Using a dopamine type 1A receptor agonist in high-risk patients to ameliorate contrast-associated nephropathy

Ischemic Nephropathy Following Occlusion of Abdominal Aortic Aneurysm Graft: A Case Report

In this report, we present a case of a 55-year-old female with a past medical history of abdominal aortic aneurysm (AAA) graft, femoral-femoral bypass graft, questionable history of chronic kidney disease (CKD), abdominal hernia repair, alcoholic pancreatitis, chronic abdominal pain on opioids, and tobacco abuse who presented with acute on chronic abdominal pain with an unexplained rise of creatinine and anuria. The patient was found to have complete occlusion of AAA graft and was determined to have ischemic nephropathy (IN).

Prevention of contrast-induced nephropathy through a knowledge of its pathogenesis and risk factors

Contrast-induced nephropathy (CIN) is an iatrogenic acute renal failure (ARF) occurring after the intravascular injection of iodinated radiographic contrast media. During the past several years, in many patients undergoing computed tomography, iodinated contrast media have not been used for the fear of ARF, thereby compromising the diagnostic procedure. But recent studies have demonstrated that CIN is rarely occurring in patients with normal renal function and that preexisting chronic renal failure and/or diabetes mellitus represent(s) predisposing condition(s) for its occurrence. After the description of CIN and its epidemiology and pathophysiology, underlying the important role played by dehydration and salt depletion, precautions for prevention of CIN are listed, suggested, and discussed. Maximum priority has to be given to adequate hydration and volume expansion prior to radiographic procedures. Other important precautions include the need for monitoring renal function before, during, and after contrast media injection, discontinuation of potentially nephrotoxic drugs, use of either iodixanol or iopamidol at the lowest dosage possible, and administration of antioxidants. A long list of references is provided that will enable readers a deep evaluation of the topic.

Acute kidney injury by radiographic contrast media: pathogenesis and prevention

It is well known that iodinated radiographic contrast media may cause kidney dysfunction, particularly in patients with preexisting renal impairment associated with diabetes. This dysfunction, when severe, will cause acute renal failure (ARF). We may define contrast-induced Acute Kidney Injury (AKI) as ARF occurring within 24-72 hrs after the intravascular injection of iodinated radiographic contrast media that cannot be attributed to other causes. The mechanisms underlying contrast media nephrotoxicity have not been fully elucidated and may be due to several factors, including renal ischaemia, particularly in the renal medulla, the formation of reactive oxygen species (ROS), reduction of nitric oxide (NO) production, and tubular epithelial and vascular endothelial injury. However, contrast-induced AKI can be prevented, but in order to do so, we need to know the risk factors. We have reviewed the risk factors for contrast-induced AKI and measures for its prevention, providing a long list of references enabling readers to deeply evaluate them both.

Side effects of radiographic contrast media: pathogenesis, risk factors, and prevention

Radiocontrast media (RCM) are medical drugs used to improve the visibility of internal organs and structures in X-ray based imaging techniques. They may have side effects ranging from itching to a life-threatening emergency, known as contrast-induced nephropathy (CIN). We define CIN as acute renal failure occurring within 24-72 hrs of exposure to RCM that cannot be attributed to other causes. It usually occurs in patients with preexisting renal impairment and diabetes. The mechanisms underlying CIN include reduction in medullary blood flow leading to hypoxia and direct tubule cell damage and the formation of reactive oxygen species. Identification of patients at high risk for CIN is important. We have reviewed the risk factors and procedures for prevention, providing a long list of references enabling readers a deep evaluation of them both. The first rule to follow in patients at risk of CIN undergoing radiographic procedure is monitoring renal function by measuring serum creatinine and calculating the eGFR before and once daily for 5 days after the procedure. It is advised to discontinue potentially nephrotoxic medications, to choose radiocontrast media at lowest dosage, and to encourage oral or intravenous hydration. In high-risk patients N-acetylcysteine may also be given.

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.

Differential effects between intravenous and targeted renal delivery of fenoldopam on renal function and blood pressure in patients undergoing cardiac catheterization

A randomized, controlled clinical trial demonstrated that intravenous (IV) fenoldopam did not prevent further deterioration in renal function after contrast administration in patients with chronic renal insufficiency. This lack of effect may have been a consequence of the inability to administer an effective renal dose of IV fenoldopam. This study sought to determine whether compared with IV administration, selective intrarenal (IR) fenoldopam would increase local concentration, leading to a higher glomerular filtration rate (GFR), and, because of first-pass renal elimination, result in lower systemic drug levels and less decrease in systemic blood pressure (BP). A randomized, controlled, open-label, partial crossover design trial was conducted in which 33 patients who underwent coronary angiography were randomized in a 1:2 ratio to control or fenoldopam (initially IV, then crossed over to IR through a bifurcated renal infusion catheter). Compared with IV fenoldopam, IR administration was associated with a significantly higher GFR (73.7 +/- 3.1 vs 62.6 +/- 2.5 ml/min, p = 0.0007) and renal plasma flow (537.2 +/- 34.0 vs 494.0 +/- 35.5 ml/min, p <0.01), lower fenoldopam plasma levels (3.3 +/- 0.3 vs 4.8 +/- 0.3 ng/ml, p <0.0001), and greater nadir systolic BP (125.5 +/- 3.6 vs 117.4 +/- 2.8 mm Hg, p <0.0001). Two hours after drug discontinuation after contrast administration, GFRs in the patients who received IR fenoldopam remained higher than in controls (+15.0 ml/min [+25%] vs -8.0 ml/min [-14.0%], p <0.05). In conclusion, this pilot trial demonstrates that the IR infusion of fenoldopam is safe and practical, producing greater renal effect and less reduction of BP than IV infusion. It would be appropriate to restudy this renal vasodilator for the prevention of contrast nephropathy, using selective IR delivery.

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.

Prevention of Contrast Media–induced Nephrotoxicity after Angiographic Procedures

Contrast medium-induced nephrotoxicity (ie, contrast nephrotoxicity [CN]) remains an important complication of angiographic procedures. If administration of iodinated contrast medium is deemed necessary in patients at high risk of CN, volume expansion should be offered and the lowest possible dose of nonionic isosmolar dimeric or nonionic low-osmolar monomeric contrast medium should be used. Prophylactic administration of fenoldopam or acetylcysteine has not offered consistent protection against CN. Intravenous acetylcysteine could be considered in emergency situations. Recently, sodium bicarbonate infusion has been shown to reduce the risk of CN. Hemofiltration for several hours before and after contrast medium injection may offer good protection against CN in patients with advanced renal disease. Prophylactic hemodialysis does not offer any protection against CN.

Preventing contrast nephropathy: what is the best strategy? A review of the literature

Patients receiving radiocontrast for diagnostic and interventional procedures are at risk for developing contrast nephropathy (CN). In fact, radiocontrast nephropathy is currently the third leading cause of hospital-acquired renal failure. Understanding that CN has been associated with increased length of hospitalization and mortality, determining the best prevention strategy is of utmost importance. Patients at the greatest risk for developing acute renal failure are patients with diabetes and underlying renal insufficiency. Several therapies have been investigated for the prevention of CN; unfortunately, very few have shown a consistent benefit. Therapies that have been studied include saline hydration, N-acetylcysteine (NAC), theophylline, calcium channel blockers, diuretics, dopamine, endothelin receptor antagonists, atrial natriuretic peptide, angiotensin-converting enzyme inhibitors, and prostaglandin E-1. Using adequate hydration, using low-osmolar dyes, and minimizing the dose of contrast have all been shown to be effective in reducing CN and are considered the standard of care. While trials with many pharmacologic agents have produced conflicting results, intervention with NAC has also been promising. This article reviews the pathophysiology, risk factors, and therapies that are currently available for the prevention of CN.

Prevention of radiocontrast-induced nephropathy

Radiocontrast administration is a common cause of hospital-acquired acute renal failure. It is associated with significant in-hospital and long-term morbidity and mortality and increases the costs of medical care by at least extending the hospital stay. Although individuals with normal renal function generally are not considered to be at particular risk, patients with preexisting renal failure are much more likely to experience this complication after radiocontrast agent administration. Typically, serum creatinine levels begin to increase at 48 to 72 hours, peak at 3 to 5 days, and return to baseline within another 3 to 5 days. A variety of therapeutic interventions, including saline hydration, diuretics, mannitol, calcium channel antagonists, theophylline, endothelin receptor antagonists, and dopamine, have been used in an attempt to prevent radiocontrast-induced nephropathy. Of these, saline hydration is the sole efficacious therapy to protect against radiocontrast-induced nephropathy. Recent advances have examined the impact of fenoldopam (dopamine-1 [DA-1] receptor; DA-1 agonist), the antioxidant N-acetylcysteine, iso-osmolar contrast agents, hemodialysis, and hemofiltration in ameliorating radiocontrast-induced nephropathy. This review focuses on current interventions to ameliorate radiocontrast-induced acute renal failure and provides an analysis of some of the recent studies conducted to halt radiocontrast-induced nephropathy.

Fenoldopam andN-acetylcysteine for the Prevention of Radiographic Contrast Material-Induced Nephropathy: A Review

Radiographic contrast material-induced nephropathy (RCIN) is the third most common cause of hospital-acquired renal insufficiency and has been associated with an increase in patient mortality. Many strategies to prevent RCIN have been explored unsuccessfully. The standard of care remains hydration with 0.45% sodium chloride before and after administration of contrast material. Recently, N-acetylcysteine and fenoldopam have been studied to determine their efficacy in preventing RCIN. Of seven prospective studies using various dosing regimens of N-acetylcysteine, four revealed beneficial results. Although some discrepancies exist, the data strongly suggest that N-acetylcysteine has a role in patients at risk for the development of RCIN. The data for fenoldopam are more limited, with only one retrospective study showing benefit. Additional prospective data are required to determine if fenoldopam has a role in the prevention of RCIN.

Critical issues in nephrology

Renal and electrolyte problems are common in patients in the ICU. Several advances that occurred in the recent past have been incorporated in the diagnosis and management of these disorders and were reviewed in this article. Unfortunately, many important questions remain unanswered, especially in the area of ARF, where new therapies are anxiously awaited to make the transition from bench to bedside. Better studies are sorely needed to define the best approach to dialysis in patients who have ARF.

Radiocontrast-induced nephropathy and percutaneous coronary intervention: a review of preventive measures

Injectable and absorbable contrast media for the use in radiology, all of which contains iodine as an essential component, has been, and continues to be, one of the main sources of agents which cause hospital-acquired renal failure. Although numerous methods have been explored to prevent renal contrast damage, radiocontrast-induced nephropathy continues to be a concern in patients with existing renal insufficiency, who undergo contrast-enhanced radiographic examinations. Patients who develop contrast-induced nephropathy (CIN) have a worse prognosis and an increased risk of complications and mortality. Prevention of CIN during radiocontrast procedures continues to elude clinicians and is a chief concern during percutaneous coronary intervention, as these patients often have multiple comorbidities. A wide variety of animal and clinical investigations, and substances have been tried in order to prevent this complication, including: dialysis, contrast volume and type; adenosine antagonists; acetylcysteine; fenoldopam; and various others. The purpose of this review is to appraise all the past and current strategies employed to prevent CIN, especially during percutaneous coronary intervention.

Renal dysfunction after vascular surgery

PURPOSE OF REVIEW

The purpose of this review is to focus on the static incidence of renal dysfunction, the lack of evidence of benefit of traditional renoprotective strategies, and newer techniques that may provide an insight into the mechanisms of acute perioperative renal injury associated with vascular surgery.

RECENT FINDINGS

Recent studies that have investigated the long-term results of aortic surgery still report a significant incidence of postoperative renal dysfunction. This finding remains consistent in several reports. However, less invasive techniques such as endovascular repair seem to be associated with reduced inflammation and postoperative renal dysfunction. The possible association between genetic heterogeneity and renal dysfunction in vascular surgical patients is an exciting new area of research.

SUMMARY

Renal dysfunction after major vascular surgery remains a significant problem. New insights into the mechanisms of acute renal injury and less invasive techniques of vascular repair may help reduce the incidence of renal dysfunction in this patient population. The lack of a truly 'renoprotective' agent has hampered our efforts in preventing this major complication of vascular surgery.