Prevention of contrast media-induced renal dysfunction with prostaglandin E1: a randomized, double-blind, placebo-controlled study

The Preventive Effect of Alprostadil on the Contrast-Induced Nephropathy of Coronary Heart Disease Treated by Percutaneous Coronary Intervention in Moderate and High-Risk Population Stratified by Mehran Score

The Mehran risk score (MRS) was used to classify patients with coronary heart disease and evaluate the preventive effect of alprostadil on contrast-induced nephropathy (CIN) after percutaneous coronary intervention. The patients (n = 1146) were randomized into an alprostadil and control group and then divided into 3 groups on the basis of the MRS: low-risk, moderate-risk, and high-risk groups. The primary end point was the occurrence of CIN (alprostadil + hydration vs simple hydration treatment); secondary end points included serum creatinine, blood urea nitrogen, creatinine clearance rate, cystatin C, interleukin-6, C-reactive protein, proteinuria, and differences in the incidence of major adverse events. In the low-risk, moderate-risk, and high-risk groups, the incidence of CIN in the control and alprostadil group was 2.9 versus 2.6% (P = .832), 11.4 versus 4.9% (P = .030), 19.1 versus 7.7% (P = .041), respectively. Multivariate logistic regression analysis showed that alprostadil treatment was a favorable protective factor for moderate-risk and high-risk CIN patients (OR = 0.343, 95% CI: 0.124-0.951, P = .040). Alprostadil can be used as a preventive treatment for moderate- and high-risk CIN patients classified by the MRS. The reduction of CIN by alprostadil may be related to an anti-inflammatory effect.

Dysregulation of HULC promotes contrast-induced nephropathy (CIN) via regulating signaling pathway of miRNA-512 and prostaglandin E1 (PGE1)

It has been shown that contrast-induced nephropathy (CIN) can be attenuated by the administration of PGE1. As an enzyme responsible for the production of PGE1, PTGS1 was confirmed in this study as a miR-512 target. Meanwhile, HULC has been identified as a competing endogenous RNA of miR-512. Therefore, in this study, we tested the diagnostic value of HULC and miR-512 in subjects with or without CIN. In addition, we evaluated the regulatory relationship among HULC, miR-512, PTGS1 and PGE1 in vitro. We enrolled 320 patients with coronary heart disease and divided them into a CIN group and a non-CIN group. Subsequently, we detected the differential expression of miR-512, HULC and PGE1 in the two groups. We also used a dual luciferase reporter assay to evaluate the regulatory relationship among HULC, miR-512, PTGS1 and PGE1 in THP-1 cells. In patients with CIN, the expression levels of HULC and PGE1 were lower, but the expression level of miR-512 was higher. MiR-512 could directly bind to and negatively regulate the expression of PTGS1 and HULC. The expression of HULC was positively correlated with the expression of PTGS1 and PGE1, while negatively correlated with the expression of miR-512. The findings of this study demonstrated that deregulation of lncRNA-HULC/miR-512/PTGS1/PGE1 might be involved in the pathogenesis of CIN.

Effect of Alprostadil on the Prevention of Contrast-Induced Nephropathy: A Meta-Analysis of 36 Randomized Controlled Trials

Contrast-induced nephropathy (CIN) is the third leading cause of acquired acute renal injury in hospitalized patients. Alprostadil plays a role in the maintenance and redistribution of intrarenal blood flow and the excretion of electrolytes and water. However, the effectiveness of alprostadil in preventing CIN remains controversial. Thirty-six articles with a total of 5495 patients were included in this study. Both groups (experimental group and control group) received standard hydration therapy. In the experimental group, patients received different doses of alprostadil. Serum creatinine (SCr), blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), cystatin C, creatinine clearance rate (CCr), and β2-microglobulin (β2-MG) were measured at 24, 48, and 72 hours after contrast media injection. The incidence of CIN in the experimental group was significantly lower than that in the control group (6.56% vs 16.74%). The level of SCr, cystatin C, BUN, and β2-MG in the experimental group was lower than those in the control group; CCr and eGFR in the experimental group were higher than those in the control group. This study demonstrated that alprostadil may reduce the incidence of CIN in patients undergoing coronary angiogram and/or percutaneous coronary intervention.

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.

Prostaglandin E1 administration for prevention of contrast-induced acute kidney injury: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

PGE1 has been studied for prevention of CI-AKI in several RCTs and significant heterogeneous results exist.

METHODS

We searched PubMed, EMBase, and Cochrane Central Register of Controlled Trials up to December 26, 2017 for RCTs comparing PGE1 with placebo or other active medications for the prevention of CI-AKI in patients. Odds ratio and 95% confidence interval (CI) were used for pooling dichotomous data, while mean difference and 95% confidence interval for pooling continuous data.

RESULTS

Seven RCTs involving 1760 patients were included in this meta-analysis. All these 7 trials reported the incidence of CI-AKI and compared with placebo or other treatment options, PGE1 was associated with a reduced risk of CI-AKI (OR: 0.38, 95% CI: 0.28-0.53; P < .001) and only a trend for lower post procedure serum creatinine (Scr) levels compared with control groups at 48 hours (MD: -0.03 mg/dL, 95% CI: -0.08 to 0.02 mg/dL; P = .25; 6 trials combined). But the postprocedure Scr levels were significantly reduced in PGE1 groups compared with control groups at 72 hours (MD: -0.07 mg/dL, 95% CI: -0.11 to -0.04 mg/dL; P < .001; 4 trials combined). We also meta-analyzed the postprocedure cystatin C (CysC) at 24 and 48 hours with 2 trials. There were lower postprocedure CysC levels in PGE1 groups than those in control groups (MD: -0.18 mg/L, 95% CI: -0.33 to -0.03 mg/L; P = .02 at 24 hours and MD: -0.14 mg/L, 95% CI: -0.23 to -0.06 mg/L; P = .001 at 48 hours).

CONCLUSIONS

PGE1 provides effective nephroprotection against CI-AKI and may act as a part of effective prophylactic pharmacological regimens.

Efficacy of alprostadil for preventing of contrast-induced nephropathy: A meta-analysis

Contrast-induced nephropathy (CIN) has become the third-leading cause of hospital-acquired acute renal injury. Although alprostadil has been proposed as an effective preventative measure, this conclusion remains inconsistent. Thus, we performed a meta-analysis of the published studies on this topic to evaluate the preventative effect of alprostadil on CIN. Databases, including PubMed, the Web of Science, Cochrane Library, Wanfang, the China Biological Medicine Database (SinoMed) and the China National Knowledge Infrastructure (CNKI) were systematically searched. Nineteen clinical trials involving 2267 individuals were identified. We utilized a random or a fixed effect model to calculate the pooled odd ratios (ORs) and the standardized mean differences (SMD), respectively. Compared to the control group, the CIN risk decreased significantly in the alprostadil group (P < 0.00001, OR = 0.29, 95% CI = 0.21-0.39). In the subgroup of coronary angiography patients, the use of alprostadil also decreased the risk of CIN (P < 0.00001, OR = 0.27, 95% CI: 0.19-0.39). In conclusion, Alprostadil might be associated with a significant reduction in postcontrast Scr, BUN and CysC level and decrease the incidence of CIN.

Iloprost as an acute kidney injury-triggering agent in severely atherosclerotic patients

Background

Iloprost, a stable prostacyclin analog, is used as a rescue therapy for severe peripheral arterial disease (PAD). It has systemic vasodilatory and anti-aggregant effects, with severe vasodilatation potentially causing organ ischaemia when severe atherosclerosis is the underlying cause. In this study, we retrospectively analysed renal outcomes after iloprost infusion therapy in 86 patients.

Methods

Eighty-six patients with PAD who received iloprost infusion therapy were retrospectively analysed. Clinical and biochemical parameters were recorded before (initial, Cr1), during (third day, Cr2), and after (14th day following the termination of infusion therapy, Cr3) treatment. Acute kidney injury (AKI) was defined according to KDIGO guidelines as a ≥ 0.3 mg/dl (26.52 μmol/l) increase in creatinine levels from baseline within 48 hours.

Results:

Cr2 (1.46 ± 0.1 mg/dl) (129.06 ± 8.84 μmol/l) and Cr3 (1.53 ± 0.12 mg/dl) (135.25 ± 10.61 μmol/l) creatinine levels were significantly higher compared to the initial value (1.15 ± 0.6 mg/dl) (101.66 ± 53.04 μmol/l). AKI was observed in 36 patients (41.86%) on the third day of iloprost infusion. Logistic regression analysis revealed smoking and not using acetylsalicylic acid as primary predictors (p = 0.02 and p = 0.008, respectively) of AKI during iloprost treatment. On the third infusion day, patients’ urinary output significantly increased (1813.30 ± 1123.46 vs 1545.17 ± 873.00 cm³) and diastolic blood pressure significantly decreased (70.07 ± 15.50 vs 74.14 ± 9.42 mmHg) from their initial values.

Conclusion

While iloprost treatment is effective in patients with PAD who are not suitable for surgery, severe systemic vasodilatation can cause renal ischaemia, resulting in nonoliguric AKI. Smoking, no acetylsalicylic acid use, and lower diastolic blood pressure are the clinical risk factors for AKI during iloprost treatment.

Comparative Effectiveness of 12 Treatment Strategies for Preventing Contrast-Induced Acute Kidney Injury: A Systematic Review and Bayesian Network Meta-analysis

BACKGROUND

To simultaneously evaluate the relative efficacy of multiple pharmacologic strategies for preventing contrast-induced acute kidney injury (AKI).

STUDY DESIGN

Systematic review containing a Bayesian network meta-analysis of randomized controlled trials.

SETTING & POPULATION

Participants undergoing diagnostic and/or interventional procedures with contrast media.

SELECTION CRITERIA FOR STUDIES

Randomized controlled trials comparing the active drug treatments with each other or with hydration alone.

INTERVENTION

Any of the following drugs in combination with hydration: N-acetylcysteine (NAC), theophylline (aminophylline), fenoldopam, iloprost, alprostadil, prostaglandin E₁, statins, statins plus NAC, bicarbonate sodium, bicarbonate sodium plus NAC, ascorbic acid (vitamin C), tocopherol (vitamin E), α-lipoic acid, atrial natriuretic peptide, B-type natriuretic peptide, and carperitide.

OUTCOMES

The occurrence of contrast-induced AKI.

RESULTS

The trial network included 150 trials with 31,631 participants and 4,182 contrast-induced AKI events assessing 12 different interventions. Compared to hydration, ORs (95% credible intervals) for contrast-induced AKI were 0.31 (0.14-0.60) for high-dose statin plus NAC, 0.37 (0.19-0.64) for high-dose statin alone, 0.37 (0.17-0.72) for prostaglandins, 0.48 (0.26-0.82) for theophylline, 0.62 (0.40-0.88) for bicarbonate sodium plus NAC, 0.67 (0.54-0.81) for NAC alone, 0.64 (0.41-0.95) for vitamins and analogues, 0.70 (0.29-1.37) for natriuretic peptides, 0.69 (0.31-1.37) for fenoldopam, 0.78 (0.59-1.01) for bicarbonate sodium, and 0.98 (0.41-2.07) for low-dose statin. High-dose statin plus NAC or high-dose statin alone were likely to be ranked the best or the second best for preventing contrast-induced AKI. The overall results were not materially changed in metaregressions or subgroup and sensitivity analyses.

LIMITATIONS

Patient-level data were unavailable; unable to include some treatment agents; low event rates; imbalanced distribution of participants among treatment strategies.

CONCLUSIONS

High-dose statins plus hydration with or without NAC might be the preferred treatment strategy to prevent contrast-induced AKI in patients undergoing diagnostic and/or interventional procedures requiring contrast media.

Effects of alprostadil and iloprost on renal, lung, and skeletal muscle injury following hindlimb ischemia-reperfusion injury in rats

OBJECTIVES

To evaluate the effects of alprostadil (prostaglandin [PGE1] analog) and iloprost (prostacyclin [PGI2] analog) on renal, lung, and skeletal muscle tissues after ischemia reperfusion (I/R) injury in an experimental rat model.

MATERIALS AND METHODS

Wistar albino rats underwent 2 hours of ischemia via infrarenal aorta clamping with subsequent 2 hours of reperfusion. Alprostadil and iloprost were given starting simultaneously with the reperfusion period. Effects of agents on renal, lung, and skeletal muscle (gastrocnemius) tissue specimens were examined.

RESULTS

Renal medullary congestion, cytoplasmic swelling, and mean tubular dilatation scores were significantly lower in the alprostadil-treated group than those found in the I/R-only group (P<0.0001, P=0.015, and P<0.01, respectively). Polymorphonuclear leukocyte infiltration, pulmonary partial destruction, consolidation, alveolar edema, and hemorrhage scores were significantly lower in alprostadil- and iloprost-treated groups (P=0.017 and P=0.001; P<0.01 and P<0.0001). Polymorphonuclear leukocyte infiltration scores in skeletal muscle tissue were significantly lower in the iloprost-treated group than the scores found in the nontreated I/R group (P<0.0001).

CONCLUSION

Alprostadil and iloprost significantly reduce lung tissue I/R injury. Alprostadil has more prominent protective effects against renal I/R injury, while iloprost is superior in terms of protecting the skeletal muscle tissue against I/R injury.

PGC1α drives NAD biosynthesis linking oxidative metabolism to renal protection

The energetic burden of continuously concentrating solutes against gradients along the tubule may render the kidney especially vulnerable to ischemia. Indeed, acute kidney injury (AKI) affects 3% of all hospitalized patients.^1,2 Here we show that the mitochondrial biogenesis regulator, PGC1α,^3,4 is a pivotal determinant of renal recovery from injury by regulating NAD biosynthesis. Following renal ischemia, PGC1α^−/− mice developed local deficiency of the NAD precursor niacinamide (Nam), marked fat accumulation, and failure to re-establish normal function. Remarkably, exogenous Nam improved local NAD levels, fat accumulation, and renal function in post-ischemic PGC1α^−/− mice. Inducible tubular transgenic mice (iNephPGC1α) recapitulated the effects of Nam supplementation, including more local NAD and less fat accumulation with better renal function after ischemia. PGC1α coordinately upregulated the enzymes that synthesize NAD de novo from amino acids whereas PGC1α deficiency or AKI attenuated the de novo pathway. Nam enhanced NAD via the enzyme NAMPT and augmented production of the fat breakdown product beta-hydroxybutyrate (β-OHB), leading to increased prostaglandin PGE₂, a secreted autocoid that maintains renal function.⁵ Nam treatment reversed established ischemic AKI and also prevented AKI in an unrelated toxic model. Inhibition of β-OHB signaling or prostaglandins similarly abolished PGC1α-dependent renoprotection. Given the importance of mitochondrial health in aging and the function of metabolically active organs, the results implicate Nam and NAD as key effectors for achieving PGC1α-dependent stress resistance.

Contrast-induced Nephropathy

Contrast-induced nephropathy (CIN) is a serious complication of angiographic procedures resulting from the administration of contrast media (CM). It is the third most common cause of hospital acquired acute renal injury and represents about 12% of the cases. CIN is defined as an elevation of serum creatinine (Scr) of more than 25% or ≥0.5 mg/dl (44 μmol/l) from baseline within 48 h. More sensitive markers of renal injury are desired, therefore, several biomarkers of tubular injury are under evaluation. Multiple risk factors may contribute to the development of CIN; these factors are divided into patient- and procedure-related factors. Treatment of CIN is mainly supportive, consisting mainly of careful fluid and electrolyte management, although dialysis may be required in some cases. The available treatment option makes prevention the corner stone of management. This article will review the recent evidence concerning CIN incidence, diagnosis, and prevention strategies as well as its treatment and prognostic implications.

Prevention of contrast-induced nephropathy with prostaglandin E1 in high-risk patients undergoing percutaneous coronary intervention

PURPOSE

Contrast-induced nephropathy (CIN) is an important complication in the use of iodinated contrast media. The present study aimed to assess the safety and efficacy of prostaglandin E1 (PGE1) in prevention of CIN in patients with high-risk factors undergoing percutaneous coronary intervention (PCI).

METHODS

The study group consisted of 163 patients who had undergone a coronary intervention procedure between January 1, 2012 and October 31, 2012. Study participants were randomly assigned to either the PGE1 group (82 patients) or the control group (81 patients). Patients in the PGE1 group received PGE1 intravenous infusion of 20 ng/kg/min for 6 h before and after the administration of contrast media. The control group received 0.9 % sodium chloride solution for routine hydration only. A nonionic, low-osmolality contrast agent was used in our laboratory at this time. Serum creatinine (Scr) values and estimated glomerular filtration rate were measured before and within 48 h of the administration of contrast agents. CIN was defined as an increase of ≥0.5 mg/dL or ≥ a 25 % increase in Scr concentrations over baseline within 48 h of angiography.

RESULTS

The amount of contrast agent administered was similar for the PGE1 and control groups (156 ± 63 vs. 161 ± 68 mL, P > 0.05). The incidence of CIN was lower in the PGE1 group than in the control group (3.7 vs. 11.1 %, P < 0.05). No serious adverse effects were observed.

CONCLUSIONS

In patients with high-risk factors undergoing PCI, the use of PGE1 for prevention of CIN is safe and efficacious.

Beneficial effects of intra-arterial and intravenous prostaglandin E1 in intestinal ischaemia-reperfusion injury

OBJECTIVES

Ischaemia-reperfusion (I/R) injury is encountered in conditions that diminish intestinal blood flow. There is no clinically feasible technique available for mucosal preservation.

METHODS

One hundred Wistar rats were subjected to intestinal ischaemia for 15 and 60 min (I15', I60'), followed by 1 and 7 days of reperfusion (R1d, R7d). Rats were subjected to ischaemia by clamping the superior mesenteric artery. Prostaglandin E1 (PGE1) (2.500 ng/kg intra-arterial bolus or 20 ng/kg intravenous infusion) was administered immediately prior to the commencement of the experimental period. Animals were divided into 20 groups: sham (laparotomy alone), sacrificed at 1 or 7 days; saline administration, 15 or 60 min of ischaemia, 1 or 7 days of reperfusion; prostaglandin E1 administration, 15 or 60 min of ischaemia, 1 or 7 days of reperfusion, each one for intra-arterial or intravenous administration. Ileal segments were excised and assessed for histopathological score, polymorphonuclear (PMN) leucocytes encountered and myeloperoxidase (MPO) activity measurement.

RESULTS

I/R caused deterioration of histological characteristics. Prophylactic administration of PGE1 resulted in a significant decrease in the histological score compared with the respective saline group (analysis of variance, P < 0.005). In groups treated with PGE1, PMN leucocyte infiltration was lower for the 60 min of ischaemia group (I60'/R1d *P = 0.026; I60'/R7d P = 0.015). I15'/R7d did not lead to a significant reduction in PMN infiltration (P = 0.061). Pretreatment with PGE1 attenuates MPO levels after intestinal I/R injury (P < 0.05). No differences were encountered between types of administration.

CONCLUSIONS

Results of this study showed that administration of prostaglandin E1 prevents I/R injury by diminishing histological damage parameters, inhibiting PMN leucocyte infiltration and attenuating MPO activity.

Combined use of hydration and alprostadil for preventing contrast-induced nephropathy following percutaneous coronary intervention in elderly patients

Contrast-induced nephropathy (CIN) is a complex syndrome of acute kidney injury that follows exposure to intravascular contrast media. Although a series of preventive measures have been developed, CIN remains a major challenge encountered in elderly patients by interventional cardiologists. No data are currently available concerning the potential effects of the combined use of hydration and alprostadil in the prevention of CIN following percutaneous coronary intervention (PCI) in elderly patients. Therefore, the aim of the present study was to investigate the ability of a combination of hydration and alprostadil to prevent CIN following PCI in elderly patients. From June 1, 2010 to January 31, 2012, 85 elderly patients undergoing PCI were included in the present study. The included patients were randomly allocated into three groups: the control (22 cases), hydration (28 cases) and hydration + alprostadil (35 cases) group. Serum creatinine (SCr) levels were measured prior to PCI and then daily for 3 days following PCI. Creatinine clearance (Ccr) was also calculated. Following investigation of the incidence of CIN, a significant decline in Ccr was observed in the control group but not in the hydration + alprostadil group after PCI. The reduction in the level of Ccr from baseline in the hydration + alprostadil group was the smallest among the three groups. Moreover, the highest incidence of CIN was in the control group (6 cases, 27.27%), followed by the hydration group (3 cases, 10.71%) and the hydration + alprostadil group (1 case, 2.86%). Therefore, the combined use of hydration and alprostadil significantly reduces the incidence of CIN in elderly patients undergoing PCI. Hydration and alprostadil are suggested to act synergistically to protect renal function. In conclusion, the combined use of hydration and alprostadil is more effective in the prevention of CIN in elderly patients undergoing PCI compared with hydration alone.

Alprostadil plays a protective role in contrast-induced nephropathy in the elderly

PURPOSE

To evaluate the protective effects of alprostadil on contrast-induced nephropathy (CIN) in elderly patients.

METHODS

We randomized 370 patients into the control or alprostadil group. The patients in the control group were injected with 100 ml sterile saline and the patients in the alprostadil group with alprostadil (0.4 μg/kg/day) in 100 ml sterile saline before and after iohexol-enhanced (100 ml) computed tomography (CT). Serum creatinine (Scr), blood urea nitrogen (BUN), cystatin C (CysC), and creatinine clearance (Ccr) were analyzed or calculated. ΔScr and ΔCysC were determined by the changes between baseline and highest Scr and CysC levels. The standard for CIN was a postdose Scr increase >44.2 μmol/l or >25 % over baseline.

RESULTS

In the control group, peak Scr (P < 0.05) and ΔScr (P < 0.01) were higher than those in the alprostadil group. The postdose CysC at 24 h (P < 0.05), 48 h (P < 0.05), and 72 h (P < 0.05), peak CysC (P < 0.01), and ΔCysC (P < 0.05) in the control group were higher than those in the alprostadil group. The incidence of CIN in the control group was 22.2 %, which was higher than in the alprostadil group (9.1 %, P < 0.01). Subgroup analyses in patients with advanced age (≥ 80 years), concomitant hypertension or diabetes, and abnormal baseline renal function (Ccr ≤ 60 ml/min) showed that the alprostadil group had lower ΔScr and ΔCysC than the control group after contrast-enhanced CT examination in all four subgroups (P < 0.05 or P < 0.01).

CONCLUSIONS

In this cohort of older patients undergoing contrast CT, the use of alprostadil reduced the incidence of CIN.

Use of alpha-lipoic acid in prevention of contrast-induced nephropathy in diabetic patients

In this prospective study, we aimed to determine the protective antioxidant role of alpha-lipoic acid (ALA) on development of contrast-induced nephropathy (CIN) in diabetic patients undergoing coronary angiography. Seventy-eight diabetic patients undergoing coronary angiography were included. Thirty-nine patients were randomized to control group and 39 patients to ALA group. Both groups were hydrated on the day of angiography, and the ALA group had also received three doses of "Thioctacid 600 mg HR, MEDA Manufacturing GmbH" in pill form. Serum creatinine clearance, cystatin C, and urinary neutrophil gelatinase-associated lipocalin (NGAL) were studied before and after angiography. We defined CIN as either ≥25% or ≥0.5 mg/dL increase in serum creatinine at 48th hour after angiography. Baseline clinical characteristics were similar in both groups. Mehran risk score and creatinine clearance were comparable in control and therapy groups (5.59 ± 1.96 vs. 5.49 ± 1.73, p = 0.54 and 89 ± 21 vs. 96 ± 24, p = 0.13, respectively). The volumes of contrast media (median values of 80 mL vs. 75 mL) and hydration with saline (2862 ± 447 mL vs. 2637 ± 592 mL) were also similar (p > 0.05). The incidence of CIN was the same (8%) in both the groups. Alterations in serum creatinine, cystatin C, and urinary NGAL levels before and after the procedure were comparable between the ALA and control groups (group p-values were >0.05 in two-way repeated measures analysis of variance). We presented for the first time that ALA therapy added to hydration does not decrease the risk of CIN development in diabetic patients undergoing coronary angiography.

Oral prostaglandin e1 in combination with sodium bicarbonate and normal saline in the prevention of contrast-induced nephropathy: a pilot study

The purpose of this study was to evaluate the use of prostaglandin E1 (PGE1) as a renal protective medication for patients exposed to contrast agents, as well as to demonstrate the safety, efficacy, and low side-effect profile of PGE1. A prospective, randomized, double-blind study was designed to compare combination of intravenous sodium bicarbonate, normal saline, and oral PGE1 200 μg versus the combination and placebo for renal protection from contrast agents. All patients receiving nonionic contrast during their interventional procedure were eligible for enrollment. Creatinine levels were recorded before and after the administration of contrast and renal protective medications. Contrast-induced nephrotoxicity (CIN) was defined as an increase of 0.5 mg/dL or greater in creatinine level, or an increase of 25% or more above baseline. Age, gender, total amount of contrast used, and incidence of renal failure requiring dialysis were recorded. We conducted the study on 41 patients. Of these, 20 patients received PGE1 and 21 received the placebo. The study group comprised 29 males and 12 females. Diabetes mellitus occurred in 41.5% of the cases (including 40% of PGE1 and 43% of placebo patients). Average contrast use was 77.2 mL (range, 15 to 200 mL). Mean age of the groups was 67.2 years. Average baseline creatinine level was 1.17. The differences between the groups were not statistically significant. CIN by definition occurred in one patient, who received the placebo. Incidence of new onset renal failure requiring dialysis was zero. Postcontrast change in creatinine level for the study was 0.11. There was a change in the creatinine level of 0.161 in the PGE1 group and 0.061 in the placebo group; an improvement of 0.10. PGE1 was not effective in significantly altering postcreatinine levels (p = 0.176). None of the patients enrolled in the study suffered any side effects from taking the PGE1 tablet. Although preliminary, this study shows that the addition of PGE1 for the prevention of CIN is well-tolerated by patients and is a safe modality. Additional studies are required to evaluate efficacy.

The effect of renin-angiotensin-aldosterone system blockade on contrast-induced acute kidney injury: a propensity-matched study

BACKGROUND

The role of the angiotensin-converting enzyme (ACE) inhibitor and angiotensin receptor blocker (ARB) in the pathophysiology of contrast-induced acute kidney injury (AKI) is controversial, and the available literature is contradictory.

STUDY DESIGN

A retrospective propensity score-matched study to analyze the effect of ACE-inhibitor/ARB therapy on the development of contrast-induced AKI.

SETTING & PARTICIPANTS

Using propensity score matching, 1,322 ACE-inhibitor/ARB recipients and nonrecipients were paired for analysis from 5,299 patients and fulfilled the inclusion criteria among 11,447 patients receiving coronary angiography (CAG) or percutaneous coronary intervention.

PREDICTORS

ACE-inhibitor/ARB use based on prescription and risk factors for contrast-induced AKI.

OUTCOMES

The incidence of contrast-induced AKI defined by AKI Network (AKIN) criteria: an absolute increase in serum creatinine levels ≥0.3 mg/dL or a relative increase ≥50% from baseline values within 48 hours after exposure to the contrast medium.

MEASUREMENTS

Baseline serum creatinine, hemoglobin, and albumin levels; volume of contrast agents; preprocedural medication; and post-CAG serum creatinine levels.

RESULTS

An ACE inhibitor/ARB was prescribed for 64.0% of patients receiving CAG. ACE-inhibitor/ARB users showed an increased incidence of contrast-induced AKI after propensity score matching (11.4% vs 6.3%; P < 0.001). In multivariable analysis, use of ACE inhibitors/ARBs remained an independent and significant predictor of contrast-induced AKI in an unmatched cohort (OR, 1.39; 95% CI, 1.10-1.76; P = 0.06). In the matched cohort, use of ACE inhibitors/ARBs also was associated with a higher adjusted OR of contrast-induced AKI (OR, 1.43; 95% CI, 1.06-1.94; P = 0.02).

LIMITATIONS

A retrospective study at a single center.

CONCLUSIONS

Use of ACE inhibitors/ARBs during CAG has a possible influence to increase the incidence of contrast-induced AKI. Further randomized clinical trials are warranted to confirm the effect of ACE-inhibitor/ARB therapy on the development of contrast-induced AKI.

Association between preoperative statin therapy and postoperative change in glomerular filtration rate in endovascular aortic surgery

BACKGROUND

Acute kidney injury during endovascular aortic repair can result in a reduction in the postoperative glomerular filtration rate (GFR). The 'pleiotropic' effects of statins offer a potential mechanism of reducing the postoperative decline in the GFR. We therefore tested the hypothesis that in patients undergoing endovascular aortic repair, the GFR decreases less in patients taking preoperative statins than in those who do not.

METHODS

A cohort investigation of 501 consecutive patients who underwent endovascular aortic repair between June 2005 and March 2007 in an academic tertiary care centre. Multivariable linear regression was used to assess the association between the statin use and the postoperative GFR, after adjusting for the baseline GFR and other confounding covariables selected using a stepwise criterion.

RESULTS

The statin use was not associated with a change in the postoperative GFR (P=0.94); the difference (95% confidence interval) in the mean postoperative GFR (statins minus no statins) was estimated at 0.1 (-3.1, +3.4) ml min(-1) 1.73 m(-2). A decrease in the GFR of ≥ 25% (the threshold to diagnose contrast-induced nephropathy) developed in 26 of 192 patients given statins before operation (13.5%) compared with 36 of 296 patients who were not taking statins (12.2%).

CONCLUSIONS

Statin therapy is not associated with a statistically significant change in the mean postoperative GFR in patients undergoing endovascular aortic surgery, nor a reduction in the risk of a GFR decline of >25%.

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.

Contrast-induced nephropathy in patients undergoing percutaneous coronary intervention

Contrast Induced Nephropathy (CIN) is a feared complication of numerous radiological procedures that expose patients to contrast media. The most notorious of these procedures is percutaneous coronary intervention (PCI). Not only is this a leading cause of morbidity and mortality, but it also adds to increased costs in high risk patients undergoing PCI. It is thought to result from direct cytotoxicity and hemodynamic challenge to renal tissue. CIN is defined as an increase in serum creatinine by either ≥0.5 mg/dL or by ≥25% from baseline within the first 2-3 days after contrast administration, after other causes of renal impairment have been excluded. The incidence is considerably higher in diabetics, elderly and patients with pre-existing renal disease when compared to the general population. The nephrotoxic potential of various contrast agents must be evaluated completely, with prevention as the mainstay of focus as no effective treatment exists. The purpose of this article is to examine the pathophysiology, risk factors, and clinical course of CIN, as well as the most recent studies dealing with its prevention and potential therapeutic interventions, especially during PCI. The role of gadolinium as an alternative to iodinated contrast is also discussed.

Prevention of acute kidney injury and protection of renal function in the intensive care unit. Expert opinion of the Working Group for Nephrology, ESICM

BACKGROUND

Acute renal failure on the intensive care unit is associated with significant mortality and morbidity.

OBJECTIVES

To determine recommendations for the prevention of acute kidney injury (AKI), focusing on the role of potential preventative maneuvers including volume expansion, diuretics, use of inotropes, vasopressors/vasodilators, hormonal interventions, nutrition, and extracorporeal techniques.

METHOD

A systematic search of the literature was performed for studies using these potential protective agents in adult patients at risk for acute renal failure/kidney injury between 1966 and 2009. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, and use of potentially nephrotoxic drugs and radiocontrast media. Where possible the following endpoints were extracted: creatinine clearance, glomerular filtration rate, increase in serum creatinine, urine output, and markers of tubular injury. Clinical endpoints included the need for renal replacement therapy, length of stay, and mortality. Studies are graded according to the international Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) group system.

CONCLUSIONS AND RECOMMENDATIONS

Several measures are recommended, though none carries grade 1A. We recommend prompt resuscitation of the circulation with special attention to providing adequate hydration whilst avoiding high-molecular-weight hydroxy-ethyl starch (HES) preparations, maintaining adequate blood pressure using vasopressors in vasodilatory shock. We suggest specific vasodilators [corrected] under strict hemodynamic control, sodium bicarbonate for emergency procedures administering contrast media, and periprocedural hemofiltration in severe chronic renal insufficiency undergoing coronary intervention.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s00134-009-1678-y) contains supplementary material, which is available to authorized users.

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.

Prevention of contrast-induced nephropathy: an overview

Many unknowns remain concerning how best to reduce a patient's risk of contrast-induced nephropathy (CIN). Many interventions have been proposed, but few have gone unchallenged, and new questions have arisen from analysis of serum creatinine variations in patients who have not been exposed to radiographic iodinated contrast media (RICM). Use of alternate imaging tests that do not use RICM is the most direct way to avoid CIN. Hydration remains the bulwark of intervention when RICM must be administered. The administration of N-acetylcysteine is a popular pharmacologic prophylaxis against CIN but its efficacy is unclear. Hemodialysis has not been effective, but hemofiltration has shown good results in limited series.

Iloprost prevents contrast-induced nephropathy in patients with renal dysfunction undergoing coronary angiography or intervention

BACKGROUND

The prevention of contrast-induced nephropathy, which accounts for considerable morbidity and mortality, remains a vexing problem. Contrast-induced renal vasoconstriction is believed to play a pivotal role in the pathogenesis of contrast-induced nephropathy. The aim of this study was to examine the efficacy of the prostacyclin analog iloprost in preventing contrast-induced nephropathy in patients with renal dysfunction undergoing a coronary procedure.

METHODS AND RESULTS

We conducted a randomized, double-blind, placebo-controlled trial of iloprost in 208 patients with a serum creatinine concentration >or=1.4 mg/dL who underwent coronary angiography and/or intervention. Iloprost 1 ng kg(-1) min(-1) or placebo was administered intravenously beginning 30 to 90 minutes before and ending 4 hours after the procedure. Contrast-induced nephropathy was defined by an absolute increase in serum creatinine >or=0.5 mg/dL or a relative increase >or=25% measured 2 to 5 days after the procedure. Contrast-induced nephropathy occurred in 23 of the 105 patients (22%) in the control group and in 8 of the 103 patients (8%) in the iloprost group (odds ratio, 0.29; 95% confidence interval, 0.12 to 0.69; P=0.005). In the control group, the estimated glomerular filtration rate declined from 49.7+/-15.5 to 46.6+/-16.6 mL min(-1) 1.73 m(-2) (P=0.01). In the iloprost group, the estimated glomerular filtration rate increased marginally from 47.5+/-14.5 to 48.6+/-16.1 mL min(-1) 1.73 m(-2) (P=0.26). The mean absolute estimated glomerular filtration rate decline in the control group was greater than its change in the iloprost group (difference, 4.2 mL min(-1) 1.73 m(-2); 95% confidence interval, 1.1 to 7.3; P=0.008).

CONCLUSIONS

Prophylactic administration of iloprost may protect against contrast-induced nephropathy in high-risk patients undergoing a coronary procedure.

Incidence of contrast-induced nephropathy in patients with chronic renal insufficiency undergoing multidetector computed tomographic angiography treated with preventive measures

Contrast-induced nephropathy (CIN) is associated with adverse outcomes. Strategies for its prevention have been evaluated for patients undergoing invasive coronary and peripheral angiography, including treatment with N-acetylcysteine, sodium bicarbonate, and use of iso-osmolar nonionic contrast. Recently, multidetector computed tomographic angiography (MDCTA) of the coronary and peripheral arteries has been introduced as an accurate method for assessing vascular stenosis and has been widely adopted for assessment of outpatients with suspected coronary artery disease or peripheral arterial disease. To date, the incidence of CIN in outpatients with chronic renal insufficiency (CRI) treated with CIN-preventive strategies undergoing MDCTA remains unknown. Thus, we evaluated the incidence of CIN in outpatients with CRI (creatinine 1.5 to 2.5 mg/dl) undergoing MDCTA using CIN-preventive measures; 400 patients with CRI (78.5% men, mean age 76 years, 41% with diabetes) underwent MDCTA with iodixanol for detection of coronary artery disease or peripheral arterial disease (mean contrast volume 101 cc). CIN was defined as a nonallergic creatinine increase of >0.5 mg/dl. Creatinine levels were obtained before and 3 to 5 days after MDCTA; the average creatinine levels were 1.80 mg/dl and 1.75 mg/dl, respectively (p = NS), with an average change of -0.03 mg/dl. In the study cohort, only 7 patients (1.75%) experienced a creatinine increase >0.5 mg/dl, satisfying the definition of CIN. In conclusion, multivariate analysis, diabetes was the only predictor for CIN (odds ratio 5.9, 95% confidence interval 1.0 to 33.3, p = 0.045). No patient required hemodialysis. In conclusion, in patients with CRI undergoing MDCTA and receiving CIN-preventive measures, the incidence of CIN is low.

Contrast-induced nephropathy

Contrast induced nephropathy (CIN) is an iatrogenic disorder, resulting from exposure to contrast media. Contrast-induced hemodynamic and direct cytotoxic effects on renal structures are highly evident in its pathogenesis, whereas other mechanisms are still poorly understood. CIN is typically defined as an increase in serum creatinine by either > or =0.5 mg/dl or by > or =25% from baseline within the first 2-3 days after contrast administration. Although rare in the general population, CIN has a high incidence in patients with an underlying renal disorder, in diabetics, and the elderly. The risk factors are synergistic in their ability to produce CIN. The best way to prevent CIN is to identify the patients at risk and to provide adequate peri-procedural hydration. The role of various drugs in prevention of CIN is still controversial and warrants future studies. Despite remaining uncertainty regarding the degree of nephrotoxicity produced by various contrast agents, in current practice non-ionic low-osmolar contrast media are preferred over the high-osmolar contrast media in patients with renal impairment.

Prevention of contrast induced nephropathy: recommendations for the high risk patient undergoing cardiovascular procedures

Contrast induced nephropathy (CIN) is the third leading cause of hospital acquired renal failure and is associated with significant morbidity and mortality. Chronic kidney disease is the primary predisposing factor for CIN. As estimated glomerular filtration rate<60 ml/1.73 m2 represents significant renal dysfunction and defines patients at high risk. Modifiable risk factors for CIN include hydration status, the type and amount of contrast, use of concomitant nephrotoxic agents and recent contrast administration. The cornerstone of CIN prevention, in both the high and low risk patients, is adequate parenteral volume repletion. In the patient at increased risk for CIN it is often appropriate to withhold potentially nephrotoxic medications, and consider the use of n-acetylcysteine. In patients at increased risk for CIN the use of low or iso-osomolar contrast agents should be utilized and strategies employed to minimize contrast volume. In these patients serum creatinine should be obtained forty-eight hours post procedure and it is often appropriate to continue withholding medications such as metformin or non steroidal anti-inflammatories until renal function returns to normal.

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.

Effect of prostaglandin E1 on ischemia-reperfusion injury during abdominal aortic aneurysm surgery

OBJECTIVE

Abdominal aortic aneurysm (AAA) surgery subjects the lower extremities to ischemia and reperfusion. Although it is not extensive or prolonged, ischemia of the lower extremities during aortic cross-clamping is gradually and steadily induced. We studied the effects of prostaglandin E1 (PGE1) on ischemia-reperfusion injury of the lower extremities during AAA repair.

METHODS

During AAA surgery, two near-infrared spectroscopy probes were positioned on each calf muscle to monitor oxygen metabolism in the lower extremities. We also measured lactate concentration in both iliac veins.

RESULTS

Near-infrared spectroscopy signals responded sensitively to aortic cross-clamping and declamping. Lactate increased time-dependently during aortic cross-clamping. The continuous venous administration of PGE1 (20 ng/kg per minute) inhibited the accumulation of lactate during aortic cross-clamping. Declamping of the first iliac artery resulted in a further but transient increase in ipsilateral venous lactate, which may be one component in the mechanism of declamping shock. Prostaglandin E1 eliminated the transient increase in ipsilateral lactate. The administration of PGE1 inhibited the contralateral accumulation of lactate after first declamping, and the lactate level decreased gradually before the second declamping.

CONCLUSIONS

Prostaglandin E1 seems to have a protective effect against ischemia-reperfusion injury of the lower extremities during AAA surgery.

Iloprost for prevention of contrast-mediated nephropathy in high-risk patients undergoing a coronary procedure. Results of a randomized pilot study

OBJECTIVE

The prevention of contrast-mediated nephropathy (CMN), which accounts for considerable morbidity and mortality, remains a vexing problem. Contrast induced renal vasoconstriction is believed to play a pivotal role in the CMN mechanism. The aim of this pilot study was to examine the safety and efficacy of two doses of the prostacyclin analogue iloprost in preventing CMN in high-risk patients undergoing a coronary procedure.

METHODS

Forty-five patients undergoing coronary angiography and/or intervention who had a serum creatinine concentration >or=1.4 mg/dL were randomized to receive iloprost at 1 or 2 ng/kg/min or placebo, beginning 30-90 minutes before and terminating 4 hours after the procedure. CMN was defined by an absolute increase of serum creatinine >or=0.5 mg/dL or a relative increase of >or=25% measured 2 to 5 days after the procedure. Study drug infusion was discontinued in 2 patients in the low-dose iloprost group due to flush/nausea and in 5 patients in the high-dose group due to severe hypotension.

RESULTS

The mean creatinine concentration change in the placebo group (0.02 mg/dL) was unfavorable compared to that in the low-dose iloprost group (-0.11 mg/dL; p=0.08) and high-dose iloprost group (-0.23 mg/dL; p=0.048). The difference between the absolute changes in creatinine clearance was favorable compared to placebo for both the low (mean difference 6.1 mL/min, 95%CI -0.5 to 12.8 mL/min, p=0.07) and the high-dose iloprost group (11.8 mL/min, 95%CI 4.7 to 18.8 mL/min, p=0.002). Three cases of CMN were recorded; all in the placebo group (p=0.032).

CONCLUSIONS

The results of this pilot study suggest that prophylactic administration of iloprost may effectively prevent CMN, but higher dosages are connected with substantial tolerability issues.

Uroangiographic Contrast Media-Induced Nephropathy: Correlations between Their Physicochemical Properties and Renal Damage

Contrast media-induced nephropathy (CN) is an important cause of hospital-acquired acute renal failure. Patients with both diabetes mellitus and renal impairment are at high risk. CN pathophysiology involves activation of the tubulo-glomerular feedback and vasoactive mediators such as renin-angiotensin 2, endothelin, adenosine, ADH, etc. The risk of CN can be minimized by the use of non-ionic, low or isoosmolar, contrast material, adequate hydration and prophylactic pharmacological measures. In patients with chronic renal failure who are undergoing arteriography (e.g. coronary angiography and angioplasty), periprocedural hemofiltration appears effective in preventing further renal damage due to contrast agents.

PGE2 alleviates kidney and liver damage, decreases plasma renin activity and acute phase response in cirrhotic rats with acute liver damage

In this study, we evaluated the effect of prostaglandin E2 (PGE2) on renal and hepatic function using an experimental cirrhosis model plus acute liver damage (ALD). Male Wistar rats treated with carbon tetrachloride (CCl4) for 8 weeks were used for the cirrhosis model. Cirrhotic rats were further exposed to an additional acute dose of CCl4 to induce ALD and then treated with PGE2 intramuscularly twice a day for 7 days (200 microg/Kg/day). PGE2 administration started 3 h after the additional dosing of CCl4 and PGE2 effect on hepatorenal function was examined on days 1, 2, 3, and 7. PGE2-treatment ameliorated the decrease in urinary sodium excretion, and normalized serum activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and plasma renin observed in cirrhotic rats with ALD. In addition, PGE2-treatment decreased mean arterial pressure, glomerular hypercellularity and thickening of the kidney capillary wall, and liver steatosis and cellular necrosis. Also, PGE2 increased the number of regenerative nodules. Finally, PGE2-treatment inhibited the increase in Alpha 1-acid glycoprotein (pAGP), fibrinogen, and Apo A-1 mRNA expression by 83%, 59%, and 77%, respectively. These results suggest that PGE2 administration may decrease the expression of acute phase proteins. In conclusion, PGE2-treatment improved hepatic and renal function and may be useful to down-regulate the acute phase response in cirrhotic rats presenting ALD induced by CCl4.

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.

Clinical and Experimental Evidence for Prevention of Acute Renal Failure Induced by Radiographic Contrast Media

Acute renal failure still occurs as a complication after radiographic examination using iodinated radiocontrast medium. The incidence rate of radiocontrast medium-induced nephropathy (radiocontrast nephropathy) is low (2 - 3%) in general. However, the rate is remarkably elevated in patients with pre-existing renal insufficiency. Radiocontrast nephropathy is associated with increased morbidity and mortality, particularly in patients with percutaneous coronary interventions. Although the reduction in renal blood flow and direct toxic action on renal tubular cells are considered to be involved, little is known about the etiology of radiocontrast nephropathy. A number of agents that improve renal circulation have been clinically tested for prevention of radiocontrast nephropathy, but none of them has succeeded. Protection of renal tubular cells against oxidative stress is another approach to avoid radiocontrast nephropathy. Prophylactic effects of antioxidants such as N-acetylcysteine and ascorbic acid have been reported by several investigators, although the effectiveness of these compounds is still a matter of debate. At present, hydration is regarded as the only effective, though incomplete, prophylactic regimen for radiocontrast nephropathy. Recently, we have shown that caspase-dependent apoptosis is an important factor in the pathogenesis of radiocontrast nephropathy and clarified cellular mechanisms underlying the radiocontrast media-induced apoptosis. This review summarizes clinical and experimental evidence for the etiology and prevention of radiocontrast nephropathy.

Prevention of contrast media nephrotoxicity--the story so far

Contrast media nephrotoxicity (CMN) in patients with pre-existing renal impairment remains a clinically significant problem. The first step to reduce the chance of CMN is to identify patients at risk through the use of screening questionnaires and renal function measurement. Patients at risk requiring injection of contrast medium (CM) because of important clinical indications should receive a small dose of either non-ionic iso-osmolar dimeric or non-ionic low osmolar monomeric CM and hydration. Intravenous infusion (1 ml/kg body weight/h) of 0.9% saline starting 4 h before CM injection and continuing for at least 12 h afterwards is effective in reducing the incidence of CMN. Prophylactic haemodialysis does not lower the risk of this complication. The value of pharmacological manipulation with renal vasodilators (calcium channel blockers, dopamine, atrial natriuretic peptide, fenoldopam (selective dopamine-1 receptor agonist), prostaglandin E(1), non-selective adenosine receptors antagonist (theophylline), non-selective endothelin receptor antagonist or the antioxidant acetylcysteine has not been fully proven. However, haemofiltration for several hours before and after contrast medium injection offers good protection against CMN in patients with advanced renal disease.

Prevention and nondialytic treatment of acute renal failure

Based on the progress made during the last few years in understanding the pathophysiology of acute renal failure, a plethora of therapeutic drug and nondrug interventions have been developed and tested in animal and human forms of this disease. The first part of this article focuses on the role of volume expansion and vasopressors in the prevention and treatment of acute renal failure in the critically ill. From all prophylactic measures that have been proposed, volume expansion, or at least correction of volume depletion, remains the most efficient and most evidence-based intervention in these patients. Norepinephrine is, out of all the vasopressors, probably the most appropriate to use in cases of hypotension, provided circulating volume is adequate. In hypotensive septic patients, vasopressin has been shown to be useful. Direct renal vasodilating substances, the most popular still being low-dose dopamine, have never been proved to be useful in carefully performed prospective trials. Moreover dopamine especially is associated with a number of side effects and complications. From the agents acting on tubular factors, the diuretic mannitol and loop diuretics are the most prescribed. Only in specific situations such as rhabdomyolysis and kidney transplant surgery has it been shown that mannitol was able to prevent acute renal failure. The loop diuretics are able, after establishing adequate circulating volume, to promote diuresis in some forms of oliguric acute renal failure; however, some recent papers have shown that the administration of loop diuretics may actually be associated with increased mortality and delayed recovery of renal function. The last few years have seen a number of trials with acetylcysteine in the prevention of mainly radiocontrast nephropathy. Although the results are still conflicting, the majority indicates that acetylcysteine, when applied together with adequate volume expansion, may be a useful drug to incorporate in the standard treatment procedures in patients at risk for acute renal failure. Interventions to stimulate the recovery process of the damaged kidney with growth factors, although theoretically sound, have thus far not led to successful results.

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.

Nephrotoxic effects in high-risk patients undergoing angiography

BACKGROUND

The use of iodinated contrast medium can result in nephropathy. Whether iso-osmolar contrast medium is less nephrotoxic than low-osmolar contrast medium in high-risk patients is uncertain.

METHODS

We conducted a randomized, double-blind, prospective, multicenter study comparing the nephrotoxic effects of an iso-osmolar, dimeric, nonionic contrast medium, iodixanol, with those of a low-osmolar, nonionic, monomeric contrast medium, iohexol. The study involved 129 patients with diabetes with serum creatinine concentrations of 1.5 to 3.5 mg per deciliter who underwent coronary or aortofemoral angiography. The primary end point was the peak increase from base line in the creatinine concentration during the three days after angiography. Other end points were an increase in the creatinine concentration of 0.5 mg per deciliter or more, an increase of 1.0 mg per deciliter or more, and a change in the creatinine concentration from day 0 to day 7.

RESULTS

The creatinine concentration increased significantly less in patients who received iodixanol. From day 0 to day 3, the mean peak increase in creatinine was 0.13 mg per deciliter in the iodixanol group and 0.55 mg per deciliter in the iohexol group (P=0.001; the increase with iodixanol minus the increase with iohexol, -0.42 mg per deciliter [95 percent confidence interval, -0.73 to -0.22]). Two of the 64 patients in the iodixanol group (3 percent) had an increase in the creatinine concentration of 0.5 mg per deciliter or more, as compared with 17 of the 65 patients in the iohexol group (26 percent) (P=0.002; odds ratio for such an increase in the iodixanol group, 0.09 [95 percent confidence interval, 0.02 to 0.41]). No patient receiving iodixanol had an increase of 1.0 mg per deciliter or more, but 10 patients in the iohexol group (15 percent) did. The mean change in the creatinine concentration from day 0 to day 7 was 0.07 mg per deciliter in the iodixanol group and 0.24 mg per deciliter in the iohexol group (P=0.003; value in the iodixanol group minus the value in the iohexol group, -0.17 mg per deciliter [95 percent confidence interval, -0.34 to -0.07]).

CONCLUSIONS

Nephropathy induced by contrast medium may be less likely to develop in high-risk patients when iodixanol is used rather than a low-osmolar, nonionic contrast medium.

Contrast nephropathy : an evidence-based approach to prevention

Contrast-induced nephropathy occurs in 2-10% of patients exposed to intravascular radiographic contrast agents and results in significant morbidity and mortality. Although the exact mechanism of this disorder has not been fully elucidated, contrast nephropathy is probably due to a combination of decreased renal medullary blood flow, resulting in medullary ischemia, and direct toxicity to renal tubules. Contrast nephropathy is most commonly defined as either a >25% increase or a >0.5 mg/dL rise in serum creatinine level within 48 hours of contrast medium exposure. Baseline characteristics associated with an increased risk for development of contrast nephropathy include the presence of baseline renal dysfunction, diabetes mellitus, congestive heart failure, volume depletion, and concomitant administration of nephrotoxic drugs. Many strategies have been investigated in an effort to prevent the occurrence of renal dysfunction following contrast media exposure. Intravenous hydration has been shown to significantly decrease the incidence of nephropathy in high-risk patients. However, trials of several prophylactic pharmacologic interventions have been mostly disappointing, including the administration of calcium channel antagonists, diuretics, dopamine, endothelin receptor antagonists and fenoldopam. The use of N-acetylcysteine has been shown in some trials to decrease the incidence of contrast nephropathy in patients with a baseline renal dysfunction, and should currently be strongly considered in this high-risk patient subgroup in addition to hydration. Our purpose is to review the contemporary literature regarding contrast-induced renal dysfunction and present an evidence-based approach for prevention of this complication.