Prostaglandin E1: a new agent for the prevention of renal dysfunction in high risk patients caused by radiocontrast media? PGE1 Study Group

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

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

Efficacy of Alprostadil in Preventing Contrast-Induced Nephropathy: A Systematic Review and Meta-Analysis

This study aimed to determine the efficacy of alprostadil in preventing contrast-induced nephropathy (CIN). Eligible studies were searched using the keywords through the databases of PubMed, Cochrane, Embase, China Biological Medicine Database, China National Knowledge Infrastructure, and Vanfun. Quality evaluation of the included studies was conducted according to international evidence evaluation and recommended Grades of Recommendations Assessment, Development, and Evaluation standards. We included 29 studies with 5623 patients. Compared with hydration, 10 µg/d alprostadil or 20 µg/d alprostadil plus hydration significantly decreased the incidence of CIN. Compared with hydration, alprostadil plus hydration significantly reduced serum creatinine and blood urea nitrogen at 24, 48, and 72 hours and 7 days after coronary angiography (CAG). Alprostadil (20 µg/d) plus hydration significantly decreased serum cystatin versus hydration at 24, 48, and 72 hours after CAG. Compared with hydration, alprostadil plus hydration significantly increased glomerular filtration rate at 24 and 72 hours after CAG. Alprostadil plus hydration significantly decreased neutrophil gelatinase-associated lipocalin levels compared to hydration at 24, 48, and 72 hours after CAG. Alprostadil plus hydration significantly decreased urine macroglobulin versus hydration at 24 and 48 hours after CAG.

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.

Prostanoids and their analogues for the treatment of pulmonary hypertension in neonates

BACKGROUND

Persistent pulmonary hypertension of the newborn (PPHN) is a disease entity that describes a physiology in which there is persistence of increased pulmonary arterial pressure. PPHN is characterised by failure to adapt to a functional postnatal circulation with a fall in pulmonary vascular resistance. PPHN is responsible for impairment in oxygenation and significant neonatal mortality and morbidity. Prostanoids and their analogues may be useful therapeutic interventions due to their pulmonary vasodilatory and immunomodulatory effects.

OBJECTIVES

Primary objective• To determine the efficacy and safety of prostanoids and their analogues (iloprost, treprostinil, and beraprost) in decreasing mortality and the need for extracorporeal membrane oxygenation (ECMO) among neonates with PHSecondary objective• To determine the efficacy and safety of prostanoids and their analogues (iloprost, treprostinil, and beraprost) in decreasing neonatal morbidity (necrotizing enterocolitis (NEC), chronic lung disease (CLD), retinopathy of prematurity (ROP), intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), length of hospital stay, and duration of mechanical ventilation) and improving neurodevelopmental outcomes among neonates with PHComparisons• Prostanoids and their analogues at any dosage or duration used to treat PPHN versus 'standard treatment without these agents', placebo, or inhaled nitric oxide (iNO) therapy• Prostanoids and their analogues at any dosage or duration used to treat refractory PPHN as an 'add-on' therapy to iNO versus iNO alone SEARCH METHODS: We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 9), MEDLINE via PubMed (1966 to 16 September 2018), Embase (1980 to 16 September 2018), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to 16 September 2018). We also searched clinical trials databases, conference proceedings of the Pediatric Academic Societies (1990 to 16 September 2018), and the reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials. We contacted authors who have published in this field as discerned from the reference lists of identified clinical trials and review authors' personal files.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials evaluating prostanoids or their analogues (at any dose, route of administration, or duration) used in neonates at any gestational age less than 28 days' postnatal age for confirmed or suspected PPHN.

DATA COLLECTION AND ANALYSIS

We used the standard methods of Cochrane Neonatal to conduct a systematic review and to assess the methodological quality of included studies (neonatal.cochrane.org/en/index.html). Three review authors independently assessed the titles and abstracts of studies identified by the search strategy and obtained full-text versions for assessment if necessary. We designed forms for trial inclusion or exclusion and for data extraction. We planned to use the GRADE approach to assess the quality of evidence.

MAIN RESULTS

We did not identify any eligible neonatal trials evaluating prostanoids or their analogues as sole agents in the treatment of PPHN.

AUTHORS' CONCLUSIONS

Implications for practiceCurrently, no evidence shows the use of prostanoids or their analogues as pulmonary vasodilators and sole therapeutic agents for the treatment of PPHN in neonates (age 28 days or less).Implications for researchThe safety and efficacy of different preparations and doses and routes of administration of prostacyclins and their analogues in neonates must be established. Well-designed, adequately powered, randomized, multi-center trials are needed to address the efficacy and safety of prostanoids and their analogues in the treatment of PPHN. These trials should evaluate long-term neurodevelopmental and pulmonary outcomes, in addition to short-term outcomes.

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.

Current and Future Treatments for Persistent Pulmonary Hypertension in the Newborn

Persistent pulmonary hypertension in newborn (PPHN) is a serious and possibly fatal syndrome characterized by sustained foetal elevation of pulmonary vascular resistance at birth. PPHN may manifest secondary to other conditions as meconium aspiration syndrome, infection and congenital diaphragmatic hernia. This MiniReview provides the reader with an overview of current and future treatment options for patients with PPHN without congenital diaphragmatic hernia. The study is based on systematic searches in the databases PubMed and Cochrane Library and registered studies on Clinicaltrials.gov investigating PPHN. Inhaled nitric oxide (iNO) is well documented for treatment of PPHN, but 30% fail to respond to iNO. Other current treatment options could be sildenafil, milrinone, prostaglandin analogues and bosentan. There are several ongoing trials with sildenafil, but evidence is lacking for the other treatments and/or for the combination with iNO. Currently, there is no evidence for effect in PPHN of other treatments, for example tadalafil, macitentan, ambrisentan, riociguat and selexipag used for pulmonary arterial hypertension in adults. Experimental studies in animal models for PPHN suggest effect of a series of approaches including recombinant human superoxide dismutase, L-citrulline, Rho-kinase inhibitors and peroxisome proliferator-activated receptor-γ agonists. We conclude that iNO is the most investigated and the only approved pulmonary vasodilator for infants with PPHN. In the iNO non-responders, sildenafil currently seems to be the best alternative either alone or in combination with iNO. Systematic and larger clinical studies are required for testing the other potential treatments of PPHN.

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.

Sodium Bicarbonate Prevents Contrast-Induced Nephropathy in Addition to Theophylline: A Randomized Controlled Trial

In this study, we investigated whether hydration with sodium bicarbonate is superior to hydration with saline in addition to theophylline (both groups) in the prophylaxis of contrast-induced nephropathy (CIN). It was a prospective, randomized, double-blinded study in a university hospital on 2 general intensive care units (63% of investigations) and normal wards.After approval of the local ethics committee and informed consent 152 patients with screening serum creatinine ≥1.1 mg/dL and/or at least 1 additional risk factor for CIN undergoing intravascular contrast media (CM) exposure were randomized to receive a total of 9 mL/kg bicarbonate 154 mmol/L (group B; n = 74) or saline 0.9% (group S; n = 78) hydration within 7 h in addition to intravenous application of 200 mg theophylline. Serum creatinine was determined immediately before, 24 and 48 h after CM exposure. As primary endpoint we investigated the incidence of CIN (increase of serum creatinine ≥0.5 mg/dL and/or ≥25% within 48 h of CM).Both groups were comparable regarding baseline characteristics. Incidence of CIN was significantly less frequent with bicarbonate compared to sodium hydration (1/74 [1.4%] vs 7/78 [9.0%]; P = 0.035). Time course of serum creatinine was more favorable in group B with decreases in serum creatinine after 24 h (-0.084 mg/dL [95% confidence interval: -0.035 to -0.133 mg/dL]; P = 0.008) and 48 h (-0.093 mg/dL (-0.025 to -0.161 mg/dL); P = 0.007) compared to baseline which were not observed in group S.In patients at increased risk of CIN receiving prophylactic theophylline, hydration with sodium bicarbonate reduces contrast-induced renal impairment compared to hydration with saline.

Brain natriuretic peptide for prevention of contrast-induced nephropathy after percutaneous coronary intervention or coronary angiography

BACKGROUND

Many methods reportedly prevent contrast-induced nephropathy (CIN), but the effect of brain natriuretic peptide (BNP) on CIN is unknown. In this study we investigated recombinant BNP use before coronary angiography (CA) or nonemergent percutaneous coronary intervention (PCI) in patients with unstable angina.

METHODS

One thousand patients with unstable angina were prospectively evaluated. The patients were randomly assigned to: group A, isotonic normal saline (NaCl 0.9%, 1 mL/kg/h) for 24 hours before CA or PCI; and group B, human recombinant BNP (rhBNP; 0.005 μg/kg/min). Serum creatinine (Scr) levels and estimated glomerular filtration rate were measured before and 24, 48, and 72 hours, and 7 days after the procedure. The primary outcome was CIN incidence defined according to a relative (≥ 25%) or absolute (≥ 0.5 mg/dL and 44 μmol/L, respectively) increase in Scr from baseline within 48 hours. The secondary end points were the changes in the Scr and estimated glomerular filtration rate, before and after the procedure.

RESULTS

Contrast volume, a history of diabetes mellitus, and BNP administration independently predicted CIN. The incidence of CIN was significantly greater in group A than in group B (14.8% vs 5.6%; P < 0.01). Renal function was less compromised in patients who received rhBNP. The Scr of all patients with CIN remained increased for 24 hours, but it was lower and recovered faster in patients who received rhBNP.

CONCLUSIONS

rhBNP administration before CA or PCI protects renal function and can significantly decrease CIN incidence.

Acute kidney injury by radiographic contrast media: pathogenesis and prevention

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

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.

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

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

Prophylaxis of contrast-induced nephrotoxicity

Contrast-induced nephrotoxicity (CIN) is a form of acute kidney injury that follows intravascular contrast media exposure. CIN may be preventable because its risk factors are well established and the timing of renal insult is commonly known in advance. However, contrast-induced nephrotoxicity is still the third leading cause of iatrogenic renal failure. This important complication accounts up to 10% of acute renal failure cases in hospitalized patients and it is associated with increased short- and long-term morbidity and mortality. Prolonged hospitalization follows and overall increases healthcare resource utilization. This paper will discuss the various prophylactic procedures tested in clinical trials.

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.

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.

[Effects of salvianolate combined with alprostadil and reduced glutathione on progression of chronic renal failure in patients with chronic kidney diseases: a long-term randomized controlled trial]

BACKGROUND

Effects of traditional Chinese medicine salvianolate combined with alprostadil and reduced glutathione on delay of progression in patients with acute kidney injury has been confirmed, but the role of this combination therapy on the progression of chronic renal failure is uncertain.

OBJECTIVE

To investigate the long-term effects of regular administration of salvianolate combined with Western medicine on the progression of chronic renal failure in patients with chronic kidney diseases (CKDs).

DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS

The study was performed at the ward of the Nephrology Department, Changhai Hospital, Second Military Medical University from August 2004 to October 2010. Thirty patients with CKDs at stage 2 to 4 and impaired renal function were recruited and randomly assigned to a treatment group or a control group, which consisted of 15 patients in each. Based on conventional therapy with the same oral medicines in the control group, patients in the treatment group were treated with salvianolate combined with alprostadil and reduced glutathione liquid intravenously for 7 to 10 d. Patients in the control group did not receive this combination therapy. The therapy was repeated monthly in patients in the treatment group. The follow-up time was an average of four years.

MAIN OUTCOME MEASURES

Assessment of renal function, count of white blood cells, and test of serum hemoglobin, electrolytes and albumin were performed before and every year after treatment. Study endpoints were the serum creatinine level doubled from baseline or receiving replacement therapy. Number of remaining patients in each group was calculated at the end of every year.

RESULTS

White blood cell count, serum albumin and electrocyte levels changed little in two groups after four years (P>0.05). Average serum hemoglobin levels in patients in the treatment group was elevated markedly compared with that in the control group after being treated for two years (P<0.01). The percentage of patients reaching the study termination in the treatment group (40%) decreased significantly compared with that (93%) in the control group (P<0.01).

CONCLUSION

The regular integrated traditional Chinese and Western medicine can effectively delay the deterioration of renal function in patients with CKDs over a period of four years.

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.

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 nephropathy--a review of current literature and guidelines

The use of iodine-based contrast agents always entails the risk of contrast-induced nephropathy (CIN). The recently observed dramatic increase in the number of examinations and therapeutic procedures using iodine-based contrast media led us to conduct a thorough analysis of the growing number of scientific reports and collective works devoted to contrast-induced nephropathy, based on current definitions, epidemiology, pathophysiology, risk factors, successful prophylaxis and guidelines of the European Society of Urogenital Radiology (ESUR).

Radiological contrast agents are the third most common cause of nephropathy among in-patients, accounting for 11–12% of cases. CIN is connected with some clinically significant consequences, including increased morbidity, prolonged hospitalisation, increased risk of complications, potential need for dialysis and increased mortality rate. A significant increase in the number of examinations applying iodine-based contrast media in the course of inpatient procedures requires close cooperation of the clinician and radiologist, supported by knowledge of all CIN issues. In order to protect patients from contrast-induced nephropathy, it is necessary to monitor their renal function, indentify patients with risk factors, refer patients for examinations in a responsible manner, and undertake successful preventive measures.

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.

Risk Factors and Therapy Strategies for Contrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is associated with increased morbidity and mortality, as well as increased costs for medical care, particularly in patients with diabetes mellitus and chronic renal failure. A key step to safer CIN is to identify patients at risk and applying proven preventive interventions. Extracellular volume expansion, minimizing the dose of contrast media, using low-osmolar non-ionic contrast media, stopping the intake of nephrotoxic drugs, and avoiding short intervals between procedures have all been shown to be effective in reducing CIN. The aim of the present review is to summarize the knowledge about the risk factors and prophylactic treatments of CIN.

Effects of allopurinol and vitamin E on renal function in patients with cardiac coronary artery bypass grafts

Background:

Acute renal failure is a common complication of cardiac surgery, with oxidants found to play an important role in renal injury. We therefore assessed whether the supplemental antioxidant vitamin E and the inhibitor of xanthine oxidase allopurinol could prevent renal dysfunction after coronary artery bypass graft (CABG) surgery.

Methods:

Of 60 patients with glomerular filtration rate (GFR) < 60 mL/min scheduled to undergo CABG surgery, 30 were randomized to treatment with vitamin E and allopurinol for 3–5 days before surgery and 30 to no treatment. Serum creatinine levels and potassium and creatinine clearances were measured preoperatively and daily until day 5 after surgery.

Results:

The patients consisted of 31 males and 29 females, with a mean age of 63 ± 9 years. After surgery, there were no significant differences in mean serum creatinine (1.2 ± 0.33 vs 1.2 ± 0.4 mg/dL; p = 0.43) concentrations, or creatinine clearance (52 ± 12.8 vs 52 ± 12.8 mL/min; p = 0.9). The frequency of acute renal failure did not differ in treatment group compared with control (16% vs 13%; p = 0.5). Length of stay in the intensive care unit (ICU) was significantly longer in the control than in the treated group (3.9 ± 1.5 vs 2.6 ± 0.7 days; p < 0.001).

Conclusion:

Prophylactic treatment with vitamin E and allopurinol had no renoprotective effects in patients with pre-existing renal failure undergoing CABG surgery. Treatment with these agents, however, reduces the duration of ICU stay.

Comparison of iodixanol and iohexol in patients undergoing intravenous pyelography: a prospective controlled study

BACKGROUND

Nephropathy associated with contrast medium exposure is a well-known complication of IVP. However, it is uncertain whether iso-osmolar non-iodinated contrast medium (iodixanol) is less nephrotoxic than low-osmolar contrast medium (iohexol).

MATERIALS AND METHODS

In this single-center, double-blind, prospective study, 50 patients undergoing IVP were randomized into two groups receiving different contrast medium: iodixanol and iohexol. Patients in high risk for contrast nephropathy were included, 28 with renal insufficiency and 19 with diabetes mellitus. We compared the nephrotoxic effect (contrast nephropathy), complement and cytokines profile between the iodixanol and iohexol groups. The mean volume of contrast medium in each IVP procedure was 0.8 mL/kg.

RESULTS

The incidence of contrast nephropathy was 4 percent among all patients (one iodixanol and one iohexol). We found no significant differences in contrast nephropathy and allergic reactions between the two groups. There was no significant difference in cytokine profiles in both groups (p > 0.05).The incidence of allergic reaction was 16 percent among all patients. Twelve percent (3/25) had late reaction after iohexol exposure compared to four percent (2/25) with iodixanol (p = 1.0). One patient had severe skin rash due to late adverse reaction after iodixanol. No mortality was found.

CONCLUSIONS

New iodixanol and iohexol contrast medium for routine IVP examination are safe and have low nephrotoxicity profile, especially in elderly or high-risk patients. Iodixanol contrast medium has an increased risk to induce severe late adverse reaction compared to iohexol. Allergic reaction may be the main adverse effect after contrast medium infusion.

Clinical significance and preventive strategies for contrast-induced nephropathy

PURPOSE OF REVIEW

Contrast-induced nephropathy continues to be a common cause of in-hospital acute kidney injury. Published studies on pathogenesis, clinical significance, diagnosis, and preventive measures have dramatically increased significantly in the past several years. This review will focus on new developments in contrast-induced nephropathy.

RECENT FINDINGS

Studies on the clinical significance of contrast-induced nephropathy are reviewed along with initial reports of biomarkers in diagnosing this complication of iodinated contrast administration. Emerging literature on the relative nephrotoxicity of iso-osmolar versus low-osmolar contrast media and the value of bicarbonate hydration are discussed. More recent preventive measures using prostacyclin, 'statins', and erythropoietin are also reviewed.

SUMMARY

Contrast-induced nephropathy is an increasing cause of acute kidney injury and is associated with significant mortality and morbidity. Future developments in this field will focus on refining the clinical significance of this complication, earlier diagnosis with biomarkers, clarifying the role for bicarbonate and iso-osmolar contrast agents as preventive strategies, and the introduction of new prophylactic techniques on the basis of an improved understanding of pathogenesis at the cellular level.

Review Article: is it time to embrace haemodiafiltration for centre-based haemodialysis?

Improvements in survival in dialysis patients over the past few decades have been disappointing. Recent prospective trials such the haemodialysis study have not shown conclusive improvements. Two recent observational studies have found a striking survival advantage for haemodiafiltration (HDF). This review covers the differences between HDF and conventional haemodialysis (HD) and the history of the technological advances in the HDF technique. In addition, it explores the putative benefits of HDF over HD. While the observational studies provide a basis for optimism that HDF will provide benefit to dialysis patients, definitive conclusions cannot be drawn until the results of randomized controlled trials are available. While the evidence in favour of HDF at this stage is observational only, there are no studies suggesting that the treatment is detrimental. The use of HDF should probably be increased, particularly in centres where an increase in the frequency and duration of dialysis cannot be readily achieved.

Medical therapy of acute kidney injury

Pharmacologic interventions for the prevention and therapy of acute kidney injury (AKI) can be roughly divided into 2 main strategies: Optimising renal perfusion and modulation of intrarenal pathophysiological mechanisms, i.e. formation of free oxygen radicals, inflammation, tubular cast formation and renal (tubular) regeneration. Improvement of impaired renal perfusion can be achieved by optimising systemic haemodynamics by volume expansion and the appropriate use of inotropes and/or vasopressors. Up to now prospective randomised controlled trials on selective renal vasodilatation have turned out rather unsuccessful, with the exception of the adenosine antagonist theophylline, in certain indications like drug-induced renal failure or contrast nephropathy. Studies in humans on pharmacological interventions interfering with intrarenal pathophysiological mechanisms of AKI are also sparse. Investigated compounds comprise N-acetyl-cysteine, mannitol and antioxidants like selenium or vitamin C. The results are heterogeneous and a significant beneficial effect of either substance could not yet be convincingly demonstrated.

[Iodinated contrast agent-induced nephropathy]

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

Prevention of Contrast-Induced Nephropathy in the Emergency Department

STUDY OBJECTIVE

Contrast-induced nephropathy is the third leading cause of hospital-acquired acute renal failure. Expanded use of contrast-enhanced imaging exposes an ever-widening number of patients to this renal toxin. We perform an evidence-based emergency medicine review comparing different therapies to prevent contrast-induced nephropathy. We limit our review to prophylactic therapies that are practical for an emergency department setting.

METHODS

We searched MEDLINE, EMBASE, and the Cochrane Library for randomized trials comparing a wide range of medications to prevent contrast-induced nephropathy. We defined contrast-induced nephropathy by a commonly used surrogate measure of renal failure: a 25% or 0.5 mg/dL absolute increase in serum creatinine level from baseline 48 to 72 hours postcontrast. We limited our review to only trials for patients with baseline renal insufficiency, who are most at risk for contrast-induced nephropathy. We excluded prophylactic protocols requiring more than 2 hours precontrast to initiate and any trials of experimental medications or those that required invasive monitoring. We used standard criteria to appraise the quality of published trials.

RESULTS

We found 7 randomized trials; 3 using N-acetylcysteine, 2 using theophylline, and 1 each using bicarbonate and ascorbic acid. Although many of these trials showed statistically significant reductions in the risk for contrast-induced nephropathy, none were sufficiently powered to detect reductions in mortality rate or the need for dialytic therapy.

CONCLUSION

Evidence from randomized trials shows that these interventions (theophylline, bicarbonate, and ascorbic acid) under review were appropriate to an ED setting and decreased the risk of contrast-induced nephropathy. The case for the effectiveness (N-acetylcysteine) was less certain.

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.

Risk prediction of contrast-induced nephropathy

In order to make appropriate decisions about clinical management, it is important for physicians to be able to stratify patients according to their risk for contrast-induced nephropathy (CIN). The most important risk marker for nephropathy after exposure to iodinated contrast media is preexisting renal impairment. The risk of CIN is elevated and becomes clinically important in patients with chronic kidney disease characterized by an estimated glomerular filtration rate <60 mL/min per 1.73 m(2). In patients with renal impairment, diabetes mellitus amplifies the risk of CIN and complicates postprocedure management. Other markers associated with an increased risk of CIN include cardiovascular disease, periprocedural hemodynamic instability, use of nephrotoxic drugs, and anemia. The effect of risk factors is additive, and the presence of multiple risk factors in the same patient can create a very high risk for CIN and acute renal failure requiring dialysis. Risk models incorporating baseline and periprocedural characteristics have been developed using data from large databases of percutaneous coronary intervention patients. These schemes are potentially valuable, but at present the most practical approach to risk prediction is based on a simple model incorporating renal function and diabetes mellitus.

Epidemiology and prognostic implications of contrast-induced nephropathy

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

Facts and fallacies concerning the prevention of contrast medium-induced nephropathy

OBJECTIVE

The aim of this article is to extract from recent medical literature and nephrologic practice the facts and fallacies concerning the possible prophylaxis of contrast medium-induced nephropathy.

DATA SOURCES, STUDY SELECTION, AND DATA EXTRACTION

A MEDLINE/PubMed search (1985 to January 2006) was conducted, including all relevant articles investigating the pathogenesis and prevention of contrast medium-induced nephropathy from a nephrologic critical point of view.

DATA SYNTHESIS

Considerable efforts have been made to develop pharmacologic therapy for the prevention of contrast medium-induced nephropathy, especially in patients at risk, such as elderly subjects and those with preexisting renal impairment, hypovolemia, or dehydration. There is general consensus that hydration protocols implemented before and after imaging with contrast medium may be effective in preventing contrast medium-induced nephropathy. However, definitive and convincing data related to amounts to be infused, infusion timing, and type of solutions (half-isotonic, isotonic saline solution, or bicarbonate) are lacking. Forced diuresis with furosemide or mannitol and use of dopamine, together with concomitant hydration, have been proved to be ineffective or even more risky in the event of inadequate maintenance of euvolemia. Various direct or indirect vasodilators have been investigated (atrial natriuretic peptide, calcium channel blockers, angiotensin-converting enzyme inhibitors, and endothelin receptor antagonists), yet results have been inconsistent and inconclusive. Recent large meta-analyses concerning the protective role of antioxidant action of N-acetylcysteine have led to the conclusion that the statistical significance of the results is borderline. Preventive hemodialysis has not proved to be useful; on the contrary, it might worsen the clinical conditions by inducing hypotension. Hemofiltration, despite some positive studies, is too complex and cannot be used extensively.

CONCLUSIONS

: It is believed that prevention is actually achieved by correcting hypovolemia, dehydration, or both. Normalization of body fluids is probably the true objective to be achieved by preventive measures in all patients, not only in those at risk. Because limited data have been collected in intensive care units, at present, no firm or specific recommendations can yet be provided for the critically ill.

Prophylaxis of contrast material-induced nephropathy in patients in intensive care: acetylcysteine, theophylline, or both? A randomized study

PURPOSE

To prospectively compare the protective effect of acetylcysteine, theophylline, and both agents combined in patients who are admitted to the intensive care unit with at least one risk factor for contrast material-induced nephropathy and who receive at least 100 mL of iodinated contrast medium.

MATERIALS AND METHODS

Institutional ethics review board approval and informed consent were obtained. A total of 91 patients (mean age, 58.5 years+/-14.8 [standard deviation]; 31 women, 60 men; 150 examinations) were admitted to the intensive care unit with at least one risk factor for contrast-induced nephropathy and received either (a) 200 mg theophylline 30 minutes before contrast medium administration (group T), (b) 600 mg acetylcysteine twice daily on the day of and (if possible) the day before the examination (group A), or (c) both agents combined (group AT). The primary endpoint for this study was the incidence of contrast-induced nephropathy (chi2 test).

RESULTS

Groups T, A, and AT were comparable with regard to baseline creatinine levels and the amount of contrast medium administered. The incidence of contrast-induced nephropathy in groups T, A, and AT was 2%, 12%, and 4%, respectively, and was significantly lower in group T than in group A (P=.047). There was no significant difference in the incidence of contrast-induced nephropathy between groups A and AT (P=.148) or between groups T and AT (P=.53). For group A, serum creatinine did not change after 12, 24, or 48 hours compared with baseline. Creatinine levels in group T decreased 12 hours (1.19 mg/dL+/-0.58; P=.008) and 48 hours (1.16 mg/dL+/-0.55; P=.034) after contrast material injection compared with baseline (1.25 mg/dL+/-0.61). In group AT, creatinine significantly decreased 24 hours (1.21 mg/dL+/-0.74; P=.003) and 48 hours (1.17 mg/dL+/-0.69; P<.001) after contrast material injection compared with baseline (1.28 mg/dL+/-0.74). Group A had significantly higher maximal increases in creatinine than groups T and AT (P=.014).

CONCLUSION

For prophylaxis of contrast-induced nephropathy in patients who are admitted to the intensive care unit and who receive 100 mL or more of contrast medium, theophylline is superior to acetylcysteine.

Overview of clinical studies in hemodiafiltration: what do we need now ?

Despite several technical advances in dialysis treatment modalities and a better patient care management including correction of anemia, suppression of secondary hyperparathyroidism, lipid and oxidative stress profiles improvement, the morbidity and the mortality of dialysis patients still remain still elevated. Recent prospective interventional trials in hemodialysis (HEMO study and 4D study) were not very conclusive in showing any significant improvement in dialysis patient outcomes. High-efficiency convective therapies, such as online hemodiafiltration (HDF), are claimed to be superior to conventional diffusive hemodialysis (HD) in improving the dialysis efficacy and in reducing intradialytic morbidity and all-cause and cardiovascular mortality in dialysis patients. The aim of this report was, first, to review the evidence-based facts tending to prove the superiority of HDF vs. HD in terms of efficacy and tolerance, and, second, to analyze the needs to prove the clinical superiority of HDF in terms of reducing morbidity and all-cause mortality of dialysis patients. A systematic review of studies comparing HDF and HD has been performed in the microbiological safety of online production, the solute removal capacity of small and medium-size uremic toxins, and its implication in the reduction of the bioactive dialysis system vs. patient interaction. Major planned randomized international studies comparing HDF and HD in terms of morbidity and mortality have been reviewed. To conclude, it is thought that these long-term prospective randomized trials will clarify on a scientific evidence-based level the putative beneficial role of high-efficiency HDF modalities on dialysis patient outcomes.

Contrast-induced nephropathy: Pharmacological prophylaxis

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

Reducing the Risks for Contrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is one of the most serious adverse events associated with the use of contrast media (CM). Patients who develop this complication can have increased morbidity, higher rates of mortality, lengthy hospital stays, and poor long-term outcomes. Although CIN cannot be eliminated, the chances of developing this condition can be reduced by using appropriate prevention strategies. An important first step to reduce the chance of CIN is to identify risk factors associated with this condition. Patients with a previously elevated serum creatinine level, especially when secondary to diabetic nephropathy, are at great risk for developing CIN. Other patient-related risk factors include concurrent use of nephrotoxic medications, dehydration, congestive heart failure, age greater than 70 years, and probably the presence of diabetes mellitus even if serum creatinine is normal. Adequate hydration is widely accepted as an important prophylactic measure for preventing CIN, but the optimal hydration regimen is still debatable. The risk of CIN increases with greater doses of CM, as well as with the type of CM used. A high-osmolar CM poses a greater risk of CIN than does a low-osmolar CM and, as recent but limited data suggest, the use of an isoosmolar CM is less nephrotoxic than a low-osmolar CM in patients with renal impairment following intra-arterial procedures, although this finding needs to be verified in future clinical studies. Pharmacologic agents such as calcium channel blockers, dopamine, atrial natriuretic peptide, fenoldopam, prostaglandin El, and endothelin receptor antagonist have not been proven effective against CIN development. Controversies still exist on the possible effectiveness of theophylline and N-acetylcysteine. Simple strategies for the prevention of CIN in at-risk patients are reviewed and unproven interventions are discussed.

Nephropathy induced by contrast media: pathogenesis, risk factors and preventive strategies

With the increasing use of contrast media in diagnostic and interventional procedures, nephropathy induced by contrast media has become the third leading cause of hospital-acquired acute renal failure. It is also associated with a significant risk of morbidity and death. The current understanding of the pathogenesis indicates that contrast-medium nephropathy is caused by a combination of renal ischemia and direct toxic effects on renal tubular cells. Patients with pre-existing renal insufficiency, diabetes mellitus and congestive heart failure are at highest risk. Risk factors also include the type and amount of contrast medium administered. Therapeutic prevention strategies are being extensively investigated, but there is still no definitive answer. In this article, we review the current evidence on the causes, pathogenesis and clinical course of contrast-medium nephropathy as well as therapeutic approaches to its prevention evaluated in clinical trials.

N-acetylcysteine prophylaxis significantly reduces the risk of radiocontrast-induced nephropathy: comprehensive meta-analysis

The objectives of this study was to assess the overall effect of N-acetylcysteine (NAC) in preventing radiocontrast-induced nephropathy (RCIN) using all available data in the literature. RCIN is associated with increased morbidity and mortality. Existing randomized trials of NAC are small and show inconsistent results. Prior meta-analyses do not include data from the most current studies. We used standard search protocols to identify all published articles and abstracts of prospective trials using NAC with fluid hydration compared to hydration alone in patients with chronic renal insufficiency undergoing contrast procedures. A rise in serum creatinine by 0.5 mg/dl or 25% above baseline at 48-72 hr after contrast exposure was used as the primary outcome. We identified 14 trials of NAC with 1,584 patients published as full-text articles. Using a random-effects model, the use of oral NAC resulted in a significant reduction in the risk for developing RCIN (RR = 0.57; 95% CI = 0.37-0.84; P = 0.01). This finding did not significantly change in a fixed-effect model (RR = 0.55; 95% CI = 0.42-0.73) or when the data were reanalyzed using only randomized trials in all forms (i.e., articles and abstracts; RR = 0.67; 95% CI = 0.47-0.95). We identified only one important difference between the positive and the negative studies: the cumulative exposure to contrast media (174 vs. 152 ml). Metaregression did not show a significant relationship between contrast volume and the RR of developing RCIN (P > 0.10). In the trials showing benefit for NAC, the treated patients' postprocedure creatinine unexpectedly decreased by 0.21 mg/dl (95% CI = 0.33-0.08). Prophylaxis with NAC significantly reduces the risk for RCIN. The reasons for improvement in serum creatinine in patients treated with NAC are unclear, but may include improved renal blood flow due to NAC and/or vigorous hydration.

Short- and long-term renal outcomes of immediate prophylactic hemodialysis after cardiovascular catheterizations in patients with severe renal insufficiency

BACKGROUND

The short- and long-term effects of prophylactic hemodialysis (HD) immediately after cardiovascular catheterizations on renal function in patients with severe baseline renal insufficiency remain unknown though previous studies reported non-beneficial very-short-term effect in less severe patients.

METHODS AND RESULTS

Patients who had pre-procedural serum creatinine (Scr) between 2.5 and 5.5 mg/dl were retrospectively studied. Twenty of them (14 M/6 F, aged 69 +/- 2 years) had received prophylactic HD after radiocontrast exposure and constituted the HD group. Another 20 patients were case-matched to the baseline demographics of the HD group and served as the non-HD group. The baseline Scr were 3.9 +/- 0.2 and 3.5 +/-0.2 mg/dl, respectively (p = NS). Although the Scr at 3 months was significantly higher in the HD group (4.3 +/- 0.3 vs. 3.4 +/- 0.2 mg/dl, p = 0.02), the absolute and percentage increments from baseline to 3 months (0.4 +/- 0.2 vs. 0.0 +/- 0.2 mg/dl, p = NS, and 11 +/- 5% vs. 1 +/- 7%, p = NS, respectively) and 6 months (0.6 +/- 0.3 vs. 0.4 +/- 0.4 mg/dl, p = NS, and 18 +/- 8% vs. 8 +/- 10%, p = NS, respectively) were not statistically different. Patients who developed end-stage renal disease requiring permanent HD at 1 year were also similar in both groups (four vs. three, respectively, p = NS).

CONCLUSIONS

Our study confirmed that prophylactic HD immediately after contrast media administration in catheterizations failed to affect the short- and long-term renal and clinical outcomes even in patients with severe baseline renal insufficiency.

Emerging drugs for renal failure

Renal failure involves a significant impairment of the essential functions of the kidney, which can be either acute with sudden and rapid onset (acute renal failure [ARF]) or chronic with gradual onset (chronic renal failure [CRF]). ARF, if detected early, may be halted or reversed, whereas CRF is generally irreversible. Without treatment or intervention, both forms of renal failure lead to end stage renal failure (ESRF) or end stage renal disease (ESRD), requiring renal replacement therapy (RRT) in the form of dialysis or renal transplantation for survival. However, provision of RRT requires expert teams working in specialised units, making therapy of patients with renal failure expensive; furthermore, RRT is complex, with its own complications. Although pharmacological interventions have shown promise in experimental models, these have not been as successful in the clinical setting (e.g., administration of atrial natriuretic peptide, low-dose dopamine). At present, drugs are administered during CRF to either reduce one of the many risk factors of CRF (e.g., angiotensin-converting enzyme inhibitors, statins) or to deal with the consequences of CRF (e.g., erythropoietin, calcitriol). Recent evidence suggests that some of these interventions may provide further direct beneficial effects via reduction of renal inflammation. Although these interventions have greatly improved the prospects for patients suffering ESRF, the development of novel drugs and therapies with which to reduce the consequences of renal failure and ESRD remain topics of great interest. This article reviews the therapies available for the prevention and management of renal failure in adults and describes, in detail, emerging drugs and novel interventions that may soon become available for the treatment or prevention of ESRF.