Use of iso-osmolar nonionic dimeric contrast media in multidetector row computed tomography angiography for patients with renal impairment

Feasibility study of a synchronized diastolic injection with low contrast volume for proper quantitative assessment of aortic regurgitation in porcine models

OBJECTIVES

To evaluate the in vivo feasibility of aortography with one accurately timed diastolic low-volume contrast injection for quantitative assessment of aortic regurgitation (AR) post transcatheter aortic valve replacement (TAVR).

BACKGROUND

With the rise of a minimalistic approach for TAVR, aortography (re)emerges as a pragmatic tool for AR assessment. In a mock circulation system, we have validated the accuracy of a single diastolic injection triggered by electrocardiogram (ECG) with low-contrast volume.

METHODS

Two-phase experiment: first, a series of aortograms were performed in a porcine model, with 8 mL of contrast using the synchronized (SYNC) and the conventional non-synchronized (NS) injections. In a second phase, we developed a model of AR by inserting partially unsheathed Wallstents of 6-10 mm of diameter across the pig's aortic valve, performing SYNC injections with 8 mL of contrast and NS injections with 8 mL and 15 mL (rate: 20 mL/sec). Respective accuracies of SYNC vs. NS were assessed using Passing-Bablock regression. An angiography core laboratory performed quantitative AR assessment with videodensitometry (VD-AR).

RESULTS

The SYNC injections produced higher opacification of the aortic root compared with NS injections (P = 0.04 for density). In the second phase, a regression line for predicting VD-AR based on the SYNC injection resulted in a lower intercept and a slope closer to the line of identity (y = 11.9 + 0.79x, P < 0.001, r²  = 0.94) with the NS-8 mL than with the NS-15 mL injection (y = 26.5 + 0.55x, P < 0.001, r²  = 0.81).

CONCLUSION

Synchronized diastolic injection with low contrast volume produced denser images in the aortic root and more accurate than the conventional injection; thus, may be an appealing alternative for assessment of AR post TAVR.

A novel synchronised diastolic injection method to reduce contrast volume during aortography for aortic regurgitation assessment: in vitro experiment of a transcatheter heart valve model

AIMS

In the minimalist transcatheter aortic valve implantation (TAVI) era, the usage of transoesophageal echocardiography has become restricted. Conversely, aortography has gained clinical ground in quantifying prosthetic valve regurgitation (PVR) during the procedure. In a mock circulation system, we sought to compare the contrast volume required and the accuracy of aortographic videodensitometric PVR assessment using a synchronised diastolic and standard (non-synchronised) injection aortography.

METHODS AND RESULTS

Synchronised diastolic injection triggered by the signal stemming from the mock circulation was compared with standard non-synchronised injection. A transcatheter heart valve was implanted and was deformed step by step by advancing a screw perpendicularly to the cage of the valve in order to create increasing PVR. Quantitative measurement of PVR was derived from time-density curves of both a reference area (aortic root) and a region of interest (left ventricle) developed by a videodensitometric software. The volume of contrast required for the synchronised diastolic injection was significantly less than in the non-synchronised injection (8.1 [7.9-8.5] ml vs. 19.4 [19.2-19.9] ml, p<0.001). The correlation between the two methods was substantial (Spearman's coefficient rho ranging from 0.991 to 0.968). Intraobserver intra-class correlation coefficient for both methods of injection was 0.999 (95% CI: 0.996-1.000) for the synchronised diastolic and 0.999 (95% CI: 0.996-1.000) for the non-synchronised injection group. The mean difference in the rating was 0.17% and limits of agreement were ±1.64% for both groups.

CONCLUSIONS

A short synchronised diastolic injection enables contrast volume reduction during aortography without compromising the accuracy of the quantitative assessment of PVR using videodensitometry.

Feasibility of ultra-low contrast 64-slice computed tomography angiography before transcatheter aortic valve implantation: a real-world experience

AIMS

To investigate the feasibility, image quality, and clinical implications of an ultra-low-dose contrast injection computed tomography angiography (CTA) protocol in patients scheduled for transcatheter aortic valve implantation (TAVI).

METHODS AND RESULTS

Images obtained with 64-slice CT were retrospectively evaluated in 162 TAVI candidates with a body mass index (BMI) of ≤29 kg/m(2). A multiphasic, low iodine dose and BMI-adapted CM protocol was administered in all patients (BMI <22 kg/m(2): 40 mL; BMI 22-29 kg/m(2): 55 mL). All images were evaluated for image quality, vessel attenuation, and estimated radiation dose. The anatomy, diameters, perimeter, and area of the aortic annulus were assessed. Anatomy and diameters of peripheral vessels were also evaluated. Image quality of the aortic root and ilio-femoral vessels was diagnostic in all patients. Vascular attenuation was >200 HU at any vessel level. The mean diameters of the aortic annulus were 22 ± 3 mm (range: 16-28 mm) × 26 ± 3 mm (range: 20-33 mm); the mean perimeter was 77.0 ± 7.1 mm. After CTA, a total of 137 patients (84.6%) underwent TAVI. Mean estimated radiation dose was 20.2 ± 4.6 mSv.

CONCLUSION

With our protocol, we achieved images of the aortic annulus and aorto-iliac anatomy of sufficient quality to allow patient selection and procedural planning for TAVI, with a substantial reduction of the amount of injected CM.

Randomised trial of no hydration vs. sodium bicarbonate hydration in patients with chronic kidney disease undergoing acute computed tomography-pulmonary angiography

BACKGROUND

Hydration to prevent contrast-induced acute kidney injury (CI-AKI) induces a diagnostic delay when performing computed tomography-pulmonary angiography (CTPA) in patients suspected of having acute pulmonary embolism.

AIM

To analyze whether withholding hydration is non-inferior to sodium bicarbonate hydration before CTPA in patients with chronic kidney disease (CKD).

METHODS

We performed an open-label multicenter randomized trial between 2009 and 2013. One hundred thirty-nine CKD patients were randomized, of whom 138 were included in the intention-to-treat population: 67 were randomized to withholding hydration and 71 were randomized to 1-h 250 mL 1.4% sodium bicarbonate hydration before CTPA. Primary outcome was the increase in serum creatinine 48-96 h after CTPA. Secondary outcomes were the incidence of CI-AKI (creatinine increase > 25%/> 0.5 mg dL(-1) ), recovery of renal function, and the need for dialysis within 2 months after CTPA. Withholding hydration was considered non-inferior if the mean relative creatinine increase was ≤ 15% compared with sodium bicarbonate.

RESULTS

Mean relative creatinine increase was -0.14% (interquartile range -15.1% to 12.0%) for withholding hydration and -0.32% (interquartile range -9.7% to 10.1%) for sodium bicarbonate (mean difference 0.19%, 95% confidence interval -5.88% to 6.25%, P-value non-inferiority < 0.001). CI-AKI occurred in 11 patients (8.1%): 6 (9.2%) were randomized to withholding hydration and 5 (7.1%) to sodium bicarbonate (relative risk 1.29, 95% confidence interval 0.41-4.03). Renal function recovered in 80.0% of CI-AKI patients within each group (relative risk 1.00, 95% confidence interval 0.54-1.86). None of the CI-AKI patients developed a need for dialysis.

CONCLUSION

Our results suggest that preventive hydration could be safely withheld in CKD patients undergoing CTPA for suspected acute pulmonary embolism. This will facilitate management of these patients and prevents delay in diagnosis as well as unnecessary start of anticoagulant treatment while receiving volume expansion.

The incidence of contrast-induced nephropathy (CIN) following transarterial chemoembolisation (TACE) in patients with hepatocellular carcinoma (HCC)

PURPOSE

The purpose of this retrospective study was to investigate the incidence of contrast-induced nephropathy (CIN) caused by transarterial chemoembolisation (TACE) in patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

One hundred forty-one patients treated between 2005 and 2008 undergoing 305 consecutive sessions of TACE were enrolled. CIN was defined as an increase in the serum creatinine level of more than 0.5 mg/dl or more than 25 % from baseline within 3 days after TACE without any other identifiable cause of acute kidney injury.

RESULTS

CIN by the present definition was observed after 2.6 % of the TACE sessions. No patient showed clinical signs or symptoms of acute renal failure, or required haemodialysis. None of the patients with an estimated glomerular filtration rate of <60 ml/min/1.73 m(2) developed CIN.

CONCLUSION

The present study suggests that TACE is a relatively safe procedure in terms of the risk of CIN under vigorous periprocedural hydration and that the incidence of CIN is comparable to that of AKI associated with intravenous CM administration.

KEY POINTS

• CIN would be lower for non-coronary arterial intervention than for coronary intervention. • The present study suggests that the CIN rates following TACE are low. • The incidence of CIN is comparable to that after intravenous CM administration.

Meta-analysis: serum creatinine changes following contrast enhanced CT imaging

PURPOSE

Contrast induced nephropathy (CIN) is defined as a decrease in renal function following administration of contrast media. The aim of this meta-analysis was to asses the overall risk of CIN, chronic loss of kidney function and the need for renal replacement therapy (RRT) after intravenous contrast enhanced CT-scan. Secondly, we aimed to identify subgroups at increased risk for CIN.

MATERIALS AND METHODS

A literature search in Pubmed, Medline, Embase and Cochrane databases was performed. Data extraction was carried out independently by two reviewers. Meta-analysis and meta-regression were performed using an exact likelihood approach.

RESULTS

Forty studies evaluating the incidence of CIN after CT were included. The pooled incidence of CIN was 6.4% (95% CI 5.0-8.1). The risk of RRT after CIN was low, 0.06% (95% CI 0.01-0.4). The decline in renal function persisted in 1.1% of patients (95% CI 0.6-2.1%). Patients with chronic kidney disease (odds ratio 2.26, p<0.001) or diabetes mellitus (odds ratio 3.10, p<0.001) were at increased risk for the development of CIN.

CONCLUSION

CIN occurred in 6% of patients after contrast enhanced CT. In 1% of all patients undergoing contrast enhanced CT the decline in renal function persisted.

Baseline incidence and severity of renal insufficiency evaluated by estimated glomerular filtration rates in patients scheduled for contrast-enhanced CT

BACKGROUND

Although pre-existing renal insufficiency (RI) is the most important risk factor for contrast-induced nephropathy (CIN), the background distribution of baseline renal function has not been investigated thoroughly in patients scheduled for contrast-enhanced CT.

PURPOSE

To investigate the incidence and severity of baseline RI evaluated by estimated glomerular filtration rates (eGFR) in patients who underwent contrast-enhanced CT at an academic center.

MATERIAL AND METHODS

A total of 6586 patients (3630 men and 2956 women; mean age 57.0 ± 11.9 years) who underwent contrast-enhanced CT between January and December 2008 were retrospectively studied. Of these, 829 had cardiovascular diseases (CVD), 5116 had oncologic diseases, 178 had diabetes mellitus (DM), and 1572 had chronic liver disease (CLD). The eGFR (mL/min/1.73 m(2)) was calculated from their serum creatinine level. Mild, moderate-a, moderate-b, and severe RI were recorded at 60 < =eGFR < 90, 45 < =eGFR < 60, 30 < =eGFR < 45 and eGFR < 30, respectively.

RESULTS

Of the 6586 patients, 1.6%, 3.7%, 13.7%, and 54.2% were judged to present with severe, moderate-b, moderate-a, and mild RI, respectively. While moderate-b-to-severe RI was recorded in 133 (3.2%) of 4161 patients aged 70 years or less, it was observed in 218 (9.0%) of the 2425 patients who were 71 years or older. Among the 829 CVD patients, 9.9% manifested moderate-b-to-severe- and 73.0% mild-to-moderate-a RI. The corresponding rates were 4.4% and 68.9% for oncologic disease, 16.9% and 61.2% for DM, and 4.8% and 71.5% for CLD patients. By univariate analysis, there was a significant association between moderate-b-to-severe RI and the advanced age, CVD, DM, and non-oncologic disease. Multivariate analysis showed that the advanced age, DM, and non-oncologic disease were statistically associated with moderate-b-to-severe RI.

CONCLUSION

The incidence of RI of eGFR < 45mL/min/1.73 m(2) at baseline was high in patients with advanced age, CVD and DM and in patients without oncologic disease.

Creatinine increases after intravenous contrast administration: incidence and impact

OBJECTIVE

The incidence of creatinine increases after intravenous contrast (postcontrast creatinine increases, PCCI) is controversial, ranging from 0% to >25%. We sought to determine what factors influenced these divergent estimates of PCCI incidence. Where possible, the association of PCCI with long-term adverse outcomes was also studied.

MATERIALS AND METHODS

Both observational studies and prospective randomized trials were reviewed. Definitions of clinically significant PCCI, incidence of PCCI, and its association with baseline kidney function, the setting in which intravenous contrast was administered, and the short- and long-term consequences of PCCI were extracted.

RESULTS

Baseline renal function impairment and inpatient versus outpatient status are the major risk factors for PCCI. PCCI is possibly associated with clinically significant short- and long-term adverse events.

CONCLUSIONS

PCCI occurs despite a number of potential confounding issues. The incidence is increased as kidney function at baseline is diminished and for inpatients. There is limited data on long-term outcomes following PCCI in this setting.

No increased risk for contrast-induced nephropathy after multiple CT perfusion studies of the brain with a nonionic, dimeric, iso-osmolal contrast medium

BACKGROUND AND PURPOSE

Contrast-induced nephropathy (CIN) is one of the most common causes of in-hospital acute renal failure. The aim of this study was to assess the risk for CIN after repeated administration of the nonionic, dimeric, iso-osmolal contrast agent iodixanol regardless of pre-existing renal function. Changes in serum creatinine (SCr) levels were compared with those of control subjects who did not receive iodinated contrast media (CM).

MATERIALS AND METHODS

Between January 2005 and March 2007, a total of 100 consecutive patients were prospectively included. Patients underwent a CT perfusion (CTP) study of the brain from clinical signs of acute cerebral infarction. CTP was performed with an intravenous bolus of 60 mL of iodixanol-270. Precontrast and postcontrast SCr levels were obtained, and the CTP study was repeated within 32 hours and postcontrast SCR was assessed. The control group consisted of 100 patients scheduled for plain cranial CT examination, who were not exposed to iodinated CM.

RESULTS

Mean baseline SCr level was 0.96 +/- 0.35 mg/dL in the contrast group and 1.14 +/- 0.74 mg/dL in the control group. After repeated administration of CM, a total of 7 patients had a relative increase of greater than or equal to 25% compared with baseline. In the control group, a relative increase of 25% or more was seen in 12 patients. The difference in the incidence of the rise in SCr of >25% was not significantly different (P = .094).

CONCLUSION

Multiple contrast-enhanced studies with intravenously administered iodixanol are not associated with a higher risk for CIN compared with a control group receiving no CM.

The PREDICT study: a randomized double-blind comparison of contrast-induced nephropathy after low- or isoosmolar contrast agent exposure

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 m(2)) 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 >or= 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 m(2) for the iopamidol 370 group vs 49.9 mL/min/1.73 m(2) for the iodixanol 320 group; p = 0.16). Increases in the serum creatinine value of >or= 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 >or= 2.0 mg/dL, baseline estimated GFR of <or= 40 mL/min/1.73 m(2), 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.

Iso-osmolality versus low-osmolality iodinated contrast medium at intravenous contrast-enhanced CT: effect on kidney function

PURPOSE

To determine the effects of iso-osmolality contrast medium compared with a low-osmolality agent on renal function (serum creatinine [SCr] and glomerular filtration rate [GFR]) in high-risk patients undergoing intravenous contrast material-enhanced CT.

MATERIALS AND METHODS

This HIPAA-compliant study was IRB-approved; formal consent was obtained. One hundred seventeen patients (83 men, 34 women; mean age, 64.3 years; range, 18-86 years) with decreased renal function underwent contrast-enhanced CT with either iso-osmolality iodixanol (n = 61) or low-osmolality iopromide (n = 56). Outcome measures were of SCr increase or GFR decrease for 3 days after CT, a SCr increase (of >or=0.5 mg/dL [44.2 micromol/L, 25%] or >or=1.0 mg/dL [88.4 micromol/L, 50%]), a GFR reduction (of >or=5 mL/min), and patient outcome at 30- and 90-day follow-up.

RESULTS

Iodixanol decreased SCr (mean +/- standard deviation) from 1.77 mg/dL +/- 0.24 (156.47 micromol/L +/- 21.22) at baseline to 1.65 mg/dL +/- 0.35 (145.86 micromol/L +/- 30.94, P = .046) at day 1, 1.73 mg/dL +/- 0.53 (152.93 micromol/L +/- 46.85, not significant) at day 2, and 1.73 mg/dL +/- 0.55 (152.93 micromol/L +/- 48.62, not significant) at day 3 (not significant). Iopromide increased SCr from 1.75 mg/dL +/- 0.32 (154.7 micromol/L +/- 28.29) at baseline to 1.8 mg/dL +/- 0.42 (159.12 micromol/L +/- 15.59) at day 1, 1.77 mg/dL +/- 0.49 (156.47 micromol/L +/- 43.32) at day 2, and 1.77 mg/dL +/- 0.62 (156.47 micromol/L +/- 54.81) at day 3 (not significant). Iodixanol increased and iopromide decreased GFR on all 3 days after CT (not significant). Fewer patients in the iodixanol group (8.5%) than in the iopromide group (27.8%) had SCr increase 0.5 mg/dL or higher (>or=25%, P = .012). Two patients in each group had SCr increase of 1.0 mg/dL or more (not significant). More patients in the iopromide group (42.3%) than in the iodoxanol group (24.1%) had a GFR reduction of 5 mL/min or higher (P = .0426). No patient had a contrast material-related adverse event at 30- or 90-day follow-up.

CONCLUSION

Intravenous contrast material application in high-risk patients is unlikely to be associated with permanent adverse outcomes. SCr levels after contrast material administration are lower in iodixanol than iopromide groups.

Radiologists’ knowledge and perceptions of the impact of contrast-induced nephropathy and its risk factors when performing computed tomography examinations: A survey of European radiologists

BACKGROUND

The past decade has seen a proliferation in the number of CT procedures. As increasing numbers of elderly patients with multiple comorbidities undergo contrast media (CM)-enhanced procedures, more patients are at risk for contrast-induced nephropathy (CIN).

OBJECTIVES

To understand whether radiologists are sufficiently aware of the incidence, impact and risk factors of CIN, and whether they are taking sufficient measures to prevent CIN among patients undergoing CT.

MATERIALS AND METHODS

A telephone or online survey was conducted in 2005 with 509 radiologists from 10 European countries. Participants had a minimum of 3 years' experience and performed at least 50 CT scans per week.

RESULTS

Most (88%) radiologists believed that CIN is an important issue. While 45% identify that a patient is experiencing CIN when the serum creatinine level increases >25% (0.5mg/dL) from baseline within 48h, the remainder used criteria that might lead to significant under-diagnosis. Most (72%) radiologists believed that CIN is associated with increased morbidity; 56% did not believe that it is associated with increased mortality. Most respondents agreed that pre-existing renal impairment (97%), dehydration (90%) and diabetes (89%) were risk factors for CIN; however, 26%, 30% and 46%, respectively, did not identify advanced age, CM dose or congestive cardiac failure as risk factors. Only 7% of radiologists thought they were always made aware of CIN associated with their cases and 28% never consulted a nephrologist to discuss patients at risk of CIN or who had developed CIN.

CONCLUSION

There is highly variable awareness of the definition, impact and risk factors for CIN among European radiologists. Data regarding the importance of CIN in CT are limited. Improved efforts are required to better educate radiologists and referring physicians and to institute appropriate protocols to identify at-risk patients and prevent CIN.

Contrast-induced nephropathy in patients with chronic kidney disease undergoing computed tomography: a double-blind comparison of iodixanol and iopamidol

BACKGROUND

Based on a single clinical trial, it has been suggested that the contrast agent iodixanol, which is isotonic to human plasma, may be less nephrotoxic than other nonionic contrast agents in renally impaired patients after intra-arterial injection. We compared the effects on renal function of iopamidol-370 injection (796 mOsm/kg) and iodixanol-320 (290 mOsm/kg) in patients with chronic kidney disease undergoing contrast-enhanced multidetector computed tomography (CE-MDCT) examinations using a multicenter, double-blind, randomized, parallel-group design.

METHODS

A total of 166 patients with stable moderate-to-severe chronic kidney disease (screening and baseline serum creatinine, SCr, > or =1.5 mg/dL and/or creatinine clearance, CrCl, < or =60 mL/min) who were undergoing CE-MDCT of the liver or peripheral arteries were randomized to receive equi-iodine IV doses (40 gI) of either iopamidol-370 (370 mgI/mL) or iodixanol-320 (320 mgI/mL) at 4 mL/s. SCr and CrCl were obtained at screening, baseline, and at 48-72 +/- 6 hours after dose (mean, 57.4 hours). Contrast-induced nephropathy (CIN) was defined as an absolute increase > or =0.5 mg/dL (44.2 micromol/L) and/or a relative increase in SCr > or =25% from baseline.

RESULTS

A total of 153 patients were included in the final analysis (13 patients excluded because of lack of follow-up, hemodialysis to remove contrast, average daily CrCl variation >1% at screening). The 2 study groups were comparable with regard to age, gender distribution, the presence of diabetes, concomitant medications, hydration, and contrast dose. Mean predose SCr was 1.6 +/- 0.4 mg/dL in both groups (P = 0.9). An absolute increase > or =0.5 mg/dL (44.2 micromol/L) in SCr was observed in none of the patients receiving iopamidol-370 and in 2.6% (2/76) of patients receiving iodixanol-320 (95% confidence interval -6.2, 1.0, P = 0.2). A relative increase > or =25% in SCr occurred in 4% (3/77) of patients receiving iopamidol-370 and in 4% (3/76) of the patients receiving iodixanol-320 (95% confidence interval -6.2, 6.1, P = 1.0).

CONCLUSION

The rate of CIN was similarly low in risk patients after intravenous administration of iopamidol-370 or iodixanol-320 for CE-MDCT.

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

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

Incidence of Radiocontrast Nephropathy in Patients Undergoing Acute Stroke Computed Tomography Angiography

BACKGROUND AND PURPOSE

Minimal research has evaluated the renal safety of emergent computed tomography angiography (CTA) procedures, consecutive contrast medium application, and the long-term outcome in acute stroke patients. We investigated the incidence of contrast-induced renal impairment in these populations.

METHODS

We retrospectively reviewed patients with acute stroke syndrome who received a CTA of the brain with or without the neck within 24 hours from onset of symptoms. All creatinine results and additional conventional angiography findings were recorded. With a positive history of renal disease, contrast administration was delayed until creatinine results were available. Radiocontrast nephropathy (RCN) was defined as a >/=25% increase in serum creatinine from the baseline value up to 5 days after CTA.

RESULTS

Four hundred eighty-one patients were reviewed, and 224 met the inclusion criteria. There were 7 of 224 (3%) who fulfilled the criteria for RCN. A number of patients underwent emergent CTA without knowledge of their creatinine value; 2 of 93 (2%) developed RCN. There were 36 patients who received an additional digital subtraction angiogram, and none of these developed subsequent RCN. No patients required dialysis, and 9 of 68 (13%) had a >25% increase in their creatinine levels at a late (>30 days) follow-up.

CONCLUSIONS

Overall, these results illustrate that there is a low incidence of RCN in acute stroke patients undergoing emergency CTA.

Evaluation of the nephrotoxicity of iodixanol in patients with predisposing factors to contrast medium induced nephropathy referred for contrast enhanced computed tomography

To determine the risk of developing contrast induced nephropathy (CIN) in intermediate-risk patients receiving iodixanol, an iso-osmolar, dimeric non-ionic contrast agent, for CT in a clinical setting. Hundred consecutive patients referred for a contrast enhanced CT with a serum creatinine concentration>1.1mg/dl and/or a glomerular filtration rate (GFR)<90ml/min were included. Exclusion criteria were a serum creatinine>2.0mg/dl and a GFR<30ml/min or concurrent nephrotoxic agents. Between 60 and 140ml (mean 97+/-42ml) iodixanol (320mgI/ml) were administered at a flow of 2.5-3ml/s. Hydration with 500ml NaCl i.v. was performed before and after contrast injection. Follow-up was completed in 99 patients (age, 64+/-13 years, 68 men). CIN was defined as increase in serum creatinine concentration +0.5mg/dl or >25% above baseline within 72h after contrast administration. Serum creatinine concentration and GFR were 1.40+/-0.22, 1.29+/-0.29, and 1.26+/-0.29mg/dl and 52.2+/-13.9, 51.3+/-21.1, and 51.5+/-15.1ml/min on days 0, 3, and 7, respectively. Three out of 99 (3%) patients who received 90-110ml iodixanol revealed a CIN on day 3 without persistence on day 7. No specific therapy was needed. One out of 99 patients reported an exanthema on days 3 and 7. With the use of iodixanol in intermediate-risk patients, 3% of the patients develop CIN on day 3 without need for a specific therapy or persistence on day 7.

Iodixanol

OBJECTIVE

To assess the risk of contrast-induced nephropathy in cancer patients with underlying renal insufficiency receiving the iso-osmolar intravenous contrast agent iodixanol for diagnostic computed tomography (CT) examinations.

METHODS

Institutional review board approval was obtained with waiver of informed consent. Our study was a retrospective evaluation comparing the incidence of contrast-induced nephropathy in consecutive patients with underlying renal insufficiency undergoing diagnostic CT examinations receiving iodixanol from November 2003 to June 2005 with a comparison group of patients with normal baseline renal function over the same period. Renal insufficiency was considered a serum creatinine level more than 1.2 mg/dL in females and more than 1.5 mg/dL in males. Contrast nephropathy was considered an absolute elevation of 0.5 mg/dL or 25% elevation in serum creatinine level.

RESULTS

In the group of patients receiving iodixanol with underlying renal insufficiency (189 patients), 9.0% developed contrast nephropathy (P = 0.015) with 4.8% of patients developing irreversible renal damage (P = 0.03). This compared with 4.9% of patients receiving iodixanol (185 patients) and 3.1% of patients receiving iohexol (194 patients) with normal baseline renal function developing contrast nephropathy (P = 0.38) with 3.2% of the iodixanol patients and 1.0% of the iohexol patients developing irreversible renal damage (P = 0.13).

CONCLUSIONS

The risk of contrast-induced nephropathy is significantly higher in patients with underlying renal insufficiency receiving iodixanol than that for patients with normal baseline renal function, but this should not serve as an absolute contraindication for these patients to receive intravenous iodinated contrast for diagnostic CT examinations particularly in patients with life-threatening clinical questions in which contrasted CT may provide valuable information.

Contrast Medium Administration in the Elderly Patient: Is Advancing Age an Independent Risk Factor for Contrast Nephropathy after Angiographic Procedures?

Contrast medium-induced nephropathy (CMIN) is the third leading cause of hospital-acquired acute renal dysfunction. Even if the number of patients over 75 years of age undergoing diagnostic and/or interventional procedures and requiring administration of contrast medium (CM) is growing constantly, at present there is no definitive consensus regarding the role of advancing age and related morphologic or functional renal changes as an independent risk factor for CMIN. The authors review the evidence from recent medical literature on the definition, pathophysiology, and clinical presentation of CMIN as well as therapeutic approaches to its prophylaxis. Attention is focused on advancing age as a preexisting physiologic condition that is, per se, able to predispose the patient to CM-induced renal impairment, assuming that every elderly patient is potentially at risk for CMIN.

Selection of contrast media

The pathophysiologic mechanisms of contrast-induced nephropathy (CIN) have been reviewed by Persson and Tepel. They focus on the renal response to contrast media (CM). In this section, we focus on the CM itself. Aspects of importance with regard to CIN include the route of administration, the volume of CM, the manner of X-ray attenuation, and the specific chemical structure of the CM.