Prevention of Contrast-Induced Acute Kidney Injury by Furosemide With Matched Hydration in Patients Undergoing Interventional Procedures: A Systematic Review and Meta-Analysis of Randomized Trials

Differential Incidence of Contrast-Associated Acute Kidney Injury: Comparing Intravenous and Intraarterial Contrast Administration

PURPOSE OF THE REVIEW

Contrast-associated acute kidney injury (CA-AKI) remains a significant concern in diagnostic and invasive procedures, particularly in the context of iodinated contrast material administration. The traditional definition of CA-AKI, based on serum creatinine elevation following contrast exposure, may not accurately capture its multifactorial nature.

RECENT FINDINGS

Studies have provided new insights into the differential incidence of CA-AKI between intravenous and intraarterial contrast administration, emphasizing the importance of tailored preventative strategies for high-risk procedures. This higher risk may arise from two proposed mechanisms: one implicating free radical formation leading to cytotoxicity and apoptosis in renal cells and another suggesting that contrast media alter renal hemodynamics, particularly in the outer medulla, by constricting the vasa recta and reducing medullary flow. Advances in technology and patient care, including contemporary use of low-osmolar contrast agents and hydration protocols, mitigate CA-AKI risk. Diagnostic and invasive procedures should not be avoided solely due to concerns about renal dysfunction if the patient is likely to benefit clinically.

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.

The effect of perioperative diuretic administration on acute kidney injury in patients with acute myocardial infarction after percutaneous coronary intervention: a real-world retrospective study

PURPOSE

The relationship between diuretic use and contrast-induced acute kidney injury (CI-AKI) after contrast exposure remains unclear. In this study, we conducted a retrospective analysis using propensity score matching (PSM) to investigate the effect of perioperative diuretic administration on contrast-induced acute kidney injury (CI-AKI) in patients with acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI).

METHODS

A total of 1894 patients with AMI who underwent PCI were retrospectively analyzed using PSM and multivariate models. Depending on whether diuretics were used, the patients were divided into two groups: the perioperative diuretic group (497 patients, 26.2%) and the non-diuretic group (1397 patients, 73.8%). And the relationship between perioperative diuretic administration and CI-AKI was evaluated by multiple regression models. Furthermore, Kaplan Meier survival curve ratio was used to evaluate and compare overall postoperative survival between the two groups.

RESULTS

Most patients who received diuretics were older (67 vs. 60 years, respectively, p < 0.001) and women (22.5% vs. 15.2%, p < 0.001) and had combined hypertension (62.8% vs. 47%, p < 0.001), atrial fibrillation (5.4% vs. 1.8%, p < 0.001), stroke (9.3% vs. 4.9%, p < 0.001), and diabetes mellitus (33.4% vs. 23.6%, p < 0.001) compared to those who did not. After the baseline characteristics were balanced using the PSM model, no significant difference was observed in the incidence of postoperative CI-AKI (22.7% vs. 19.5%, p = 0.356) and major cardiovascular adverse events (21.5% vs. 18.7%, p = 0.398). Multiple regression analysis showed no association between perioperative diuretic administration and postoperative CI-AKI occurrence (odds ratio: 1.14, 95% confidence interval: 0.86-1.51, p = 0.371). Further subgroup analysis and sensitivity analysis confirmed the above findings.

CONCLUSION

We found no significant association between perioperative diuretic administration and postoperative CI-AKI in patients with AMI who underwent PCI.

Association between dose reduction of renin-angiotensin-aldosterone system inhibitors before coronary artery angiography and acute kidney injury: a propensity score-matched study

OBJECTIVE

The aim of this study was to investigate the association between dose reduction of renin-angiotensin-aldosterone system inhibitors (RAASis) and Acute kidney injury (AKI). AKI, which is commonly observed in hospitalized patients, increases mortality. Although RAASis and coronary artery angiography (CAG) are reported to be risk factors for AKI, whether dose reduction of RAASis can prevent AKI after CAG remains unknown.

METHODS

In this retrospective propensity score (PS)-matched cohort from the RWD database, which includes 20 million patients from 190 hospitals in Japan, we examined the impact of dose reduction of RAASis on the development of AKI after CAG. The subjects were patients with an estimated glomerular filtration rate (eGFR) of 15-60 mL/min/1.73 m2, and the exposure of interest was the presence of a dose reduction in RAASis within 3 days before CAG was performed. Propensity score matching was performed with 19 baseline characteristics using a logistic regression model.

RESULTS

We identified 3329 patients who were prescribed RAASis at least one month before admission and underwent CAG. Six hundred seventy-four patients had a dose reduction 3 days prior to undergoing CAG, and 2655 patients did not. AKI was observed in 34 (5.0%) patients in the reduction group and 137 (5.2%) patients in the control group. There was no significant difference in the primary outcome between the two groups in the PS-matched cohort (OR: 1.08, 95% CI: 0.70-1.66).

CONCLUSIONS

A reduction in the dose of RAASis did not prevent the development of AKI among patients undergoing CAG.

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

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

Transcatheter Aortic Valve Replacement-Associated Acute Kidney Injury: An Update

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is a relatively novel minimally invasive procedure for the treatment of symptomatic patients with severe aortic stenosis. Although it has been proven effective in improving mortality and quality of life, TAVR is associated with serious complications, such as acute kidney injury (AKI).

SUMMARY

TAVR-associated AKI is likely due to several factors such as sustained hypotension, transapical approach, volume of contrast use, and baseline low GFR. This narrative review aims to present an overview of the latest literature and evidence regarding the definition of TAVR-associated AKI, its risk factors, and its impact on morbidity and mortality. The review used a systematic search strategy with multiple health-focused databases (Medline, EMBASE) and identified 8 clinical trials and 27 observational studies concerning TAVR-associated AKI. Results showed that TAVR-associated AKI is linked to several modifiable and nonmodifiable risk factors and is associated with higher mortality. A variety of diagnostic imaging modalities have the potential to identify patients at high risk for development of TAVR-AKI; however, there are no existing consensus recommendations regarding their use as of this time. The implications of these findings highlight the importance of identifying high-risk patients for which preventive measures may play a crucial role, and should be maximized.

KEY MESSAGE

This study reviews the current understanding of TAVR-associated AKI including its pathophysiology, risk factors, diagnostic modalities, and preventative management for patients.

Clinical Observation of Patients Undergoing Glioma Surgery under Propofol and Sevoflurane Anesthesia: A Retrospective Study

Objective

To observe the effects of propofol and sevoflurane anesthesia on patients undergoing glioma surgery.

Methods

192 patients with gliomas treated in our hospital from January 2016 to January 2021 were selected. All patients were randomly divided into observation group and control group. The observation group was given sevoflurane and the control group was given propofol. The clinical effects of the two groups were observed.

Results

Comparison of clinical indexes related to intraoperative conditions between the two groups revealed that the time of anesthesia and extubation after operation in the observation group were shorter than those in the control group, and the difference was statistically significant (P < 0.05). The amount of intraoperative bleeding in the observation group was less than that in the control group, and the difference was statistically significant (P < 0.05). There was no significant difference in intracranial operation time, operation time, fluid volume, and urine volume between the two groups (P < 05). Comparing the recovery time of anesthesia between the two groups, the recovery time of orientation and the time of eye-opening in the observation group were significantly shorter than those in the control group (P < 0.05). Comparing the consciousness and cognitive function of the two groups, the OAAS score of the observation group after extubation, before leaving the operating room and 1 hour after extubation, was significantly higher than that of the control group (P < 0.05), and the MMSE score l h after extubation was significantly higher than that of the control group (P < 0.05). Comparing the incidence of postoperative complications between the two groups, the number of cases of restlessness, urinary infection, deep vein thrombosis, and hypertension in the observation group was lower than that in the control group, with statistical significance (P < 0.05).

Conclusion

The anesthesia time and extubation time of the sevoflurane anesthesia group were shorter than that of the propofol anesthesia group, and the orientation recovery time and eye-opening time were shortened. The OAAS score of the sevoflurane anesthesia group was higher than that of the propofol anesthesia group after extubation, before extubation, and 1 hour after extubation. The probability of postoperative complications in the sevoflurane anesthesia group was lower than that in the propofol anesthesia group. Sevoflurane anesthesia may be more suitable for surgical induction of glioma patients than propofol anesthesia.

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

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

Admission electrolyte and osmotic pressure levels are associated with the incidence of contrast-associated acute kidney injury

This retrospective study aimed to explore the relationships between electrolytes and osmotic pressure homeostasis with contrast-associated acute kidney injury (CA-AKI) risk in patients with percutaneous coronary intervention or coronary angiography. We totally enrolled 4386 hospitalized patients, who were categorized into five groups based on the predetermined cutoff values of electrolytes and osmotic pressure. CA-AKI was defined as an increase in serum creatine by 0.5 mg/dL (44.2 mol/L) or a 25% increase of the highest level post-operation compared to baseline. Multivariable logistic analysis was used to examine the association of CA-AKI incidence with electrolytes and osmotic pressure levels. Piecewise linear regression models and restricted cubic spline analysis were further utilized to determine the nonlinear relationship. The results showed U-shaped relationships between sodium, chloride, magnesium, and osmotic pressure levels and CA-AKI incidence. The lowest incidence was observed in the categories of 139–141.9 mmol/L, 107.0–109.9 mmol/L, 0.91–1.07 mmol/L, and 290.0–299.9 mOsm/kg, respectively. J-shaped associations were observed for potassium and phosphate levels and CA-AKI incidence, with the lowest incidence in the categories of 3.50–4.09 mmol/L and 0.96–1.28 mmol/L, respectively. A negative correlation was observed between calcium level and CA-AKI incidence, with the lowest CA-AKI risk in the category of ≥ 2.58 mmol/L. In conclusion, abnormally higher or lower sodium, chloride, magnesium, phosphate, and osmotic pressure levels on admission were associated with increased risks of CA-AKI. While for potassium and calcium, the status of hyperkalemia and hypocalcemia on admission showed more susceptibility for CA-AKI.

Tolvaptan Improves Contrast-Induced Acute Kidney Injury

OBJECTIVE

Contrast-induced acute kidney injury (CI-AKI) is a serious side effect of contrast media use. The purpose of this study was to investigate the role and mechanism of tolvaptan (TOL) in CI-AKI.

METHODS

24 Wistar male rats were randomly divided into 4 groups (n = 6). And a rat model of CI-AKI was established. Then, the blood and urine of rats in each group were collected to detect relevant parameters. HE staining was utilized for the observation of the pathological changes of rat kidney tissues, TUNEL assay for the detection of tubular cell apoptosis, biochemical detection for the confirmation of oxidative stress level in kidney tissues, and western blot for the test of the expression of apoptotic proteins and the Nrf2 signaling pathway-related proteins in kidney tissues.

RESULTS

TOL could significantly reduce the serum level of urea nitrogen, creatinine, and neutrophil gelatinase-associated lipocalin and decrease serum Cys-C and urine KIM-1 in CI-AKI rats. The result above meant that TOL could improve kidney injury and reduce tubular cell apoptosis in CI-AKI rats. In addition, TOL contributed to a reduction of oxidative stress level by downregulating myeloperoxidase level and increasing the activities of superoxide dismutase and glutathione peroxidase in the kidney tissue of CI-AKI rats. After the pretreatment of TOL, the expression of proapoptotic proteins cleaved-caspase 3 and BAX, as well as mitochondrial fusion proteins DRP1 and MFN2 was downregulated, while the expression of Bcl-2 and PINK1 was upregulated in the kidney tissue of CI-AKI rats. Further, TOL could activate the Nrf2 signaling pathway, and the Nrf2 inhibitor ML385 reversed the effect of TOL on CI-AKI.

CONCLUSION

TOL can improve CI-AKI by activating the Nrf2/HO-1 signaling pathway, inhibiting oxidative stress response, and reducing tubular cell apoptosis.

Serum Level of Complement C1q is Associated with Contrast-Associated Acute Kidney Injury in Patients Undergoing Emergency Percutaneous Coronary Intervention

Background

As an inflammatory factor, complement C1q is related to the prevalence and progression of atherosclerosis; however, in patients undergoing emergency percutaneous coronary intervention (PCI), it is unclear whether C1q is related to the prevalence of contrast-associated acute kidney injury (CA-AKI).

Methods

From November 2018 to March 2021, 1182 patients who underwent emergency PCI were continuously recruited. Patients were divided into CA-AKI group (n = 234) and non-CA-AKI group (n = 948). CA-AKI was defined as an increase in serum creatinine from the baseline level (≥25% or ≥0.5 mg/dL) 48–72 hours after contrast exposure. All subjects were tested for serum C1q levels when they were admitted to the hospital.

Results

Among the 1182 patients undergoing emergency PCI, 234 patients (19.80%) developed CA-AKI. The level of preoperative serum complement C1q in the CA-AKI group was significantly higher than that in the non-CA-AKI group. Logistic regression and restricted cubic spline analyses showed that the incidence of CA-AKI was positively associated with the serum C1q level pre-PCI. Univariate and multivariate logistic regression analyses showed that C1q was an independent predictor of whether CA-AKI occurred after emergency PCI. The area under the curve (AUC) of the C1q was 0.703 [95% confidence interval (CI) 0.667–0.739] in patients receiving emergency PCI. CA-AKI model included the following three predictors: C1q, eGFR, and IABP use. The AUC of forecast probability was 0.718 [95% CI 0.682–0.754].

Conclusion

In patients receiving emergency PCI procedure, a high C1q level before PCI is associated with the increased risk of CA-AKI.

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

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

[Contrast media use in kidney disease - clinical practice recommendations]

Contrast media use in patients with renal disease regularly ensures discussions in everyday clinical practice. Both X-ray and MRI contrast media are predominantly eliminated by the kidneys and therefore closely linked to kidney function. Risk stratification prior to contrast media use in patients with pre-existing renal dysfunction should be based on eGFR-determination. Patients with an eGFR ≥ 30 ml/min require an individual risk assessment. In patients with advanced renal insufficiency ensuring euvolemia is crucial. Currently, there is no evidence for any other preventive approach. Therefore, no further specific procedures preventing contrast-associated kidney injury are recommended. Timing of contrast media injection and dialysis sessions in patients with end stage renal disease is necessary only after MRI contrast media use. Independently, acute kidney injury requires a patient individual decision.

Left Ventricular End-Diastolic Pressure and B-Type Natriuretic Peptide Levels Guidance of Low-Dose Furosemide Treatment to Prevent Contrast-Induced Nephropathy in Patients with Percutaneous Coronary Intervention: A Randomized Controlled Trial

Objective. We aimed to explore the preventive effect of low-dose furosemide administration guided by left ventricular end-diastolic pressure (LVEDP) and B-type natriuretic peptide (BNP) based on adequate hydration on contrast-induced nephropathy (CIN) in patients with percutaneous coronary intervention (PCI). Methods. This parallel randomized clinical trial was conducted at a tertiary hospital in China. A total of 1053 consecutive patients (71.98% men) who underwent PCI at our hospital were enrolled. Pre-PCI plasma BNP levels were recorded. Patients enrolled received a continuous intravenous infusion of normal saline starting 4 h before PCI until 24 h after surgery. LVEDP was measured immediately after surgery. Patients in the control group received intravenous furosemide injection (20 mg). Patients in the experimental group received furosemide if they showed LVEDP ≥15 mmHg, a post-PCI BNP level ≥100 pg/mL, and/or a post-PCI BNP value > 150% of the pre-PCI value. The primary and secondary outcome measures were serum creatinine levels, glomerular filtration rate, and creatinine clearance rate measured before and after PCI. CIN incidence was compared between the two groups. Logistic regression analysis was used to study the risk factors for CIN. Results. CIN incidence was significantly higher in the control group than in the experimental group ( $P<0.05$ ). Logistic regression analysis showed that elevated LVEDP and BNP levels were risk factors. As LVEDP increased, the CIN incidence also increased (odds ratio (OR) 1.038, 95% confidence interval (CI) 1.006–1.070). The OR of BNP was 1.001 (95% CI 1.000–1.002). Conclusions. Low-dose furosemide administration guided by LVEDP or BNP is superior to direct low-dose administration on the basis of adequate hydration during PCI. This trial is registered with ChiCTR-IOR-14005250

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.

Application of nanotechnology in acute kidney injury: From diagnosis to therapeutic implications

Acute kidney injury (AKI), a major health issue concerning ~50% of patients treated in intensive care units, generally leads to severe renal damage associated with high mortality rate. The application of nanotechnology for the management of AKI has profound potential of further development, providing innovative strategies for predicting the early onset and progression of renal disease and improving the treatment efficacy of the life-threating AKI. This review has comprehensively summarized the nanomedicines in the application of AKI diagnosis and emphatically discussed the unique potential of various nanotechnology-based drug delivery systems (e.g., polymeric nanoparticles, organic nanoparticles, inorganic nanoparticles, lipid-based nanoparticles, hydrogels etc.) in the treatment of AKI, allowing for improved therapeutic index by enhancing both efficacy and safety concurrently. These approaches may mechanically mitigate oxidative stress, inflammation, and mitochondrial and other organellar damage, etc. In addition, the combination of nanotechnology with stem cells-based therapy or gene therapy has been explored for reducing renal tissues damage and promoting kidney repair or recovery from AKI. The review provides insights into the synthesis, advantages, and limitations of innovative nanomedicine application in the early detection and effective treatment of AKI.

Association between Diabetes Mellitus and Contrast-Associated Acute Kidney Injury: A Systematic Review and Meta-Analysis of 1.1 Million Contrast Exposure Patients

BACKGROUND

Although diabetes mellitus (DM) has been a common risk factor of contrast-associated acute kidney injury (CA-AKI) for a long time, several current studies showed that DM is not an independent risk factor. Due to this diverse finding, we aim to conduct a systematic review assessing the effect of DM on CA-AKI.

METHODS

We searched Ovid Medline, Embase, and Cochrane Database of Systematic Reviews (to June 1, 2020) for studies assessing the association between DM and CA-AKI. Random meta-analysis was performed to derive the pooled estimates of the adjusted odds ratio (OR) and corresponding 95% confidence intervals (CIs).

RESULTS

A total of 84 studies involving 1,136,827 participants were included in this meta-analysis. The presence of DM was associated with an higher risk of CA-AKI (pooled OR: 1.58, 95% CI: 1.48-1.70, I2 = 64%). Furthermore, the predictive effect of elevated CA-AKI for was stronger in the subgroup of DM patients with chronic kidney disease (CKD) (OR: 2.33, 95% CI: 1.21-4.51), while the relationship between DM and CA-AKI was not significant in subgroup patients without CKD (OR: 1.12, 95% CI: 0.73-1.72).

CONCLUSION

This is the first meta-analysis to prove that DM is an independent risk factor of CA-AKI in patients. While the predictive value of DM for CA-AKI in patients with normal kidney function was weakened, more protective treatments are needed in diabetic patients with kidney dysfunction to avoid the occurrence of CA-AKI.

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.

Change in Kidney Function and 2-Year Mortality After Transcatheter Aortic Valve Replacement

IMPORTANCE

Chronic kidney disease (CKD) is prevalent in the population of patients undergoing transcatheter aortic valve replacement (TAVR). Data on the association of TAVR with kidney function are scarce, as are data on the relationship between changes in kidney function after TAVR and mortality.

OBJECTIVE

To describe the changes in kidney function (both periprocedural and at steady state) after TAVR and to explore the association of TAVR with midterm mortality.

DESIGN, SETTING, AND PARTICIPANTS

This single-center, retrospective cohort study was conducted at a public, tertiary academic medical center, which serves as a regional referral center for valvular heart interventions. Consecutive cases of patients undergoing TAVR from November 5, 2008, to December 31, 2019, were included in the study, with available baseline and post-TAVR data on kidney function.

EXPOSURES

Steady state (1 month) change in kidney function after TAVR. Significant improvement or deterioration in renal function was defined as a greater than or equal to 10% change in estimated glomerular filtration rate (eGFR).

MAIN OUTCOMES AND MEASURES

Overall mortality at 2-year follow-up.

RESULTS

A total of 894 patients (mean [SD] age, 82.2 [7.1] years; 452 women ([51.2%]) were evaluated. A total of 362 patients (40.5%) were treated from 2017 to 2019, 348 patients (38.9%) were treated from 2013 to 2016, and 184 patients (20.5%) were treated from 2008 and 2012. Patients had a mean (SD) Society of Thoracic Surgeons (STS) score of 5.2% (4.0%) and a mean (SD) eGFR of 65.1 (23.1) mL/min/1.73 m2. Acute kidney injury occurred in 115 (11.1%) patients by 48 hours, of whom 73 (63.5%) resolved by discharge. One month after TAVR, eGFR improved by at least 10% in 329 patients (36.8%) and deteriorated by at least 10% in 233 patients (26.1%). Overall, CKD stage remained stable or improved in 720 patients (80.6%), and only 5 patients (0.97%) progressed to stage 5 CKD 1 month after TAVR. A deterioration of 10% or greater in eGFR 1 month after TAVR was associated with a hazard ratio of 2.16 (95% CI, 1.24-5.24; P = .04) at 2-year mortality. Patients who showed CKD status resolution (eGFR improvement to >60 mL/min/1.73 m2 after TAVR) had a similar 2-year mortality to those with baseline eGFR greater than 60 mL/min/1.73 m2 and vice versa. Factors associated with steady state CKD status resolution after TAVR included lower STS score, higher left ventricular ejection fraction, higher baseline eGFR, no acute kidney injury at discharge from the TAVR admission, and lower contrast-eGFR ratio.

CONCLUSIONS AND RELEVANCE

In this cohort study, kidney outcomes after TAVR were reassuring; greater than 80% of patients showed stable or improved kidney function 1 month after the procedure. Improvement in kidney function was associated with a lower 2-year mortality, whereas deterioration in kidney function was associated with increased mortality. Our data suggest that cardiorenal syndrome was a possible cause of CKD in patients in need of TAVR and that there was potential for improvement in both renal and cardiac function after this procedure.

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.

Kidney protection in thoracoabdominal aortic aneurysm surgery

Acute kidney injury (AKI) is a common complication of both open and endovascular repair of thoracoabdominal aortic aneurysms (TAAA). Its definition varies across difference studies, some standardized definitions (RIFLE, AKIN, KDIGO) have been proposed but still not uniformly employed in published papers. Acute kidney injury is multifactorial and is associated with increased in-hospital mortality, long-term mortality and late renal function decline. In addition, AKI is also associated with perioperative spinal cord ischemia. No specific pharmacological strategy has received a strong recommendation with high level of evidence as a protective measure. Fenoldopam, methylprednisolone or mannitol use to prevent AKI is commonly employed, but not supported by literature data. Avoiding nephrotoxic drugs and maintaining an adequate MAP, during and after the procedure plays a key role in preserving kidney function. During open TAAA surgery, renal arteries may be reimplanted using different techniques. The choice of the best option must be tailored to the patient, to reduce ischemic time and guarantee long-term patency. Current experience suggests that cold crystalloid solutions are the best substrates in preventing ischemia-reperfusion injury. Renal perfusion using Custodiol^® (Dr Franz-Kohler Chemie GmbH; Bensheim, Germany) 4 °C, even if currently considered off-label, represents an encouraging organ protection tool. In endovascular TAAA repair, techniques such as fusion imaging, use of diluted contrast, and CO<inf>2</inf> subtraction angiography have the potential to reduce postoperative AKI. Visceral vessels patency is closely related to the anatomy. Therefore, accurate endograft design according to these characteristics is crucial for long-term preservation of renal function.

Initial evidence of a 50% reduction of contrast media using digital variance angiography in endovascular carotid interventions

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Digital Variance Angiography (DVA) is a novel medical image processing method.

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DVA provides better image quality than Digital Subtraction Angiography (DSA).

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The quality reserve of DVA allows the reduction of contrast agents in angiography.

Purpose

In previous clinical studies Digital Variance Angiography (DVA) provided higher signal-to-noise ratio (SNR) and better image quality than Digital Subtraction Angiography (DSA). Our aim was to investigate whether this quality reserve of DVA provides an opportunity for the reduction of iodinated contrast media (ICM) in carotid X-ray angiography (CXA).

Method

Our prospective study enrolled 26 patients (67.0 ± 8.1 years) undergoing carotid percutaneous transluminal angioplasty. The SNR of DSA and DVA image pairs obtained by a standard (100 %, 6 mL ICM) or a low-dose (50 %, 3 mL ICM) protocol were compared. Visual evaluation of all images was performed by five specialists using a 5-grade rating scale. The quality of DSA₁₀₀ and DVA₅₀ videos was also compared.

Results

DVA provided more than two-fold SNR, the median SNR_DVA/SNR_DSA ratio was 2.06 (100 %) and 2.25 (50 %). In the visual evaluation, the DVA₁₀₀ score (3.73 ± 0.06) was significantly higher than the DSA₁₀₀ score (3.52 ± 0.07, Wilcoxon p < 0.001), and the DVA₅₀ score (3.64 ± 0.13) was also significantly higher than the DSA₅₀ score (3.01 ± 0.17, Wilcoxon p < 0.001). While the low-dose protocol significantly decreased the DSA score (Mann-Whitney p < 0.01, DSA₁₀₀ vs DSA₅₀), it had no effect on the DVA score (DVA₁₀₀ vs DVA₅₀). There was no statistical difference between the DSA₁₀₀ and DVA₅₀ scores. Evaluators preferred the diagnostic value of DVA₅₀ to DSA₁₀₀ videos in 61% of comparisons, the interrater agreement was 69 % (Fleiss’ kappa 0.35, p < 0.001)

Conclusions

Our data show that DVA allows a substantial (50 %) ICM reduction in CXA without affecting the quality and diagnostic value of angiograms.

Near-drowning: new perspectives for human hypoxic acute kidney injury

Concepts regarding hypoxic acute kidney injury (AKI) are derived from widely used warm ischemia-reflow (WIR) models, characterized by extensive proximal tubular injury and associated with profound inflammation. However, there is ample clinical and experimental data indicating that hypoxic AKI may develop without total cessation of renal blood flow, with a different injury pattern that principally affects medullary thick limbs in the outer medulla. This injury pattern likely reflects an imbalance between blood and oxygen supply and oxygen expenditure, principally for tubular transport. Experimental models of hypoxic AKI other than WIR are based on mismatched oxygen delivery and consumption, particularly within the physiologically hypoxic outer medulla. However, evidence for such circumstances in human AKI is lacking. Recent analysis of the clinical course and laboratory findings of patients following near-drowning (ND) provides a rare glimpse into such a scenario. This observation supports the role of renal hypoxia in the evolution of AKI, as renal impairment could be predicted by the degree of whole-body hypoxia (reflected by lactic acidosis). Furthermore, there was a close association of renal functional impairment with indices of reduced oxygen delivery (respiratory failure and features of intense sympathetic activity) and of enhanced oxygen consumption for active tubular transport (extrapolated from the calculated volume of consumed hypertonic seawater). This unique study in humans supports the concept of renal oxygenation imbalance in hypoxic AKI. The drowning scenario, particularly in seawater, may serve as an archetype of this disorder, resulting from reduced oxygen delivery, combined with intensified oxygen consumption for tubular transport.

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.

Role of Hypoxia in Renal Failure Caused by Nephrotoxins and Hypertonic Solutions

Hypoxia plays a role in the pathogenesis of acute kidney injury under diverse clinical settings, including nephrotoxicity. Although some nephrotoxins exert direct renal parenchymal injury, likely with consequent altered oxygenation, others primarily reduce renal parenchymal oxygenation, leading to hypoxic tubular damage. As outlined in this review, nephrotoxin-related renal hypoxia may result from an altered renal oxygen supply (cyclosporine), enhanced oxygen consumption for tubular transport (agents inducing osmotic diuresis), or their combination (nonsteroidal anti-inflammatory drugs, radiocontrast agents, and others). Most agents causing hypoxic renal injury further supress physiologic low medullary Po₂, in which a limited regional blood supply barely matches the intense regional tubular transport and oxygen consumption. The medullary tubular transport and blood supply are finely matched, securing oxygen sufficiency. Predisposition to hypoxia-mediated nephrotoxicity by medical conditions, such as chronic kidney disease or diabetes, may be explained by malfunctioning of control systems that normally maintain medullary oxygenation. However, this propensity may be diminished by hypoxia-mediated adaptive responses governed by hypoxia-inducible factors. Recent reports have suggested that inhibitors of sodium-glucose cotransporters and the administration of hypertonic saline may be added to the growing list of common therapeutic interventions that intensify medullary hypoxia, and potentially could lead to hypoxic acute kidney injury.

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.

The Role of Xuefu Zhuyu Decoction in Prevention of Contrast-Induced Nephropathy after Percutaneous Coronary Intervention

Objective

This study aimed to investigate the effect of Xuefu Zhuyu decoction on preventing contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI).

Methods

A total of 256 patients undergoing selective PCI for coronary artery disease were consecutively enrolled and randomly divided into two groups: Group A (n = 126) and Group B (n = 130). Before and after PCI, all patients routinely received antiplatelet aggregation therapy, antilipidemic therapy, and hydration therapy. Besides routine therapy, patients in Group B received Xuefu Zhuyu decoction from 3 days before PCI to 3 days after PCI. Serum creatinine (Scr), estimated glomerular filtration rate (eGFR), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured, respectively, at baseline (72 h before PCI) and at 24, 48, and 72 h after PCI.

Results

Compared with Group A, Group B presented a lower fluctuation of SCr and eGFR (P < 0.01). The incidence of CIN was less in Group B. According to the definition, CIN occurred in 5 patients (2.0%) in the intervention group and 5 (4.0%) in the control group (P=0.167). In terms of oxidative stress, Group B had a lower MDA (P < 0.05), but a higher SOD (P < 0.05).

Conclusions

Compared with the control group, Xuefu Zhuyu decoction intervention therapy increased the level of SOD and reduced MDA. The Xuefu Zhuyu decoction intervention group presented a higher level of eGFR at 24, 48, and 72 h after PCI in patients with coronary heart disease and a lower level of Scr. The results are propitious to prove that Xuefu Zhuyu decoction might play an antioxidative stress role in the prevention of CIN after PCI.

Bedside Renal Doppler Ultrasonography and Acute Kidney Injury after TAVR

Acute kidney injury (AKI) following transcatheter aortic valve replacement (TAVR) is associated with a dismal prognosis. Elevated renal resistive index (RRI), through renal Doppler ultrasound (RDU) evaluation, has been associated with AKI development and increased systemic arterial stiffness. Our pilot study aimed to investigate the performance of Doppler based RRI to predict AKI and outcomes in TAVR patients. From May 2018 to May 2019, 100 patients with severe aortic stenosis were prospectively enrolled for TAVR and concomitant RDU evaluation at our institution (Nouvel Hôpital Civil, Strasbourg University, France). AKI by serum Creatinine (sCr-AKI) was defined according to the VARC-2 definition and AKI by serum Cystatin C (sCyC-AKI) was defined as an sCyC increase of greater than 15% with baseline value. Concomitant RRI measurements as well as renal and systemic hemodynamic parameters were recorded before, one day, and three days after TAVR. It was found that 10% of patients presented with AKI_sCr and AKI_sCyC. The whole cohort showed higher baseline RRI values (0.76 ± 0.7) compared to normal known and accepted values. AKI_sCyC had significant higher post-procedural RRI one day (Day 1) after TAVR (0.83 ± 0.1 vs. 0.77 ± 0.6, CI 95%, p = 0.005). AUC for AKI_sCyC was 0.766 and a RRI cut-off value of ≥ 0.795 had the most optimal sensitivity/specificity (80/62%) combination. By univariate Cox analysis, Mehran Risk Score, higher baseline right atrial pressure at baseline > 0.8 RRI values one day after TAVR (HR 6.5 (95% CI 1.3-32.9; p = 0.021) but not RRI at baseline were significant predictors of AKI_sCyC. Importantly, no significant impact of baseline biological parameters, renal or systemic parameters could be demonstrated. Doppler-based RRI can be helpful for the non-invasive assessment of AKI development after TAVR.

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.

Loop Diuretics in Acute Kidney Injury Prevention, Therapy, and Risk Stratification

BACKGROUND

Loop diuretics (LD) are widely used in emergency and intensive care medicine.

SUMMARY

The substances increase the clearance of electrolytes and water; thus, they allow us to control hypervolemia and to prevent patients from pulmonary edema. LD are also frequently applied to patients with an acute decrease in glomerular filtration rate, namely, acute kidney injury (AKI). Nevertheless, volume depletion may be associated with reduced renal perfusion and possibly slower restitution or even aggravation of kidney dysfunction. Several trials on the preventive or therapeutic efficacy of LD have been published since the early 1970s. Our review article is intended to summarize the most important references related to this topic. In addition, we discuss the diagnostic value of the so-called furosemide stress test. The currently available data indicate that LD may act in a beneficial manner as long as euvolemia is maintained (matched hydration). Key Massages: LD are not beneficial for AKI treatment if kidney-related endpoints are considered. In certain situations, AKI prevention with LD can be associated with favorable outcomes as long as euvolemia is maintained. LD can help to identify AKI subjects at a higher risk of AKI progression, but the exact clinical consequences need to be determined.

Impact of furosemide on mortality and the requirement for renal replacement therapy in acute kidney injury: a systematic review and meta-analysis of randomised trials

OBJECTIVE

To examine the impact of furosemide on mortality and the need for renal replacement therapy (RRT) in adult patients with acute kidney injury (AKI) based on current evidence.

DATA SOURCES

PubMed (Medline) and Embase were searched from 1998 to October 2018.

STUDY SELECTION

We retrieved data from randomised controlled trials comparing prevention/treatment with furosemide at any stage of AKI with alternative treatment/standard of care/placebo. The outcome was short-term mortality and the requirement for RRT, when applicable.

DATA EXTRACTION

Two reviewers independently extracted appropriate data. PRISMA guidelines were followed for data preparation and reporting.

DATA SYNTHESIS

We identified 20 relevant studies (2608 patients: 1330 in the treatment arm and 1278 in the control arm). Heterogeneity between studies was deemed acceptable, and the publication bias was low. Furosemide had neither an impact on mortality (OR = 1.015; 95% CI 0.825-1.339) nor the need for RRT (OR = 0.947; 95% CI 0.521-1.721). Furosemide had also no effect on the outcomes in strata defined by intervention strategy (prevention/treatment), AKI origin (cardio-renal syndrome, post-cardiopulmonary bypass, critical illness), control arm comparator (RRT, saline/placebo/standard of care) and its dose (< 160/≥ 160 mg) (p > 0.05 for all). Subjects who received furosemide with matched hydration in prevention of contrast-induced nephropathy (CIN) had a less frequent need for RRT (OR = 0.218; 95% CI 0.05-1.04; p = 0.055).

CONCLUSIONS

Furosemide administration has neither an impact on mortality nor the requirement for RRT. Patients at risk of CIN may benefit from furosemide administration. Further well-designed RCTs are needed to verify these findings.

Contrast Nephropathy Associated with Percutaneous Coronary Angiography and Intervention

Contrast nephropathy (CN) is acute kidney injury (AKI) that occurs within 24 to 72 hours of iodinated contrast medium (ICM) administration. Mechanisms of CN include hyperviscosity, free radical formation, and renal medullary oxygen supply/demand mismatch. Although risk factors for CN have been identified, it remains uncertain whether ICM causes or is simply associated with AKI. The cornerstones of CN prevention are using low-osmolal ICM, intravenous hydration, and statins, especially in patients with chronic kidney disease. With appropriate CN risk mitigation, coronary angiography and intervention should not be routinely withheld from patients with acute coronary syndromes.

Elevated high-sensitivity C-reactive protein combined with procalcitonin predicts high risk of contrast-induced nephropathy after percutaneous coronary intervention

Background

Contrast-induced nephropathy (CIN) is common after percutaneous coronary intervention (PCI) and always leads to a poor prognosis. Compared with conventional detection methods, either high-sensitivity C-reactive protein (hs-CRP) or procalcitonin have higher sensitivity and specificity for predicting CIN, but their combination has not been explored. This prospective study investigated the value of hs-CRP combined with procalcitonin for predicting CIN after PCI.

Methods

All patients undergoing PCI admitted to our hospital during the year 2016 were consecutively enrolled (n = 343). The patients received adequate hydration before PCI and 20 mg furosemide after the procedure. CIN was diagnosed by a 25% elevation in serum creatinine or ≥ 44.2 μmol/L (0.5 mg/dL) serum creatinine within 48 to 72 h after intravenous injection of contrast media.

Results

Patients with high hs-CRP or procalcitonin had higher rates of CIN relative to those patients with low values. For predicting CIN, hs-CRP combined with procalcitonin showed an area under the receiver operating characteristic curve of 0.67, with optimal cut-off value 0.0643610, and the sensitivity and specificity were higher than hs-CRP or procalcitonin alone. The logistic regression analysis showed that high-risk factors of CIN were acute myocardial infarction and highly elevated hsCRP and procalcitonin.

Conclusions

Prior to PCI, an elevation of the inflammatory biomarkers hsCRP and procalcitonin are a risk factor for postoperative CIN. This study suggests that the combination of hsCRP and procalcitonin is a better predictor of CIN after PCI then either hsCRP or procalcitonin alone.

Trial registration number

ChiCTR-IOR-14005250. Date of registration 2014-09-24.

Incidence, determinants and impact of acute kidney injury in patients with diabetes mellitus and multivessel disease undergoing coronary revascularization: Results from the FREEDOM trial

BACKGROUND

The incidence and prognostic significance of acute kidney injury (AKI) in patients with diabetes mellitus and multivessel coronary artery disease undergoing coronary revascularization is not well known. The current analysis included patients randomized to PCI vs. CABG as part of the FREEDOM trial. We sought to examine the impact of AKI and its predictors in diabetic patients with multivessel coronary artery disease undergoing PCI vs. CABG.

METHODS

We conducted a pre-specified subgroup analysis of the FREEDOM trial to examine the incidence, correlates and impact of AKI according to revascularization strategy. AKI predictors were identified using multivariable logistic regression and associations between AKI and outcomes were examined using Cox regression. The primary endpoint was the composite occurrence of all-cause death, stroke or myocardial infarction at 5 years of follow-up.

RESULTS

KI occurred more frequently in patients following CABG (15.6%) compared with PCI (9.1%) (p < 0.001). AKI was associated with a higher risk for major cardiovascular events (MACE) at 5 years (34.6% vs. 20.5%, p < 0.001), an effect that remained large and significant irrespective of CABG (HR = 2.18 95% CI 1.44-3.31, p ≤0.001) or PCI (HR = 2.08 95% CI 1.35-3.21, p < 0.0001). There was a non-significant interaction (p-value = 0.89) between the revascularization method and AKI, supporting that AKI is a significant risk factor in both revascularization methods.

CONCLUSIONS

Although risk for AKI was higher in patients undergoing CABG, the impact of AKI on MACE was substantial irrespective of revascularization strategy. Preventive strategies to identify patients at risk for AKI are warranted to mitigate the long-term effects of this complication.

Contrast-associated acute kidney injury: does it really exist, and if so, what to do about it?

For decades, when contrast agents are administrated, physicians have been concerned because of the risk of inducing acute kidney injury (AKI). Recent literature questions the existence of AKI induced by contrast, but animal studies clearly showed harmful effects. The occurrence of contrast-associated AKI was likely overestimated in the past because of confounders for AKI. Several strategies have been investigated to reduce contrast-associated AKI but even for the most important one, hydration, there are conflicting data. Even if the occurrence rate of contrast-associated AKI is low, AKI is related to worse outcomes. Therefore, besides limiting contrast agent usage, general AKI preventive measurements should be applied in at-risk patients.

Contrast induced nephropathy after coronary or vascular intervention: More biomarkers than answers

Rising urine NGAL and serum creatinine after 48 hr are potentially useful in predicting persistent creatinine increase in patients with contrast-induced AKI. Urinary NGAL may allow for early identification of a high-risk cohort following PCI. Future studies are needed to determine whether renal biomarkers are affected by clinical variables, such as heart failure acute mechanical circulatory support (AMCS) and whether they can be used to identify patients who would benefit from either AMCS reno-protection during PCI remains unknown.

Safety and Efficacy of Tolvaptan for the Prevention of Contrast-Induced Acute Kidney Injury in Patients with Heart Failure and Chronic Kidney Disease

Background

Tolvaptan is a promising drug for the prevention of contrast-induced acute kidney injury (CI-AKI) because it induces aquaresis without adversely affecting renal hemodynamics. CI-AKI is a major cause of acute renal failure associated with increased morbidity and mortality.

Objective

To investigate the effectiveness of different doses of tolvaptan for the prevention of CI-AKI.

Method

Ninety-one consecutive patients with congestive heart failure (CHF) and chronic kidney disease (CKD) were prospectively enrolled as the tolvaptan group in this study (T-group; 7.5-mg: n = 42, 15-mg: n = 49). In addition, 91 consecutive patients with CHF and CKD were collected retrospectively as a control group (C-group, n = 91). All patients received continuous intravenous infusion of isotonic saline, and tolvaptan was administered to the T-group.

Results

One patient developed CI-AKI in the T-group versus 3 in the C-group (1.1 vs. 3.3%, p = 0.61). On the other hand, the change of serum creatinine in the T-group was lower than that in the C-group. Additionally, in the 7.5-mg group, serum creatinine was unchanged up to 72 h after contrast administration, showing a significant difference from the 15-mg group (-0.00 ± 0.09 vs. 0.05 ± 0.12 mg/dL, p = 0.009). Similarly, the change of eGFR was significantly smaller in the 7.5-mg group than that in the 15-mg group (0.7 ± 5.4 vs. -2.8 ± 5.1 mL/min/1.73 m², p = 0.002). No patient required hemodialysis and there was no prolongation of hospitalization due to exacerbation of heart failure.

Conclusions

Compared to hydration alone, tolvaptan combined with hydration could be a safer method for preventing CI-AKI while avoiding exacerbation of heart failure, and a dosage of 7.5-mg might be safer than 15-mg.

[Kidney function in contrast media-enhanced imaging]

BACKGROUND

The potential adverse reactions to contrast media-enhanced imaging regularly offer challenges in decision-making for nephrologists and radiologists.

OBJECTIVE

The clinical pictures of contrast media-induced acute kidney injury (CI-AKI) and nephrogenic systemic fibrosis (NSF) were evaluated, which are both caused by contrast media and closely linked to the kidney function.

MATERIAL AND METHODS

The literature in PubMed and Medline was searched for the terms "kidney function" and "contrast media" and complemented by our own experiences.

RESULTS

While there is an ongoing re-evaluation of the clinical relevance of CI-AKI, no new cases of NSF have recently been reported under consideration of certain preventive interventions and very restricted use of gadolinium-based contrast agents.

CONCLUSION

Considering the results of the latest clinical research, the potential risk of CI-AKI has been overestimated for a long time and should no longer outweigh the diagnostic benefit of contrast media-enhanced imaging. Nevertheless, the most effective prophylaxis for CI-AKI is the avoidance of unnecessary administration of contrast media.

Cardiopulmonary Bypass and AKI: AKI Is Bad, So Let's Get Beyond the Diagnosis

It is now well-established that AKI is a serious and common complication following cardiopulmonary bypass (CPB) in both children and adults, adverse outcomes may occur in the short term as well as long term, with higher incidence of chronic kidney disease, increased healthcare utilization and higher frequency of cardiovascular events in patients who develop post-CPB AKI. Despite the advances in our understanding of the pathogenesis of the disease and the improvement in diagnostic tools, our therapeutic options have remained suboptimal. There are multiple challenges in designing a clinical therapeutic AKI trial, including a multi-factorial etiology, difficulties with accurate diagnosis of AKI, achievement of adequate study power, and determination of appropriate outcomes. We are often left with "supportive" care. Studies have shown some benefit to AKI bundles, but adherence to bundle guidelines may be suboptimal. Current best practices should include maintenance of adequate renal perfusion pressure and avoidance of fluid overload, with consideration of early renal replacement therapy. Finally, multi-center trials of AKI therapies are crucial to finding treatment for this devastating complication of CPB.