Experience with iodixanol, a new nonionic dimeric contrast medium. Preliminary results from the human phase I study

Iodixanol supplementation in freezing extender improves the antioxidant capacity of semen

The aim of this study was to evaluate the effect of supplementing bovine semen freezing extender with different concentrations of iodixanol on post-thaw sperm characteristics. Six ejaculates of three Nellore bulls were pooled and diluted in commercial extender (BotuBov®) and then divided into 4 groups: control group (without adding iodixanol); groups G1.5, G3, or G6 according to the concentration of iodixanol solution (RedCushion®). After dilution, the samples were cooled and frozen. Post-thaw semen evaluation included sperm motility by CASA immediately after thawing and after 60 min of incubation at 37°C, flow cytometry analysis for integrity of plasma and acrosomal membranes, membrane destabilization and translocation of phosphatidylserine, mitochondrial membrane potential, and formation of intracellular anion superoxide (O 2 - ), hydrogen peroxide (H2 O2 ), and membrane lipid peroxidation. The group G6 presented significantly higher (p < .05) total and progressive motility, percentage of plasma and acrosomal membrane integrity, and H2 O2 than control and group G1.5. Furthermore, group G6 showed lower (p < .05) lipid peroxidation than control. In addition, regardless of the concentration used, the percentage of spermatozoa without phosphatidylserine translocation was higher (p < .05) in all iodixanol supplemented groups. In conclusion, iodixanol supplementation preserved the motility and integrity of sperm membranes during cryopreservation and protected against lipid peroxidation.

A comparison of two types of contrast media used in endoscopic retrograde cholangiopancreatography: A retrospective study

BACKGROUND

Post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) is one of the most serious complications of ERCP. Various procedures can reduce the incidence of PEP, such as wire-guided cannulation, prophylactic pancreatic stent placement, and pretreatment anal insertion of NSAIDs. Recently, iso-osmolar contrast media (IOCM) have been used for ERCP in several hospitals to reduce the risk of PEP in Japan. However, the effect of IOCM is uncertain because few reports have examined IOCM in relation to PEP.

AIM

This study aimed to investigate the relationship between contrast media used and the incidence of PEP.

METHODS

This retrospective study included all qualifying patients who had undergone ERCP at Hamamatsu University Hospital between January 2012 and January 2020. This study examined whether there was a difference in the onset of PEP between patients administered IOCM and high osmolar contrast medium (HOCM). Propensity score matching was used to analyze patient characteristics and ERCP procedures. Amidotrizoic acid was used as HOCM and iodixanol as IOCM.

RESULTS

ERCP was performed on 458 patients, and 830 procedures were conducted. After propensity score matching, 162 patients from the amidotrizoic acid group and 162 patients from the iodixanol group were selected. The incidence of PEP was 10.5% (17) in the amidotrizoic acid group and 9.3% (15) in the iodixanol group (P = 0.71). Changes in serum amylase levels post- and pre-ERCP were 240.6 ± 573.8 U/L and 142.7 ± 382.1 U/L in the amidotrizoic acid and iodixanol groups, respectively (P = 0.072).

CONCLUSION

Iodixanol had no prophylactic effect on PEP and clinical outcomes.

Iodixanol in Femoral Arteriography

Two contrast media, iodixanol (Visipaque, Nycomed) 270 mg I/ml and iohexol (Omnipaque, Nycomed) 300 mg I/ml, were compared in femoral arteriography, in 147 patients. Both contrast media were diagnostically effective for use in femoral arteriography, without any significant difference. Pain was reported in connection with injection of iohexol by 36% of the patients, after injection of iodixanol none reported pain. Seventy-two percent of the patients in the iodixanol group reported a sensation of warmth in connection with contrast injection versus 90% in the iohexol group. The average intensity of the warmth was greater with iohexol than with iodixanol. Fourteen percent of patients in the iodixanol group and 1% in the iohexol group reported one or more subjective adverse events.

Iodixanol in Cardioangiography in Patients with Coronary Artery Disease

Iodixanol is a new nonionic, dimeric contrast medium. With the addition of 18 mmol/l Na+ and 0.3 mmol/l Ca++ to iodixanol 320 mg I/ml a plasma-isotonic solution was obtained. The purpose was to evaluate the suitability of iodixanol for use in cardioangiography by determining the diagnostic efficacy, patient tolerability, and cardiac and renal side-effects. Initially, 14 patients with coronary artery disease were examined using iodixanol. A double-blind, randomized study was then performed in 72 patients, comparing iodixanol and iohexol. Serum and urine were sampled before the examination, and one and 2 days after. The diagnostic information was good and the number of adverse events low with iodixanol. The patients reported significantly less of a sensation of warmth following injection of iodixanol than iohexol. Our results also indicate that iodixanol 320 mg I/ml influences renal function to a lesser degree than does iohexol 350 mg I/ml. We therefore conclude that isotonic iodixanol is a safe contrast medium for use in cardioangiography.

Iodixanol in Abdominal Digital Subtraction Angiography

The safety, tolerability and efficacy of iodixanol 270 mg I/ml were compared to those of iohexol 300 mg I/ml in a double-blind, randomized, parallel abdominal intra-arterial DSA phase III trial. Fifty-nine patients were included in the trial; 39 patients received iodixanol and 20 received iohexol. The mean volume of iodixanol administered was 235.8 ml (0.93 g I/kg b.w.) while the mean volume of iohexol was 254.7 ml (1.10 g I/kg b.w.). No differences in diagnostic information and radiographic density were apparent in spite of the difference in the concentration of iodine. No serious adverse events occurred. Four patients (10%) in the iodixanol group and 2 (10%) in the iohexol group experienced adverse events. Eight percent of the injections of iodixanol promoted discomfort, compared to 12%) of the injections of iohexol. An increase in S-urea and S-creatinine was seen with both agents the first day after injection, but appeared to be less pronounced with iodixanol than with iohexol. Other serum tests revealed no changes of clinical importance. Both iodixanol and iohexol were found to be effective, safe and well tolerated contrast media for abdominal intra-arterial DSA.

The pharmacokinetic profile, tolerability and safety of the iodinated, non-ionic, dimeric contrast medium Iosimenol 340 injection in healthy human subjects

Background

Iosimenol 340 injection is a new isotonic iodinated contrast medium for X-ray angiography.

Purpose

To investigate the pharmacokinetics and biotransformation, tolerability, and safety of Iosimenol 340 in healthy human subjects.

Material and Methods

Twenty-four subjects were enrolled and randomized to receive either Iosimenol 340 (0.5, 1.5 or 3.0 mL/kg) or placebo (0.9% saline). In each dosing group, six subjects received Iosimenol 340 and two subjects received placebo. Safety was assessed by physical examination, vital signs, electrocardiography, and laboratory tests. Adverse events were recorded throughout the study up to 14 days after dosing. Blood samples were collected from 10 min before until 48 h after the start of dosing and urine samples were collected from 15 min before until 96 h after the start of dosing. Iosimenol was quantified in plasma and urine by measuring iodine concentrations with X-ray fluorescence. High-performance liquid chromatography was used to assess iosimenol biotransformation.

Results

Mean half-lives (mean ± standard deviation [SD]) of iosimenol were 0.17 ± 0.08 h (10.2 ± 4.8 min) and 2.01 ± 0.32 h for distribution and terminal elimination phases, respectively. The apparent volume of distribution was 0.27 ± 0.05 L/kg, indicating distribution to the extracellular fluid volume. Iosimenol was excreted within 24 h without any sign of metabolic transformation. Thirty-two adverse events were observed in 14 subjects. All were mild or moderate, and were transient in nature.

Conclusion

Iosimenol was not metabolized, had a distribution volume corresponding to the extracellular space, and was rapidly excreted through the kidneys by glomerular filtration. The area under the plasma concentration curve and the peak plasma concentration was proportional to dose, while clearance was independent of dose. Iosimenol 340 was well tolerated.

Use of iodixanol self-generated density gradients to enrich for viable urothelial cells from nonneurogenic and neurogenic bladder tissue

Suspensions of viable urothelial cells (UC) isolated from patient bladder biopsies often contain considerable amounts of extraneous materials comprised of cellular debris, dead and dying UC, and red blood cells. We have consistently observed an inversely proportional relationship between UC attachment efficiency and the amount of extraneous materials in the suspension; viable UC cell attachment efficiency decreases as the amount of extraneous materials in the cell suspension increases. Processing the initial cell isolate to reduce the amount of extraneous materials can enrich for viable UC capable of attaching and proliferating in ex vivo cultures. In this report, we describe the isolation of an enriched population of viable UC from nonneurogenic and neurogenic bladder tissue biopsies using iodixanol self-generated density gradients (OptiPrep), and characterization by trypan blue exclusion, fluorescence-activated cell sorting, immunofluorescence, and growth kinetics.

An efficient process for the purification of helper-dependent adenoviral vector and removal of helper virus by iodixanol ultracentrifugation

The preparation of large amount of purified helper-dependent adenoviral vector material is hampered by the lack of development of downstream processes with proven records on separation and recovery efficiencies. In order to facilitate the use of clinical-grade helper-dependent virus material for large-scale in vivo studies, a three-step purification scheme consisting of (1) an anion-exchange chromatography for initial capturing of virus, (2) a shallow iodixanol density gradient ultracentrifugation for the removal of helper virus from helper-dependent virus, and (3) a size-exclusion chromatography for the removal of iodixanol and residual protein contaminants as a polishing step was developed. The use of a fast iodixanol density ultracentrifugation step was highly effective in separating infectious helper-dependent virus from contaminating helper virus. The overall downstream processing scheme gave 80% infectious particle yield. The contamination ratio of helper virus in the helper-dependent virus preparation are reduced from 2.57 to 0.03% corresponding to a reduction of helper virus by factors of 85 by two iodixanol purification steps. It was also demonstrated that size-exclusion chromatography is an excellent step for the removal of iodixanol and polishing of the final helper-dependent virus preparation.

Initial clinical experience of selective coronary angiography using one prolonged injection and a 180° rotational trajectory

OBJECTIVE

Evaluate the safety of prolonged coronary injections during a rotational acquisition covering 180 degrees.

BACKGROUND

Rotational angiography has been adapted to coronary angiography and shown to reduce radiation and contrast exposure. Three-dimensional (3D) reconstructions and other advanced applications require imaging over a 180 degrees -arc with a single but longer injection of larger contrast volumes.

METHODS

Thirty patients referred for angiography were enrolled. Blood pressure (BP), heart rate (HR), symptoms, and ectopy were recorded before-and-after injections.

RESULTS

Pre and post-injection HRs for the LCA/RCA were not statistically different (LCA-pre-injection 63+/-13 bpm vs. LCA-post-injection 62+/-11 bpm, P=0.54 and RCA-pre-injection 65+/-12 bpm vs. RCA-post-injection 65+/-10, P=0.88). Central aortic pressure values were not statistically different for the RCA injections (RCA-systolic-pre-injection 118+/-14 mm Hg vs. RCA-systolic-post-injection 112+/-25 mm Hg, P=0.15, and RCA diastolic-pre-injection 69+/-9 mm Hg vs. RCA-diastolic-post-injection 60+/-10 mm Hg, P=0.88) but were statistically significant for the LCA injections (LCA systolic-pre-injection 122+/-19 mm Hg vs. LCA-systolic-post-injection 116+/-17 mm Hg, P=0.0004, and LCA-diastolic-pre-injection 69+/-10 mm Hg vs. LCA-diastolic-post-injection 65+/-9 mm Hg, P=0.0007). There were no symptoms or electrical events documented during or immediately post-injection.

CONCLUSION

This study demonstrates the feasibility and safety of longer coronary injections. There were no significant HR changes, clinically insignificant pressure changes, and no adverse reactions. Additional studies will be needed to assure its safety in a larger and clinically more varied patient population.

The use of iodixanol as a density gradient material for separating human sperm from semen

Iodixanol, a new nonionic density gradient material with relatively low osmolality and high density, was evaluated to determine its suitability for the separation of human sperm from semen for their subsequent therapeutic use. Using a three-layer iodixanol gradient (approximately 1.17/1.15/1.05 g/mL), sperm were centrifuged at 1000g for 30 min and collected from the 1.05/1.15 interface. Using this method, a mean of 78% of the motile and 99% of the morphologically normal sperm originally present in the semen were recovered at the interface. There was no significant increase in the percentage of motile or morphologically normal sperm in the final preparation compared to the original semen. Sperm survived iodixanol density gradient centrifugation well, showing only modest declines in motility (18%) and velocity (35%) during a subsequent 24-h incubation period. When iodixanol was compared to Percoll density gradient centrifugation with semen from the same ejaculate, there was no significant difference between methods with regard to sperm yield, enrichment of motile or morphologically normal sperm in the preparation or sperm survival following separation. Iodixanol provides a suitable, nontoxic alternative to Percoll for the preparation of human sperm for therapeutic use.

A randomized comparison of iodixanol and iohexol in adult body computed tomography scanning

RATIONALE AND OBJECTIVES

We compared the safety and imaging efficacy of iodixanol-270 (270 mg I/ml), iodixanol-320 (320 mg I/ml), both of which are isosmolal to blood, and iohexol-300 (300 mg I/ml) for body computed tomography (CT) scanning.

METHODS

One hundred twenty-six patients from the University of Wisconsin Hospital and Temple University Hospital scheduled to undergo body CT examinations were randomly assigned to receive either iodixanol-270, iodixanol-320, or iohexol-300. Patients were monitored with questioning and vital signs before injection, immediately after injection, and at 24 and 48 hr. Extensive laboratory evaluation also was performed.

RESULTS

No serious reactions or deaths occurred in any group. The occurrence of overall minor adverse events (usually warmth, headache, taste distortion, rash) was similar for the different groups. Laboratory results showed no significant difference across groups. There was no significant difference in image quality detected among groups.

CONCLUSION

There was no detectable difference in safety and imaging efficacy among the three contrast groups in this study. However, patients from the University of Wisconsin experienced significantly less injection discomfort with iodixanol-270 than with iohexol-300. Large clinical studies may more definitively determine the presence and nature of the relative advantages of iodixanol compared with currently available ionic and nonionic contrast agents.

Comparison of iodixanol and ioxaglate for adult aortography and renal/visceral angiography: a phase III clinical trial

RATIONALE AND OBJECTIVES

We investigated whether iodixanol offers improved safety or tolerance compared with ioxaglate and evaluated whether iodixanol-enhanced radiographs are diagnostically comparable or superior to those produced with ioxaglate. Iodixanol is a new isosmotic hexa-iodinated nonionic contrast agent being evaluated for intravascular use.

METHODS

Fifty-four adult patients undergoing renal or visceral angiography, aortography, or both were enrolled in a prospective, randomized, double-blind, two-center study in which iodixanol and ioxaglate were compared. Subjects were monitored for adverse events, injection-associated discomfort, and changes in laboratory parameters and vital signs. Efficacy was measured by the overall quality of angiographic enhancement.

RESULTS

No serious adverse events occurred during this trial. Mild-to-moderate adverse events were more common in patients receiving ioxaglate (p = .041). Injection-associated pain was reported by three patients receiving ioxaglate and none receiving iodixanol (p = .093). Clinical laboratory and vital-sign data showed no differences between groups, and there was no difference in the overall quality of angiographic visualization (p = .711).

CONCLUSION

Iodixanol resulted in improved safety and patient tolerability while providing images of equivalent diagnostic efficacy compared with ioxaglate.

Comparison of iodixanol with iohexol in excretory urography

RATIONALE AND OBJECTIVES

We compared the safety and efficacy of iodixanol, a nonionic, dimeric, iodinated contrast agent, with that of iohexol, a monomeric agent, in adult excretory urography.

METHODS

The study used a randomized, double-blind, parallel-comparison design to evaluate image quality, vital signs, laboratory values, and adverse reactions. Seventy-five patients from each of two centers were included. One third received iodixanol at 270 mg I/ml, one third received iodixanol at 320 mg I/ml, and one third received iohexol at 300 mg I/ml. The dose for every patient was 1 ml/kg of body weight. The radiographs were interpreted and evaluated for quality by the primary investigator at each center. There were no important differences among the three groups in terms of demographics.

RESULTS

Evaluation of each phase of the radiographic study showed almost uniform good-to-excellent opacification, with no significant differences among the three agents. No significant differences existed for the three groups in terms of vital signs, hematology, blood and urine chemistry, and injection discomfort. There were no deaths or serious reactions during the study, nor was there a statistically significant difference among the number of adverse events for the three agents.

CONCLUSION

Iodixanol at both 270 and 320 mg I/ml proved to be a safe and effective contrast material for intravenous urography. In this study, its profile was essentially indistinguishable from that of iohexol at 300 mg I/ml.

A randomized comparison of iodixanol and iohexol in adult intracranial computed tomography scanning

RATIONALE AND OBJECTIVES

Nonionic iodinated contrast media have proved effective for computed tomography (CT) of the head and have demonstrated greater tolerability than their ionic counterparts. Iodixanol is a new nonionic agent with the added attribute of being isosmolar to blood and having less than half the osmolality of iohexol. Phase I safety, tolerance, and pharmacokinetic studies have indicated that iodixanol may be associated with fewer adverse effects than iohexol while providing equivalent diagnostic information.

METHODS

We compared the safety and efficacy of iodixanol at 270 mg I/ ml (IOD-270) and at 320 mg I/ml (IOD-320) with iohexol 300 mg I/ml (IOH-300).

RESULTS

No statistically significant differences in the quality of images or in the occurrence of adverse events were found among the three treatment groups. Pairwise comparisons of injection-associated discomfort revealed that significantly more patients in the IOH-300 group experienced discomfort than in either the IOD-270 or IOD-320 groups.

CONCLUSION

Iodixanol at 270 or 320 mg I/ml was found to be safe and effective when administered intravenously at a volume of 100 ml for intracranial CT scans in adult patients.

Iodixanol and ioxaglate in adult aortography and peripheral arteriography: a phase III clinical trial

RATIONALE AND OBJECTIVES

This study compared the safety and efficacy of iodixanol with those of ioxaglate in adult patients undergoing aortography or peripheral arteriography.

METHODS

Forty-six patients were enrolled in this controlled, randomized, double-blind, two-center study. The patients were monitored for adverse events, injection-related discomfort, and trends in laboratory data or vital signs. Diagnostic efficacy was assessed by the quality of contrast enhancement.

RESULTS

All procedures were diagnostic, with no significant difference in quality of visualization (p = .205). No significant difference was seen in the number of patients experiencing mild or moderate adverse effects (p = .106). Patients receiving ioxaglate reported a significantly greater incidence of injection-related pain (p = .025).

CONCLUSION

The results of this study support the conclusion that iodixanol at 320 mg I/kg is safe and effective for adult aortography and peripheral arteriography and causes significantly less injection-related pain than ioxaglate.

Image quality and safety after iodixanol in intravenous urography; a comparison with iohexol

A double-blind, randomized phase III study compared intravenous urography in 100 adult patients receiving iodixanol 320 mgI ml-1 (Visipaque) with 99 patients receiving iohexol 350 mgI ml-1 (Omnipaque). The aim of the study was to investigate differences in image quality between a non-ionic dimeric contrast medium (CM) and a non-ionic monomer at 40 ml per patient and 60-100 ml per patient volume levels. There were no statistically significant differences between iodixanol and iohexol with respect to overall diagnostic information, which was found to be optimal in 86% and 79%, respectively. Immediately after the injection, the renal border was better delineated with iohexol than with iodixanol (p = 0.0001). Marked papillary blush occurred more often in the iodixanol group (16%) than in the iohexol group (0%), as did visualization of the collecting ducts (24% vs 5%) (p = 0.001). The incidence of adverse events was similar and low for both contrast media. In patients who received the higher doses of CM (60-100 ml), the frequency of discomfort was significantly lower after iodixanol than after iohexol (p = 0.006). We conclude that, in intravenous urography, iodixanol provides at least as good image quality as does iohexol. Iodixanol may cause less discomfort than iohexol, in particular when larger volumes of CM are injected.

Effect of iodixanol on in vitro bleeding time

RATIONALE AND OBJECTIVES

Both monomeric and dimeric ionic radio contrast media (CM) have been shown to be more anticoagulant than nonionic monomeric CM. Iodixanol is a relatively new nonionic dimeric contrast medium. We investigated whether the dimeric structure of iodixanol would produce the same level of anticoagulation that has been observed using nonionic monomeric CM.

METHODS

We used a global screening device that operates under physiologic flow conditions to monitor the effects of iodixanol on in vitro bleeding time (IVBT). This flow dynamic technique perfuses nonanticoagulated whole blood through a hollow fiber device. A leak in the fiber is created by a precision needle, and the resulting pressure fluctuations within the fiber are monitored to examine the ability of the hemostatic system to close the leak by forming a stable platelet plug.

RESULTS

In 20 donors, iodixanol (25% CM/blood, v/v) was shown to lengthen the mean IVBT (18.74 min) compared with the normal blood mean IVBT (4.24 min).

CONCLUSION

The addition of dimeric iodixanol to normal blood affects the IVBT in the same manner as nonionic monomeric CM (ioversol, iopamidol, and iohexol).

Iodixanol in leg phlebography: a randomized, double-blind parallel group phase III trial comparing iodixanol to ioxaglate

PURPOSE

To evaluate the safety and efficacy of iodixanol (Visipaque) in phlebography in order to obtain experience from the use of this contrast medium in this i.v. indication.

PATIENTS AND METHODS

Phlebography was performed in 150 patients, as a comparative prospective, double-blind, randomized parallel group study comparing iodixanol 270 mgI/ml with ioxaglate 320 mgI/ml. The tolerability was assessed from occurrence of discomfort, adverse events up to 30 min following injection and late adverse events. Efficacy was assessed by recording the diagnostic information on each venous segment. Statistical analysis was performed using the Cochran-Mantel-Haenszel test in order to correct for a possible centre effect.

RESULTS

Frequency of patients reporting discomfort (P=0.002) or adverse events (P<0.001) was statistically significantly lower after the injection of iodixanol than after ioxaglate. There was no statistical difference regarding late adverse events and diagnostic information.

CONCLUSION

Iodixanol 270 mgI/ml yielded the same diagnostic information as ioxaglate 320 mgI/ml and was associated with fewer patients reporting adverse events and discomfort.

Immediate and late adverse reactions in coronary angiography. A comparison between iodixanol and ioxaglate

PURPOSE AND METHODS

In 120 patients in a double-blind, randomized, pa rallel study, iodixanol (Visipaque), a nonionic dimer isotonic with blood, was compared with ioxaglate (Hexabrix), an ionic low-osmolar dimer, in coronary angiography regarding early and late adverse reactions. Haemodynamic and electrophysiologic parameters were also analyzed.

RESULTS

Visipaque resulted in significantly fewer early adverse contrast medium-related reactions (p<0.05). Visipaque also demonstrated significantly fewer effects on electrophysiologic parameters. Both contrast media reduced systolic and diastolic blood pressures at the 1st injection in the left coronary artery. Late adverse reactions were unusual with both contrast media and occurred only as urticaria with a frequency of 1.7%, which is lower than reported in i.v. studies. One serious adverse reaction, a myocardial infarction in a male patient with severe cardiovascular disease, occurred in the Visipaque group. This event was considered to be procedure- and disease-related rather than related to the type of contrast medium used.

CONCLUSION

We found Visipaque safe for coronary angiography, causing fewer early adverse reactions than Hexabrix and also fewer effects on electrophysiologic parameters. Late adverse reactions seemed to be unusual with intra-arterial administration of contrast media.

Absorption and excretion of iodixanol after intragastric administration to rats

Absorption and excretion of iodixanol 320 mg I/ml were investigated in rats after intragastric administration of 2.5 g I/kg b.w. Animals were observed for up to 96 hours after treatment, and blood, urine and feces taken at several time-points throughout the experiment. Concentrations of iodixanol in serum and urine were measured by means of reversed-phase high-performance liquid chromatography. Fecal concentrations of iodixanol, based on iodine measurements, were determined by X-ray fluorescence spectrometry. Serial radiographs were obtained and histopathological examination was performed on selected tissues. The results indicate that less than 1% of the intragastric dose of iodixanol is absorbed from the intestine into the blood stream. No adverse clinical signs were observed, and there were no treatment-related histomorphological findings.

Cardiac hemodynamic effects of iodixanol, iopamidol, and ioxaglate following left coronary injections in anesthetized dogs

RATIONALE AND OBJECTIVES

Iodixanol, a dimeric, nonionic X-ray contrast medium, has been formulated at 320 mg iodine per milliliter and supplemented with Na+, Ca2+, and Cl- to produce an osmolality that approximates that of plasma. We compared the effects of left main coronary artery injections of iodixanol, ioxaglate, and iopamidol on cardiac mechanical function in dogs.

METHODS

Six mixed-breed dogs were anesthetized and prepared for recordings for electrocardiogram, aortic and left ventricular pressures, and the first derivative of left ventricular pressure, dP/dt. The test solutions and saline were injected into the left coronary artery in a randomized order. The series of four injections were repeated three times in each animal for a total of 12 injections per dog.

RESULTS

Iodixanol caused significantly lower (p < .05) reduction in peak left ventricular pressure (-1.7 +/- 0.9% vs -0.7 +/- 2.0%), in diastolic aortic pressure (-1.3 +/- 1.1% vs -9 +/- 1.3%), and in left ventricular dP/dt (0.3 +/- 1.3% vs -13.2 +/- 2.4%) than did ioxaglate. Iodixanol also produced smaller cardiovascular effects than did iopamidol, but the differences were not statistically significant. Injections of both iopamidol and ioxaglate caused significant decreases from baseline parameter values; however, the changes with iodixanol were not significant.

CONCLUSION

The isotonic formulation of iodixanol caused smaller cardiovascular hemodynamic effects than did iopamidol and ioxaglate and may offer increased safety in patients with severe cardiac disease.

Iodixanol in intravenous urography: a comparison of iodixanol 270 mgI/ml, iodixanol 320 mgI/ml and iopamidol 300 mgI/ml (NIOPAM)

The first European trial of iodixanol (Nycomed Imaging AS) in adult intravenous urography is reported. Iodixanol is a new non-ionic, dimeric contrast medium of low osmolality. A double-blind, randomized, three group parallel study comparing iodixanol 270 mgI/ml, iodixanol 320 mgI/ml and iopamidol 300 mgI/ml (Niopam) was undertaken. A total of 173 of 180 patients entered completed the trial. Efficacy was evaluated with regard to overall diagnostic information and pyelographic density 5 min after contrast medium administration. Efficacy was found to increase with increasing iodine concentration, with no significant difference between the three contrast media. The incidence of adverse events was low, with no significant difference between the groups. Discomfort occurred less frequently with iodixanol than with iopamidol. We conclude that iodixanol is a safe and efficacious contrast medium for use in intravenous urography.

A double-blind study comparing safety, tolerability and efficacy of iodixanol 320 mgI/ml and ioxaglate 320 mgI/ml in cerebral arteriography

Iodixanol is a new nonionic dimer, isotonic with blood at all concentrations. Iodixanol 320 mgI/ml was compared in a double-blind, randomized study to the ionic dimer ioxaglate 320 mgI/ml for evaluation of safety and efficacy parameters during cerebral arteriography. Eighty adult patients were enrolled and all completed the trial. Radiographic efficacy was assessed from the diagnostic information and the radiographic density. Safety was evaluated by recording discomfort and other adverse events, changes in ECG, heart rate and blood pressure, changes in intra-arterial blood pressure and circulation time. No difference between the two contrast media were noted radiographically. No clinically important changes from baseline or between the two contrast media were found in ECG, heart rate, blood pressure or intra-arterial blood pressure. Although not statistically significant, a somewhat longer mean circulation time was found with iodixanol, probably due to its slightly higher viscosity. Injection-associated warmth sensation and pain were more intense with ioxaglate than with iodixanol, and pain was statistically more frequent after injection of ioxaglate. A high incidence of adverse events other than discomfort is reported in this study, mainly related to the selective arteriographic procedure itself. The adverse events related to the contrast medium were more frequent with ioxaglate (27% of the total number of adverse events) than with iodixanol (10%). The new isotonic nonionic dimer iodixanol offers significantly better comfort to the patient than does ioxaglate. This is an important feature, especially in relatively risky procedures that are unpleasant for the patients, such as conventional cerebral angiography.

Iodixanol and ioxaglate in cardioangiography: a double-blind randomized phase III study

A new non-ionic, dimeric contrast medium iodixanol (Nycomed AS, Norway) has a very low osmolality and is isotonic with blood. It has been compared with ioxaglate (Hexabrix, Laboratoire Guerbet, France) in a double-blind, randomized, parallel trial. The aims of the trial were to evaluate and compare the safety (vital signs, adverse events, discomfort and clinical-chemical parameters in blood and urine) and radiographic efficacy (diagnostic information and radiographic density) of iodixanol 320 mg I/ml vs ioxaglate (Hexabrix 320 mg I/ml) in coronary angiography and left ventriculography. Seventy-six patients referred for cardioangiography, two patients were withdrawn, 36 receiving iodixanol and 38 ioxaglate were included in the trial. Six patients (16%) in the iodixanol group and 16 (42%) patients in the ioxaglate group reported adverse events (P = 0.02). One serious adverse event occurred in the iodixanol group where a patient experienced transient cortical blindness and transitory global amnesia, but the patient recovered completely the day after the examination. Twenty-six patients reported injection-associated sensation of warmth in the iodixanol group versus 34 in the ioxaglate group (P = 0.06). Following contrast injection there were no differences between the groups regarding vital signs (ECG, heart rate, left ventricular pressures). Both contrast media were well tolerated by the kidneys, and on average only minor effects on clinical-chemical parameters in blood and urine were observed in the two groups. The radiographic efficacy was good in both groups.

Iodixanol in femoral arteriography (phase III): a comparative double-blind parallel trial between iodixanol and iopromide

Iodixanol is a new non-ionic, dimeric contrast medium (CM) which is formulated to be isotonic with blood in all clinically relevant concentrations. This is a report of a parallel, double-blind study comparing the safety and efficacy of iodixanol with iopromide (Ultravist) in aortofemoral arteriography. One hundred consecutive, eligible patients scheduled to undergo peripheral arteriography were entered into the study and randomly allocated to receive one or other CM. Radiographic quality, discomfort, adverse events, femoral blood flow and renal function were examined. Ninety-five patients were successfully included in the study. Radiographic quality (efficacy) was found to be similar in both groups. Three patients (6%) in the iodixanol group and five patients (11%) in the iopromide group reported adverse events. In this respect there was no statistically significant difference between the two groups (P = 0.48), and all adverse events were mild and transient. Forty-six (97%) patients in the iodixanol group and 45 (100%) patients in the iopromide group experienced a sensation of warmth (discomfort) in connection with one or more of the injections. There was no statistically significant difference in the frequency of discomfort in the two groups. However, the intensity of warmth was significantly milder following iodixanol than after iopromide (P = 0.003, two-sided Mantel-Haenszel test). The mean percentage increase in femoral blood flow was found to be less with iodixanol (43.4%) than with iopromide (96.3%) (P < 0.05, Student's t-test). Renal function was affected slightly after administration of both CM. Serum creatinine and creatinine clearance were affected more by iodixanol than by iopromide, while the excretion of tubular enzymes was more affected by iopromide. In conclusion, this comparison between iodixanol and iopromide showed both contrast media to be safe, effective and well tolerated and the only major difference between them was in their effect on femoral blood flow.

Safety and tolerability of iodixanol in healthy volunteers with reference to two monomeric X-ray contrast media

The low osmolar, non-ionic X-ray contrast media have shown a lower frequency of adverse events than the older ionic ones. In this study changes in routine clinical-chemical parameters in blood and urine, vital signs and adverse events were recorded in six groups of 10 healthy male volunteers receiving either iodixanol, a new non-ionic, dimeric X-ray contrast medium for general vascular use, or one of the two non-ionic, monomeric contrast media iopentol and iopamidol. Minor decreases were observed in the values for haemoglobin, haematocrit and erythrocytes 5 min and 3 days after injection of iodixanol. A minor increase was seen in platelets and total protein after 3 days. A transient increase in serum osmolality was seen 5 min after the injections of iopentol and iopamidol. This was not seen in any iodixanol group. The level of thyrotropin showed an increase in all groups at 3 days. It was back to normal within 21 days. No changes of clinical importance were seen regarding blood pressure, heart rate or ECG in any volunteer. No severe adverse events were reported. All events were of short duration, and of mild or moderate intensity. The results, however, may indicate a lower frequency of adverse events/discomfort after the administration of the dimeric iodixanol than the 2 monomeric contrast media iopentol and iopamidol.

The effect of iodixanol, a new isotonic contrast agent, on femoral blood flow in man

Both ionic and non-ionic contrast media (CM) injected intra-arterially produce peripheral vasodilatation and a sensation of heat or even pain. This effect has been considered to be predominantly related to the osmolality of the CM used. Iodixanol is a non-ionic dimeric CM which can be made isotonic with blood at iodine concentrations up to 400 mg/ml. To assess the degree of peripheral vasodilatation following aortic injection of iodixanol, the change in femoral artery blood flow has been assessed non-invasively. Dupex ultrasound flow-velocity records were taken from the contralateral femoral artery in 10 patients undergoing transfemoral aortography. Volume flow, mean velocity, pulsatility index and peak systolic velocity were continuously recorded before and up to 2 min after injection of 60 ml of iodixanol at an iodine concentration of 320 mg/ml (iodixanol 320). Transient changes consistent with vasodilatation were observed in all patients. The greatest changes were observed during the time period 18-24 s after injection. Volume flow, mean velocity and pulsatility index all changed significantly from baseline (mean changes of 80.6%, 73% and -42.7% respectively). Peak systolic velocity did not change significantly. Intra-arterial injections of isotonic iodixanol 320 produces a significant increase in femoral blood flow in man. Factors other than hypertonicity must therefore be implicated in the vasodilatory effect of contrast media.