Prevention of Contrast-Induced Nephropathy by Central Venous Pressure–Guided Fluid Administration in Chronic Kidney Disease and Congestive Heart Failure Patients

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.

The impact of the stress hyperglycemia ratio on the risk of contrast-associated acute kidney injury in patients undergoing coronary angiography: a large real-world cohort study

BACKGROUND

Contrast-associated acute kidney injury (CA-AKI) is an important complication in the perioperative period of coronary angiography (CAG). Dysglycemia is closely associated with the occurrence of CA-AKI. However, the association between stress hyperglycemia and CA-AKI in patients undergoing CAG remains unclear. The study aims to investigate the association of the stress hyperglycemia ratio (SHR) and CA-AKI under CAG in a large real-world cohort.

METHODS

This was a retrospective observational study, and patients undergoing CAG were enrolled. SHR is calculated by dividing the random blood glucose with the estimated average glucose derived from the glycosylated hemoglobin (HbA1c), and subjects were divided into five groups according to SHR. The outcome was CA-AKI defined as an increase in serum creatinine of ≥ 0.3 mg/dL (26.5 μmol/L) or 1.5-fold higher than normal levels in 48 h. The association was assessed with logistic regression and restricted cubic spline analysis.

RESULTS

In 19,965 participants (men: 73.3%, mean age: 63.1 ± 10.8 years) undergoing CAG, a total of 1,621 CA-AKI cases occurred. There were reverse J-shaped associations between the SHR and CA-AKI after adjustment for other confounding factors. Moreover, SHR improved the predictive effectiveness of the traditional Mehran score (AUC 0.65 vs 0.63, P < 0.001), a predictive model of CA-AKI in patients undergoing percutaneous coronary intervention.

CONCLUSIONS

There were reverse J-shaped associations of SHR with CA-AKI risk among patients undergoing CAG, and the assessment of SHR before CAG may assist clinicians in identifying patients at higher risk of CA-AKI.

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.

Acute Kidney Injury Management Strategies Peri-Cardiovascular Interventions

In many countries, the aging population and the higher incidence of comorbid conditions have resulted in an ever-growing need for cardiac interventions. Acute kidney injury (AKI) is a common complication of these interventions, associated with higher mortalities, chronic or end-stage kidney disease, readmission rates, and hospital and post-discharge costs. The AKI pathophysiology includes contrast-associated AKI, hemodynamic changes, cardiorenal syndrome, and atheroembolism. Preventive measures include limiting contrast media dose, optimizing hemodynamic conditions, and limiting exposure to other nephrotoxins. This review article outlines the current state-of-art knowledge regarding AKI pathophysiology, risk factors, preventive measures, and management strategies in the peri-interventional period.

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.

Contemporary Methods for Predicting Acute Kidney Injury After Coronary Intervention

BACKGROUND

Acute kidney injury (AKI) is the most common complication after percutaneous coronary intervention (PCI). Accurately estimating patients' risks not only creates a means of benchmarking performance but can also be used prospectively to inform practice.

OBJECTIVES

The authors sought to update the 2014 National Cardiovascular Data Registry (NCDR) AKI risk model to provide contemporary estimates of AKI risk after PCI to further improve care.

METHODS

Using the NCDR CathPCI Registry, we identified all 2020 PCIs, excluding those on dialysis or lacking postprocedural creatinine. The cohort was randomly split into a 70% derivation cohort and a 30% validation cohort, and logistic regression models were built to predict AKI (an absolute increase of 0.3 mg/dL in creatinine or a 50% increase from preprocedure baseline) and AKI requiring dialysis. Bedside risk scores were created to facilitate prospective use in clinical care, along with threshold contrast doses to reduce AKI. We tested model calibration and discrimination in the validation cohort.

RESULTS

Among 455,806 PCI procedures, the median age was 67 years (IQR: 58.0-75.0 years), 68.8% were men, and 86.8% were White. The incidence of AKI and new dialysis was 7.2% and 0.7%, respectively. Baseline renal function and variables associated with clinical instability were the strongest predictors of AKI. The final AKI model included 13 variables, with a C-statistic of 0.798 and excellent calibration (intercept = -0.03 and slope = 0.97) in the validation cohort.

CONCLUSIONS

The updated NCDR AKI risk model further refines AKI prediction after PCI, facilitating enhanced clinical care, benchmarking, and quality improvement.

A novel explainable online calculator for contrast-induced AKI in diabetics: a multi-centre validation and prospective evaluation study

BACKGROUND

In patients undergoing percutaneous coronary intervention (PCI), contrast-induced acute kidney injury (CIAKI) is a frequent complication, especially in diabetics, and is connected with severe mortality and morbidity in the short and long term. Therefore, we aimed to develop a CIAKI predictive model for diabetic patients.

METHODS

3514 patients with diabetes from four hospitals were separated into three cohorts: training, internal validation, and external validation. We developed six machine learning (ML) algorithms models: random forest (RF), gradient-boosted decision trees (GBDT), logistic regression (LR), least absolute shrinkage and selection operator with LR, extreme gradient boosting trees (XGBT), and support vector machine (SVM). The area under the receiver operating characteristic curve (AUC) of ML models was compared to the prior score model, and developed a brief CIAKI prediction model for diabetes (BCPMD). We also validated BCPMD model on the prospective cohort of 172 patients from one of the hospitals. To explain the prediction model, the shapley additive explanations (SHAP) approach was used.

RESULTS

In the six ML models, XGBT performed best in the cohort of internal (AUC: 0.816 (95% CI 0.777-0.853)) and external validation (AUC: 0.816 (95% CI 0.770-0.861)), and we determined the top 15 important predictors in XGBT model as BCPMD model variables. The features of BCPMD included acute coronary syndromes (ACS), urine protein level, diuretics, left ventricular ejection fraction (LVEF) (%), hemoglobin (g/L), congestive heart failure (CHF), stable Angina, uric acid (umol/L), preoperative diastolic blood pressure (DBP) (mmHg), contrast volumes (mL), albumin (g/L), baseline creatinine (umol/L), vessels of coronary artery disease, glucose (mmol/L) and diabetes history (yrs). Then, we validated BCPMD in the cohort of internal validation (AUC: 0.819 (95% CI 0.783-0.855)), the cohort of external validation (AUC: 0.805 (95% CI 0.755-0.850)) and the cohort of prospective validation (AUC: 0.801 (95% CI 0.688-0.887)). SHAP was constructed to provide personalized interpretation for each patient. Our model also has been developed into an online web risk calculator. MissForest was used to handle the missing values of the calculator.

CONCLUSION

We developed a novel risk calculator for CIAKI in diabetes based on the ML model, which can help clinicians achieve real-time prediction and explainable clinical decisions.

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).

Renal Insufficiency Increases the Combined Risk of Left Ventricular Hypertrophy and Dysfunction in Patients at High Risk of Cardiovascular Diseases

BACKGROUND

The identification of asymptomatic structural and functional cardiac abnormalities can help us to recognize early and intervene in patients at pre-heart failure (HF). However, few studies have adequately evaluated the associations of renal function and left ventricular (LV) structure and function in patients at high risk of cardiovascular diseases (CVD).

METHODS

Patients undergoing coronary angiography and/or percutaneous coronary interventions were enrolled from the Cardiorenal ImprovemeNt II (CIN-II) cohort study, and their echocardiography and renal function were assessed at admission. Patients were divided into five groups according to their estimated glomerular filtration rate (eGFR). Our outcomes were LV hypertrophy and LV systolic and diastolic dysfunction. Multivariable logistic regression analyses were conducted to investigate the associations of eGFR with LV hypertrophy and LV systolic and diastolic dysfunction.

RESULTS

A total of 5610 patients (mean age: 61.6 ± 10.6 years; 27.3% female) were included in the final analysis. The prevalence of LV hypertrophy assessed by echocardiography was 29.0%, 34.8%, 51.9%, 66.7%, and 74.3% for the eGFR categories >90, 61-90, 31-60, 16-30, and ≤15 mL/min per 1.73 m² or for patients needing dialysis, respectively. Multivariate logistic regression analysis showed that subjects with eGFR levels of ≤15 mL/min per 1.73 m2 or needing dialysis (OR: 4.66, 95% CI: 2.96-7.54), as well as those with eGFR levels of 16-30 (OR: 3.87, 95% CI: 2.43-6.24), 31-60 (OR: 2.00, 95% CI: 1.64-2.45), and 61-90 (OR: 1.23, 95% CI: 1.07-1.42), were significantly associated with LV hypertrophy. This reduction in renal function was also significantly associated with LV systolic and diastolic dysfunction (all P for trend <0.001). In addition, a per one unit decrease in eGFR was associated with a 2% heightened combined risk of LV hypertrophy and systolic and diastolic dysfunction.

CONCLUSIONS

Among patients at high risk of CVD, poor renal function was strongly associated with cardiac structural and functional abnormalities. In addition, the presence or absence of CAD did not change the associations. The results may have implications for the pathophysiology behind cardiorenal syndrome.

What Promotes Acute Kidney Injury in Patients with Myocardial Infarction and Multivessel Coronary Artery Disease-Contrast Media, Hydration Status or Something Else?

Multivessel coronary artery disease (MVCAD) is found in approximately 50% of patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI). Although we have data showing the benefits of revascularization of significant non-culprit coronary lesions in patients with AMI, the optimal timing of angioplasty remains unclear. The most common reason for postponing subsequent percutaneous treatment is the fear of contrast-induced acute kidney injury (CI-AKI). Acute kidney injury (AKI) is common in patients with AMI undergoing PCI, and its etiology appears to be complex and incompletely understood. In this review, we discuss the definition, pathophysiology and risk factors of AKI in patients with AMI undergoing PCI. We present the impact of AKI on the course of hospitalization and distant prognosis of patients with AMI. Special attention was paid to the phenomenon of AKI in patients undergoing multivessel revascularization. We analyze the correlation between increased exposure to contrast medium (CM) and the risk of AKI in patients with AMI to provide information useful in the decision-making process about the optimal timing of revascularization of non-culprit lesions. In addition, we present diagnostic tools in the form of new biomarkers of AKI and discuss ways to prevent and mitigate the course of AKI.

Management of Patients With Kidney Disease in Need of Cardiovascular Catheterization: A Scientific Workshop Cosponsored by the National Kidney Foundation and the Society for Cardiovascular Angiography and Interventions

Patients with chronic kidney disease (CKD) are at an increased risk of developing cardiovascular disease (CVD), whereas those with established CVD are at risk of incident or progressive CKD. Compared with individuals with normal or near normal kidney function, there are fewer data to guide the management of patients with CVD and CKD. As a joint effort between the National Kidney Foundation and the Society for Cardiovascular Angiography and Interventions, a workshop and subsequent review of the published literature was held. The present document summarizes the best practice recommendations of the working group and highlights areas for further investigation.

[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.

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.

Effect of Clinical Decision Support With Audit and Feedback on Prevention of Acute Kidney Injury in Patients Undergoing Coronary Angiography: A Randomized Clinical Trial

IMPORTANCE

Contrast-associated acute kidney injury (AKI) is a common complication of coronary angiography and percutaneous coronary intervention (PCI) that has been associated with high costs and adverse long-term outcomes.

OBJECTIVE

To determine whether a multifaceted intervention is effective for the prevention of AKI after coronary angiography or PCI.

DESIGN, SETTING, AND PARTICIPANTS

A stepped-wedge, cluster randomized clinical trial was conducted in Alberta, Canada, that included all invasive cardiologists at 3 cardiac catheterization laboratories who were randomized to various start dates for the intervention between January 2018 and September 2019. Eligible patients were aged 18 years or older who underwent nonemergency coronary angiography, PCI, or both; who were not undergoing dialysis; and who had a predicted AKI risk of greater than 5%. Thirty-four physicians performed 7820 procedures among 7106 patients who met the inclusion criteria. Participant follow-up ended in November 2020.

INTERVENTIONS

During the intervention period, cardiologists received educational outreach, computerized clinical decision support on contrast volume and hemodynamic-guided intravenous fluid targets, and audit and feedback. During the control (preintervention) period, cardiologists provided usual care and did not receive the intervention.

MAIN OUTCOMES AND MEASURES

The primary outcome was AKI. There were 12 secondary outcomes, including contrast volume, intravenous fluid administration, and major adverse cardiovascular and kidney events. The analyses were conducted using time-adjusted models.

RESULTS

Of the 34 participating cardiologists who were divided into 8 clusters by practice group and center, the intervention group included 31 who performed 4327 procedures among 4032 patients (mean age, 70.3 [SD, 10.7] years; 1384 were women [32.0%]) and the control group included 34 who performed 3493 procedures among 3251 patients (mean age, 70.2 [SD, 10.8] years; 1151 were women [33.0%]). The incidence of AKI was 7.2% (310 events after 4327 procedures) during the intervention period and 8.6% (299 events after 3493 procedures) during the control period (between-group difference, -2.3% [95% CI, -0.6% to -4.1%]; odds ratio [OR], 0.72 [95% CI, 0.56 to 0.93]; P = .01). Of 12 prespecified secondary outcomes, 8 showed no significant difference. The proportion of procedures in which excessive contrast volumes were used was reduced to 38.1% during the intervention period from 51.7% during the control period (between-group difference, -12.0% [95% CI, -14.4% to -9.4%]; OR, 0.77 [95% CI, 0.65 to 0.90]; P = .002). The proportion of procedures in eligible patients in whom insufficient intravenous fluid was given was reduced to 60.8% during the intervention period from 75.1% during the control period (between-group difference, -15.8% [95% CI, -19.7% to -12.0%]; OR, 0.68 [95% CI, 0.53 to 0.87]; P = .002). There were no significant between-group differences in major adverse cardiovascular events or major adverse kidney events.

CONCLUSIONS AND RELEVANCE

Among cardiologists randomized to an intervention including clinical decision support with audit and feedback, patients undergoing coronary procedures during the intervention period were less likely to develop AKI compared with those treated during the control period, with a time-adjusted absolute risk reduction of 2.3%. Whether this intervention would show efficacy outside this study setting requires further investigation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03453996.

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.

Prevention and Management of AKI in ACS Patients Undergoing Invasive Treatments

PURPOSE OF REVIEW

Management of patients presenting with acute coronary syndrome (ACS) includes invasive procedures that may increase the risk of acute kidney injury (AKI). AKI adversely affects the outcomes of such procedures and complicates the management of ACS. We have summarized several strategies for the prevention and management of AKI in this critical patient group including in the pre-procedural, intraprocedural, and post-procedural settings.

RECENT FINDINGS

Definitive prevention and management strategies for AKI in patients presenting with ACS requiring invasive management can be confounded by the variation in data outcomes. Pre-procedural hydration with normal saline when accounting for time to catheterization, radial artery access, contrast stewardship, and close monitoring of renal function after catheterization should be implemented.

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-Associated Acute Kidney Injury: Advances and Challenges

A decrease in renal function that follows intravascular administration of contrast medium (CM) within a few days is reported as contrast-induced acute kidney injury (CI-AKI). In clinical practice, the imaging procedure is frequently deferred when clinicians consider that the renal risks caused by CM outweigh the benefits of enhanced imaging. However, with an in-depth understanding of AKI and contrast medium, scholars have realized that the decrease in renal function after CM is caused by contrast medium factors and noncontrast medium factors (such as anemia and hemodynamic instability). Therefore, acute kidney injury caused by CM has been overestimated in the past. The term “contrast-associated acute kidney injury (CA-AKI)” has been increasingly used to indicate AKI after intravascular administration of contrast medium compared with CI-AKI. CA-AKI can increase the risk of death and chronic kidney disease. However, its pathophysiological mechanism has not been fully elucidated, and the effectiveness of various preventive and therapeutic measures have been questioned. These present challenges for us. In this article, we will review the diagnostic criteria, epidemiology, risk factors, pathophysiological mechanisms and treatment of CA-AKI to provide optimized imaging procedures in clinical practice.

Malnutrition Increases the Risk of Left Ventricular Remodeling

OBJECTIVES

Malnutrition is associated with increased incidence of heart failure (HF). Left ventricular (LV) remodeling is one of the most important processes in the occurrence and evolution of HF. However, the association between nutritional status and LV remodeling is not well known. The study aimed to investigate the association between malnutrition and LV remodeling.

DESIGN

The study was a retrospective observation study.

SETTING AND PARTICIPANTS

We included patients from the registry of Cardiorenal Improvement study from January 2007 to December 2018 at Guangdong Provincial People's Hospital.

MEASUREMENTS

The primary endpoint was LV remodeling, defined as an absolute decrease in LV ejection fraction ≥10% after discharge compared with baseline. Nutritional status was assessed by the Controlling Nutritional Status (CONUT) score. Eligible patients were divided into absent-mild malnutrition group (CONUT score ≤4) and moderate-severe malnutrition group (CONUT score >4). Univariable and multivariable logistic regression was performed to verify the association between malnutrition and left ventricular remodeling.

RESULTS

A total of 7,217 patients (mean age 61.3±10.5 years, 71.7% male) were included in the final analysis, among which 712 (9.9%) had LV remodeling. The incidence of LV remodeling in moderate-severe malnutrition group was significantly higher than that in absent-mild malnutrition group (12.9% vs. 9.5%, p=0.002). In multivariable logistic regression, moderate-severe malnutrition group was significantly associated with 1.69-fold increased risk of LV remodeling after adjusting confounders (OR: 1.69, CI: 1.32-2.16). Similar results were observed in subgroup stratified by age, gender, and coronary artery disease.

CONCLUSION

Nearly one eighth of patients were classified as moderate-severe malnutrition, 12% of whom had LV remodeling. Moderate-severe malnutrition was associated with 69% increased risk of LV remodeling. Further studies are needed to prospectively evaluate the nutrition-oriented managements on outcomes in LV remodeling.

A contemporary simple risk score for prediction of contrast-associated acute kidney injury after percutaneous coronary intervention: derivation and validation from an observational registry

BACKGROUND

Contrast-associated acute kidney injury can occur after percutaneous coronary intervention (PCI). Prediction of the contrast-associated acute kidney injury risk is important for a tailored prevention and mitigation strategy. We sought to develop a simple risk score to estimate contrast-associated acute kidney injury risk based on a large contemporary PCI cohort.

METHODS

Consecutive patients undergoing PCI at a large tertiary care centre between Jan 1, 2012, and Dec 31, 2020, with available creatinine measurements both before and within 48 h after the procedure, were included; only patients on chronic dialysis were excluded. Patients treated between 2012 and 2017 comprised the derivation cohort and those treated between 2018 and 2020 formed the validation cohort. The primary endpoint was contrast-associated acute kidney injury, defined according to the Acute Kidney Injury Network. Independent predictors of contrast-associated acute kidney injury were derived from multivariate logistic regression analysis. Model 1 included only pre-procedural variables, whereas Model 2 also included procedural variables. A weighted integer score based on the effect estimate of each independent variable was used to calculate the final risk score for each patient. The impact of contrast-associated acute kidney injury on 1-year deaths was also evaluated.

FINDINGS

32 378 PCI procedures were performed and screened for inclusion in the present analysis. After the exclusion of patients without paired creatinine measurements, patients on chronic dialysis, and multiple procedures, 14 616 patients were included in the derivation cohort (mean age 66·2 years, 29·2% female) and 5606 were included in the validation cohort (mean age 67·0 years, 26·4% female). Contrast-associated acute kidney injury occurred in 860 (4·3%) patients. Independent predictors of contrast-associated acute kidney injury included in Model 1 were: clinical presentation, estimated glomerular filtration rate, left ventricular ejection fraction, diabetes, haemoglobin, basal glucose, congestive heart failure, and age. Additional independent predictors in Model 2 were: contrast volume, peri-procedural bleeding, no flow or slow flow post procedure, and complex PCI anatomy. The occurrence of contrast-associated acute kidney injury in the derivation cohort increased gradually from the lowest to the highest of the four risk score groups in both models (2·3% to 34·9% in Model 1, and 2·0% to 38·8% in Model 2). Inclusion of procedural variables in the model only slightly improved the discrimination of the risk score (C-statistic in the derivation cohort: 0·72 for Model 1 and 0·74 for model 2; in the validation cohort: 0·84 for Model 1 and 0·86 for Model 2). The risk of 1-year deaths significantly increased in patients with contrast-associated acute kidney injury (10·2% vs 2·5%; adjusted hazard ratio 1·76, 95% CI 1·31-2·36; p=0·0002), which was mainly due to excess 30-day deaths.

INTERPRETATION

A contemporary simple risk score based on readily available variables from patients undergoing PCI can accurately discriminate the risk of contrast-associated acute kidney injury, the occurrence of which is strongly associated with subsequent death.

FUNDING

None.

Length of Preprocedure Fasting Was Associated With Contrast Associated-Acute Kidney Injury in High-Risk Patients Undergoing Coronary Angiography

Hydration is recommended to prevent contrast associated-acute kidney injury (CA-AKI) but interactions between blood pressure, left ventricular end diastolic pressure (LVEDP) and hydration status on CA-AKI are incompletely understood. This analysis presents the results of a single-center prospective study of patients undergoing coronary angiography with a predicted risk of CA-AKI >14%. 146 patients were enrolled with a mean (±SD) age of 71 ± 11 years; 94 (64.4%) were men, 142 (97.3%) had hypertension, 96 (65.8%) had diabetes mellitus and the mean (SD) serum creatinine was 1.21 ± 0.36 mg/dl. CA-AKI occurred in 31 (21%) patients. There were no significant differences in demographics, comorbidities, renal function, LVEDP, systolic blood pressure, diastolic blood pressure, heart rate, mean arterial pressure or pulse pressure in patients who developed versus those who did not develop CA-AKI. There was no association between the amount of peri-procedure intravenous fluids and change in creatinine postprocedure. In multivariate analysis, hemoglobin, the time that the patient was fasting from solids (NPO time), and contrast volume were associated with the development of CA-AKI. There was a highly significant interaction (p = 0.0028) between the amount of intravenous fluids, NPO time and contrast volume and changes in postprocedure creatinine. In summary, hemoglobin, NPO time and contrast volume, but not hemodynamic variables, correlated with worsening renal function following coronary angiography in this population of high-risk patients. Results suggested that intravenous hydration is important in subgroups of patients depending on NPO time and contrast volume.

Meta-analysis of intravascular volume expansion strategies to prevent contrast-associated acute kidney injury following invasive angiography

OBJECTIVE

To perform a detailed analysis of published data regarding intravascular volume expansion to prevent contrast-associated acute kidney injury (CA-AKI) and to determine if an ideal dose of IV fluids can be recommended.

BACKGROUND

Administration of contrast media during invasive angiography is associated with CA-AKI. Intravascular volume expansion is the most effective intervention to prevent CA-AKI, yet evidenced based protocols are lacking.

METHODS

Literature review and meta-analysis of randomized controlled trials (RCT) of patients receiving IV volume expansion as prophylaxis for CA-AKI was performed. Normal saline, Lactated Ringer's and sodium bicarbonate were included. The primary outcome was incidence of CA-AKI.

RESULTS

37 RCTs studying 12,166 patients were included. Mean age was 67 ± 5 years, 70% of the patients were male. 68% had chronic kidney disease, 41% diabetes, and 30% heart failure. The incidence of CA-AKI was 9.5% (95% CI: 8-12%). IV expansion versus no volume administration was associated with a lower risk of CA-AKI (RR:0.62; 95% CI: 0.49-0.77, p < .001). Intensive IV volume expansion was associated with a reduced risk of CA-AKI(RR: 0.66; 95%CI: 0.52-0.85, p < .01). The intensive IV volume expansion arm received significantly more fluids than the standard protocols: 1,574(1,123 - 1,913) ml versus 849(558-1,067) ml (p = .03) without significant difference in the duration of infusion (median of 12 vs. 17 hr, p = .1) or pulmonary edema (1.7% vs 1.3%, p = .7).

CONCLUSIONS

Despite high variability in protocols used, IV volume expansion is effective in preventing CA-AKI. Intensive IVF expansion (median 1.6 L over 17 hr) was associated with decreased risk of CA-AKI.

Hydration for prevention of kidney injury after primary coronary intervention for acute myocardial infarction: a randomised clinical trial

OBJECTIVE

To evaluate the efficacy of aggressive hydration compared with general hydration for contrast-induced acute kidney injury (CI-AKI) prevention among patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI).

METHODS

The Aggressive hydraTion in patients with STEMI undergoing pPCI to prevenT Contrast-Induced Acute Kidney Injury study is an open-label, randomised controlled study at 15 teaching hospitals in China. A total of 560 adult patients were randomly assigned (1:1) to receive aggressive hydration or general hydration treatment. Aggressive hydration group received preprocedural loading dose of 125/250 mL normal saline within 30 min, followed by postprocedural hydration performed for 4 hours under left ventricular end-diastolic pressure guidance and additional hydration until 24 hours after pPCI. General hydration group received ≤500 mL 0.9% saline at 1 mL/kg/hour for 6 hours after randomisation. The primary end point is CI-AKI, defined as a >25% or 0.5 mg/dL increased in serum creatinine from baseline during the first 48-72 hours after primary angioplasty. The safety end point is acute heart failure.

RESULTS

From July 2014 to May 2018, 469 patients were enrolled in the final analysis. CI-AKI occurred less frequently in aggressive hydration group than in general hydration group (21.8% vs 31.1%; risk ratio (RR) 0.70, 95% CI 0.52 to 0.96). Acute heart failure did not significantly differ between the aggressive hydration group and the general hydration group (8.1% vs 6.4%, RR 1.13, 95% CI 0.66 to 2.44). Several subgroup analysis showed the better effect of aggressive hydration in CI-AKI prevention in male, renal insufficient and non-anterior myocardial infarction participants.

CONCLUSIONS

Comparing with general hydration, the peri-operative aggressive hydration seems to be safe and effective in preventing CI-AKI among patients with STEMI undergoing pPCI.

Acute Kidney Injury Following In-Patient Lower Extremity Vascular Intervention: From the National Cardiovascular Data Registry

OBJECTIVES

The authors analyzed data from the NCDR (National Cardiovascular Data Registry) PVI Registry and defined acute kidney injury (AKI) as increased creatinine of ≥0.3 mg/dl or 50%, or a new requirement for dialysis after PVI.

BACKGROUND

AKI is an important and potentially modifiable complication of peripheral vascular intervention (PVI). The incidence, predictors, and outcomes of AKI after PVI are incompletely characterized.

METHODS

A hierarchical logistic regression risk model using pre-procedural characteristics associated with AKI was developed, followed by bootstrap validation. The model was validated with data submitted after model creation. An integer scoring system was developed to predict AKI after PVI.

RESULTS

Among 10,006 procedures, the average age of patients was 69 years, 58% were male, and 52% had diabetes. AKI occurred in 737 (7.4%) and was associated with increased in-hospital mortality (7.1% vs. 0.7%). Reduced glomerular filtration rate, hypertension, diabetes, prior heart failure, critical or acute limb ischemia, and pre-procedural hemoglobin were independently associated with AKI. The model to predict AKI showed good discrimination (optimism corrected c-statistic = 0.68) and calibration (corrected slope = 0.97, intercept of -0.07). The integer point system could be incorporated into a useful clinical tool because it discriminates risk for AKI with scores ≤4 and ≥12 corresponding to the lower and upper 20% of risk, respectively.

CONCLUSIONS

AKI is not rare after PVI and is associated with in-hospital mortality. The NCDR PVI AKI risk model, including the integer scoring system, may prospectively estimate AKI risk and aid in deployment of strategies designed to reduce risk of AKI after PVI.

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.

Pentoxifylline for the prevention of contrast-induced nephropathy: systematic review and meta-analysis of randomised controlled trials

OBJECTIVES

To summarise current evidence on the use of pentoxifylline (PTX) to prevent contrast-induced nephropathy (CIN).

METHODS

The PubMed, Embase and CENTRAL databases were searched for randomised controlled trials including patients with and without PTX undergoing contrast media exposure. We analysed the incidence of CIN and serum creatinine changes before and after contrast media exposure. All statistical analyses were conducted with Review Manager V.5.3.

RESULTS

We finally enrolled in seven randomised controlled trials with a total of 1484 patients in this analysis. All of seven included studies were performed in patients undergoing angioplasty or stenting. The overall rates of CIN were 8.8% and 10.4% in the PTX groups and control groups, respectively. However, no significant reduction in the CIN rate was observed in the patients treated with PTX compared with the control groups (OR 0.81, 95% CI 0.57 to 1.13, I²=0, p=0.21). All studies reported no hospital mortality and the new requirement for dialysis during the trials.

CONCLUSION

Perioperative administration of PTX to patients undergoing angioplasty did not significantly reduce the development of CIN but showed some weak tendency of lower serum creatinine increase. Based on the available trials, the evidence does not support the administration of PTX for the prevention of CIN. More trials with larger sample sizes are needed to evaluate the role of PTX in CIN prevention.

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.

A Simple Nomogram to Predict Contrast-Induced Acute Kidney Injury in Patients with Congestive Heart Failure Undergoing Coronary Angiography

Background

Patients with congestive heart failure (CHF) are vulnerable to contrast-induced kidney injury (CI-AKI), but few prediction models are currently available. Therefore, we aimed to establish a simple nomogram for CI-AKI risk assessment for patients with CHF undergoing coronary angiography.

Methods

A total of 1876 consecutive patients with CHF (defined as New York Heart Association functional class II-IV or Killip class II-IV) were enrolled and randomly (2:1) assigned to a development cohort and a validation cohort. The endpoint was CI-AKI defined as serum creatinine elevation of ≥0.3 mg/dL or 50% from baseline within the first 48–72 hours following the procedure. Predictors for the simple nomogram were selected by multivariable logistic regression with a stepwise approach. The discriminative power was assessed using the area under the receiver operating characteristic (ROC) curve and was compared with the classic Mehran score in the validation cohort. Calibration was assessed using the Hosmer–Lemeshow test and 1000 bootstrap samples.

Results

The incidence of CI-AKI was 9.06% (170) in the total sample, 8.64% (n = 109) in the development cohort, and 9.92% (n = 61) in the validation cohort (P=0.367). The simple nomogram including four predictors (age, intra-aortic balloon pump, acute myocardial infarction, and chronic kidney disease) demonstrated a similar predictive power as the Mehran score (area under the curve: 0.80 vs. 0.75, P=0.061), as well as a well-fitted calibration curve.

Conclusions

The present simple nomogram including four predictors is a simple and reliable tool to identify CHF patients at risk of CI-AKI, whereas further external validations are needed.

Prevention of Contrast-Induced Nephropathy by Inferior Vena Cava Ultrasonography-Guided Hydration in Chronic Heart Failure Patients

INTRODUCTION

Contrast-induced nephropathy (CIN) is a common complication resulting from the administration of contrast media. This study was designed to determine whether inferior vena cava (IVC) ultrasonography (IVCU)-guided hydration can reduce the risk of CIN in chronic heart failure patients undergoing coronary angiography or coronary angiography with percutaneous coronary intervention compared with standard hydration.

METHODS

This prospective clinical trial enrolled 207 chronic heart failure patients from February 2016 to November 2017, who were randomly assigned to either the IVCU-guided hydration group (n = 104) or the routine hydration group (n = 103). In the IVCU-guided group, the hydration infusion rate was set according to the IVC diameter determined by IVCU, while the control group received intravenous infusion of 0.9% saline at 0.5 mL/(kg·h). Serum Cr was measured before and 48-72 h after the procedure. All patients were followed up for 18 months. The incidence of nephropathy and major adverse cardiovascular or cerebrovascular events (MACCEs) was also compared between the 2 groups.

RESULTS

Statistically significant difference between the 2 groups regarding the occurrence of CIN was observed (12.5 vs. 29.1%, p = 0.004). The hydration volume of the IVCU-guided group was significantly higher than that of the routine group (p < 0.001). In addition, patients receiving IVCU-guided hydration had significantly lower risk of developing MACCEs than patients in the control group during the 18-month follow-up (14.4 vs. 27.2%, p = 0.027).

CONCLUSION

Our findings support that IVCU-guided hydration is superior to standard hydration in prevention of CIN and may substantially reduce longtime composite major adverse events.

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

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

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.

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.

Post-PCI acute heart failure is an independent predictor of long-term mortality in patients with chronic kidney disease

BACKGROUND

This study aimed to clarify the association of post-percutaneous coronary intervention (PCI) acute heart failure (AHF) with all-cause long-term mortality in patients with chronic kidney disease (CKD).

METHODS

In this prospective, observational study, 610 patients with CKD and coronary artery disease (CAD) undergoing PCI were included in the final analysis. Patients were divided to the non post-PCI AHF group (n = 557) and the post-PCI AHF group (n = 53). The diagnosis of post-PCI AHF was based on symptoms, prior cardiovascular history, and potential cardiac and noncardiac precipitants.

RESULTS

The overall incidence of post-PCI AHF was 53/610 (8.7%). The incidence of all-cause long-term mortality was significantly higher in the post-PCI AHF group than in the non post-PCI AHF group (50.9% vs 23.2%, P < .01). The median follow-up period was 7.3 years (interquartile range: 3.7-8.4). After adjusting for left ventricular ejection fraction <40% at discharge, CKD stage, acute myocardial infarction, age and smoking, post-PCI AHF was the strongest predictor of all-cause long-term mortality (hazard ratio: 8.08; 95% CI: 3.04-21.48; P < .01).

CONCLUSIONS

In patients with CKD and CAD undergoing PCI, post-PCI AHF is the strongest predictor of all-cause long-term mortality.

Implications of Renal Disease in Patients Undergoing Peripheral Arterial Interventions

Since the first peripheral endovascular intervention (PVI) in 1964, the procedure's technical aspects and indications have advanced significantly. Today, endovascular procedures span the spectrum of presentations from acute limb ischemia to critical limb ischemia and symptomatic limiting claudication. Goals of PVI remain restoring limb perfusion, minimizing rates of amputation and mortality, and sparing the need for the high-risk bypass surgery. Unfortunately, there are no large randomized controlled trials that address the optimal approach to peripheral arterial disease revascularization in chronic kidney disease (CKD) patients.

Elevated left ventricular end diastolic pressure is associated with increased risk of contrast-induced acute kidney injury in patients undergoing percutaneous coronary intervention

AIMS

To study the correlation between intra-procedural left ventricular end-diastolic pressure (LVEDP) and the development of contrast-induced acute kidney injury (CI-AKI) in patients undergoing percutaneous coronary intervention (PCI).

METHODS AND RESULTS

A single center retrospective observational study compared clinical and hemodynamic characteristics of patients who developed post-PCI CI-AKI with those did not. CI-AKI was defined as an absolute increase in serum creatinine ≥0.5 mg/dl or an increase ≥25% from baseline 48-72 h after the administration of contrast medium. Among 1301 consecutive patients who underwent PCI, 125 patients (9.6%) developed CI-AKI. The CI-AKI group had a higher average LVEDP (18.4 ± 8.7 vs 14.4 ± 6.6 mm Hg; p < .0001) and higher prevalence of elevated LVEDP (≥20 mm Hg) than those without CI-AKI (47.2% vs 23.3%, p < .0001). After adjustments, elevated LVEDP remained independently associated with CI-AKI (OR 2.21; 95% CI 1.40-3.50). LVEDP predicted the development of CI-AKI with a receiver operating characteristic area under curve (AUC) of 0.64. The association between elevated LVEDP and the risk of CI-AKI was stronger in patients with reduced ejection fraction (EF ≤ 40%) (OR = 4.08; 95% CI: 1.68-9.91) than those with preserved EF (OR = 1.69; 95% CI: 0.94-3.04) (p value for interaction = .0003). Patients who had LVEDP ≥ 20 mm Hg and LVEF ≤ 40% had a post-PCI incidence rate of developing CI-AKI of 36.5%.

CONCLUSIONS

Elevated intra-procedural LVEDP (≥20 mm Hg) is independently associated with increased risk of CI-AKI for patients undergoing cardiac catheterization and PCI, especially in the setting of reduced LVEF (≤40%).

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.