AJR ARRS: Your Link to CME
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]


     


This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kuhn, M. J.
Right arrow Articles by So, G. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kuhn, M. J.
Right arrow Articles by So, G. J.
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
Hotlight (NEW!)
Right arrow
What's Hotlight?
DOI:10.2214/AJR.07.3370
AJR 2008; 191:151-157
© American Roentgen Ray Society


Original Research

The PREDICT Study: A Randomized Double-Blind Comparison of Contrast-Induced Nephropathy After Low- or Isoosmolar Contrast Agent Exposure

Matthew J. Kuhn1, Nan Chen2, Dushyant V. Sahani3, Dan Reimer4, Edwin J. R. van Beek5, Jay P. Heiken6 and George J. So7

1 Department of Radiology, Southern Illinois University School of Medicine, 800 E Carpenter St., Springfield, IL 62769.
2 Department of Nephrology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
3 Department of Radiology, Massachusetts General Hospital, Boston, MA.
4 Radiologists PC, Mobile, AL.
5 Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City, IA.
6 Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO.
7 Department of Radiology, Torrance Memorial Medical Center, Torrance, CA.

Received October 31, 2007; accepted after revision January 23, 2008.

 
This study was funded by a clinical grant from Bracco Diagnostics, Inc., Princeton, NJ.

D. V. Sahani has a research agreement with GE Healthcare and is a member of the Speaker Bureau with Bracco Diagnostics.

G. J. So has a research contract with Bracco Diagnostics.

Address correspondence to M. J. Kuhn (mkuhn{at}st-johns.org).


Abstract
Top
Abstract
Introduction
Subjects and Methods
Results
Discussion
References
 
OBJECTIVE. The objective of the PREDICT (patients with renal impairment and diabetes undergoing computed tomography) study was to compare the incidence of contrast-induced nephropathy (CIN) after administration of low-osmolar (iopamidol 370, 796 mOsm/kg) or isoosmolar (iodixanol 320, 290 mOsm/kg) contrast medium in patients with diabetes and chronic kidney disease undergoing CT.

SUBJECTS AND METHODS. Two hundred sixty-three patients with moderate to severe chronic kidney disease (estimated glomerular filtration rate [GFR] = 20–59 mL/min/1.73 m2) and diabetes mellitus were randomized to receive at least 65 mL of iopamidol 370 or iodixanol 320 for a CT procedure. Serum creatinine levels were measured at baseline and 48–72 hours after contrast administration. CIN was defined as an increase in the serum creatinine level after contrast administration of ≥ 25% from the baseline level. The incidence of CIN in the total study population and the incidence of CIN in patients at increased risk for CIN were compared using Fisher's exact test.

RESULTS. Two hundred forty-eight patients were included in the CIN analysis: 125 receiving iopamidol 370 and 123 receiving iodixanol 320. Study population demographics were comparable, as was baseline renal function (estimated GFR = 47.6 mL/min/1.73 m2 for the iopamidol 370 group vs 49.9 mL/min/1.73 m2 for the iodixanol 320 group; p = 0.16). Increases in the serum creatinine value of ≥ 25% occurred in seven patients (5.6%) receiving iopamidol 370 and in six patients (4.9%) receiving iodixanol 320 (95% CI, –4.8% to 6.3%; p = 1.0). The mean serum creatinine change from the baseline level was 0.04 mg/dL in both groups (analysis of covariance, p = 0.80). In patients with a baseline serum creatinine value of ≥ 2.0 mg/dL, baseline estimated GFR of ≤ 40 mL/min/1.73 m2, or those receiving > 140 mL of contrast medium, the incidence of CIN was low and comparable between the two study groups (p = 1.0 in all instances).

CONCLUSION. The incidence of CIN in patients with diabetes and chronic kidney disease receiving IV contrast medium was not significantly different after CT using iopamidol 370 or iodixanol 320.

Keywords: contrast-induced nephropathy • contrast media • CT • diabetes mellitus • iodixanol • iopamidol • kidney disease • renal insufficiency


Introduction
Top
Abstract
Introduction
Subjects and Methods
Results
Discussion
References
 
Contrast-induced nephropathy (CIN) is usually defined as a sudden, rapid deterioration in renal status after administration of iodinated contrast medium with no alternative clinical explanation [1, 2]. The incidence of CIN in patients with normal renal function is less than 3% but can be much higher in individuals with one or more risk factors for CIN (12–50%) [37]. Most studies define CIN as an increase in the serum creatinine value (≥ 0.5 mg/dL, ≥ 25%, or both) or a diminution of renal function identified by a decrease in creatinine clearance or the estimated glomerular filtration rate (GFR) 2–3 days after contrast medium exposure [8, 9]. Recently, investigators have suggested that a relative increase of 25% is more clinically meaningful and more sensitive as a quantifier of renal damage than an absolute increase in serum creatinine of 0.5 mg/dL because a relative 25% increase in serum creatinine value intrinsically adjusts for baseline renal function [10].

Preexisting renal dysfunction and diabetes mellitus are both independent predictors of CIN [3, 11]. The use of low-osmolar contrast media is associated with a significantly lower incidence of CIN compared with high-osmolar contrast media in patients with baseline renal insufficiency [5, 1214]. Whether the use of an isotonic contrast agent confers any additional benefit compared with a low-osmolar agent is less clear [15]. Few clinical studies have compared the renal effects of a low-osmolar and an isoosmolar contrast agent after IV contrast medium administration in patients with kidney disease, and few patients in those studies have been reported to have diabetes mellitus [16, 17]. Here, we report results of the PREDICT (patients with renal impairment and diabetes undergoing computed tomography) study, which compared the incidence of CIN in patients with diabetes and moderate to severe chronic renal failure undergoing MDCT after IV administration of a low-osmolar (iopamidol 370, 796 mOsm/kg) or an isoosmolar (iodixanol 320, 290 mOsm/kg) contrast agent.


Subjects and Methods
Top
Abstract
Introduction
Subjects and Methods
Results
Discussion
References
 
The PREDICT study was a multicenter, randomized, double-blind, parallel-group comparison of iopamidol 370 (Isovue, 370 mg I/mL, Bracco Diagnostics Inc.) and iodixanol 320 (Visipaque, 320 mg I/mL, GE Healthcare) conducted at 23 sites in North America and China between January 2006 and April 2007. The study was approved by the ethics committee or institutional review board of each part icipating center and was conducted in com pliance with the principles of the Declaration of Helsinki and subsequent amendments. Written informed consent was obtained from each patient at the time of enrollment in the study.

Patient Population
Patients 18 years old and older with type 1 or type 2 diabetes mellitus and chronic renal impairment (estimated glomerular filtration rate [GFR] = 20–59 mL/min/1.73 m2) scheduled to undergo a clinically indicated contrast-enhanced MDCT examination were considered for eligibility at each participating study center, provided that the procedure called for at least 65 mL of contrast agent to be administered. Patients were excluded from the trial if they were pregnant or lactating or if they had New York Heart Association class IV congestive heart failure, hypersensitivity to iodine-containing compounds, hyperthyroidism, uncontrolled diabetes mellitus, or unstable renal function. Patients were also excluded if they received any iodinated contrast agent within 7 days before the administration of the investigational product or were scheduled to receive an iodinated contrast agent within 72 hours after administration of the investigational product, if they received any nephrotoxic medication (chemotherapeutic agents, nonsteroidal antiinflammatory drugs other than acetylsalicylic acid up to 325 mg/d) within 24 hours before to 24 hours after the administration of the study agent, or if they had medical conditions or circumstances that would have substantially decreased the chances of obtaining reliable data.


Figure 1
View larger version (33K):
[in this window]
[in a new window]
[as a PowerPoint slide]
 
Fig. 1 Flowchart shows progress of PREDICT (patients with renal impairment and diabetes undergoing computed tomography) study. GFR = glomerular filtration rate.

 
A total of 264 patients were enrolled, of whom 263 were randomized: 132 patients to the iopamidol 370 group and 131 patients to the iodixanol 320 group (Fig. 1). Five patients pre maturely discontinued investigational product admini stra tion, two in the iopamidol 370 group and three in the iodixanol 320 group. In these five patients, serum creatinine values were not obtained after contrast administration. The remaining 258 pa tients received randomized contrast agents and completed the postdose safety evaluations. Of these, 10 patients were excluded from the CIN analysis because the baseline estimated GFR was outside the specified range (n = 3), a critical clinical event occurred after the imaging procedure (n = 2), or collection of the serum creatinine sample after contrast administration was premature (n = 5).

Study Conduct
Baseline estimated GFR was calculated via the abbreviated Modification of Diet in Renal Disease method [18] from a serum creatinine value obtained within 72 hours of enrollment in the study and before initiation of any prophylactic hydration regimen and administration of the investigational product. Blood samples were also obtained 48–72 hours after administration of the investigational product. Cen tral laboratories were used for evalu ations of serum creatinine levels to ensure consist ency of measurement and reporting of laboratory data.

Prophylaxis of CIN via hydration was undertaken for each patient in whom it was deemed clinically necessary or desirable. Prophy lactic hydration was administered before, during, or after (or a combination of those times) contrast administration according to the clinical practice or protocols of each site. For analysis purposes, a patient was considered to have received hydration before the procedure if at least 500 mL of IV fluid was administered within 12 hours of contrast medium administration. The only prophylactic medication permitted in this protocol was N-acetylcysteine, which was administered at the sole discretion of the investigator.

Patients referred for CT angiography or CT of the brain, head and neck, thorax, abdomen, or pelvis were eligible for entry in the study. Once enrolled, patients were randomly assigned to receive an IV bolus of either iopamidol 370 or iodixanol 320 as part of their scheduled MDCT procedure. All groups and individuals associated with the trial remained blinded until the database was unlocked and the data analyzed. To ensure blinding at the investigational sites, a third party managed the preparation, dispensing, and accountability of the investigational agents. The drug-dispensing person at each site was responsible for preserving the blind and therefore did not participate in any study assessments. The investigational products were warmed to body temperature (37°C) and then administered IV by power injection. The actual dose administered to each patient was determined by the investigator based on the clinical requirements of the examination being performed and was recorded at the time of the procedure.

CIN Evaluation
CIN was prospectively defined as an increase in serum creatinine level of at least 25% at 48–72 hours after receiving the contrast dose. Decreases in estimated GFR of at least 25% and mean changes in serum creatinine levels from baseline were also assessed. The incidence of CIN, along with any changes in concomitant medications and general observations of the patient's clinical renal status, was evaluated. In addition, the proportion of patients who required dialysis, died, or required dialysis and died from acute renal failure due to CIN was recorded. The rate of CIN was also evaluated in three prospectively defined higher-risk subgroups: those with a baseline serum creatinine value of ≥ 2.0 mg/dL, those with a baseline estimated GFR of ≤ 40 mL/min/1.73 m2, and those receiving > 140 mL of contrast medium.

Statistical Analysis
Evaluable patients for CIN analysis included patients who provided informed consent, met all the inclusion and none of the exclusion criteria, had an estimated GFR of between 20 and 59 mL/min/1.73 m2 at screening, received randomized investigational product, and had serum creatinine collected as required by the protocol. Continuous variables (age, body weight, body mass index, contrast dose, dose of contrast medium by body weight, volume of IV hydration, serum creatinine level, creatinine clearance) were summarized as mean ± 1 SD. For categoric variables such as sex, race, type of diabetes mellitus, use of any volume supplementation, and use of con comitant nephrotoxic medications, the number and percentage of patients in each category were calculated.

Statistical testing was based on two-sided tests at a 95% level, and CIs were calculated for the observed differences between groups. The comparisons of baseline data between the two treatment groups were performed using the chi-square test or Fisher's exact test (categoric variables) or the Student's t test (continuous variables). A two-sided Student's t test was used for comparison of mean changes in serum creatinine levels and in estimated GFRs at baseline and 48–72 hours after contrast administration in patients who received iopamidol 370 and those who received iodixanol 320.

Mean changes from baseline in serum creatinine level and estimated GFR were tested for normality and analyzed with an analysis of covariance model, treating baseline measurements as covariate. The rates of increases in serum creatinine level of ≥ 25% and decreases in estimated GFR of ≥ 25% from baseline were analyzed using Fisher's exact test. The proportions of patients in each group with CIN were compared, and 95% CIs were calculated for the observed differences between groups. An analysis of CIN rates was also performed in the subgroup of patients with creatinine clearance of ≤ 40 mL/min, serum creatinine level of ≥ 2.0 mg/dL, or both. All statistical analyses were conducted using SAS software (version 8.2, SAS Institute) under the Windows operating system (Microsoft).


Results
Top
Abstract
Introduction
Subjects and Methods
Results
Discussion
References
 
Comparability of Study Groups
Of the 248 evaluable patients, 125 received iopamidol 370 and 123 received iodixanol 320. The demographic, clinical, and procedural characteristics of patients in the two groups are presented in Table 1. The two study groups were comparable with regard to demographic variables such as sex distribution, age, and weight, as well as procedural variables such as the volume of contrast agent administered, prophylactic use of N-acetylcysteine, and patient hydration. Baseline serum creatinine levels were comparable in the two groups (1.46 ± 0.44 mg/dL in the iopamidol 370 group vs 1.41 ± 0.38 mg/dL in the iodixanol 320 group, p = 0.34), as was the calculated estimated GFR (47.6 ± 13.5 mL/min/1.73 m2 in the iopamidol 370 group vs 49.9 ± 11.6 mL/min/1.73 m2 in the iodixanol 320 group; p = 0.16).


View this table:
[in this window]
[in a new window]

 
TABLE 1: Demographics and Procedural Characteristics

 

The rate of hydration was low, but a comparable number of patients in the two groups were hydrated: 11 in the iopamidol 370 group and nine in the iodixanol 320 group (p = 0.82). The mean administered volume (± SD) of hydration was similar in the two groups (iopamidol 370 vs iodixanol 320, 832.5 ± 740.2 vs 928.4 ± 803.2 mL, respectively; p = 0.78).

Patients in both groups received a similar volume of contrast agent (iopamidol: mean = 106.5 mL, range = 66–185 mL; iodixanol: mean = 101.6 mL, range = 70–150 mL; p = 0.12); however, because of the higher iodine concentration of iopamidol 370, patients receiving that agent had a higher total iodine dose than those receiving iodixanol 320 (39.4 vs 32.5 g I, respectively; p < 0.0001). Most pa tients enrolled underwent CT of the chest, abdomen, or pelvis (77%) or CT angio graphy (18%), and the remaining patients underwent CT or the brain or head and neck. No differences were evident between the two study groups with regard to the type of studies performed.

The Incidence of CIN and Postdose Serum Creatinine Changes
A postdose increase in serum creatinine value of at least 25% occurred in 5.6% (7/125) of the patients receiving iopamidol 370 and in 4.9% (6/123) of the patients receiving iodixanol 320 (95% CI of the difference, –4.8% to 6.3%; p = 1.0) (Table 2). The mean serum creatinine change from baseline was also comparable between the two treatment groups (0.04 mg/dL for both groups; p = 0.80), as was the mean change in estimated GFR from baseline (–0.77 mL/min/1.73 m2 for iopamidol 370 and –0.46 mL/min/1.73 m2 for iodixanol 320; p = 0.61). A decrease in estimated GFR of at least 25% was noted in three patients in each group.


View this table:
[in this window]
[in a new window]

 
TABLE 2: Serum Creatinine Levels and Estimated Glomerular Filtration Rates (GFRs) Before and After Contrast Administration and Incidence of Contrast-Induced Nephropathy (CIN)

 

Further analysis of higher-risk subpopulations (i.e., those with a baseline serum creatinine value of ≥ 2.0 mg/dL, those with a baseline estimated GFR of ≤ 40 mL/min/1.73 m2, and those receiving > 140 mL of con trast medium) was performed. Twenty-one patients had a baseline serum creatinine value of ≥ 2.0 mg/dL: 12 in the iopamidol 370 group and nine in the iodixanol 320 group. Baseline demographics were similar between the two agents for all higher-risk subpopulations, although as in the overall population, patients in the iopamidol group received significantly more iodine because of the higher iodine concentration of iopamidol versus iodixanol for any given contrast medium volume. The incidence of CIN was very low (no cases, one case, or two cases [< 10%]) and was comparable between the two contrast agent groups for all three higher-risk sub populations (p = 1.000 in all cases).

Two patients in the iopamidol 370 group experienced a worsening in clinical status 48–72 hours after investigational product administration. One patient showed increased urination 10 hours after contrast administration, and another reported worsening edema that resolved by day 7 after the CT examination. Neither change in clinical status was reported as an adverse event, and neither was considered related to contrast agent administration. No patient in this trial required dialysis and no patient died from acute renal failure.


Discussion
Top
Abstract
Introduction
Subjects and Methods
Results
Discussion
References
 
The major finding of this prospective head-to-head trial is the low and comparable incidence of CIN after IV administration of the isoosmolar dimer iodixanol 320 and the low-osmolar nonionic monomer iopamidol 370 in high-risk patients with stable, moderate to severe baseline renal dysfunction and diabetes mellitus. In our study, reporting data from 248 patients, an overall rate of CIN of 5.2% was observed, with no difference seen between the patients who received iopamidol 370 and those who received iodixanol 320. Furthermore, the results of the PREDICT study failed to show a difference between the two study groups in the subpopulations with the most severe baseline renal dysfunction (serum creatinine value ≥ 2 mg/dL and estimated GFR ≤ 40 mL/min/1.73 m2) and those receiving the highest doses of contrast medium (> 140 mL).

Diabetes mellitus is known to be an independent predictor of CIN [3, 11]. In patients with normal renal function, diabe tic patients have a higher risk of developing CIN than nondiabetic patients, and this risk increases progressively as renal function declines, with those with both severe chronic kidney disease and diabetes having the highest risk of developing CIN [35]. Prediabetic patients may also be at increased risk: In a recent study, the incidence of CIN (defined as a ≥ 25% increase in the serum creatinine value over the baseline value within 48 hours of angiography) in patients stratified by fasting blood glucose level was inter mediate in prediabetic patients (11.4%) com pared with healthy patients (5.5%) and diabetic patients (20%) [19]. In addition, clinical outcomes for patients with both renal in sufficiency and diabetes have been shown to be more severe than for patients with either condition in isolation. In a study of 7,445 con secutive patients undergoing cardiac interventions, Nikolsky and Mehran [20] found that 1-year mortality was substantially higher for patients with both renal insufficiency and diabetes (25.9%) than for those with renal insufficiency (17.5%) or diabetes (6.7%) alone.

In previous studies, investigators have established that the use of low-osmolar contrast agents is associated with a significantly lower incidence of CIN com pared with the use of high-osmolar contrast agents [5, 1214], at least in patients with baseline renal in sufficiency. Several head-to-head comparisons of isoosmolar contrast medium and low-osmolar contrast medium have examined the incidence of CIN in patients with preexisting renal dysfunction undergoing cardiac or other interventional angiography (or both) [2123]. The number of patients with diabetes in these studies was limited, except in one small study in which all patients had reduced renal function (mean serum creatinine value = 1.5–1.6 mg/dL) and diabetes [22]. In that study, conducted in 129 patients under going coronary or aortofemoral angiography, a significant decrease in the rate of CIN was observed when the isoosmolar agent iodixanol was used rather than the low-osmolar agent iohexol (3% vs 26%, respectively; p < 0.001). How ever, the results of subsequent studies and analyses of the literature have suggested that the low incidence of CIN observed with the isoosmolar contrast med ium in that study [22] may not be reproducible [15, 2426]. Published rates of CIN after iodixanol range from 3% to 21% after intraarterial use [15] and from 3% to 9% after IV use [2729]. In several reports, researchers have also suggested that the low-osmolar contrast medium comparator used in that study [22], iohexol, may be associated with a higher incidence of CIN than some of the other available low-osmolar contrast agents [15, 26, 30]. These studies suggest that given the low rates of CIN observed in patients with renal insufficiency receiving intraarterial iopamidol (osmolality, 796 mOsmol/kg) com pared with intraarterial io hexol (osmolality, 844 mOsmol/kg), factors other than contrast medium osmolality may play a significant role in the pathogenesis of CIN.

A meta-analysis of clinical studies funded by GE Healthcare, the manufacturer of iodixanol, suggested that iodixanol results in lower rises of serum creatinine values and fewer cases of CIN than other low-osmolar contrast agents [31]. However, most patients in that analysis did not have baseline renal dysfunction; the low-osmolar contrast agents were not evaluated individually; and the overall analysis was heavily weighted to just two contrast agents, the low-osmolar iohexol (28% of patients) and the ionic dimer ioxaglate (59% of patients). The meta-analysis contained only one study in which iopamidol was compared with iodixanol in 144 patients; in that study, CIN was observed only after iodixanol [32].

Recently, the largest head-to-head trial reporting results from a comparison of iodixanol and a low-osmolar contrast agent (iopamidol) in high-risk patients was published [33]. The CARE (cardiac angiography in renally impaired patients) trial [33] enrolled 414 patients with an estimated GFR between 20 and 59 mL/min/1.73 m2 undergoing cardiac catheterization. Overall, no difference was found between the two study groups with respect to the incidence of CIN: An increase in serum creatinine level of ≥ 25% was observed in 20 patients (9.8%) receiving iopamidol and in 26 patients (12.4%) receiving iodixanol (p = 0.44). In patients with diabetes (n = 170), there was also no statistically significant difference in the incidence of CIN between iopamidol and iodixanol (10.3% vs 15.2%, respectively; p = 0.37). However, mean postdose serum creatinine increases in that study were significantly lower with iopamidol 370 than with iodixanol 320, both in the total population (0.07 vs 0.12 mg/dL, respectively; p = 0.03) and in the population of patients with diabetes (0.07 vs 0.16 mg/dL, p = 0.01).

In most published studies examining the incidence of CIN, investigators have focused on intraarterial administration of contrast medium in patients with renal dysfunction. The risk of CIN with any contrast medium is estimated to be more than twofold lower when administered IV rather than intraarterially [2435]. Several studies have examined the incidence of CIN after the IV use of iodixanol in patients with mild to moderate kidney disease. In patients with mild renal impairment (serum creatinine value > 1.1 mg/dL, GFR < 90 mL/min/1.73 m2, or both), a CIN rate of 3% was observed [27]. A separate study in 100 consecutive patients with a base line serum creatinine level of ≥ 1.5 mg/dL undergoing CT with iodixanol reported a 9% rate of CIN [28]. A recent retrospective evaluation compared CIN rates after IV iodixanol in patients with normal baseline renal function or with under lying renal insufficiency. CIN developed in 9% of the 189 patients with renal insufficiency receiving iodixanol, with 4.8% of patients developing irreversible renal damage. In patients with normal renal function at base line, CIN was observed in 4.9% of patients receiving io dixanol, with irreversible renal damage developing in 3.2% of patients [29].

Few studies are available in which the incidence of CIN is compared after IV administration of iodixanol or one of the low-osmolar contrast agents in patients with renal impairment. Carraro and colleagues [16] compared the effect of iodixanol and the nonionic monomer iopromide on renal function in 64 patients with mild to moderate renal insufficiency (serum creatinine level = 1.5–3.0 mg/dL) undergoing excretory urography. CIN in that study was defined as an increase of ≥ 50% in serum creatinine level within 24 hours of the examination. A postprocedure increase in serum creatinine level was observed in both study groups, but no significant difference between the two groups was found. Transient CIN developed in one patient who received iodixanol. A second study, available only as an abstract, compared iodixanol and iobitridol in 50 patients with more severe renal impairment (mean baseline serum creatinine level = 2.6–2.7 mg/dL) undergoing cranial or whole-body CT (Kolehmainen H and Soiva M, presented at the 2003 annual meeting of the European Society of Urogenital Radiology Congress). No difference in the incidence of CIN was found between the two study groups: Four patients in each group (17%) had a ≥ 0.5 mg/dL increase in serum creatinine level.

More recently, the IMPACT (Isovue-370 and Visipaque-320 in Renally Impaired Patients Undergoing Computed Tomography) study compared the effects on renal function of iopamidol 370 with iodixanol 320 in 153 patients with renal impairment undergoing contrast-enhanced MDCT [17]. All patients had stable, moderate to severe chronic renal disease (serum creatinine level ≥ 1.5 mg/dL, creatinine clearance = 10–59 mL/min, or both), and a relative increase in serum creatinine value of ≥ 25% was observed in three of 76 patients (4%) who had received iodixanol and in three of 77 patients (4%) who had received iopamidol 370. Approximately 24% of the patients in the IMPACT study were diabetic, and only one case of CIN was recorded in a patient with diabetes. Eighteen patients had a baseline serum creatinine value of ≥ 2.0 mg/dL (11 receiving iopamidol and seven receiving iodixanol). Of these higher-risk patients, CIN was observed in none of the patients who received iopamidol and in two patients who received iodixanol. These findings support the conclusion that the rate of CIN after IV administration of contrast medium is low and is not significantly different in patients with moderate to severe chronic renal dysfunction receiving iodixanol or iopamidol.

Our study, the PREDICT study, differs from the IMPACT study in that we report results for a larger patient population (248 vs 153 patients in the IMPACT trial) and on a patient population at significantly higher risk for developing CIN—that is, patients with both diabetes mellitus and chronic kidney disease.

Taken together, the results of the PREDICT, IMPACT, and CARE studies add to the growing body of evidence that although CIN does occur after IV contrast medium ad ministration, it occurs less frequently than after intraarterial contrast medium administration and with a similar frequency after iopamidol or iodixanol administration. Whether these findings are related to the route of administration or characteristics of the different patient populations involved is not known. However, patients perceived to be at high risk for developing CIN after intraarterial ad ministration of contrast medium may, in fact, be reasonably good candidates for undergoing contrast-enhanced MDCT. For example, elderly patients, who more commonly have decreased levels of renal function and have diabetes, or patients who may require repeat exposures or examinations with higher doses of contrast agent may be considered at relatively low risk for development of CIN when contrast medium is administered IV.

In the PREDICT study, the absolute difference between CIN rates in the two groups was small (0.7%), and the 95% CI around the observed difference (–4.8% to 6.3%) strongly suggests that if a difference existed between the two agents, the trial would have shown that difference. Given the low rates of CIN observed in this study, approximately 7,000 patients per group (14,000 patients in all) would be needed to show a significant difference between the two contrast agents in terms of the rate of CIN. Although such a difference may have been statistically significant, the clinical relevance of such a small difference would remain questionable.

To maximize enrollment in a difficult study, we permitted patients with a fairly wide range of kidney disease (estimated GFR, 20–59 mL/min/1.73 m2) to be enrolled provided that the patient also had diabetes mellitus. However, this range in kidney disease is identical to that used in other recent studies, such as the IMPACT study by Barrett et al. [17], and evaluation of CIN in those patients at the highest risk (i.e., lowest GFR) shows a comparable safety profile for the two agents in the sickest patients.

In the PREDICT study, iopamidol 370 was chosen as the comparator agent because it is a low-osmolar contrast medium with a reported incidence of CIN comparable to that of iodixanol 320 in other studies. The highest available concentration for each agent was used in this trial based on the assumption that the safety at lower concentrations will be equal to or better than the safety at a higher concentration. Although the two study populations were comparable in nearly every respect, patients receiving iopamidol 370 received a higher total iodine dose than those receiving iodixanol 320 by virtue of the greater iodine concentration of iopamidol 370 (370 mg I/mL vs 320 mg I/mL for iodixanol). Despite the greater iodine dose, there was no statistically significant difference in the rate of CIN observed with the two agents.

The type of power injector used for each examination (single- or double-headed) was not recorded, so we cannot determine from our data which patients received a saline flush as part of their injection. Without a saline chaser, some contrast medium may be left in the IV line, reducing the total dose administered to the patient and resulting in a possible overestimation of the recorded dose for that patient. However, randomization would be expected to balance this variable between the two study groups, and the administered volume was similar for both agents in our study. No pretreatment regimen was recommended or required in this study, and most patient examinations did not meet the definition of hydration defined for this study (i.e., at least 500 mL of IV fluid within 12 hours of the procedure). Sites were allowed to use bicarbonate hydration if they wished, and a small but equal proportion of patients in the two groups received bicarbonate hydration. However, the use of any type of prophylaxis in our study was very low, so it cannot be determined from our data whether any prophylactic measure is helpful in lowering the incidence of CIN in high-risk patients undergoing CT procedures. The low incidence of CIN in our study suggests that when using iopamidol or iodixanol extensive prophylaxis is not required in most patients. Whether these findings can be extrapolated to patients undergoing CT with other low-osmolar agents is unclear.

Fifteen patients (5.7%) were excluded from the CIN analysis before the trial data were unblinded, seven in the iopamidol 370 group and eight in the iodixanol 320 group. These patients were excluded because their baseline estimated GFR was outside the screening range (n = 3), because their post-dose blood samples were obtained less than 45 hours after contrast medium exposure (n = 5), because they did not have a postdose serum creatinine value at 45–72 hours after contrast administration (n = 5), or because of unrelated critical clinical events (n = 2). However, none of these cases met the criteria for CIN, and inclusion of these patients in the analysis would not have changed the findings of the study.

In conclusion, the incidence of CIN in high-risk diabetic patients with moderate to severe chronic renal impairment receiving IV contrast medium is low and is not statistically significantly different after administration of iopamidol 370 or iodixanol 320. These results confirm those of earlier published studies showing a similar rate of CIN after administration of the low-osmolar agent iopamidol or of the isoosmolar agent iodixanol in high-risk patients.


References
Top
Abstract
Introduction
Subjects and Methods
Results
Discussion
References
 

  1. Mehran R, Nikolsky E. Contrast-induced nephropathy: definition, epidemiology, and patients at risk. Kidney Int2006; 100[suppl]:S11 –S15
  2. Morcos SK, Thomsen HS, Webb JA. Contrast-media-induced nephrotoxicity: a consensus report. Contrast Media Safety Committee, European Society of Urogenital Radiology (ESUR). Eur Radiol1999; 9:1602 –1613[CrossRef][Medline]
  3. McCullough PA, Wolyn R, Rocher LL, Levin RN, O'Neill WW. Acute renal failure after coronary intervention: incidence, risk factors, and relationship to mortality. Am J Med 1997;103 : 368–375[CrossRef][Medline]
  4. Rihal CS, Textor SC, Grill DE, et al. Incidence and prognostic importance of acute renal failure after percutaneous coronary intervention. Circulation 2002;105 :2259 –2264[Abstract/Free Full Text]
  5. Lautin EM, Freeman NJ, Schoenfeld AH, et al. Radiocontrast-associated renal dysfunction: incidence and risk factors. AJR 1991; 157:49 –58[Abstract/Free Full Text]
  6. Weisberg LS, Kurnik PB, Kurnik BR. Risk of radiocontrast nephropathy in patients with and without diabetes mellitus. Kidney Int 1994; 45:259 –265[Medline]
  7. Parfrey P, Griffiths SM, Barrett BJ, et al. Contrast material–induced renal failure in patients with diabetes mellitus, renal insufficiency, or both: a prospective controlled study. N Engl J Med 1989; 320:143 –149[Abstract]
  8. Thomsen HS. Guidelines for contrast media from the European Society of Urogenital Radiology. AJR 2003;181 :1463 –1471[Free Full Text]
  9. McCullough PA, Sandberg KR. Epidemiology of contrast-induced nephropathy. Rev Cardiovasc Med 2003;4 [suppl 5]:S3 –S9
  10. Solomon R, Barrett B. Follow-up of patients with contrast-induced nephropathy. Kidney Int 2006;100 [suppl]:S46 –S50[CrossRef]
  11. Mehran R, Aymong ED, Nikolsky E, et al. A simple risk score for prediction of contrast-induced nephropathy after percutaneous coronary intervention: development and initial validation. J Am Coll Cardiol 2004; 44:1393 –1399[Abstract/Free Full Text]
  12. Taliercio CP, Vlietstra RE, Ilstrup DM, et al. A randomized comparison of the nephrotoxicity of iopamidol and diatrizoate in high risk patients undergoing cardiac angiography. J Am Coll Cardiol 1991; 17:384 –390[Abstract]
  13. Rudnick MR, Goldfarb S, Wexler L, et al. Nephrotoxicity of ionic and nonionic contrast media in 1196 patients: a randomized trial. Kidney Int 1995;47 : 254–261[Medline]
  14. Barrett BJ, Carlisle EJ. Meta-analysis of the relative nephrotoxicity of high- and low-osmolality iodinated contrast media. Radiology 1993;188 : 171–178[Abstract/Free Full Text]
  15. Solomon R. The role of osmolality in the incidence of contrast-induced nephropathy: a systematic review of angiographic contrast media in high risk patients. Kidney Int2005; 68:2256 –2263[CrossRef][Medline]
  16. Carraro M, Malalan F, Antonione R, et al. Effects of a dimeric vs a monomeric nonionic contrast medium on renal function in patients with mild to moderate renal insufficiency: a double-blind, randomized clinical trial. Eur Radiol 1998;8 : 144–147[CrossRef][Medline]
  17. Barrett BJ, Katzberg RW, Thomsen HS, et al. Contrast-induced nephropathy in patients with chronic kidney disease undergoing computed tomography: a double-blind comparison of iodixanol and iopamidol. Invest Radiol 2006;41 : 815–821[CrossRef][Medline]
  18. Johnson C, Levey AS, Coresh J, Levin A, Lau J, Eknoyan G. Clinical practice guidelines for chronic kidney disease in adults. Part II. Glomerular filtration rate, proteinuria, and other markers. Am Fam Physician 2004; 70:1091 –1097[Medline]
  19. Toprak O, Cirit M, Yesil M, et al. Impact of diabetic and pre-diabetic state on development of contrast-induced nephropathy in patients with chronic kidney disease. Nephrol Dial Transplant2007; 22:819 –826[Abstract/Free Full Text]
  20. Nikolsky E, Mehran R. Understanding the consequences of contrast-induced nephropathy. Rev Cardiovasc Med2003; 4[suppl 5]:S10 –S18[Medline]
  21. Chalmers N, Jackson RW. Comparison of iodixanol and iohexol in renal impairment. Br J Radiol 1999;72 : 701–703[Abstract]
  22. Aspelin P, Aubry P, Fransson S, et al. Nephrotoxic effects in high-risk patients undergoing angiography. N Engl J Med 2003; 348:491 –499[Abstract/Free Full Text]
  23. Jo SH, Youn TJ, Koo BK, et al. Renal toxicity evaluation and comparison between Visipaque (iodixanol) and Hexabrix (ioxaglate) in patients with renal insufficiency undergoing coronary angiography: the RECOVER study—a randomized controlled trial. J Am Coll Cardiol 2006; 48:924 –930[Abstract/Free Full Text]
  24. Baker CSR, Wragg A, Kumar S, De Palma R, Baker LRI, Knight CJ. A rapid protocol for the prevention of contrast-induced renal dysfunction: the RAPPID study. J Am Coll Cardiol 2003;41 :2114 –2118[Abstract/Free Full Text]
  25. Boccalandro F, Amhad M, Smalling RW, Sdringola S. Oral acetylcysteine does not protect renal function from moderate to high doses of intravenous radiographic contrast. Cathet Cardiovasc Interv 2003; 58:336 –341[CrossRef][Medline]
  26. Sharma SK, Kini A. Effect of nonionic radiocontrast agents on the occurrence of contrast-induced nephropathy in patients with mild-moderate chronic renal insufficiency: pooled analysis of the randomized trials. Catheter Cardiovasc Interv 2005;65 : 386–393[CrossRef][Medline]
  27. Sandstede JJ, Roth A, Machann W, Kaupert C, Hahn D. Evaluation of the nephrotoxicity of iodixanol in patients with predisposing factors to contrast medium induced nephropathy referred for contrast enhanced computed tomography. Eur J Radiol 2007;63 : 120–123[CrossRef][Medline]
  28. Becker CR, Reiser MF. Use of isoosmolar nonionic dimeric contrast media in multidetector row computed tomography angiography for patients with renal impairment. Invest Radiol 2005;40 : 672–675[CrossRef][Medline]
  29. Cheruvu B, Henning K, Mulligan J, et al. Iodixanol: risk of subsequent contrast nephropathy in cancer patients with underlying renal insufficiency undergoing diagnostic computed tomography examinations. J Comput Assist Tomogr 2007;31 : 493–498[CrossRef][Medline]
  30. Solomon R, Dumouchel W. Contrast media and nephropathy: findings from systematic analysis and Food and Drug Administration reports of adverse effects. Invest Radiol 2006;41 : 651–660[CrossRef][Medline]
  31. McCullough PA, Bertrand ME, Brinker JA, et al. A meta-analysis of the renal safety of isosmolar iodixanol compared with low-osmolar contrast media. J Am Coll Cardiol 2006;48 : 692–699[Abstract/Free Full Text]
  32. Verow P, Nossen JO, Sheppick A, Kjaersgaard P. A comparison of iodixanol with iopamidol in aortofemoral angiography. Br J Radiol 1995; 68:973 –978[Abstract/Free Full Text]
  33. Solomon RJ, Natarajan MK, Doucet S, et al.; Investigators of the CARE Study. Cardiac Angiography in Renally Impaired Patients (CARE) study: a randomized double-blind trial of contrast-induced nephropathy in patients with chronic kidney disease. Circulation 2007;115 :3189 –3196[Abstract/Free Full Text]
  34. Rao QA, Newhouse JH. Risk of nephropathy after intravenous administration of contrast material: a critical literature analysis. Radiology 2006;239 : 392–397[Abstract/Free Full Text]
  35. Katzberg RW, Barrett BJ. Risk of iodinated contrast material–induced nephropathy with intravenous administration. Radiology 2007;243 : 622–628[Free Full Text]

Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:


Home page
J Am Coll CardiolHome page
F. G. Kushner, M. Hand, S. C. Smith Jr, S. B. King III, J. L. Anderson, E. M. Antman, S. R. Bailey, E. R. Bates, J. C. Blankenship, D. E. Casey Jr, et al.
2009 Focused Updates: ACC/AHA Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction (Updating the 2004 Guideline and 2007 Focused Update) and ACC/AHA/SCAI Guidelines on Percutaneous Coronary Intervention (Updating the 2005 Guideline and 2007 Focused Update): A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines
J. Am. Coll. Cardiol., December 1, 2009; 54(23): 2205 - 2241.
[Full Text] [PDF]


Home page
CirculationHome page
F. G. Kushner, M. Hand, S. C. Smith Jr, S. B. King III, J. L. Anderson, E. M. Antman, S. R. Bailey, E. R. Bates, J. C. Blankenship, D. E. Casey Jr, et al.
2009 Focused Updates: ACC/AHA Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction (Updating the 2004 Guideline and 2007 Focused Update) and ACC/AHA/SCAI Guidelines on Percutaneous Coronary Intervention (Updating the 2005 Guideline and 2007 Focused Update): A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines
Circulation, December 1, 2009; 120(22): 2271 - 2306.
[Full Text] [PDF]


Home page
Am. J. Roentgenol.Home page
E. K. Paulson and C. A. Coursey
CT Protocols for Acute Appendicitis: Time for Change
Am. J. Roentgenol., November 1, 2009; 193(5): 1268 - 1271.
[Full Text] [PDF]


Home page
J Am Coll Cardiol IntvHome page
E. Cantor and L. Lim
The Relative Renal Safety of Iodixanol Compared With Low-Osmolar Contrast Media
J. Am. Coll. Cardiol. Intv., November 1, 2009; 2(11): 1163 - 1164.
[Full Text] [PDF]


Home page
J Am Coll Cardiol IntvHome page
M. Reed, P. Meier, U. U. Tamhane, K. B. Welch, M. Moscucci, and H. S. Gurm
The Relative Renal Safety of Iodixanol Compared With Low-Osmolar Contrast Media: A Meta-Analysis of Randomized Controlled Trials
J. Am. Coll. Cardiol. Intv., July 1, 2009; 2(7): 645 - 654.
[Abstract] [Full Text] [PDF]


Home page
RadiologyHome page
P. Capasso, S. D. Weisbord, M. C. Heinrich, and M. Uder
Comment on Meta-analyses of Trials Comparing Contrast Media
Radiology, July 1, 2009; 252(1): 316 - 318.
[Full Text] [PDF]


Home page
RadiologyHome page
M. D. Cohen, U. J. Schoepf, and P. Costello
Is the Use of Intravenous Contrast Material Truly Safe in Patients with Impaired Renal Function?
Radiology, May 1, 2009; 251(2): 613 - 615.
[Full Text] [PDF]


Home page
Mayo Clin Proc.Home page
S. Goldfarb, P. A. McCullough, J. McDermott, and S. B. Gay
Contrast-Induced Acute Kidney Injury: Specialty-Specific Protocols for Interventional Radiology, Diagnostic Computed Tomography Radiology, and Interventional Cardiology
Mayo Clin. Proc., February 1, 2009; 84(2): 170 - 179.
[Abstract] [Full Text] [PDF]


Home page
Nephrol Dial TransplantHome page
C. A. Herzog
Kidney disease in cardiology
Nephrol. Dial. Transplant., January 1, 2009; 24(1): 34 - 37.
[Full Text] [PDF]


Home page
RadiologyHome page
M. C. Heinrich, L. Haberle, V. Muller, W. Bautz, and M. Uder
Nephrotoxicity of Iso-osmolar Iodixanol Compared with Nonionic Low-osmolar Contrast Media: Meta-analysis of Randomized Controlled Trials1
Radiology, January 1, 2009; 250(1): 68 - 86.
[Abstract] [Full Text] [PDF]


Home page
RadiologyHome page
C. Pering, P. Lengsfeld, P. Seidensticker, U. J. Schoepf, and P. Costello
Iso- versus Low-Osmolar Contrast Media and Contrast Medium-induced Nephropathy
Radiology, January 1, 2009; 250(1): 298 - 299.
[Full Text] [PDF]


Home page
CJASNHome page
R. Solomon
Contrast-Induced Acute Kidney Injury: Is There a Risk after Intravenous Contrast?
Clin. J. Am. Soc. Nephrol., September 1, 2008; 3(5): 1242 - 1243.
[Full Text] [PDF]


This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kuhn, M. J.
Right arrow Articles by So, G. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kuhn, M. J.
Right arrow Articles by So, G. J.
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
Hotlight (NEW!)
Right arrow
What's Hotlight?


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS