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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

Background

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

Aims

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

Methods

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

Results

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

Conclusion

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

Combined strategy of device-based contrast minimization and urine flow rate-guided hydration to prevent acute kidney injury in high-risk patients undergoing coronary interventional procedures

BACKGROUND AND AIMS

Contrast-associated acute kidney injury (CA-AKI) is a major complication following coronary procedures. We aimed to evaluate the effectiveness of a combination of urine flow rate-(UFR) guided hydration (RenalGuardTM) and device-based contrast media (CM) reduction (DyeVertTM) in CA-AKI prevention.

METHODS

Stable high-risk patients undergoing coronary procedures with the use of DyeVertTM and RenalGuardTM were prospectively included (Combined group) and matched with a similar cohort of patients treated only with RenalGuardTM in whom CM volume was controlled by operator-dependent strategies (Control group). CA-AKI was defined as a serum creatinine increase ≥0.3 mg/dL at 48 h.

RESULTS

Overall, 55 patients were enrolled and matched with comparable controls. Patients in the Combined group were exposed to a lower CM dose (Control: 55 [30-90] mL vs. Combined: 42.1 [24.9-59.4] mL; p = 0.024). A significant interaction was found between treatment allocation and serum creatinine changes (p = 0.048). CA-AKI occurred in five (9.1%) patients in the Combined group and in 14 (25.4%) patients in the Control group (OR 0.29, 95% CI [0.09-0.88]).

CONCLUSIONS

A combined strategy of device-based CM reduction plus UFR-guided hydration is superior to operator-dependent CM sparing strategies plus UFR-guided hydration in preventing CA-AKI in high-risk patient.

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.

Role of Invasive Strategy for Non-ST-Elevation Myocardial Infarction in Patients With Chronic Kidney Disease: A Systematic Review and Meta-Analysis

Patients with chronic kidney disease (CKD) have traditionally been excluded from randomized trials. We aimed to compare percutaneous coronary intervention versus conservative management, and early intervention (EI; within 24 hours of admission) versus delayed intervention (DI; after 24 to 72 hours of admission) in patients with non-ST-segment elevation myocardial infarction (NSTEMI) and concomitant CKD. An electronic literature search was performed to search for studies comparing invasive management to conservative management or EI versus DI in patients with NSTEMI with CKD. The primary outcome was all-cause mortality; secondary outcomes were acute kidney injury (AKI) or dialysis, major bleeding, and recurrent MI. Hazard ratios (HRs) for the primary outcome and odds ratios for secondary outcomes were pooled in random-effects meta-analyses. Eleven studies (140,544 patients) were analyzed. Invasive management was associated with lower mortality than conservative management (HR 0.62, 95% confidence interval 0.57 to 0.67, p <0.001, I2 = 47%), with consistent benefit across all CKD stages, except CKD 5. There was no significant mortality difference between EI and DI, but subgroup analyses showed significant benefit for EI in stage 1 to 2 CKD (HR 0.75, 95% confidence interval 0.58 to 0.97, p = 0.03, I2 = 0%), with no significant difference in stage 3 and 4 to 5 CKD. Invasive strategy was associated with higher odds of AKI or dialysis and major bleeding, but lower odds of recurrent MI compared with conservative management. In conclusion, in patients with NSTEMI and CKD, an invasive strategy is associated with significant mortality benefit over conservative management in most patients with CKD, but at the expense of higher risk of AKI and bleeding. EI appears to benefit those with early stages of CKD. Trial Registration: PROSPERO CRD42023405491.

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.

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

INTRODUCTION AND OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[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.

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.

Radiographic Contrast Media and the Kidney

AKI is a potential complication of intravascular iodinated contrast exposure. Contrast-associated AKI, which typically manifests as small and transient decrements in kidney function that develop within several days of contrast administration, is associated with serious adverse outcomes, including progressive kidney dysfunction and death. However, a causal link between the small increases in serum creatinine that characteristically occur with contrast-associated AKI and serious adverse outcomes remains unproven. This is important given mounting evidence that clinically indicated, potentially lifesaving radiographic procedures are underutilized in patients with CKD. This has been hypothesized to be related to provider concern about precipitating contrast-associated AKI. Intravascular gadolinium-based contrast, an alternative to iodinated contrast that is administered with magnetic resonance imaging, has also been linked with potential serious adverse events, notably the development of nephrogenic systemic fibrosis in patients with severe impairment in kidney function. Patients hospitalized in the intensive care unit frequently have clinical indications for diagnostic and therapeutic procedures that involve the intravascular administration of contrast media. Accordingly, critical care providers and others treating critically ill patients should possess a sound understanding of the risk factors for and incidence of such outcomes, the ability to perform evidence-based risk-benefit assessments regarding intravascular contrast administration, and knowledge of empirical data on the prevention of these iatrogenic complications.

Elevation of Preprocedural Systemic Immune Inflammation Level Increases the Risk of Contrast-Associated Acute Kidney Injury Following Coronary Angiography: A Multicenter Cohort Study

Background

Inflammation and immune responses play an important role in the pathophysiology of contrast-associated acute kidney injury (CA-AKI), and systemic immune inflammation index (SII) has recently emerged as a new parameter for immune and inflammatory response evaluation. However, limited research has been undertaken to explore the relationship between SII and CA-AKI following coronary angiography (CAG).

Patients and Methods

From January 2007 to December 2020, 46,333 patients undergoing CAG were included from 5 Chinese tertiary hospitals. SII was calculated as total peripheral platelets count × neutrophil-to-lymphocyte ratio. Patients were categorized by preprocedural SII quartiles: Q1 ≤404.5, Q2 >404.5 and ≤631.7, Q3 >631.7 and ≤1082.8, Q4 >1082.8. Univariable and multivariable logistic regression were used to reveal the link between preprocedural SII and CA-AKI.

Results

A total of the 46,333 patients (62.9 ± 11.5 years, female 28.1%) were included in the study. The incidence of CA-AKI was 8.4% in Q1 group, 8.7% in Q2 group, 9.4% in Q3 group, 15.1% in Q4 group. In the multivariable model, comparing the highest (Q4 group) to lowest (Q1 group) SII level categories, preprocedural SII was related to a higher risk of CA-AKI after fully adjusting for well-known confounders, and there was no statistically difference in the other two SII level categories (Q2 and Q3 groups) compared with Q1 group (adjusted model 3: Q2 group: OR: 0.98, 95% CI: 0.87–1.11, P = 0.771; Q3 group: OR: 1.04, 95% CI: 0.92–1.18, P = 0.553; Q4: OR: 1.65, 95% CI: 1.45–1.88, p < 0.001; P for trend < 0.001). Similar results were found for all the subgroups analysis except for patients undergoing PCI, and the interaction analyses for age, PCI and AMI were significant. In addition, Kaplan–Meier curves demonstrated that the lowest quartile group showed the worst all-cause mortality in a significant SII level-dependent manner among the four groups (Log rank test; p < 0.0001).

Conclusion

Elevated preprocedural SII level was a significant and independent risk factor for CA-AKI following CAG. Higher-quality prospective studies are needed to validate the predictive value of SII for CA-AKI.

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.

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.

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.

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.

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.