Renal Insufficiency After Contrast Media Administration Trial II (REMEDIAL II): 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.

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).

Management Considerations for Acute Coronary Syndromes in Chronic Kidney Disease

PURPOSE OF REVIEW

Propensity of patients with chronic kidney disease (CKD) to adverse outcomes of acute coronary syndromes (ACS) derives, in part, from imperfection in management. Dearth of data resulting from underrepresentation of patients with CKD in ACS trials and underuse of evidence-based testing and therapy compound biological risks inherent to CKD. We sought in this narrative review to critically appraise contemporary evidence and offer suggested approaches to practicing clinicians for the optimization of ACS management in patients with CKD.

RECENT FINDINGS

Updated multisociety chest pain guidelines emphasize the diversity of clinical presentations of ACS, pertinent to recognition of ACS in patients with CKD. Evolving tools to predict and prevent acute kidney injury complicating invasive management of ACS serve to support improved access to and safety of percutaneous coronary intervention (PCI) in CKD patients, who remain at elevated risk. Growth in use of radial access, advances in PCI quality, incorporation of intravascular imaging, and new options and insights in pharmacotherapy contribute to an evolving calculus of ischemic and bleeding risk in ACS with bearing on management in CKD patients. Key opportunities to improve outcomes of ACS for patients with CKD center on avoiding underuse of beneficial medical and invasive therapies; enhancing safety of therapies by leveraging evidence-based strategies to prevent acute kidney injury; and devoting specific effort to investigation of ACS management in the context of CKD.

The Treatment of Coronary Artery Disease in Patients with Chronic Kidney Disease: Gaps, Challenges, and Solutions

Background

Chronic kidney disease (CKD) is associated with a high burden of coronary artery disease (CAD), which remains the leading cause of death in CKD patients. Despite the high cardiovascular risk, ACS patients with renal dysfunction are less commonly treated with guideline-based medical therapy and are less frequently referred for coronary revascularization.

Summary

The management of CAD is more challenging in patients with CKD than in the general population due to concerns regarding side effects and renal toxicity, as well as uncertainty regarding clinical benefit of guideline-based medical therapy and interventions. Patients with advanced CKD and especially those receiving dialysis have not traditionally been represented in randomized trials evaluating either medical or revascularization therapies. Thus, only scant data from small prospective studies or retrospective analyses are available. Recently published studies suggest that there are significant opportunities to substantially improve both cardiovascular and renal outcomes of patients with CAD and CKD, including new medications and interventions. Thus, the objective of this review is to summarize the current evidence regarding the management of CAD in CKD patients, in particular with respect to improvement of both cardiovascular and renal outcomes.

Key Messages

Adequate medical therapy and coronary interventions using evidence-based strategies can improve both cardiac and renal outcomes in patients with CAD and CKD.

Prevention of Contrast-induced Nephropathy in Patients Undergoing Percutaneous Coronary Intervention

Contrast-induced nephropathy (CIN) or contrast-induced acute kidney injury has varying definitions, but in general, increased serum creatinine level by ≥ 0.3 mg/dL (26.5 µmol/L) or 1.5x of baseline value or urine output <0.5 mL/kg/h within 1-7 days after contrast media (CM) administration can be considered as CIN. CIN is one of the most common complications and is associated with increased mortality in patients undergoing percutaneous coronary intervention (PCI). Thus, risk stratification for CIN should be made and preventive strategies should be employed in which the intensity of the approach must be tailored to patient's risk profile. In all patients, adequate hydration is required, nephrotoxic medications should be discontinued, and pre-procedural high-intensity statin is recommended. In patients with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2, IV hydration should be started 12 hours pre-procedure up until 12-24 hours after the procedure. Remote ischemic preconditioning may be performed pre-procedurally. Radial first approach for vascular access is recommended. During the procedure, low or iso-osmolar CM should be used and its volume should be limited to eGFR x 3.7. In patients at high risk for CIN, additional contrast-sparing strategies may be applied, such as using a contrast reduction system, 5 Fr catheter with no sideholes, CM dilution, limiting test injection, confirming placement using guidewire, use of stent enhancing imaging technology, using metallic/software roadmap to guide PCI, use of IVUS or dextran-based OCT, and coronary aspiration. A more advanced hydration technique based on central venous pressure, left ventricular end-diastolic pressure, or using furosemide-matched hydration, might be considered.

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.

Contrast media volume reduction with the DyeVertTM system to prevent acute kidney injury in stable patients undergoing coronary procedures

BACKGROUND

Contrast associated acute kidney injury (CA-AKI) can lead to an increased risk of adverse events. Contrast media (CM) volume reduction has been advocated as a pivotal strategy to prevent CA-AKI in stable patients undergoing percutaneous coronary procedures.

AIMS

To compare the effectiveness of CM volume reduction with the DyeVertTM system versus conventional strategy in reducing the risk of CA-AKI.

METHODS

We prospectively collected data from 136 patients with stable coronary artery disease at high risk of CA-AKI treated with left ventricular end diastolic pressure (LVEDP)- guided hydration and undergoing interventions with the use of the DyeVertTM (Osprey Medical Inc.) system. Patients previously enrolled in the LVEDP-guided hydration arm of the "Renal Insufficiency Following Contrast MEDIA Administration triaL III" (REMEDIAL III) were considered as controls. Propensity score was used to perform 1:1 matching to adjust for major confounders. The primary outcome was the occurrence of CA-AKI, as defined by an absolute increase of creatinine values ≥0.3 mg/dL at 48 h.

RESULTS

Patients in the DyeVert group were treated with a significant lower CM volume (median: 47.5 vs. 84.0 mL, p < 0.001). The trend in creatinine increase was lower (p = 0.004) and the Δ of creatinine (0-48 h) showed a higher drop (-0.18 vs. -0.10 mg/dL, p = 0.036) in the DyeVert group. The risk of CA-AKI was significantly lower in DyeVert group compared to control group (5.1% vs. 16.8%; odds ratio 0.27, 95% confidence interval [0.12-0.61]).

CONCLUSIONS

CM volume reduction with the DyeVertTM system seems to be superior to conventional strategies in reducing the occurrence of CA-AKI.

Rationale and design of the Dynamic Coronary Roadmap for Contrast Reduction (DCR4Contrast) in PCI randomized controlled trial

BACKGROUND

The clinical and anatomic complexity of patients undergoing percutaneous coronary interventions (PCI) has increased significantly over the past 2 decades. Contrast induced nephropathy (CIN) significantly impacts prognosis after PCI, therefore minimizing the risk of CIN is important in improving clinical outcomes. Dynamic Coronary Roadmap (DCR) is a PCI navigation support tool which may decrease CIN by projecting a motion-compensated virtual coronary roadmap overlay on fluoroscopy, potentially reducing iodinated contrast volume during PCI.

STUDY DESIGN AND OBJECTIVES

The Dynamic Coronary Roadmap for Contrast Reduction trial (DCR4Contrast) is a multi-center, prospective, unblinded, stratified 1:1 randomized controlled trial investigating if DCR use reduces the total contrast volume administered during PCI compared to PCI performed without DCR guidance. DCR4Contrast aims to recruit 394 patients undergoing PCI. The primary end point is the total undiluted iodinated contrast volume administered during the PCI, performed with or without DCR. As of November 14, 2022, 346 subjects have been enrolled.

CONCLUSIONS

The DCR4Contrast study will investigate the potential contrast-sparing effect of the DCR navigation support tool in patients undergoing PCI. By reducing iodinated contrast administration, DCR has the potential to contribute to reduced risk of CIN and thus increase PCI safety.

CLINICAL TRIAL REGISTRATION URL

https://clinicaltrials.gov/ct2/show/NCT04085614.

Contrast Media Volume Control and Acute Kidney Injury in Acute Coronary Syndrome: Rationale and Design of the REMEDIAL IV Trial

Background

Although the pathogenesis of acute kidney injury (AKI) in patients with acute coronary syndrome (ACS) undergoing invasive treatment is multifactorial, the role of iodinated contrast media (CM) has been well established. The DyeVert system (Osprey Medical) is designed to reduce the CM volume during invasive coronary procedures while maintaining fluoroscopic image quality.

Objective

The aim of the Renal Insufficiency Following Contrast Media Administration Trial IV (REMEDIAL IV) is to test whether the use of the DyeVert system is effective in reducing contrast-associated acute kidney injury (CA-AKI) rate in patients with ACS undergoing urgent invasive procedures.

Trial Design

Patients with ACS treated by urgent invasive approach will be enrolled. Participants will be randomly assigned into one of the following groups: (1) DyeVert group and (2) control group. In participants enrolled in the DyeVert group, CM injection will be handled by the DyeVert system. On the contrary, in the control group, CM injection will be performed by a conventional manual or automatic injection syringe. In all cases, iobitridol (a low-osmolar, nonionic CM) will be administered. Participants will receive intravenous 0.9% sodium chloride as soon as moved to the catheterization laboratory. The primary end points are CM volume administration and CA-AKI rate (ie, an increase in serum creatinine concentration of ≥0.3 mg/dL within 48 hours after CM exposure). A sample size of at least 522 randomized participants (261 in each group) is needed to demonstrate an 8.5% difference in the CA-AKI rate between the groups (that is, from 19% in the control group to 10.5% in the DyeVert group), with a 2-sided 95% confidence interval and 80% power (P < .05).

Contrast removal from coronary sinus for prevention of contrast-induced nephropathy: a review

The occurrence of contrast-induced-nephropathy (CIN) is related to the amount of contrast administration. Any removal of contrast from systemic circulation before reaching the kidneys might be beneficial using a device that removes contrast from a coronary sinus (CS). This manuscript aims to review the available literature regarding contrast removal from CS during coronary angiography or intervention for the prevention of CIN.

Marked bilateral global persistent CT nephrogram 48 h after percutaneous coronary intervention with contrast-induced nephropathy requiring transient hemodialysis with severe cardiac dysfunction

An iodinated contrast medium (CM) is generally excreted into the urinary tract within 3 min after administration. However, some cases present a persistent kidney nephrogram several hours after administration of CM. This phenomenon seems to be associated with the development and acceleration of contrast-induced nephropathy (CIN). A 74-year-old woman with chronic kidney disease and a very low ejection fraction (EF) (11%) was admitted to Sapporo Medical University Hospital because of heart failure. Coronary angiography revealed occlusion of the left anterior descending artery (LAD) on day 21 of admission. Percutaneous coronary intervention (PCI) to the LAD using 218 ml of iohexol was performed with a preventive measure for CIN by saline infusion on day 28. After PCI, she developed CIN requiring hemodialysis. Non-contrast computed tomography 48 h after PCI showed a marked bilateral persistent nephrogram with a cortical attenuation value of 168 HU. Vicarious excretion of CM was noted in the small bowel and colon. Her kidney function gradually recovered and hemodialysis was discontinued after ten sessions on day 43. The findings from this case suggest that a patient with a very low EF is at a high risk for CIN through persistent retention of the CM in the kidney cortex.

Contrast-induced acute kidney injury and its contemporary prevention

The complexity and application range of interventional and diagnostic procedures using contrast media (CM) have recently increased. This allows more patients to undergo procedures that involve CM administration. However, the intrinsic CM toxicity leads to the risk of contrast-induced acute kidney injury (CI-AKI). At present, effective therapy of CI-AKI is rather limited. Effective prevention of CI-AKI therefore becomes crucially important. This review presents an in-depth discussion of CI-AKI incidence, pathogenesis, risk prediction, current preventive strategies, and novel treatment possibilities. The review also discusses the difference between CI-AKI incidence following intraarterial and intravenous CM administration. Factors contributing to the development of CI-AKI are considered in conjunction with the mechanism of acute kidney damage. The need for ultimate risk estimation and the prediction of CI-AKI is stressed. Possibilities of CI-AKI prevention is evaluated within the spectrum of existing preventive measures aimed at reducing kidney injury. In particular, the review discusses intravenous hydration regimes and pre-treatment with statins and N-acetylcysteine. The review further focuses on emerging alternative imaging technologies, alternative intravascular diagnostic and interventional procedures, and new methods for intravenous hydration guidance; it discusses the applicability of those techniques in complex procedures and their feasibility in current practise. We put emphasis on contemporary interventional cardiology imaging methods, with a brief discussion of CI-AKI in non-vascular and non-cardiologic imaging and interventional studies.

[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.

Contrast-Induced Acute Kidney Injury: Evidence in Support of Its Existence and a Review of Its Pathogenesis and Management

The role of contrast-induced nephropathy (CIN) remains controversial. Many experts contend that CIN does not exist or is extremely rare. The diagnosis was previously made too frequently and inappropriately in the presence of coexisting and confounding comorbidities and risk factors making it difficult to singularly isolate the etiologic role of intravenous contrast media in acute kidney injury (AKI). It is probable that many patients were denied important diagnostic information from radiocontrast studies for fear of CIN. Recently, a new terminology for CIN was introduced, and the term CIN was replaced by two interrelated new terms: one is contrast-associated acute kidney injury (CA-AKI), and the second one is contrast-induced acute kidney injury (CI-AKI). CA-AKI occurs in association with risk factors or comorbidities, therefore, it is a correlative diagnosis. On the other hand, CI-AKI is a subtype of CA-AKI that results directly from iodinated contrast media. In this review, we present evidence from various studies that argue against CI-AKI and also those that suggest its existence but with much lower frequency. We will also provide the current status of the pathophysiology and management of CA-AKI/CI-AKI.

When Prevention is Truly Better than Cure: Contrast-Associated Acute Kidney Injury in Percutaneous Coronary Intervention

Contrast-associated acute kidney injury (CA-AKI) is a fairly frequent complication of cardiovascular angiography and percutaneous coronary intervention (PCI). The risk is significantly higher in patients with advanced chronic kidney disease (CKD). Prevention is the only option for avoiding the significant morbidity and mortality associated with CA-AKI. This review provides a concise and clinically directed appraisal of the latest pre-procedural and peri-procedural strategies to minimize the risk of CA-AKI in all patients undergoing PCI. By broadly implementing these evidence-based care bundles, we can dramatically improve outcomes in this vulnerable patient population.

Fluid administration strategies for the prevention of contrast-associated acute kidney injury

PURPOSE OF REVIEW

The known timing of contrast media exposure in patients identified as high-risk for contrast-associated acute kidney injury (CA-AKI) enables the use of strategies to prevent this complication of intravascular contrast media exposure. Although multiple preventive strategies have been proposed, periprocedural fluid administration remains as the primary preventive strategy. This is a critical review of the current evidence evaluating a variety of fluid administration strategies in CA-AKI.

RECENT FINDINGS

Fluid administration strategies to prevent CA-AKI include comparisons of intravenous (i.v.) to no fluid administration, different fluid solutions, duration of fluid administration, oral hydration, left ventricular end diastolic-pressure guided fluid administration and forced diuresis techniques.

SUMMARY

Despite an abundance of fluid administration trials, it is difficult to make definitive recommendations about preventive fluid administration strategies due to low scientific quality of published studies. The literature supports use of i.v. compared with no fluid administration, especially in high-risk patients undergoing intra-arterial contrast media exposure. Use of isotonic saline is recommended over 0.45% saline or isotonic sodium bicarbonate. Logistical considerations support shortened over longer i.v. fluid administration strategies, despite an absence of evidence of equivalent efficacy. Current literature does not support oral hydration for high-risk patients. The use of tailored fluid administration in heart failure patients and forced diuresis with matching fluid administration are promising new fluid administration strategies.

Optimizing the Outcomes of Percutaneous Coronary Intervention in Patients with Chronic Kidney Disease

Percutaneous coronary intervention (PCI) is one of the most common procedures performed in medicine. However, its net benefit among patients with chronic kidney disease (CKD) is less well established than in the general population. The prevalence of patients suffering from both CAD and CKD is high, and is likely to increase in the coming years. Planning the adequate management of this group of patients is crucial to improve their outcome after PCI. This starts with proper preparation before the procedure, the use of all available means to reduce contrast during the procedure, and the implementation of modern strategies such as radial access and drug-eluting stents. At the end of the procedure, personalized antithrombotic therapy for the patient's specific characteristics is advisable to account for the elevated ischemic and bleeding risk of these 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 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.

Forced Diuresis with Matched Isotonic Intravenous Hydration Prevents Renal Contrast Media Accumulation

The accumulation of contrast media in the kidneys might lead to contrast-induced acute kidney injury. In this prospective, controlled observational study, we aimed to evaluate whether forced diuresis with matched isotonic intravenous hydration prevents the accumulation of contrast media in the kidneys of patients undergoing cardiac interventional procedures. We compared the intensity of contrast media accumulation as observed in nephrograms following these procedures, with and without peri-procedural controlled renal flushing. The study group consisted of 25 patients with impaired renal function treated with the RenalGuard system. The two control groups included 25 patients with normal kidney function and 8 patients with impaired renal function undergoing similar procedures with routine pre-procedural hydration, but without controlled renal flushing. Renal contrast media accumulation at the end of each procedure was scored by blinded cardiologists. The renal contrast accumulation score (CAS) in the study group was significantly lower, with a median score of 0 (IQR (0-0)) compared with 1.5 (IQR (1-2)) in the normal renal function control group and 1 (IQR (0.38-1.62)) in the impaired renal function control group (p < 0.001 and 0.003, respectively). In a multivariate analysis of CAS, RenalGuard treatment was independently associated with lower CAS compared to both control groups. In conclusion, RenalGuard use prevents renal contrast accumulation in patients with impaired renal function undergoing cardiac procedures with intra-arterial contrast media injection.

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.

Trends in incidence and long-term prognosis of acute kidney injury following coronary angiography in Chinese cohort with 11,943 patients from 2013 to 2017: an observational study

Background

Contrast-associated acute kidney injury (CA-AKI) is a common complication with poor prognosis after coronary angiography (CAG). With the prevention methods widely being implemented, the temporal trends of incidence and mortality of CA-AKI are still unknown over the last five years. The study aims to determine the incidence and prognosis of CA-AKI in China.

Methods

This retrospective cohort study was based on the registry at Guangdong Provincial People’s Hospital in China (ClinicalTrials.gov NCT04407936). We analyzed data from hospitalization patients who underwent CAG and with preoperative and postoperative serum creatinine (Scr) values from January 2013 to December 2017.

Results

11,943 patients were included in the study, in which the mean age was 63.01 ± 10.79 years and 8,469 (71.1 %) were male. The overall incidence of CA-AKI was 11.2 %. Compared with 2013, the incidence of CA-AKI in 2017 was significantly increased from 9.7 to 13.0 % (adjusted odds ratios [aOR], 1.38; 95 %CI, 1.13–1.68; P-value < 0.01, P for trend < 0.01). The temporal trends of incidence among patients of different ages and genders yielded similar findings. During a standardized follow-up of 1 year, 178 (13.7 %) CA-AKI patients died in total, which showed no obvious decreased trend in this 5 five years from 21.1 to 16.5 (adjusted hazard ratio [aHR], 0.72; 95 %CI, 0.36–1.45; P-value = 0.35, P for trend = 0.24).

Conclusions

Our Chinese cohort showed that the incidence of CA-AKI increased significantly, while CA-AKI associated mortality showed no obvious decreased trend in the last five years. Our findings support more active measures to prevent CA-AKI and improve the prognosis of CA-AKI patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02427-6.

Tailored Versus Standard Hydration to Prevent Acute Kidney Injury After Percutaneous Coronary Intervention: Network Meta-Analysis

Background

Contrast‐induced acute kidney injury (CI‐AKI) is a serious complication after percutaneous coronary intervention. The mainstay of CI‐AKI prevention is represented by intravenous hydration. Tailoring infusion rate to patient volume status has emerged as advantageous over fixed infusion‐rate hydration strategies.

Methods and Results

A systematic review and network meta‐analysis with a frequentist approach were conducted. A total of 8 randomized controlled trials comprising 2312 patients comparing fixed versus tailored hydration strategies to prevent CI‐AKI after percutaneous coronary intervention were included in the final analysis. Tailored hydration strategies included urine flow rate–guided, central venous pressure–guided, left ventricular end‐diastolic pressure–guided, and bioimpedance vector analysis–guided hydration. Primary endpoint was CI‐AKI incidence. Safety endpoint was incidence of pulmonary edema. Urine flow rate–guided and central venous pressure–guided hydration were associated with a lower incidence of CI‐AKI compared with fixed‐rate hydration (odds ratio [OR], 0.32 [95% CI, 0.19–0.54] and OR, 0.45 [95% CI, 0.21–0.97]). No significant difference in pulmonary edema incidence was observed between the different hydration strategies. P score analysis showed that urine flow rate–guided hydration is advantageous in terms of both CI‐AKI prevention and pulmonary edema incidence when compared with other approaches.

Conclusions

Currently available hydration strategies tailored on patients' volume status appear to offer an advantage over guideline‐supported fixed‐rate hydration for CI‐AKI prevention after percutaneous coronary intervention. Current evidence suggests that urine flow rate–guided hydration as the most convenient strategy in terms of effectiveness and safety.

Urinary Dickkopf-3 and Contrast-Associated Kidney Damage

BACKGROUND

Administration of iodinated contrast medium (CM) during invasive cardiovascular procedures may be associated with impairment of kidney function.

OBJECTIVES

Urinary dickkopf-3 (DKK3), a stress-induced renal tubular epithelium-derived glycoprotein, has been identified as a biomarker predicting both acute kidney injury (AKI) and persistent kidney dysfunction.

METHODS

Urinary DKK3/creatinine ratio (uDKK3/uCr), urine and serum neutrophil gelatinase-associated lipocalin (uNGAL, sNGAL) and serum cystatin C (sCyC) were assessed in 458 patients with chronic kidney disease scheduled for invasive cardiovascular procedures requiring CM administration with universal adoption of nephroprotective interventions. Contrast-associated AKI (CA-AKI) was defined as serum creatinine increase ≥0.3 mg/dl at 48 h after CM administration. Persistent kidney dysfunction was defined as persistent estimated glomerular filtration rate reduction ≥25% at 1 month compared with baseline.

RESULTS

CA-AKI occurred in 64 or the 458 patients (14%), and baseline uDKK3/uCr ≥491 pg/mg was the best threshold for its prediction. Net reclassification improvement (NRI) was significantly increased by adding baseline uDKK3/uCr to the Mehran, Gurm, and National Cardiovascular Data Registry (NCDR) scores (all p < 0.05), and the same applied to integrated discrimination improvement (IDI) when adding uDKK3/uCr to the Gurm and NCDR scores (p < 0.001). Persistent kidney dysfunction occurred in 57 of the 458 patients (12%) and baseline uDKK3/uCr ≥322 pg/mg appeared as the best threshold for its prediction. Adding baseline uDKK3/uCr to the Mehran, Gurm, and NCDR scores significantly increased IDI and NRI (all p < 0.001).

CONCLUSIONS

Baseline uDKK3/uCr seems to be a reliable marker for improving the identification of patients with chronic kidney disease undergoing invasive coronary and peripheral procedures at risk for AKI and persistent kidney dysfunction.

[Contrast-induced acute kidney injury]

The nephrotoxicity of iodinated contrast agent/media is defined by acute renal failure occurring within 48 to 72 hours after injection of iodized contrast product, in the absence of other etiology. The risk factors for contrast agent renal injury must systematically be sought before the exam. The presence of risk factors, including the existence of a renal failure defined by a creatinine clearance (eGFR) of less than 60 mL/min/1.73 m², requires to take prevention measures including hydration. If eGFR is less than 30 mL/min/1.73 m², the advice of a nephrologist is necessary.

A prospective study on the incidence of contrast-associated acute kidney injury after recanalization of chronic total coronary occlusions with contemporary interventional techniques

BACKGROUND

Contrast-associated acute kidney injury (CA-AKI) is a potential risk associated with the percutaneous coronary interventions (PCI) for chronic total coronary occlusions (CTO). This study should evaluate the incidence of CA-AKI in an era of advanced strategies of recanalization techniques and identify modifiable determinants.

METHODS

We analysed 1924 consecutive CTO procedures in 1815 patients between 2012 and 2019. All patients were carefully monitored at least up to 48 h after a CTO procedure for changes in renal function.

RESULTS

The incidence of CA-AKI was 5.6%, but there was no relation to the technical approach such as frequency of the retrograde technique, intravascular ultrasound or radial access. Procedures with CA-AKI had longer fluoroscopy times (37.6 vs 46.1 min; p = 0.005). The major determinants of CA-AKI were age, presence of diabetes and reduced ejection fraction, as well as chronic kidney disease stage ≥2, serum haemoglobin, and fluoroscopy time. Contrast volume or contrast volume/GFR ratio were not independent determinants of CA-AKI. Periprocedural perforations were more frequent in CA-AKI patients (11.3 vs 2.3%; p < 0.001), and in-hospital mortality was higher (2.8 vs 0.4%; p < 0.001).

CONCLUSIONS

CA-AKI was associated with the risk of in-hospital adverse events. Established patient-related risk factors for CA-AKI (age, diabetes, preexisting chronic kidney disease, low ejection fraction) were confirmed in this study. In addition, the length of the procedure, coronary perforations and low preprocedural serum haemoglobin were risk factors that might be preventable in patients at high risk for CA-AKI.

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.

Factors Influencing Stent Failure in Chronic Total Occlusion Coronary Intervention

Stent failure remains one of the greatest challenges for interventional cardiologists. Despite the evolution to superior second- and third-generation drug-eluting stent designs, increasing use of intracoronary imaging and the adoption of more potent antiplatelet regimens, registries continue to demonstrate a prevalence of stent failure or target lesion revascularisation of 15-20%. Predisposition to stent failure is consistent across both chronic total occlusion (CTO) and non-CTO populations and includes patient-, lesion- and procedure-related factors. However, histological and pathophysiological properties specific to CTOs, alongside complex strategies to treat these lesions, may potentially render percutaneous coronary interventions in this cohort more vulnerable to failure. Prevention requires recognition and mitigation of the precipitants of stent failure, optimisation of interventional techniques, including image-guided precision percutaneous coronary intervention, and aggressive modification of a patient's cardiovascular risk factors. Management of stent failure in the CTO population is technically challenging and itself begets recurrence. We aim to provide a comprehensive review of factors influencing stent failure in the CTO population and strategies to attenuate these.

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.

Findings on intraprocedural non-contrast computed tomographic imaging following hepatic artery embolization are associated with development of contrast-induced nephropathy

BACKGROUND

Contrast-induced nephropathy (CIN) is a reversible form of acute kidney injury that occurs within 48-72 h of exposure to intravascular contrast material. CIN is the third leading cause of hospital-acquired acute kidney injury and accounts for 12% of such cases. Risk factors for CIN development can be divided into patient- and procedure-related. The former includes pre-existing chronic renal insufficiency and diabetes mellitus. The latter includes high contrast volume and repeated exposure over 72 h. The incidence of CIN is relatively low (up to 5%) in patients with intact renal function. However, in patients with known chronic renal insufficiency, the incidence can reach up to 27%.

AIM

To examine the association between renal enhancement pattern on non-contrast enhanced computed tomographic (CT) images obtained immediately following hepatic artery embolization with development of CIN.

METHODS

Retrospective review of all patients who underwent hepatic artery embolization between 01/2010 and 01/2011 (n = 162) was performed. Patients without intraprocedural CT imaging (n = 51), combined embolization/ablation (n = 6) and those with chronic kidney disease (n = 21) were excluded. The study group comprised of 84 patients with 106 procedures. CIN was defined as 25% increase above baseline serum creatinine or absolute increase ≥ 0.5 mg/dL within 72 h post-embolization. Post-embolization CT was reviewed for renal enhancement patterns and presence of renal artery calcifications. The association between non-contrast CT findings and CIN development was examined by Fisher’s Exact Test.

RESULTS

CIN occurred in 11/106 (10.3%) procedures (Group A, n = 10). The renal enhancement pattern in patients who did not experience CIN (Group B, n = 74 with 95/106 procedures) was late excretory in 93/95 (98%) and early excretory (EE) in 2/95 (2%). However, in Group A, there was a significantly higher rate of EE pattern (6/11, 55%) compared to late excretory pattern (5/11) (P < 0.001). A significantly higher percentage of patients that developed CIN had renal artery calcifications (6/11 vs 20/95, 55% vs 21%, P = 0.02).

CONCLUSION

A hyperdense renal parenchyma relative to surrounding skeletal muscle (EE pattern) and presence of renal artery calcifications on immediate post-HAE non-contrast CT images in patients with low risk for CIN are independently associated with CIN development.

Five-year follow-up of patients with radio-contrast-induced acute renal injury. Can intravenous sodium-bicarbonate improve long-term outcomes?

BACKGROUND/PURPOSE

Radiocontrast-induced acute kidney injury (RAKI) is a frequent complication during angiography and is associated with adverse prognosis. Most of the studies evaluating the long-term outcome of patients with RAKI are based on institutional registries. This is the first prospective study to evaluate the 5-year outcomes of patients with RAKI, and assess the effect of sodium bicarbonate (SB) in the long-term outcomes of patients with chronic kidney disease (CKD) undergoing non-emergent coronary angiography.

MATERIALS/METHODS

382 CKD stage III-IV patients undergoing elective non-emergent coronary angiography were randomized to SB (n = 192) or normal saline (NS) solution (n = 190). Incidence of RAKI, in-hospital, 1- and 5-year mortality and renal replacement therapy (RRT), and 5-year major adverse renal and cardiovascular events (MARCE) were compared between groups. Outcomes of patient with and without RAKI were compared after five-years of prospective follow-up. Multivariate predictors of RAKI and death at 5-years were determined.

RESULTS

The use of SB did not improve the incidence of RAKI, in-hospital outcomes, survival, and freedom from RRT or MARCE after 5-years of follow-up. Patients that developed RAKI had a significantly higher mortality at 1-year [8.9% Vs. 1.2%] and 5-years (36% Vs. 11%) (P < 0.01).

CONCLUSIONS

Hydration with SB showed no benefit compared to NS in preventing RAKI. The use of SB was not superior to NS after 5-years of follow-up regarding MARCE, survival or freedom of RRT. Five-year mortality among patients who developed RAKI remains high, and further research is needed to find the best preventive strategy for this high-risk group of patients.

SUMMARY

Radiocontrast-induced acute-kidney-injury (RAKI) is associated with poor long-term outcomes in observational and short-term studies. Hydration with sodium bicarbonate (SB) had been evaluated in the prevention of RAKI; but its long-term effect has not been evaluated. We randomized 382 high high-risk patients undergoing coronary angiography to SB or normal saline following them for five years. SB showed no benefit in preventing RAKI, decreasing major adverse renal and cardiovascular events, improving survival or freedom from dialysis after 5-years. This is the first study to follow patients with RAKI for a period of 5-years, showing a significantly higher mortality in this group of patients.

Effect of Combining Furosemide With Standard Hydration Therapy on Contrast-Induced Acute Kidney Injury Following Coronary Angiography or Intervention in a High-Risk Population

This study aimed to investigate whether combining furosemide with standard hydration therapy results in increased preventive effects on contrast-induced acute kidney injury (CI-AKI) following coronary angiography (CA) or percutaneous coronary intervention (PCI). Patients (n = 230) were enrolled in the study and were randomized to the furosemide group or the control group. Patients in the furosemide group received 0.2 to 0.5 mg/kg of furosemide as a continuous intravenous infusion for 24 hours postoperatively and the same standard hydration regimen received by the control group. Blood samples were obtained 24 hours before and 48 hours after the procedure and urine volume was recorded postprocedure. Patients were followed up for an average of 6 months after the procedure. The incidence of CI-AKI in the furosemide group was significantly lower than that in the control group (8.7% vs 18.3%, P = .034). Multivariate logistic regression showed that age-glomerular filtration rate-ejection fraction score and V/estimated glomerular filtration rate ratio were independent risk factors for CI-AKI. During the average 6-month follow-up, incidence of major adverse cardiovascular events (MACEs) in the furosemide group was also significantly lower. Furosemide combined with standard hydration therapy may reduce the incidence of CI-AKI and MACEs following CA or PCI.

Advances in the pathogenesis and prevention of contrast-induced nephropathy

With the increasing application of medical imaging contrast materials, contrast-induced nephropathy has become one of the leading causes of iatrogenic renal insufficiency. The underlying mechanism is associated with renal medullary hypoxia, direct toxicity of contrast agents, oxidative stress, apoptosis, immune/inflammation and epigenetic regulation in contrast-induced nephropathy. Up to date, there is no effective therapy for contrast-induced nephropathy, and thus risk predication and effective preventive strategies are keys to reduce the occurrence of contrast-induced nephropathy. It was found that the proper use of contrast medium, personalized hydration, and high-dose statins may reduce the occurrence of contrast-induced nephropathy, while antioxidants have not shown significant therapeutic benefits. Additionally, the role of remote ischemia preconditioning and vasodilators in the prevention of contrast-induced nephropathy needs further study. This review aims to discuss the incidence, pathogenesis, risk prediction, and preventive strategies for contrast-induced nephropathy.

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.

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.

A Practical Approach to Preventing Renal Complications in the Catheterization Laboratory

Contrast-induced acute kidney injury is a common complication in patients undergoing invasive procedures and is associated with increased mortality and morbidity. There is no effective approach to the management of this complication, and prevention remains of paramount importance. The 3 pillars of prevention are identification of high-risk patients, appropriate hydration before and after contrast exposure, eGFR-based contrast dosing and use of ultra-low contrast volume in high-risk patients. Most evidence supporting these practices is derived from patients undergoing coronary angiography or percutaneous coronary intervention but these basic principles can be applied to most patients undergoing contrast-based procedures in the catheterization laboratory.

Contrast-induced acute kidney injury

Although major advancements in the field of cardiology have allowed for an increasing number of patients to undergo minimally invasive imaging and interventional procedures, contrast-induced acute kidney injury (CI-AKI) continues to be a dreaded complication among patients receiving intravascular contrast media. CI-AKI is characterized by progressive decline in kidney function within a few days of contrast medium administration. Physiological changes resulting from the direct nephrotoxic effect of contrast media on tubular epithelial cells and release of vasoactive molecules have been implicated in creating a state of increased oxidative stress and subsequent ischemic renal cell injury. Over the last several years, preventive strategies involving intravenous hydration, pharmaceutical agents and renal replacement therapies have resulted in lower rates of CI-AKI. However, due to the evolving paradigm of diagnostic and therapeutic interventions, several unanswered questions remain. This review highlights the epidemiology, pathogenesis and preventive strategies of CI-AKI.

Hydration Strategies for Preventing Contrast-Induced Acute Kidney Injury: A Systematic Review and Bayesian Network Meta-Analysis

Aims

Many previous studies have examined the effect of different hydration strategies on prevention of contrast-induced acute kidney injury (CI-AKI), but the optimal strategy is unknown. We performed a network meta-analysis (NWM) of these previous studies to identify the optimal strategy.

Methods and Results

Web of Science, PubMed, OVID Medline, and Cochrane Library were searched from their inception dates to September 30, 2018. Randomized controlled trials (RCTs) were selected based on strict inclusion criteria, and a Bayesian NWM was performed using WinBUGS V.1.4.3. We finally analyzed 60 eligible RCTs, which examined 21,293 patients and 2232 CI-AKI events. Compared to intravenous 0.9% sodium chloride (reference), intravenous sodium bicarbonate (OR [95% CI]: 0.74 [0.57, 0.93]), hemodynamic guided hydration (0.41 [0.18, 0.93]), and RenalGuard guided hydration (0.32 [0.14, 0.70]) significantly reduced the occurrence of CI-AKI. Oral hydration and intravenous 0.9% sodium chloride were each noninferior to no hydration in preventing CI-AKI. Intravenous 0.9% sodium chloride, sodium bicarbonate, and hemodynamic guided hydration were each noninferior to oral hydration in preventing CI-AKI. Based on surface under the cumulative ranking curve values, the RenalGuard system was best (0.974) and hemodynamic guided hydration was second best (0.849).

Conclusion

There was substantial evidence to support the use of RenalGuard or hemodynamic guided hydration for preventing CI-AKI in high-risk patients, especially those with chronic kidney disease or cardiac dysfunction.

Practical guide to prevention of contrast-induced acute kidney injury after percutaneous coronary intervention

Contrast-induced acute kidney injury (CI-AKI) represents a common but serious complication of percutaneous coronary interventions (PCI)-and in general of all those examinations requiring iodinated contrast injection-which affects not only renal function but also long-term prognosis. While several prophylactic approaches were designed in order to prevent CI-AKI, most failed to demonstrate clear benefits in randomized trials, and their implementation is therefore discouraged in clinical practice. The most notorious examples include pre-procedural bicarbonate or N-acetylcysteine, and preprocedural withdrawal of ACE inhibitors/Angiotensin receptor blockers. Those strategies that were instead demonstrated effective include the appropriate use of preprocedural hydration, reduction in contrast volume utilization, adoption of techniques for zero- or ultra-low-contrast procedures, and pharmacological treatments with statins. In this brief review, we summarize the main preventive strategies into brief and pragmatic recommendations designed to improve everyday clinical practice.

The effect of Endovascular Aneurysm Repair on Renal Function in Patients Treated for Abdominal Aortic Aneurysm

Aim:

The effect of endovascular aneurysm repair in patients treated for abdominal aortic aneurysm has not been clearly defined. The objective of the present article was to provide a contemporary literature review and perform an analysis to determine the effect of EVAR on renal function in the early post-operative period and during follow-up.

Methods:

A systematic review of the literature was undertaken to identify all studies reporting the effect of EVAR on renal function. Outcome data were pooled and combined overall effect sizes were calculated using fixed or random-effects models.

Results:

Thirty-two studies reporting on 24846 patients were included. Acute renal failure after EVAR occurred with an estimated frequency of 9% (95%CI: 5-16%; I2=97%). Median follow-up period was 19.5 months (range 1-60 months). The estimated frequency of chronic renal failure during follow-up was 7% (95%CI: 3-17%; I2=98%). Hemodialysis was required in 2% (1-3%; I2=97%) of the cases.

Conclusion:

High-level evidence demonstrating the effect of EVAR on the incidence of acute and chronic renal failure is lacking. Based on the current available data, nearly 10% of patients undergoing EVAR for AAA have an increased risk for renal dysfunction after the procedure. Whether this deterioration may lead to a worse outcome has not been adequately proved.

Radiocontrast Toxicity

Intravenous and intraarterial contrast media are invaluable tools in the diagnosis of anatomic lesions. However, they have been associated with deleterious renal events, ranging from acute kidney injury (iodinated contrast) to nephrogenic systemic fibrosis (gadolinium-containing agents). Contrast-associated acute kidney injury has a wide incidence, likely due to differences in populations studied, with incidence likely overstated due to comorbid conditions at the time of contrast exposure. Pathophysiology includes hemodynamic and direct toxic effects. Preventative strategies include intravenous saline administration, higher urine pH, and statin administration. Importantly, because of fears of contrast-associated acute kidney injury, practitioners may be selecting only the healthiest patients for contrast exposure. Gadolinium-based contrast agents may cause their toxicity through being unbound from their ligand, and certain preparations may be less harmful than others.

Contrast Induced Acute Kidney Injury and its Impact on Mid-Term Kidney Function, Cardiovascular Events and Mortality

The existence and clinical relevance of contrast induced acute kidney injury (CI-AKI) is still heavily debated and angiographic procedures are often withheld in fear of CI-AKI, especially in CKD-patients. We investigated the incidence of CI-AKI in cardiovascular high risk patients undergoing intra-arterial angiography and its impact on mid-term kidney function, cardiovascular events and mortality. We conducted a prospective observational trial on patients undergoing planned intra-arterial angiographic procedures. All subjects received standardized intravenous hydration prior to contrast application. CI-AKI was defined according to a ≥25% increase of creatinine from baseline to either 24hrs or 48hrs after angiography. Plasma creatinine and eGFR were recorded from the institutional medical record system one and three months after hospital discharge. Patients were followed up for two years to investigate the long term effects of CI-AKI on cardiovascular events and mortality. We studied 706 (317 female) patients with a mean eGFR of 52.0 ± 15 ml·min⁻¹·1.73 m⁻². The incidence of CI-AKI was 10.2% (72 patients). In 94 (13.3%) patients serum creatinine decreased ≥25% either 24 or 48 hours after angiography. Patients with CI-AKI had a lower creatinine and a higher eGFR at baseline, but no other independent predictors of CI-AKI could be identified. Kidney function was not different between both groups one and three months after discharge. After a two year follow up the overall incidence of cardiovascular events was 56.5% in the CI-AKI group and 58.8% in the Non CI-AKI group (p = 0.8), the incidence of myocardial infarctions, however, was higher in CI-AKI-patients. Overall survival was also not different between patients with CI-AKI (88.6%) and without CI-AKI (84.7%, p = 0.48). The occurrence of CI-AKI did not have any negative impact on mid-term kidney function, the incidence of cardiovascular events and mortality. Considerable fluctuations of serum creatinine interfere with the presumed diagnosis of CI-AKI. Necessary angiographic procedures should not be withheld in fear of CI-AKI.