Contrast-induced acute kidney injury in interventional cardiology: Emerging evidence and unifying mechanisms of protection by remote ischemic conditioning

A wide scope, pan-comparative, systematic meta-analysis of the efficacy of prophylactic strategies for cardiac surgery-associated acute kidney injury

Acute kidney injury (AKI) is the most common complication of cardiac surgery. Cardiac surgery-associated AKI (CSA-AKI) is caused by systemic and renal hemodynamic impairment and parenchymal injury. Prophylaxis of CSA-AKI remains an unmet priority, for which preventive strategies based on drug therapies, hydration procedures, and remote ischemic preconditioning (RIPC) have been tested in pre-clinical and clinical studies, with variable success. Contradicting reports and scarce or insufficiently pondered information have blurred conclusions. Therefore, with an aim to contribute to consolidating the available information, we carried out a wide scope, pan-comparative meta-analysis including the accessible information about the most relevant nephroprotective approaches assayed. After a thorough examination of 1892 documents retrieved from PubMed and Web of Science, 150 studies were used for the meta-analysis. Individual odds ratios of efficacy at reducing AKI incidence, need for dialysis, and plasma creatinine elevation were obtained for each alleged protectant. Also, the combined class effect of drug families and protective strategies was also meta-analyzed. Our results show that no drug family or procedure affords substantial protection against CSA-AKI. Only, a mild but significant reduction in the incidence of CSA-AKI by preemptive treatment with dopaminergic and adrenergic drugs, vasodilators, and the RIPC technique. The integrated analysis suggests that single-drug approaches are unlikely to cope with the variety of individual pathophysiological scenarios potentially underlying CSA-AKI. Accordingly, a theragnostic approach involving the etiopathological diagnosis of kidney frailty is necessary to guide research towards the development of pharmacological combinations concomitantly and effectively addressing the key mechanisms of CSA-AKI.

P16INK4a deletion alleviates contrast-induced acute kidney injury by ameliorating renal cell apoptosis and suppressing inflammation and oxidative stress

Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of hospital-acquired acute kidney injury. Cellular senescence is associated with CI-AKI. P16INK4a (p16) is a cell cycle regulator and link to aging and senescence. We found that the expression of p16 was elevated in CI-AKI renal tissues, however its role in CI-AKI remains insufficiently understood. In this study, we used p16 knockout (p16KO) mice and wild-type (WT) littermates to establish CI-AKI mice model to elucidate the impact of p16 on CI-AKI. The results showed that serum creatinine (SCr), blood urea nitrogen (BUN), and serum neutrophil gelatinase-associated lipocalin (NGAL) levels were markedly reduced in p16KO CI-AKI mice. Both immunohistochemistry and western blot analyses confirmed that p16 knockout alleviated renal cell apoptosis. Furthermore, interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) were attenuated by downregulating NLRP3 and NF-κB inflammasomes. Additionally, ROS levels were diminished via activating Nrf2/Keap-1 pathway in p16KO CI-AKI mice. Collectively, our findings suggest that p16 deletion exerts protective effects against apoptosis, inflammation, and oxidative stress in CI-AKI mice model, p16 deletion might be a potential therapeutic strategy for ameliorating CI-AKI.

Trends in Percutaneous Balloon Mitral Valvuloplasty Complications for Mitral Stenosis in the United States (the National Inpatient Sample [2008 to 2018])

The epidemiology of mitral stenosis (MS) continues to evolve in the United States. Although the incidence of rheumatic MS has decreased in high-income countries, there is a paucity of data surrounding trends in percutaneous balloon mitral valvuloplasty (PBMV), the current first-line management strategy. This study aimed to identify contemporary trends in PBMV in the United States. Hospitalizations for adults (≥18 years) with MS who underwent PBMV were identified from the National Inpatient Sample from 2008 to 2018. Baseline co-morbidities and outcomes over the study period were determined using Poisson regression. There were 3,980 weighted PBMV cases, 70% of which were women. PBMV hospitalizations decreased from 603 in 2008 to 210 in 2018 (p <0.001). From 2008 to 2018, the age at hospitalization was unchanged in both female and male patients. In contrast, the Charlson Co-morbidity Index increased in both. Baseline heart failure (39% to 64%), hypertension (38% to 43%), and diabetes mellitus (17% to 26%) all substantially increased over the study period. In-hospital mortality occurred in 2% of female and 5% of male patients and was unchanged from 2008 to 2018. Vascular complications (12%) and acute kidney injury (10%) were the most frequent postprocedural complications during the 11-year study period. A composite of mortality or any postprocedural complication did not vary by gender (odds ratio 1.23, 95% confidence interval 0.88 to 1.72). In conclusion, the use of PBMV significantly decreased from 2008 to 2018, and patients with MS who underwent PBMV over this period had an increased burden of co-morbidities, elevated postprocedural complication rate, and no change in in-hospital mortality.

Risk factors for acute renal injury caused by contrast media after percutaneous coronary intervention and coronary angiography: A protocol for systematic review and meta-analysis

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) caused by contrast medium is one of the common complications of percutaneous coronary intervention (PCI)/coronary angiography (CAG). Early identification of the risk factors of CI-AKI in patients with PCI/CAG and help clinical staff to prevent and intervene as soon as possible is very important to improve the clinical outcome of patients. Although domestic and foreign scholars have studied and summarized the risk factors of CI-AKI in PCI/CAG, the conclusions are not the same. Therefore, in this study, meta-analysis was used to summarize the risk factors of CI-AKI in patients with PCI/CAG, and to explore the characteristics of high-risk groups of CI-AKI, to provide reference for early identification and prevention of clinical doctors and nurses.

METHODS

We will search related literature of PubMed, Embase, Cochrane Library, Web of Science, China Biology Medicine Database, China National Knowledge Infrastructure, China Science and Technology Journal Database, and Wanfang Database. Eligible studies will be screened based on inclusion criteria, and data extraction, risk of bias assessment, publication bias assessment, subgroup analysis, and quality assessment will be performed. Review Manager version 5.3 software will be used for data analysis. Each process is independently conducted by 2 researchers, and if there is any objection, it will be submitted to the third researcher for resolution.

RESULTS

We will disseminate the findings of this systematic review and meta-analysis via publications in peer-reviewed journals.

CONCLUSIONS

The results of this analysis can be used to generate a risk prediction model and provide an intervention strategy for the occurrence of CI-AKI in PCI/CAG.

Clinical Utility of a Biomarker to Detect Contrast-Induced Acute Kidney Injury during Percutaneous Cardiovascular Procedures

INTRODUCTION

Contrast-induced acute kidney injury (CI-AKI) is a major clinical complication of percutaneous cardiovascular procedures requiring iodinated contrast. Despite its relative frequency, practicing physicians are unlikely to identify or treat this condition.

METHODS

In a 2-round clinical trial of simulated patients, we examined the clinical utility of a urine-based assay that measures liver-type fatty acid-binding protein (L-FABP), a novel marker of CI-AKI. We sought to determine if interventional cardiologists' ability to diagnose and treat potential CI-AKI improved using the biomarker assay for 3 different patient types: pre-procedure, peri-procedure, and post-procedure patients.

RESULTS

154 participating cardiologists were randomly divided into either control or intervention. At baseline, we found no difference in the demographics or how they identified and treated potential complications of AKI, with both groups providing less than half the necessary care to their patients (46.4% for control vs. 47.6% for intervention, p = 0.250). The introduction of L-FABP into patient care resulted in a statistically significant improvement of 4.6% (p = 0.001). Compared to controls, physicians receiving L-FABP results were 2.9 times more likely to correctly identify their patients' risk for AKI (95% CI 2.1-4.0) and were more than twice as likely to treat for AKI by providing volume expansion and withholding nephrotoxic medications. We found the greatest clinical utility in the pre-procedure and peri-procedure settings but limited value in the post-procedure setting.

CONCLUSION

This study suggests L-FABP as a clinical marker for assessing the risk of potential CI-AKI, has clinical utility, and can lead to more accurate diagnosis and treatment.

Contrast-induced nephropathy in non-cardiac vascular procedures, a narrative review: Part 1

Contrast-induced nephropathy (CIN) is an important complication of iodinated contrast medium (CM) administration, which is associated with both short- and long-term adverse outcomes (e.g., cardiorenal events, longer hospital stay, and mortality). CIN has been mainly studied in relation to cardiac procedures, but it can also occur following non-cardiac vascular interventions. This is Part 1 of a narrative review summarizing the available literature on CIN after non-cardiac vascular diagnostic or therapeutic procedures for aortic aneurysm and carotid stenosis. We discuss the definition, pathophysiology, incidence, risk factors, biomarkers, and consequences of CIN in these settings, as well as preventive strategies and alternatives to limit iodinated CM use. Physicians and vascular surgeons should be aware of CM-related adverse events and the potential strategies to avoid them. Clearly, more research in this important field is required.

Melatonin Alleviates Contrast-Induced Acute Kidney Injury by Activation of Sirt3

Oxidative stress and apoptosis play a vital role in the pathogenesis of contrast-induced acute kidney injury (CI-AKI). The purpose of our study was to investigate the protective effects and mechanisms of melatonin against CI-AKI in a CI-AKI mouse model and NRK-52E cells. We established the CI-AKI model in mice, and the animals were pretreated with melatonin (20 mg/kg). Our results demonstrated that melatonin treatment exerted a renoprotective effect by decreasing the level of serum creatinine (SCr) and blood urea nitrogen (BUN), lessening the histological changes of renal tubular injuries, and reducing the expression of neutrophil gelatinase-associated lipid (NGAL), a marker of kidney injury. We also found that pretreatment with melatonin remarkably increased the expression of Sirt3 and decreased the ac-SOD2 K68 level. Consequently, melatonin treatment significantly decreased the oxidative stress by reducing the Nox4, ROS, and malondialdehyde (MDA) content and by increasing the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity levels. The antiapoptotic effect of melatonin on CI-AKI was revealed by decreasing the ratio of Bax/Bcl2 and the cleaved caspase3 level and by reducing the number of apoptosis-positive tubular cells. In addition, melatonin treatment remarkably reduced the inflammatory cytokines of interleukin-1β (IL-1β), tumor necrosis factor α (TNFα), and transforming growth factor β (TGFβ) in vivo and in vitro. Sirt3 deletion and specific Sirt3 siRNA abolished the above renoprotective effects of melatonin in mice with iohexol-induced acute kidney injury and in NRK-52E cells. Thus, our results demonstrated that melatonin exhibited the renoprotective effects of antioxidative stress, antiapoptosis, and anti-inflammation by the activation of Sirt3 in the CI-AKI model in vivo and in vitro. Melatonin may be a potential drug to ameliorate CI-AKI in clinical practice.

The prophylactic effect of alprostadil on contrast-induced nephropathy in renal insufficiency patients after percutaneous coronary intervention

OBJECTIVES

This study explored and analyzed the prophylactic effect of Alprostadil on contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI) in patients with renal insufficiency.

METHODS

From June 2014 to June 2017, 156 patients with coronary artery disease and renal insufficiency who electively underwent PCI in our hospital were enrolled and randomly divided into Alprostadil group (n=77) and placebo control group (n=79) by random number table. The control group was given hydration and placebo, while the observation group received hydration and Alprostadil. The alprostadil and placebo were infused intravenously 30-90 minutes before operation until four hours after surgery. The changes of biochemical indicators, serum creatinine (Scr), glomerular filtration rate (GFR), the level of neutrophil gelatinase-associated lipocalin (NGAL) in urinary neutrophils, and the incidence of CIN were compared between the two groups of patients before and after PCI surgery.

RESULTS

The difference of SCr and GFR between the two groups of patients was statistical insignificant before and after PCI surgery (P>0.05), while the level of NGAL in both groups 12 h and 24 h after operation were critically higher than those prior-operation (P<0.05), and the increase in the control group was more obvious (P<0.05). The serum CysC, Hcy, and hs-CRP levels of the two groups 24 h after surgery were remarkably higher than those before surgery (P<0.05), and the indicators in observation group were superior to those in control group after surgery (P<0.05). The difference between the two groups of patients in incidence of CIN primary endpoint was statistically insignificant (P>0.05), while the incidence of secondary endpoint of CIN ≥ 0.3 mg/dL in Alprostadil group was significantly lower than that in control group (P<0.05).

CONCLUSION

For renal insufficiency patients undergoing PCI, the associative usage of Alpromazil with routine treatment can effectively prevent CIN and is worthy of clinical promotion.

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.

Limb ischemic preconditioning ameliorates renal microcirculation through activation of PI3K/Akt/eNOS signaling pathway after acute kidney injury

Purpose

Contrast-induced acute kidney injury (CI-AKI) resulting from administration of iodinated contrast media (CM) is the third leading cause of hospital-acquired acute kidney injury and is associated with substantial morbidity and mortality. Deteriorated renal microcirculation plays an important role in CI-AKI. Limb ischemic preconditioning (LIPC), where brief and non-injurious ischemia/reperfusion is applied to a limb prior to the administration of the contrast agent, is emerging as a promising strategy for CI-AKI prevention. However, it is not known whether the renal protection of LIPC against CI-AKI is mediated by regulation of renal microcirculation and the molecular mechanisms remain largely unknown.

Methods

In this study, we examined the renal cortical and medullary blood flow in a stable CI-AKI model using 5/6-nephrectomized (NE) rat. The LIPC and sham procedures were performed prior to the injection of CM. Furthermore, we analyzed renal medulla hypoxia using in vivo labeling of hypoxyprobe. Pharmacological inhibitions and western blotting were used to determine the underlying molecular mechanisms.

Results

In this study, we found LIPC significantly ameliorated CM-induced reduction of medullary blood flow and attenuated CM-induced hypoxia. PI3K inhibitor (wortmannin) treatment blocked the regulation of medullary blood flow and the attenuation of hypoxia of LIPC. Phosphorylation of Akt/eNOS was significantly decreased via wortmannin treatment compared with LIPC. Nitric oxide synthase-inhibitor [Nω-nitro-l-arginine methyl ester (L-NAME)] treatment abolished the above effects and decreased phosphorylation of eNOS, but not Akt.

Conclusions

Collectively, the results demonstrate that LIPC ameliorates CM-induced renal vasocontraction and is mediated by activation of PI3K/Akt/eNOS signaling pathway.

Cordyceps sinensis prevents contrast-induced nephropathy in diabetic rats: its underlying mechanism

Apoptosis is recognized as an important mechanism in contrast-induced nephropathy (CIN). This study investigated the renal protective effect of cordyceps sinensis (CS) in a diabetic rat model of CIN and the mechanism of its effect. Sixty SD rats were randomly divided into 4 groups, the control group, model group, probucol group, and CS group. We used a diabetic rat model of Iodixanol-induced CIN. Serum creatinine (Scr), blood urea nitrogen (BUN), urinary kidney injury molecule-1 (KIM-1), neutrophil gelatinase associated lipocalin (NGAL) levels were measured to evaluate renal function. Total antioxidative ability (T-AOC), superoxide dismutase (SOD), and malonaldehyde (MDA) levels were assessed to discuss the effect of probucol and CS on oxidative stress. The pathologic changes in the kidney were observed by hematoxylin and eosin (HE) staining and periodic acid-Schiff (PAS) staining. Apoptosis was assessed by transmission electron microscopy and TUNEL staining. Caspase-3, Bax, Bcl2 and phospho-p38 mitogen-activated protein kinase (MAPK) protein expressions were assessed by Western blotting. The model group of rats showed significantly elevated levels of BUN, Scr, urinary KIM-1, NGAL, and parameters of oxidative stress (P<0.05). Both the probucol and CS groups demonstrated significantly lower Scr, BUN, and urinary KIM-1, NGAL levels compared to the model group (P<0.05), with no significant difference between these two groups. The probucol group and the CS group had significantly lower MDA and higher T-AOC, SOD than the model group after modeling (P<0.05). Caspase-3, Bax activation were effectively repressed while Bcl-2 expression was increased by probucol and CS pretreatment. Mechanistically, probucol and CS decreased the expression of JNK protein and increased the expression of ERK protein. CS can effectively reduce kidney damage caused by contrast medium. The underlying mechanism may be that CS accelerates the recovery of renal function and renal pathology by reducing local renal oxidative stress and influencing MAPK signal pathways.

The Value of Adding Red Cell Distribution Width to Mehran Risk Score to Predict Contrast-induced Acute Kidney Injury in Patients with Acute Coronary Syndrome

Background: Contrast-induced acute kidney injury (CI-AKI) is a relatively reversible cause of acute kidney injury (AKI) that occurs after radiocontrast media administration. It is a common complication after percutaneous coronary intervention, especially in patients with acute coronary syndrome (ACS). The aim of this study is to determine the utility of red cell distribution width (RDW) in predicting CI-AKI in patients with ACS and to determine the value of adding RDW to the Mehran risk score (MRS) on admission.

Methods: A total of 161 patients who presented with ST-elevation myocardial infarction (STEMI) or non-STEMI were identified retrospectively between January 2015 and December 2016. Patients were divided into two groups, those who developed CI-AKI after percutaneous coronary intervention (PCI) and those who did not.

Results: A total of 161 patients were analyzed. Of them, 12 developed CI-AKI (eight presented with STEMI and four presented with non-STEMI). RDW did not correlate with the development of CI-AKI (14.55 ± 1.48 vs 14.83 ± 1.21; p = 0.072). The areas under the receiver operating characteristic curves (ROCs) for RDW, MRS, and the combined model (MRS and RDW) for the prediction of CI-AKI were 0.721 (95% confidence interval (CI), 0.645 to 0.788; p=0.0024), 0.885 (95% CI, 0.825 to 0.930; p<0.0001), 0.890 (95% CI, 0.831 to 0.933; p<0.0001), respectively. Pairwise comparisons between ROCs for MRS vs the combined model yielded a non-significant p-value of 0.49. This signifies no added benefit for RDW to MRS for predicting CI-AKI.

Conclusion: RDW does not correlate with the development of CI-AKI in patients with ACS. The Mehran risk score remains a better indicator of CI-AKI risk assessment with no role for the addition of RDW to it. Further studies are needed to better assess predictors of CI-AKI in patients undergoing percutaneous coronary intervention.

Limb remote ischemic conditioning of the recipient protects the liver in a rat model of arterialized orthotopic liver transplantation

Background

Ischemic-reperfusion (IR) injury still represents a major concern in clinical transplantation, especially in the era of extreme organ shortage and extended criteria donor organs. In the present study we aimed to investigate the hepatoprotective effects of remote ischemic conditioning (RIC) in a rat model of arterialized orthotopic liver transplantation (OLT).

Methods

Male Lewis rats were used (n = 144 / 72 OLT cases; 240–340g) as donors and recipients. Livers were flushed and stored in 4°C HTK-solution for 8h before implantation. Recipients were randomly allocated into three experimental groups: RIC 1, RIC 2, Control. In RIC 1, RIC 2 groups, RIC was applied in the recipient before hepatectomy or after reperfusion (4x5-5min IR via clamping the infrarenal aorta), respectively. Animals were sacrificed at 1, 3, 24, 168h post-reperfusion (n = 6 recipient/group/time point). Hepatocellular injury, graft circulation, serum cytokines, tissue redox-stress and adenosine-triphosphate (ATP) levels have been assessed. Additional markers were analyzed, using Western blotting and reverse-transcription polymerase chain reaction.

Results

RIC 1 group showed significantly (p<0.05) improved portal venous and microcirculation flow as well as velocity. RIC has significantly reduced tissue injury according to the serum levels of transaminases and results of histopathological evaluation. Reduced TUNEL-staining (p<0.01 RIC 1–2 vs. Control) and elevated pBAD/BAD ratio was detected in the RIC groups (p<0.01 RIC 1 vs. Control). Supporting findings were obtained from measurements of serum IL-10 as well as tissue malondialdehyde and ATP levels. Hemoxygenase-1 (HO-1) mRNA-expression was significantly higher in RIC 1 compared to Control (p<0.05 RIC 1 vs. Control).

Conclusion

These results suggest that RIC might confer potent protection against the detrimental effects of IR injury including tissue damage, apoptosis, graft circulation, inflammation, tissue energetic status in OLT. HO-1 overexpression might play an orchestrating role in RIC mediated organ protection. An earlier intervention (RIC 1 protocol) was more effective than remote conditioning after graft reperfusion.

Nicorandil for the prevention of contrast-induced nephropathy: A meta-analysis of randomized controlled trials

INTRODUCTION

Nicorandil has been suggested as a preventative strategy against the incidence of contrast-induced nephropathy (CIN). However, results of relevant randomized controlled trials (RCTs) were inconsistent.

AIMS

We performed a meta-analysis of RCTs to evaluate the preventive efficacy of periprocedural treatment of nicorandil against the incidence of CIN.

METHODS

Relevant RCTs were identified via search of PubMed, Embase, and Cochrane's Library databases. Results were pooled using a random-effect model. Subgroup analyses were performed to evaluate the potential influence of administering routes on the efficacy of nicorandil against CIN incidence.

RESULTS

Four RCTs with 709 patients were included. Treatment of nicorandil significantly reduced the incidence of CIN as compared with controls (risk ration [RR]: 0.38, 95% confidence interval [CI]: 0.19 ~ 0.74, P = .005) with moderate heterogeneity (I²  = 33%). Results of subsequent subgroup analysis showed that nicorandil significantly reduced the risk of CIN if orally administered (RR: 0.32, P < .001), but did not if intravenously administered (RR: 0.47, I²  = 68%). Moreover, treatment with nicorandil was associated with significantly less increment of SCr (weight mean difference [WMD]: -3.98%, P < .001) and a tendency of less increment of cystatin C (WMD: -3.86%, P = .08) after 48-hour contrast exposure as compared with controls.

CONCLUSIONS

Periprocedural treatment with nicorandil may be preventative against the incidence of CIN in patients undergoing contrast exposure. The influence of periprocedural nicorandil on clinical outcome in these patients deserves further investigation.