Concomitant drugs with exposure to contrast media

Acute Kidney Injury Management Strategies Peri-Cardiovascular Interventions

In many countries, the aging population and the higher incidence of comorbid conditions have resulted in an ever-growing need for cardiac interventions. Acute kidney injury (AKI) is a common complication of these interventions, associated with higher mortalities, chronic or end-stage kidney disease, readmission rates, and hospital and post-discharge costs. The AKI pathophysiology includes contrast-associated AKI, hemodynamic changes, cardiorenal syndrome, and atheroembolism. Preventive measures include limiting contrast media dose, optimizing hemodynamic conditions, and limiting exposure to other nephrotoxins. This review article outlines the current state-of-art knowledge regarding AKI pathophysiology, risk factors, preventive measures, and management strategies in the peri-interventional period.

Mannitol and renal dysfunction after endovascular aortic aneurysm repair procedures: a randomized trial

OBJECTIVE

Endovascular aortic aneurysm repair (EVAR) may result in deterioration of renal function. Mannitol has renovascular and antioxidant properties that could prove beneficial in this respect.

DESIGN

A randomized prospective study.

SETTING

Attikon University Hospital, single institution.

PARTICIPANTS

Eighty-six patients undergoing elective EVAR under regional anesthesia.

METHODS

Patients received hydration alone (controls) or hydration plus mannitol (0.5 g/kg).

MEASUREMENTS AND MAIN RESULTS

Creatinine, serum cystatin-C, urine neutrophil-gelatinase-associated lipocalin (NGAL), albuminuria and serum urea were measured 24 hours and 72 hours after the procedure (baseline NGAL was measured in 19 randomly selected patients). Serum creatinine also was measured at the followup of the patients. Serum creatinine and cystatin-C were lower in the mannitol group at 24 hours postoperatively (creatinine, mannitol [n=43]; 1.07±0.26 [CI95%: 0.99-1.15] v controls [n=43]; 1.20±0.30 [CI95%: 1.11-1.30]), but not at 72 hours (creatinine, mannitol [n=43]; 1.13±0.29 [CI95%: 1.04-1.22] v controls [n=43]; 1.26±0.41 [CI95% 1.15-1.38]). Urine NGAL increased substantially at 24 hours without differences between groups. At followup (controls: 13±7 months; mannitol: 12±7 months), there were no differences between creatinine or creatinine clearance (creatinine: controls [n=28]; 1.15±0.39 [CI95% 1.02-1.29] v mannitol [n=23]; 1.05±0.27 [CI95%: 0.95-1.17]). The overall changes of creatinine and creatinine clearance with time were significant in controls but not in the mannitol group. The classification according to the RIFLE criteria yielded 4 patients at risk for renal injury and 2 with renal injury in the control group and 6 patients at risk with no patients with injury in the mannitol group, but the difference of renal dysfunction between the 2 groups was not statistically significant.

CONCLUSIONS

Mannitol plus hydration during EVAR provides a small but significant benefit for renal function. Future preventive protocols aiming at greater restoration of renal function after EVAR could include mannitol as a useful component.

Contrast-induced nephropathy in patients undergoing elective and urgent procedures

Contrast-induced nephropathy (CIN) is an acute and severe complication after contrast media administration. The most important step in preventing CIN is identifying high-risk patients. In this review, we evaluate and summarize the evidence regarding the CIN prophylaxis, including the withdrawal of the potentially nephrotoxic drugs, hydration by isotonic solution or NaHCO(3), pharmaceutical treatment with N-acetylcysteine (N-AC), adenosine antagonists, ascorbic acid, renal procedures including hemofiltration or dialysis, and to the optimal use of the contrast. We suggest it is possible to reduce the burden of CIN by carefully incorporating these recommendations. After review of published literature in this field, we conclude that the cornerstone of the CIN prevention should be combination of hydration (normal saline or NaHCO(3)) and the use of N-AC.

Contrast-induced nephropathy: pathogenesis and prevention

Contrast-induced nephropathy (CIN) is the third most common cause of acute kidney injury in hospitalized patients. Diagnostic and interventional cardiovascular procedures generate nearly half the cases. Elderly patients and those with chronic kidney disease, diabetes, and cardiovascular disease are at greatest risk. Procedure-related risk factors include large volumes of contrast and agents with a high osmolality. Renal medullary ischemia arising from an imbalance of local vasoconstrictive and vasodilatory influences coupled with increased demand for oxygen-driven sodium transport may be the key to its pathogenesis. Contrast agents may also have a direct cytotoxic effect that operates through the generation of reactive oxygen species. Pre- and post-procedure administration of normal saline, isotonic sodium bicarbonate, N-acetylcysteine, and a variety of other pharmacologic agents have been used to prevent or mitigate CIN. While normal saline is generally accepted as protective against CIN, uncertainty still surrounds the role of sodium bicarbonate and N-acetylcysteine. Dialytic therapies before, during, and after exposure to contrast have been tested with mixed results. Logistical and economic disincentives argue against these modalities.

[Iodinated contrast agent-induced nephropathy]

Contrast-induced nephropathy (CIN) is a well-known complication of therapeutic and diagnostic procedures requiring contrast administration and accounts for 10% of acute renal failure in hospitalized patients. Although the incidence of this complication is relatively low, its consequences can be catastrophic. The development of CIN is associated with increased length of hospital stay, an increased requirement for acute dialysis, and an increased risk of death. Preexisting renal dysfunction, age, diabetes, congestive heart failure, and volume of administered contrast are all associated with a risk of developing CIN. Despite a large number of clinical trials that have evaluated prophylaxis strategies for CIN, no uniform strategies have been developed so far. The use of N-acetyl-L-cysteine (NAC) or theophylline in specific subgroups of patients has been shown to reduce dialysis requirement and mortality in patients undergoing angiographic procedures. Hemofiltration has also shown positive results. In this review we will discuss the epidemiology and the risk factors for CIN and the evidence for commonly employed prophylaxis strategies, and we will provide general recommendations with respect to CIN prevention and management.A practicable strategy to prevent CIN includes: correct identification of individuals at greatest risk, thorough evaluation of whether other diagnostic maneuvers could be employed instead (i.e., sonography), application of low-osmolar contrast media at the minimum acceptable dose, stopping potential nephrotoxic drugs (NSAID), hydration with sodium chloride 0.9% 1 ml/kg per h i.v. 12 h before and after CM application, administration of acetylcysteine 600 mg twice the day before and after (in cases of emergency investigation and high-risk patients 1200 mg i.v.), and theophylline (250-350 mg) the day before and the day after CM application (in cases of emergency investigation 5 mg/kg i.v.).

Contrast-induced nephropathy

Interventional radiological procedures involving anaesthesia are generally increasing. Contrast-induced nephropathy (CIN), usually defined as an increase in serum creatinine of 44 micromol litre(-1) (0.5 mg dl(-1)) or a 25% increase from the baseline value 48 h after intravascular injection of contrast media, 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, may be a difficult differential diagnosis and the incidence does not appear to have changed over the last few decades. In the general population, the incidence of CIN is estimated to be 1-2%. However, the risk for developing CIN may be as high as 50% in some patient subgroups, such as those with diabetes mellitus and pre-existing renal impairment. The impact of CIN on clinical outcomes has been evaluated most extensively in patients undergoing percutaneous coronary intervention where it is associated with increased mortality both in hospital and at 1 yr. As treatment is limited to supportive measures while awaiting the resolution of the renal impairment, emphasis needs to be directed at prevention.

Contrast medium-induced nephropathy. Aspects on incidence, consequences, risk factors and prevention

Contrast media-induced nephropathy (CIN) is a well-known complication of radiological examinations employing iodine contrast media (I-CM). The rapid development and frequent use of coronary interventions and multi-channel detector computed tomography with concomitant administration of relatively large doses of I-CM has contributed to an increasing number of CIN cases during the last few years. Reduced renal function, especially when caused by diabetic nephropathy or renal arteriosclerosis, in combination with dehydration, congestive heart failure, hypotension, and administration of nephrotoxic drugs are risk factors for the development of CIN. When CM-based examinations cannot be replaced by other techniques in patients at risk of CIN, focus should be directed towards analysis of number and type of risk factors, adequate estimation of GFR, institution of proper preventive measures including hydration and post-procedural observation combined with surveillance of serum creatinine for 1-3 days. For the radiologist, there are several steps to consider in order to minimise the risk for CIN: use of "low-" or "iso-osmolar" I-CM and dosing the I-CM in relation to GFR and body weight being the most important as well as utilizing radiographic techniques to keep the I-CM dose in gram iodine as low as possible below the numerical value of estimated GFR. There is as yet no pharmacological prevention that has been proven to be effective.

Prevention of contrast-induced nephropathy: a critical review

PURPOSE OF REVIEW

Although contrast-induced nephropathy (CIN) is common and portends a significant morbidity and mortality, only few large and well designed trials have assessed the available prophylactic measures and there are no clear evidence-based guidelines that can easily be adopted by the clinician. We critically discuss the evidence for periprocedural hydration, pharmacological agents, periprocedural withdrawal of medication, application of renal replacement therapy and the use of contrast media.

RECENT FINDINGS

Pending confirmation of the superiority of sodium bicarbonate, NaCl 0.9% remains the fluid of choice for periprocedural hydration. A recent trial found a dose-dependent beneficial effect of acetylcysteine on CIN and mortality, adding to the controversy on the prophylactic use of this agent. Publication bias of acetylcysteine trials may have confounded the results of the meta-analyses, since negative results were more likely to be published as an abstract only. Periprocedural haemofiltration protected against CIN in a high-risk population, but the results require confirmation before the technique can be recommended.

SUMMARY

Pending randomized controlled trials with rigorous scientific design, we propose practical mixed evidence-based and opinion-based guidelines for the prevention of CIN, using a stratification of patients into three risk groups, based on their renal function and a risk-prediction model.