N-acetylcysteine versus N-acetylcysteine + theophylline for the prevention of contrast nephropathy

Association of N-acetylcysteine use with contrast-induced nephropathy: an umbrella review of meta-analyses of randomized clinical trials

Background

The effectiveness of N-acetylcysteine (NAC) in treating contrast-induced nephropathy (CIN) has been the subject of conflicting meta-analyses, but the strength of the evidence for these correlations between NAC use and CIN has not been measured overall.

Objective

To evaluate the data from randomized clinical studies (RCTs) that examined the relationships between NAC use and CIN in meta-analyses.

Methods

Between the creation of the database and April 2023, searches were made in PubMed, Cochrane Library, EMBASE, and Web of Science. N-acetylcysteine, contrast-induced nephropathy, or contrast-induced renal disease were among the search keywords used, along with terms including systematic review and meta-analysis. The Assessment of Multiple Systematic Reviews, version 2, which assigned grades of extremely low, low, moderate, or high quality to each meta-analysis's scientific quality, was used to evaluate each meta-analysis. The confidence of the evidence in meta-analyses of RCTs was evaluated using the Grading of Recommendation, Assessment, Development and Evaluations method, with evidence being rated as very low, low, moderate, or high.

Results

In total, 493 records were screened; of those, 46 full-text articles were assessed for eligibility, and 12 articles were selected for evidence synthesis as a result of the screening process. Based on the pooled data, which was graded as moderate-quality evidence, it can be concluded that NAC can decrease CIN (OR 0.72, 95% CI 0.65-0.79, p < 0.00001) and blood levels of serum creatinine (MD -0.09, 95% CI -0.17 to -0.01, p = 0.03). In spite of this, there were no associations between NAC and dialysis requirement or mortality in these studies.

Conclusion

The results of this umbrella review supported that the renal results were enhanced by NAC. The association was supported by moderate-quality evidence.

Systematic review registration

[https://clinicaltrials.gov/], identifier [CRD42022367811].

A systematic review of the incidence of hypersensitivity reactions and post-contrast acute kidney injury after ioversol: part 2-intra-arterial administration

Objectives

To evaluate the incidence of adverse drug reactions (ADRs), including hypersensitivity reactions (HSRs) and post-contrast acute kidney injury (PC-AKI), after intra-arterial (IA) administration of ioversol.

Methods and materials

A systematic literature search was performed (1980–2021) and studies documenting IA use of ioversol, and reporting safety outcomes were selected. Key information on study design, patients’ characteristics, indication, dose, and type of safety outcome were extracted.

Results

Twenty-eight studies (including two pediatric studies) with 8373 patients exposed to IA ioversol were selected. Studies were highly heterogenous in terms of design, PC-AKI definition, and studied population. PC-AKI incidence after coronary angiography was 7.5–21.9% in a general population, 4.0-26.4% in diabetic patients, and 5.5–28.9% in patients with chronic kidney disease (CKD). PC-AKI requiring dialysis was rare and reported mainly in patients with severe CKD. No significant differences in PC-AKI rates were shown in studies comparing different iodinated contrast media (ICM). Based on seven studies of ioversol clinical development, the overall ADR incidence was 1.6%, comparable to that reported with other non-ionic ICM. Pediatric data were scarce with only one study reporting on PC-AKI incidence (12%), and one reporting on ADR incidence (0.09%), both after coronary angiography.

Conclusions

After ioversol IA administration, PC-AKI incidence was highly variable between studies, likely reflecting the heterogeneity of the included study populations, and appeared comparable to that reported with other ICM. The rate of other ADRs appears to be low. Well-designed studies are needed for a better comparison with other ICM.

Key Points

• PC-AKI incidence after IA administration of ioversol appears to be comparable to that of other ICM, despite the high variability between studies.

• The need for dialysis after IA administration of ioversol is rare.

• No obvious difference was found regarding the safety profile of ioversol between IA and IV administration.

Contrast-induced nephropathy and oxidative stress: mechanistic insights for better interventional approaches

Contrast-induced nephropathy (CIN) or contrast-induced acute kidney injury (CI-AKI) is an iatrogenic acute kidney injury observed after intravascular administration of contrast media for intravascular diagnostic procedures or therapeutic angiographic intervention. High risk patients including those with chronic kidney disease (CKD), diabetes mellitus with impaired renal function, congestive heart failure, intraarterial intervention, higher volume of contrast, volume depletion, old age, multiple myeloma, hypertension, and hyperuricemia had increased prevalence of CIN. Although CIN is reversible by itself, some patients suffer this condition without renal recovery leading to CKD or even end-stage renal disease which required long term renal replacement therapy. In addition, both CIN and CKD have been associated with increasing of mortality. Three pathophysiological mechanisms have been proposed including direct tubular toxicity, intrarenal vasoconstriction, and excessive production of reactive oxygen species (ROS), all of which lead to impaired renal function. Reports from basic and clinical studies showing potential preventive strategies for CIN pathophysiology including low- or iso-osmolar contrast media are summarized and discussed. In addition, reports on pharmacological interventions to reduce ROS and attenuate CIN are summarized, highlighting potential for use in clinical practice. Understanding this contributory mechanism could pave ways to improve therapeutic strategies in combating CIN.

Avoiding the emergence of contrast-induced acute kidney injury in acute coronary syndrome: routine hydration treatment

BACKGROUND

Patients with acute coronary syndrome (ACS) have about a three-fold risk for developing contrast-induced acute kidney injury(CI-AKI). Investigating studies on routine hydration therapy have frequently included patients with stable coronary artery disease and high risk of CI-AKI [estimated glomerular filtration rate (eGFR) < 60 ml/min]. However, data on routine hydration treatment in non-ST segment elevation myocardial infarction (NSTEMI) patients with eGFR ≥60 ml/min are insufficient. We aimed to investigate the association between routine hydration therapy and CI-AKI development in NSTEMI patients at low risk for nephropathy.

METHODS AND RESULTS

We randomly assigned a total of 401 NSTEMI patients to two groups: the routine hydration group (198 patients) and the nonhydration group (control group) (203 patients). Intravenous hydration with isotonic saline (1 ml/kg/h, 0.9% sodium chloride) was given for 3-12 h before and 24 h after contrast exposure to the hydration group. CI-AKI was defined as the increase in serum creatinine values 0.5 mg/dl or 25% between 48 and 72 h after the invasive procedures. In our study, the incidence of CI-AKI development in the routine hydration group (7.1%) was significantly lower than in the nonhydration group (14.1%) (P: 0.02). This study revealed that older age, amount of contrast media, and routine hydration were independent risk factors for developing CI-AKI (P < 0.01, P: 0.04, P < 0.01, respectively).

CONCLUSION

We found that preprocedural and postprocedural intravenous hydration therapy reduces the development of CI-AKI in patients with NSTEMI at low risk for CI-AKI. We suggest administering routine hydration therapy in all ACS patients regardless of eGFR values.

Latest Clinical Evidence About Effect of Acetylcysteine on Preventing Contrast-Induced Nephropathy in Patients Undergoing Angiography: A Meta-Analysis

Contrast-induced nephropathy (CIN) is a serious complication of angiographic procedures. It is the third most common cause of hospital acquired acute renal injury. As there are currently no approved therapies for CIN, prevention could be the best strategy to address this issue. Acetylcysteine may indirectly play an antioxidant role by inducing the synthesis of glutathione. Acetylcysteine can also reduce renal vasoconstriction induced by contrast medium stimulation by stabilizing nitric oxide and acting directly or indirectly on renal cortex and medulla microcirculation. To evaluate the effect of acetylcysteine on the prevention of CIN in patients after angiography, we systematically searched and analyzed the clinical data of patients including the incidence of CIN and change in serum creatinine (SCr) at 48 hours after angiography from selected articles. The result showed that acetylcysteine significantly reduces the incidence of CIN (risk ratios: 0.78, 95% CI: 0.68-0.90, I ² = 37.3%) and the level of SCr (standardized mean difference: -0.53, 95% CI: -0.93 to -0.12, I ² = 91.5%) after angiography compared with the control group. Overall, the use of acetylcysteine in patients after angiography was associated with a significant reduction of CIN and the level of SCr.

Adenosine antagonists for prevention of contrast-induced nephropathy: A meta-analysis of randomized controlled trials with trial sequential analysis

Contrast-induced nephropathy (CIN) is caused by intravascular administration of contrast agent. The efficacy of adenosine antagonists (AAs) in preventing CIN remains controversial, and its elucidation was the objective of the present meta-analysis. A trial sequential analysis (TSA) to assess the reliability of the pooled results was also performed. The Medline, Embase, Web of Science and Cochrane databases were searched to retrieve all published randomized controlled trials (RCTs) comparing AAs with controls in preventing CIN. Heterogeneity, publication bias and quality of studies were assessed. Sensitivity, cumulative and subgroup analyses were also performed. The risk of random errors was evaluated by TSA. A total of 17 trials with 1,483 subjects were included. Pooled results indicated that AAs significantly reduced the incidence of CIN [risk ratio, 0.53; 95% confidence interval (CI), 0.29-0.95; P=0.034] and the serum creatinine (SCr) level after contrast media (CM) administration (standardized mean difference, -0.24; 95% CI, -0.44 to -0.04; P=0.019). Meta-regression did not identify any significant source of heterogeneity. In the subgroup analyses, AAs tended to exhibit a greater prevention efficacy in trials with sample sizes of ≥70, baseline SCr of <1.5 mg/dl and low study quality. TSA on the incidence of CIN indicated that the required information size determined as n=1,778 was not reached, and that the cumulative Z-curve did not cross the TSA boundary. In conclusion, the present meta-analysis of data from current RCTs suggested that AAs reduce the incidence of CIN and the SCr levels after CM administration. However, TSA showed that the risk of having a false-positive result was greater than 5% in the meta-analysis of the incidence of CIN, indicating that more evidence is required to ensure the benefit of AAs in preventing CIN.

Pharmacological interventions for the prevention of contrast-induced acute kidney injury in high-risk adult patients undergoing coronary angiography: a systematic review and meta-analysis of randomised controlled trials

Objective

Quantify the efficacy of strategies to prevent contrast-induced acute kidney injury (CI-AKI) in high-risk patients undergoing coronary angiography (CAG) with or without percutaneous coronary intervention (PCI).

Background

CI-AKI remains a common problem. The renoprotective efficacy of existing pharmacological agents remains uncertain in high-risk populations.

Methods

Systematic review and meta-analysis of randomised controlled trials (RCTs) to compare different strategies versus hydration in patients with chronic kidney disease (CKD) undergoing CAG±PCI. Primary outcome was incident CI-AKI. Fixed-effects meta-analyses estimated ORs, 95% CIs and heterogeneity.

Results

Forty-eight RCTs were included. Seven pharmacological strategies were evaluated by multiple RCTs and 10 by one RCT each. These had varying risk of bias; >25% of trials were at high risk of performance bias. Five strategies significantly reduced the odds of CI-AKI: N-acetylcysteine (NAC) (27 trials, 5694 participants; OR=0.77, 95% CI 0.65 to 0.91, p=0.002, I²=36%), ascorbic acid (four trials, 759 participants; OR=0.59, 95% CI 0.39 to 0.89, p=0.01, I²=0%), statin (two trials, 3234 participants; OR=0.59, 95% CI 0.39 to 0.89, p=0.75, I²=0%), trimetazidine (two trials, 214 participants; OR=0.27, 95% CI 0.10 to 0.71, p=0.01, I²=0%) and nicorandil (two trials, 389 participants; OR=0.47, 95% CI 0.23 to 0.94, p=0.03, I²=52%). Theophylline had a similar, but non-significant, effect. A subgroup analysis found that the benefit of NAC was highest in patients requiring a high-contrast dose.

Conclusions

Several drugs are renoprotective in patients with CKD undergoing CAG±PCI. The evidence is strongest for NAC. We recommend that NAC should be used when a high dose of contrast is anticipated.

Trial registration number

PROSPERO registration CRD42014014704.

Open Science Framework link: https://osf.io/vxg7d/?view_only=62bad0404b18405abd39ff2ead2575a8

Effectiveness of contrast-associated acute kidney injury prevention methods; a systematic review and network meta-analysis

BACKGROUND

Different methods to prevent contrast-associated acute kidney injury (CA-AKI) have been proposed in recent years. We performed a mixed treatment comparison to evaluate and rank suggested interventions.

METHODS

A comprehensive Systematic review and a Bayesian network meta-analysis of randomised controlled trials was completed. Results were tabulated and graphically represented using a network diagram; forest plots and league tables were shown to rank treatments by the surface under the cumulative ranking curve (SUCRA). A stacked bar chart rankogram was generated. We performed main analysis with 200 RCTs and three analyses according to contrast media and high or normal baseline renal profile that includes 173, 112 & 60 RCTs respectively.

RESULTS

We have included 200 trials with 42,273 patients and 44 interventions. The primary outcome was CI-AKI, defined as ≥25% relative increase or ≥ 0.5 mg/dl increase from baseline creatinine one to 5 days post contrast exposure. The top ranked interventions through different analyses were Allopurinol, Prostaglandin E1 (PGE1) & Oxygen (0.9647, 0.7809 & 0.7527 in the main analysis). Comparatively, reference treatment intravenous hydration was ranked lower but better than Placebo (0.3124 VS 0.2694 in the main analysis).

CONCLUSION

Multiple CA-AKI preventive interventions have been tested in RCTs. This network evaluates data for all the explored options. The results suggest that some options (particularly allopurinol, PGE1 & Oxygen) deserve further evaluation in a larger well-designed RCTs.

A Bayesian network meta-analysis of preventive strategies for contrast-induced nephropathy after cardiac catheterization

BACKGROUND

The optimal preventive strategy for contrast induced acute kidney injury (CIAKI) in patients undergoing cardiac catheterization remains uncertain.

OBJECTIVE

We conducted Bayesian network meta-analysis (NMA) to compare different preventive strategies for CIAKI in these cohorts.

METHODS

Forty-nine randomized controlled trials were extracted using MEDLINE, EMBASE and CENTRAL data bases (inception-1st December 2017). We calculated median of the odds ratio (OR) with the corresponding 95% credible interval (CrI). The ranking probability of each treatment was based on SUCRA (surface under the cumulative ranking curve).

RESULTS

In NMA of 28,063 patients [normal saline (NS: 9716 patients), sodium bicarbonate (NaHCO3: 4484 patients), statin (2542 patients), N-acetylcysteine (NAC: 3006 patients), NAC + NaHCO3 (774 patients), NS + NAC (3807 patients), NS + NaHCO3 (135 patients) and placebo (3599 patients)], statins reduced the relative risk of CIAKI compared with NS (OR: 0.50; 95% CrI, 0.25-0.99), and placebo (OR: 0.44; 95% CrI, 0.24-0.83). Subgroup analyses showed that in patients receiving low osmolar contrast, statins reduced the relative risk of CIAKI by 58% versus NS, and 51% versus placebo. There were no significant differences across all the treatments in terms of risk of hemodialysis or all-cause mortality. Statins had the highest probability for reducing the risk of CIAKI (SUCRA, 0.86), risk of hemodialysis (SUCRA, 0.88) and all-cause mortality (SUCRA, 0.81).

CONCLUSION

Statins were the superior preventive strategy for reducing the risk of CIAKI compared with NS alone and placebo.

Contrast-Induced Nephropathy: Update on the Use of Crystalloids and Pharmacological Measures

Contrast-induced nephropathy (CIN) is a frequent and severe complication in subjects receiving iodinated contrast media for diagnostic or therapeutic purposes. Several preventive strategies were evaluated in the past. Recent clinical studies and meta-analyses delivered some new aspects on preventive measures used in the past and present. We will discuss all pharmacological and nonpharmacological procedures. Finally, we will suggest individualized recommendations for CIN prevention.

Oral N-acetylcysteine for prophylaxis of contrast-induced nephropathy in patients following coronary angioplasty: A meta-analysis

It is acknowledged that contrast-induced nephropathy (CIN) is a common cause of acute renal insufficiency after cardiac catheterization and affects mortality and morbidity. To date, it is unknown whether oral N-acetylcysteine (NAC) is able to prevent contrast-induced nephropathy (CIN) in patients undergoing coronary angioplasty. A meta-analysis of randomized controlled trials was performed to assess the effects of NAC in the prevention of CIN in patients following coronary angioplasty. A total of 19 studies published prior to January 2015 that investigated the efficacy of oral NAC for the prevention of CIN were collected from Medline, Cochrane and Embase databases and conference proceedings from cardiology and nephrology meetings. The primary point of investigation was CIN, and the secondary points were renal failure requiring dialysis, mortality and length of hospitalization. The meta-analysis was performed using fixed- or random-effect models according to heterogeneity. Up to January 2015, 19 randomized placebo-controlled clinical trials met the inclusion criteria for the meta-analysis, including 4,514 patients. The pooled data showed that oral NAC did not reduce the CIN incidence [relative risk 0.84, 95% confidence interval (CI) 0.65-1.10; P=0.20], without heterogeneity among trials (I2=29%). Thus, the present meta-analysis suggests that oral NAC therapy is not effective as an alternative treatment to prevent CIN in patients following angioplasty. Further high quality randomized clinical controlled trials are required to confirm the usage and availability of this treatment.

Contrast-Induced Acute Kidney Injury Is Associated With Long-Term Adverse Events in Patients With Acute Coronary syndrome

Contrast-induced acute kidney injury (CI-AKI) is associated with increased mortality, morbidity, and prolonged hospitalization. Patients with acute coronary syndrome (ACS) have a 3-fold higher risk of developing CI-AKI. The aim of our study was to evaluate the predictors of CI-AKI and long-term prognosis in patients with ACS who developed CI-AKI (1083 patients were enrolled). Contrast-induced acute kidney injury was defined as an increase of ≥0.5 mg/dL and/or an increase of ≥25% of pre-percutaneous coronary intervention (PCI) to post-PCI serum creatinine levels within 48 to 72 hours after the procedure. Primary end point was defined as all-cause mortality, myocardial infarction, and cerebrovascular event at long-term follow-up (36 ± 12 months). Contrast-induced acute kidney injury occurred in 178 (16.4%) of the 1083 patients. The primary end points were significantly high in patients with ACS who developed CI-AKI ( P < .001). The occurrence of CI-AKI was identified as an independent predictor of primary end point. Risk of CI-AKI development was more frequently seen in patients with ACS. Also, patients who developed CI-AKI have worse prognosis at long-term follow-up. Additional preventive treatment strategies need to be developed in this group of patients.

Effectiveness of N-Acetylcysteine for the Prevention of Contrast-Induced Nephropathy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

Conflicting results have been obtained in trials that have evaluated the prophylactic efficacy of N‐acetylcysteine (NAC) pretreatment in the prevention of contrast‐induced nephropathy (CIN). In this meta‐analysis of randomized controlled trials, we aimed to assess the effectiveness of NAC treatment for the prevention of CIN.

Methods and Results

PubMed, EMBASE, and the Cochrane Library were electronically searched from inception to January 2016 for all relevant studies. The weighted relative risk (RR) and corresponding 95% CI for incident CIN were estimated using random effects models. Standard methods for assessing statistical heterogeneity and publication bias were used. The study included 11 480 participants and 1653 cases of CIN. The incidence of CIN was 12.8% in the NAC group versus 16.0% in the control group (RR: 0.76, 95% CI: 0.66–0.88, P=0.0002). In the patients undergoing coronary angiography, the incidence of CIN in the NAC group versus the control group was 13.7% versus 17.2% (RR: 0.74, 95% CI: 0.63–0.87, P=0.0002); in those undergoing peripheral angiography, the incidence was 6.4% versus 5.8% (RR: 1.00, 95% CI: 0.42–2.40, P=1.00); in those undergoing computed tomography, the incidence was 7.7% versus 14.8% (RR: 0.51, 95% CI: 0.29–0.89, P=0.02).

Conclusions

Our meta‐analysis showed an inverse and significant association between NAC supplementation and risk of CIN in patients undergoing coronary angiography and computed tomography, while a protective role for NAC in patients undergoing peripheral angiography was not obvious.

Strategies Preventing Contrast-Induced Nephropathy After Coronary Angiography: A Comprehensive Meta-Analysis and Systematic Review of 125 Randomized Controlled Trials

This systematic review with meta-analysis sought to determine the strength of evidence for the effects of hydration (sodium bicarbonate [SB] and normal saline [NS]), supplementations ( N-acetylcysteine [NAC] and vitamin C), and some common drugs (adenosine antagonists [AAs], statins, loop diuretics, and angiotensin-converting enzyme inhibitors [ACEIs]) on the incidence of contrast-induced nephropathy (CIN) and requirement for hemodialysis after coronary angiography. After screening, a total of 125 trials that reported outcomes were identified. Pooled analysis indicated beneficial effects of SB versus NS (odds ratio [OR] = 0.73; 95% confidence interval [CI]: 0.56-0.94; P = .01), NAC (OR = 0.79; 95% CI: 0.70-0.88; P = .001), vitamin C (OR = 0.64; 95% CI: 0.45-0.89; P = .01), statins (OR = 0.45; 95% CI: 0.35-0.57; P = .001), AA (OR = 0.28; 95% CI: 0.14-0.47; P = .001), loop diuretics (OR = 0.97; 95% CI: 0.33-2.85; P = .9), and ACEI (OR = 1.06; 95% CI: 0.69-1.61; P = .8). Overall, hydration with SB, use of supplements, such as NAC and vitamin C, and administration of statins and AA should always be considered for the prevention of CIN after coronary angiography.

N-acetylcysteine for the prevention of contrast-induced nephropathy in patients with pre-existing renal insufficiency or diabetes: a systematic review and meta-analysis

PURPOSE

To identify benefit of N-acetylcysteine (NAC) on patients with pre-existing renal insufficiency or diabetes.

BACKGROUND

NAC administration is a common method for prevention of contrast-induced nephropathy (CIN). Nevertheless, its benefit on patients with pre-existing renal insufficiency or diabetes remains uncertain and controversial.

METHODS

Randomized controlled trials (RCTs) to evaluate the efficacy of NAC for the prevention of CIN in patients with pre-existing renal insufficiency or diabetes were searched from the databases of MEDLINE, EMBASE, and Cochrane library. Pooled odds ratio (OR) with 95% confidence interval (95% CI) were calculated using fixed-effects model by the Mantel-Haenszel test.

RESULTS

Twenty RCTs involving 3466 subjects (1756 assigned to NAC and 1710 assigned to the control) were included in the pre-existing renal dysfunction group. Pooled analysis suggested a significant reduction in CIN among this group (OR, 0.76; 95% CI, 0.61-0.93; p = 0.008). However, the nine trials comparing NAC versus control among patients with diabetes (NAC, 367 subjects; control, 358 subjects) showed no benefit of NAC for prevention of CIN (OR = 0.87; 95% CI, 0.58-1.30; p = 0.50). No significant heterogeneity was detected (p = 0.07; I2 = 34% for the group of pre-existing renal dysfunction; p = 0.40; I2 = 5% for the group of diabetes).

CONCLUSION

Our results suggest that NAC decreases the incidence of contrast-induced nephropathy among patients with pre-existing renal insufficiency. The benefit was not existed in patients with diabetes.

Should acetylcysteine be used to prevent contrast induced nephropathy?

Diagnostic and therapeutic procedures that require the infusion of iodine containing contrast solutions are associated with the risk of contrast-induced nephropathy, a condition that can cause significant morbidity. Acetylcysteine has been proposed as a measure to prevent this condition. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified 20 systematic reviews including 64 randomized trials. We combined the evidence using meta-analysis and generated a summary of findings table following the GRADE approach. We concluded that even though acetylcysteine might not cause important adverse effects, it does not decrease need for dialysis, mortality or other important outcomes.

Pharmacological strategies to prevent contrast-induced acute kidney injury

Contrast-induced acute kidney injury (CI-AKI) is the most common iatrogenic cause of acute kidney injury after intravenous contrast media administration. In general, the incidence of CI-AKI is low in patients with normal renal function. However, the rate is remarkably elevated in patients with preexisting chronic kidney disease, diabetes mellitus, old age, high volume of contrast agent, congestive heart failure, hypotension, anemia, use of nephrotoxic drug, and volume depletion. Consequently, CI-AKI particularly in high risk patients contributes to extended hospitalizations and increases long-term morbidity and mortality. The pathogenesis of CI-AKI involves at least three mechanisms; contrast agents induce renal vasoconstriction, increase of oxygen free radicals through oxidative stress, and direct tubular toxicity. Several strategies to prevent CI-AKI have been evaluated in experimental studies and clinical trials. At present, intravascular volume expansion with either isotonic saline or sodium bicarbonate solutions has provided more consistent positive results and was recommended in the prevention of CI-AKI. However, the proportion of patients with risk still develops CI-AKI. This review critically evaluated the current evidence for pharmacological strategies to prevent CI-AKI in patients with a risk of developing CI-AKI.

Radiographic contrast-media-induced acute kidney injury: pathophysiology and prophylactic strategies

Contrast-induced acute kidney injury (CI-AKI) is one of the most widely discussed and debated topics in cardiovascular medicine. With increasing number of contrast-media- (CM-) enhanced imaging studies being performed and growing octogenarian population with significant comorbidities, incidence of CI-AKI remains high. In this review, pathophysiology of CI-AKI, its relationship with different types of CM, role of serum and urinary biomarkers for diagnosing CI-AKI, and various prophylactic strategies used for nephroprotection against CI-AKI are discussed in detail.

Effect of theophylline on prevention of contrast-induced acute kidney injury: a meta-analysis of randomized controlled trials

BACKGROUND

Whether treatment with adenosine receptor antagonists such as theophylline can prevent contrast-induced acute kidney injury (AKI) remains controversial.

STUDY DESIGN

We conducted a meta-analysis of randomized controlled trials using MEDLINE (1966 to July 2011), EMBASE (1980 to July 2011), Web of Science (1986 to July 2011), and the Cochrane Central Register of Controlled Trials (1996 to July 2011), without language restriction.

SETTING & POPULATION

Patients undergoing contrast procedures.

SELECTION CRITERIA FOR STUDIES

Randomized controlled trials assessing adenosine antagonists versus control for prevention of contrast-induced AKI.

INTERVENTION

Adenosine antagonists with or without N-acetylcysteine versus control with or without N-acetylcysteine.

OUTCOMES

Contrast-induced AKI, change in serum creatinine level, requirement of dialysis, and in-hospital mortality.

RESULTS

16 trials (1,412 participants) were included. Theophylline significantly decreased the risk of contrast-induced AKI (13 trials, 1,222 patients; risk ratio, 0.48; 95% CI, 0.26-0.89; P = 0.02; I(2) = 45%) and had a protective effect on the absolute change in serum creatinine concentration (13 trials, 1,170 patients; standardized mean difference, -0.31 mg/dL; 95% CI, -0.50 to -0.11; P = 0.002; I(2) = 60%). Meta-regression showed a significant relation between the relative risk of contrast nephropathy and baseline serum creatinine level or Jadad score. No clear effects of treatment on risk of dialysis and in-hospital mortality were identified.

LIMITATIONS

Power to assess clinical end points was limited.

CONCLUSIONS

Theophylline treatment significantly reduced the incidence of contrast-induced AKI and had a modest improvement on kidney function after contrast exposure in the general population. However, beneficial effects of theophylline were not observed in patients with high baseline creatinine values (serum creatinine ≥1.5 mg/dL). In addition, the long-term effect of this agent on more clinically important outcomes was not established. Future large-scale high-quality multicenter trials in participants with different underlying risks of contrast-induced AKI and that incorporate the evaluation of clinically relevant outcomes are required.

Contrast-induced acute kidney injury: the at-risk patient and protective measures

Contrast-induced acute kidney injury (CI-AKI) is a major complication following radiocontrast procedures. In this review, we characterize the recent literature on CI-AKI, risk factors, prevention, biomarkers, and new technologies. The premise of CI-AKI prophylaxis should focus on implementing mandatory standing orders before and after cardiac catheterization for hydration with normal saline or sodium bicarbonate and use of high-dose (1200-mg) N-acetylcysteine. Contrast agents may play a role in preventing CI-AKI. Implement catheter-laboratory technology and awareness to limit the amount of contrast dye used for any patient.

Does oral N-acetylcysteine reduce contrast-induced renal injury in patients with peripheral arterial disease undergoing peripheral angiography? A randomized-controlled study

The nephroprotective role of N-acetylcysteine (NAC) against contrast-induced nephropathy (CIN) in patients undergoing peripheral arterial angiography remains unclear. A total of 40 patients undergoing peripheral arterial angiography were randomized to receive intravenous (iv) hydration only (group 1) or oral NAC in addition to iv hydration (group 2; ISRCTN: 35882618). Primary outcome was reduction in the elevation of urinary retinol binding protein (RBP), albumin-creatinine ratio (ACR), and serum creatinine (serC). Groups 1 and 2 had equivocal percentage reduction in RBP and ACR levels from baseline (P = .80 and .30). A significant reduction in serC was, however, observed with NAC by third postprocedure day (P = .04). One patient in the treatment arm developed CIN compared with 3 patients in the control group (P = .33). Equivocal changes in RBP and ACR levels by both treatments seem to indicate that either is equally effective in affording renal protection.