Radiocontrast-induced nephrotoxicity and urinary alpha-glutathione S-transferase levels: effect of amlodipine administration

Navigating nephrotoxic waters: A comprehensive overview of contrast-induced acute kidney injury prevention

Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of acute kidney injury deriving from the intravascular administration of contrast media in diagnostic and therapeutic procedures and leading to longer in-hospital stay and increased short and long-term mortality. Its pathophysiology, although not well-established, revolves around medullary hypoxia paired with the direct toxicity of the substance to the kidney. Critically ill patients, as well as those with pre-existing renal disease and cardiovascular comorbidities, are more susceptible to CI-AKI. Despite the continuous research in the field of CI-AKI prevention, clinical practice is based mostly on periprocedural hydration. In this review, all the investigated methods of prevention are presented, with an emphasis on the latest evidence regarding the potential of RenalGuard and contrast removal systems for CI-AKI prevention in high-risk individuals.

Microvascular resistance in response to iodinated contrast media in normal and functionally impaired kidneys

Contrast‐induced nephropathy (CIN) is considered to result from intrarenal vasoconstriction, and occurs more frequently in impaired than in normal kidneys. It was hypothesized that iodinated contrast media would markedly change renal blood flow and vascular resistance in functionally impaired kidneys. Thirty‐six patients were enrolled (32 men; mean age, 75.3 ± 7.6 years) undergoing diagnostic coronary angiography and were divided into two groups based on the presence of chronic kidney disease (CKD), defined as an estimated glomerular filtration rate (eGFR) of < 60 mL/min per 1.73 m² (CKD and non‐CKD groups, n = 18 in both). Average peak velocity (APV) and renal artery resistance index (RI) were measured by Doppler flow wire before and after administration of the iodinated contrast media. The APV and the RI were positively and inversely correlated with the eGFR at baseline, respectively (APV, R = 0.545, P = 0.001; RI, R = −0.627, P < 0.001). Mean RI was significantly higher (P = 0.015) and APV was significantly lower (P = 0.026) in the CKD than in the non‐CKD group. Both APV (P < 0.001) and RI (P = 0.002) were significantly changed following contrast media administration in the non‐CKD group, but not in the CKD group (APV, P = 0.258; RI, P = 0.707). Although renal arterial resistance was higher in patients with CKD, it was not affected by contrast media administration, suggesting that patients with CKD could have an attenuated response to contrast media.

Risk factors for hemodialysis and mortality in patients with contrast-induced nephropathy

The purpose of this study was to identify risk factors for renal failure requiring hemodialysis and mortality in patients who developed contrast-induced nephropathy (CIN) after cardiac catheterization. Out of 13,742 patients who received cardiac catheterization at Westchester Medical Center/New York Medical College from 2005 to 2008, 268 patients (2%) with a discharge diagnosis of renal failure were screened for CIN. CIN was defined as either a >25% increase of the serum creatinine or an absolute increase in serum creatinine of 0.5 mg/dL within the first 48 hours of the procedure. Chart reviews were performed on 80 patients (1%) who met the criteria for CIN. The 80 patients in the study included 46 men and 34 women, mean age 69 ± 14 years. Of the 80 patients, 18 patients (23%) died, and 22 patients (28%) developed renal failure requiring hemodialysis. Stepwise logistic regression analysis showed that independent risk factors for mortality were the use of calcium channel blockers [odds ratio = 0.0025, 95% confidence interval (CI), 0.0001-0.1210, P < 0.01], catecholamine use (odds ratio = 71.2177, 95% CI, 4.2153-1203, P < 0.01), circulatory failure with lactic acidosis (odds ratio = 32.1405, 95% CI, 2.6331-392, P < 0.01), and renal failure requiring hemodialysis (odds ratio = 17.0376, 95% CI, 1.2344-235, P < 0.05). Significant independent risk factors for renal failure requiring hemodialysis were smoking (odds ratio = 0.06, 95% CI, 0.0045-0.8080, P < 0.05), N-acetylcysteine use (odds ratio = 0.08, 95% CI, 0.0148-0.4179, P < 0.01), anemia (odds ratio = 11.32, 95% CI, 2.57-50, P < 0.01), and circulatory failure with lactic acidosis (odds ratio = 9.76, 95% CI, 2.37-40, P < 0.01). Our data showed that risk factors for mortality in patients with CIN were catecholamine use, circulatory failure with lactic acidosis, and renal failure requiring hemodialysis. Risk factor for reducing mortality in patients with CIN was calcium channel blocker use. Significant risk factors for renal failure requiring hemodialysis were anemia, and circulatory failure with lactic acidosis. Risk factors for reducing renal failure requiring hemodialysis were N-acetylcysteine use and smoking.

Cardiological Society of India practice guidelines for angiography in patients with renal dysfunction

PREAMBLE: The potential risk of contrast-induced acute kidney injury (CI-AKI) has made utilization of coronary angiography in the work-up for the diagnosis of coronary artery disease in CKD quite low.(1) This is in contrast to increasing prevalence and severity of CAD as the serum creatinine rises.(2) In fact most CKD patients will succumb to CAD and not to ESRD.(3) Thus the judicious use of CAG/PCI in this setting is of prime importance but underused. The CSI began to develop guidelines for Indian context as most guidelines are those developed by ACC/AHA or ESC. The aim was to assist the physicians in selecting the best management strategy for an individual patient under his care based on an expert committee who would review the current data and write the guidelines with relevance to the Indian context. The guidelines were developed initially in June 2010 as an initiative of Delhi CSI. Three interventional cardiologist (SB, AS, KKS), one nephrologist (SCT) and two clinical cardiologists (ST, RG) along with Dr. Roxana Mehran (New York) and Dr. Peter McCullough (Missouri), U.S.A.; were involved in a three-way teleconference to discuss/debate the data. This was presented by SB, and over the next two hours each data subset was debated/agreed/deleted and this resulted in the "Guidelines for CAG in Renal Dysfunction Patients". These were then written and re- circulated to all for final comments. Further, these guidelines were updated and additional Task Force Members nominated by Central CSI were involved in the formation of the final CSI Guidelines. Both (Roxana Mehran and Peter McCullough) reviewed these updated Guidelines in October 2012 and after incorporating the views of all the Task Force members-the final format is as it is presented in this final document.

Effects of human Umbilical Cord Stem Cells and Granulocyte Colony- Stimulating Factor (G-CSF) on Carbon Tetrachloride-Induced Nephrotoxicity

Abstract

Background: Recently, stem cells have been used to facilitate healing in animal models of renal failure induced by acute ischemic and nephrotoxic damage. Granulocyte colony-stimulating factor (G-CSF) has been reported to stimulate stem cell mobilization from bone marrow and these cells may contribute to renal repair.

Objectives: In the present study, the effects of G-CSF and stem cell administration as monotherapy or in combination, and the relation of these effects with the duration of therapy, have been investigated in an experimental rat model of carbon tetrachloride (CCl₄)-induced nephrotoxicity.

Materials and Methods: The fifty rats included in the study were distributed into 4 main groups, Group 1, 2, 3, and 4, and two subgroups for each group, except for Group 1. All rats received an intraperitoneal injection of CCl₄. Then at 6 h, Groups 1, 2a, 3a, and 4a were administered saline, stem cells, G-CSF, and stem cell plus G-CSF, respectively. At 24 h, Groups 2b, 3b, and 4b were administered stem cells, G-CSF, and stem cell plus G-CSF, respectively. All animals were sacrificed 48 h after the CCl₄ injections. Serum urea, creatinine, sodium, and potassium levels were measured from blood samples. Tissue α-glutathione S-transferase (GST) levels were also measured from renal tissues.

Results: Serum urea was reduced in all groups when compared to Group 1, but the decrease was statistically significant only in Group 3b (P = 0.04). Serum creatinine and sodium levels were similar in all groups (P > 0.05). Tissue GST levels were lower in all groups, but the reduction was significant only in Group 4a, which was administered stem cells + G-CSF at 6 h (P = 0.01). Tubular degeneration and/or tubular dilatation were the most common pathologic changes, and their incidence was similar in all groups (P > 0.05).

Conclusions: Although both stem cell and G-CSF monotherapy led to damage reduction, the effect was not significant. However, the reduced damage by the combined use of stem cells and G-CSF, particularly during the early period, was statistically significant.

Contrast induced nephropathy in urology

Intravenous contrast agents have a distinct role in urological imaging: to study precise anatomical delineation, vascularity, and to assess the function of the renal unit. Contrast induced nephropathy (CIN) is a known adverse effect of intravenous contrast administration. The literature on incidence, pathophysiology, clinical features, and current preventive strategies available for CIN relevant to urologists was reviewed. A search of the PubMed database was done using the keywords nephropathy and media, prevention and control or prevention Contrast media (explode), all adverse effects, and kidney diseases (explode). An online search of the EMBASE database for the time ranging from 1977 to February 2009 was performed using the keywords ionic contrast medium, adverse drug reaction, major or controlled clinical study, human, nephrotoxicity, and kidney disease. Current publications and data most relevant to urologists were examined. CIN was the third most common cause of hospital-acquired renal failure. The incidence is less common with intravenous contrast administration as compared with intra-arterial administration. The pathogenesis of contrast mediated nephropathy is due to a combination of toxic injury to renal tubules and medullary ischemic injury mediated by reactive oxygen species. CIN most commonly manifests as a nonoliguric and asymptomatic transient decline in renal function. Patients who developed CIN were found to have increased mortality, longer hospital stay, and complicated clinical course. An overview of risk factors and risk prediction score for prognostication of CIN are elaborated. Preventive strategies including choice of contrast agents, maximum tolerated dose, role of hydration, hydration regime, etc. are discussed. The role of N- acetyl cysteine, Theophylline, Fenoldapam, Endothelin receptor antagonists, iloprost, atrial natriuretic peptide, and newer therapies such as targeted renal therapy (TRT) are discussed. A working algorithm based on current evidence is proposed. No current treatment can reverse or ameliorate CIN once it occurs, but prophylaxis is possible.

Contrast-induced nephropathy in interventional cardiology

Development of contrast-induced nephropathy (CIN), ie, a rise in serum creatinine by either ≥0.5 mg/dL or by ≥25% from baseline within the first 2-3 days after contrast administration, is strongly associated with both increased inhospital and late morbidity and mortality after invasive cardiac procedures. The prevention of CIN is critical if long-term outcomes are to be optimized after percutaneous coronary intervention. The prevalence of CIN in patients receiving contrast varies markedly (from <1% to 50%), depending on the presence of well characterized risk factors, the most important of which are baseline chronic renal insufficiency and diabetes mellitus. Other risk factors include advanced age, anemia, left ventricular dysfunction, dehydration, hypotension, renal transplant, low serum albumin, concomitant use of nephrotoxins, and the volume of contrast agent. The pathophysiology of CIN is likely to be multifactorial, including direct cytotoxicity, apoptosis, disturbances in intrarenal hemodynamics, and immune mechanisms. Few strategies have been shown to be effective to prevent CIN beyond hydration, the goal of which is to establish brisk diuresis prior to contrast administration, and to avoid hypotension. New strategies of controlled hydration and diuresis are promising. Studies are mixed on whether prophylactic oral N-acetylcysteine reduces the incidence of CIN, although its use is generally recommended, given its low cost and favorable side effect profile. Agents which have been shown to be ineffective or harmful, or for which data supporting routine use do not exist, include fenoldopam, theophylline, dopamine, calcium channel blockers, prostaglandin E(1), atrial natriuretic peptide, statins, and angiotensin-converting enzyme inhibitors.

A comparison of sodium bicarbonate infusion versus normal saline infusion and its combination with oral acetazolamide for prevention of contrast-induced nephropathy: a randomized, double-blind trial

BACKGROUND

Contrast-induced nephropathy (CIN) is commonly encountered. Because the therapy of choice for prevention of CIN is controversial, in this study we compared the preventive efficacy of bicarbonate (Bi) infusion in dextrose water versus normal saline (NLS) infusion alone or in combination with oral acetazolamide (AZ).

METHODS

In a double-blind and randomized clinical trial, all patients undergoing coronary angiography or percutaneous coronary intervention received NLS (NLS group), its combination with AZ (AZ group) or infusion of Bi (Bi group) before the procedures. RIFLE (risk of renal failure, injury to the kidney, failure of kidney function, loss of kidney function, and end-stage renal disease) criteria were used to define CIN-associated acute kidney injury (AKI).

RESULTS

The risk of AKI in CIN was significantly lower in the Bi and AZ groups than in the NLS group (P <or= 0.04). Comparing pre-treatment and post-treatment values in each group the following results were obtained: serum creatinine (Scr) increased and eGFR decreased significantly in the NLS group (P = 0.04) and in all patients (P = 0.001, P = 0.02, respectively). In addition, serum potassium decreased significantly in the Bi and NLS groups (P <or= 0.02). Also, serum Bi increased significantly in the Bi group (P = 0.001) whereas it decreased significantly in the AZ group (P = 0.001). Urinary pH also increased in all groups (P <or= 0.04) except the NLS group (P > 0.05).

CONCLUSIONS

It seems that both Bi and AZ reduce the risk of CIN-related AKI, and close monitoring of serum potassium is needed during bicarbonate infusion.

Differential effects of dihydropyridine calcium antagonists on doxorubicin-induced nephrotoxicity in rats

The aim of this study was to compare the roles of dihydropyridine calcium antagonists nifedipine, nitrendipine, amlodipine on doxorubicin (DXR)-induced nephrotoxicity in rats using biochemical, histopathological and immunohistochemical approaches. Male Sprague-Dawley rats were randomly divided into five experimental groups: control; DXR; DXR+nifedipine (15 mg/kg); DXR+nitrendipine (10 mg/kg); DXR+amlodipine (5 mg/kg). Results showed that treatment with DXR alone caused significant changes in the levels of urinary protein, serum creatinine (SCr), and blood urea nitrogen (BUN). Co-administration with amlodipine effectively reversed the effect of DXR on these parameters. In contrast, nifedipine and nitrendipine either had no effect or worsened DXR induced changes in the levels of urinary protein, SCr and BUN. Furthermore, DXR treatment caused significant increases in the levels of malondialdehyde (MDA), nitric oxide (NO), nitric oxide synthase (NOS) and significant decreases in the levels of reduced glutathione (GSH), glutathione-S-transferase (GST), and superoxide dismutase (SOD). These effects were significantly reduced by co-administration with amlodipine but not affected by nifedipine and worsened by nitrendipine. In addition to the biochemical changes, histopathological studies showed that DXR caused significant structural damages in the kidneys. Glomerular cell apoptosis, a decrease in Bcl-2 expression and an increase in Bax expression were observed in all rats treated with DXR. Co-administration with amlodipine effectively reversed the effect of DXR while nifedipine and nitrendipine had no effect. In conclusion, this study clearly indicated that amlodipine protected against DXR-induced nephrotoxicity while nifedipine and nitrendipine had no effect.

Strategies to reduce the risk of contrast-induced nephropathy

In view of the clinical importance of contrast-induced nephropathy (CIN), numerous potential risk-reduction strategies have been evaluated. Adequate intravenous volume expansion with isotonic crystalloid (1.0-1.5 mL/kg per hr) for 3-12 hours before the procedure and continued for 6-24 hours afterward can lessen the probability of CIN in patients at risk. There are insufficient data on oral fluids (as opposed to intravenous volume expansion) as a CIN-prevention strategy. No adjunctive medical or mechanical treatment has been proved to be efficacious in reducing risk for CIN. Prophylactic hemodialysis and hemofiltration have not been validated as effective strategies. The CIN Consensus Working Panel considered that, of the pharmacologic agents that have been evaluated, theophylline, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins), ascorbic acid, and prostaglandin E(1) deserve further evaluation. N-acetylcysteine is not consistently effective in reducing the risk for CIN. Fenoldopam, dopamine, calcium channel blockers, atrial natriuretic peptide, and l-arginine have not been shown to be effective. Use of furosemide, mannitol, or an endothelin receptor antagonist is potentially detrimental. Nephrotoxic drugs should be withdrawn before contrast administration in patients at risk for CIN.

Epidemiology and prognostic implications of contrast-induced nephropathy

Contrast-induced nephropathy (CIN), usually defined as an increase in serum creatinine of 0.5 mg/dL (44.2 mumol/L), or a 25% increase from the baseline value 48 hours after the procedure, is a common and potentially serious complication of the use of iodinated contrast media in patients at risk of acute renal injury. It is an important cause of hospital-acquired renal failure, responsible for approximately 11% of cases. CIN may be difficult to distinguish from cholesterol embolization, another cause of postprocedure renal impairment. The reported incidence of CIN varies depending on the patient population studied. The impact of postprocedural renal impairment on clinical outcomes has been evaluated most extensively in patients undergoing percutaneous coronary intervention. CIN is associated with increased mortality both in hospital and at 1 year. A higher incidence of in-hospital and late cardiovascular events, as well as longer hospital stays, has been reported in patients developing CIN. In a small proportion of patients, CIN is severe enough to require dialysis, and these patients have a particularly poor prognosis. Many of the risk markers for CIN are also predictive of a worse prognosis.

Contrast-induced nephropathy: Pharmacological prophylaxis

Contrast media-associated acute renal failure represents the third most common cause of in-hospital renal function deterioration after decreased renal perfusion and post-operative renal insufficiency. Although generally benign, this complication is associated with a mortality rate ranging from 3.8 to 64%, depending on the increase of creatinine concentration. Multiple drugs have been tested in an attempt to prevent this complication. Central to the pathophysiology of contrast-induced nephrotoxicity (CIN) is an alteration in renal hemodynamics. In an effort to reverse these hemodynamic changes, vasodilators and diuretics have been tested as prophylactic drugs. However, their effectiveness has not been confirmed. Recently, considerable interest has resulted from the initial positive data on the effectiveness of prophylactic administration of antioxidant compounds, such as acetylcysteine and ascorbic acid. In this review, we focus on the effectiveness of pharmacologic therapies for preventing CIN.