and included 1,002 patients with CKD. Patients were randomized to either simplified hydration (SH) (SH group, with normal saline from 1 hour before to 4 hours after CAG at a rate of 3 mL/kg/h) or standard hydration (control group, with normal saline 12 hours before and 12 hours after CAG at a rate of 1 mL/kg/h). The primary endpoint of CA-AKI was a ≥25% or 0.5-mg/dL rise in serum creatinine from baseline within 48 to 72 hours.

RESULTS

CA-AKI occurred in 29 of 466 (6.2%) patients in the SH group and in 38 of 455 (8.4%) patients in the control group (relative risk: 0.8; 95% CI: 0.5-1.2; P = 0.216). In addition, the risk of acute heart failure and 1-year major adverse cardiovascular events did not differ significantly between the groups. However, the median hydration duration was significantly shorter in the SH group than in the control group (6 vs 25 hours; P < 0.001).

CONCLUSIONS

In CKD patients undergoing CAG, SH is noninferior to standard hydration in preventing CA-AKI with a shorter hydration duration.