A randomized trial comparing the impact of a nonionic (Iomeprol) versus an ionic (Ioxaglate) low osmolar contrast medium on abrupt vessel closure and ischemic complications after coronary angioplasty

Deconvolution Analysis of the Non-Ionic Iomeprol, Iobitridol and Iodixanol Contrast Media-Treated Human Whole Blood Thermograms: A Comparative Study

To study the effect of non-ionic contrast media on anticoagulated and non-anticoagulated human whole blood samples, calorimetric measurements were performed. The anticoagulated plasma showed the greatest fall in the total ΔH after Iodixanol treatment. The plasma-free erythrocytes revealed a pronounced shift in the Tmax and a decrease in the ΔH of hemoglobin and transferrin. The total ΔH of Iodixanol treatment showed the highest decline, while Iomeprol and Iobitridol had fewer adverse effects. Similarly, the non-anticoagulated samples revealed a decrease both in the Tmax and the ΔH of albumin and immunoglobulin-specific transitions. The total ΔH showed that Iodixanol had more influence on the serum. The serum-free erythrocyte samples resulted in a significant drop in the Tmax of erythrocyte and transferrin (~5-6 °C). The ΔH of deconvolved hemoglobin and transferrin decreased considerably; however, the ΔH of albumin increased. Surprisingly, compared to Iomeprol and Iobitridol treatments, the total ΔH of Iodixanol was less pronounced in the non-anticoagulated erythrocyte samples. In sum, each non-ionic contrast medium affected the thermal stability of anticoagulated and non-anticoagulated erythrocyte proteins. Interestingly, Iodixanol treatment caused more significant effects. These findings suggest that conformational changes in blood components can occur, which can potentially lead to the increased prevalence of cardiovascular dysfunctions and blood clotting.

Contrast media: are there differences in nephrotoxicity among contrast media?

Iodinated contrast agents are usually classified based upon their osmolality--high, low, and isosmolar. Iodinated contrast agents are also nephrotoxic in some but not all patients resulting in loss of glomerular filtration rate. Over the past 30 years, nephrotoxicity has been linked to osmolality although the precise mechanism underlying such a link has been elusive. Improvements in our understanding of the pathogenesis of nephrotoxicity and prospective randomized clinical trials have attempted to further explore the relationship between osmolality and nephrotoxicity. In this review, the basis for our current understanding that there are little if any differences in nephrotoxic potential between low and isosmolar contrast media will be detailed using data from clinical studies.

Risks and complications of coronary angiography: a comprehensive review

Coronary angiography and heart catheterization are invaluable tests for the detection and quantification of coronary artery disease, identification of valvular and other structural abnormalities, and measurement of hemodynamic parameters. The risks and complications associated with these procedures relate to the patient’s concomitant conditions and to the skill and judgment of the operator. In this review, we examine in detail the major complications associated with invasive cardiac procedures and provide the reader with a comprehensive bibliography for advanced reading.

Contrast media and clotting: what is the evidence?

The rapid development of percutaneous coronary and peripheral vascular interventional technologies and also noninvasive imaging systems has led to a dramatic increase in the number of patients receiving contrast media (CM). Although relatively uncommon, adverse events can occur following administration of contrast, including nuisance reactions (e.g., nausea and urticaria) and potentially severe complications, such as contrast-induced nephropathy and thrombotic events. In this report, we review the evidence regarding the occurrence of thrombotic effects following iodinated CM administration during percutaneous coronary intervention.

Catheter thrombosis and percutaneous coronary intervention: fundamental perspectives on blood, artificial surfaces and antithrombotic drugs

Recent reports of catheter thrombosis among patients undergoing percutaneous coronary intervention (PCI) have had a significant impact on the development of new antithrombotic therapies. The overall incidence of this complication is unknown, mainly because of underreporting in contemporary clinical trials of coronary intervention. The etiology and pathophysiology of catheter thrombosis is also poorly understood. Introduction of a catheter or guidewire may not provoke the intense thrombotic response that follows angioplasty or stenting, but factors such as catheter materials and device size, equipment surface properties, flow conditions, procedural time and complexity, as well as the antiplatelet and anticoagulant drugs administered during the procedure influence the likelihood, rate and clinical impact of thrombosis. The crucial role of cellular interactions involving tissue-factor bearing cells and platelets in the process of thrombosis also needs to be critically explored when considering blood contact with an exogenous material. Focusing on the inherently prothrombotic environment of percutaneous coronary intervention, we review the physiologic underpinnings of catheter and guidewire thrombosis, and explore the effect of antithrombotic drugs at the interface between blood and material surfaces. We also propose a clinical classification for the diagnosis and investigation of catheter thrombosis in clinical trials of anticoagulant therapy and PCI.

[Contrast media and percutaneous coronary interventions]

Contrast media are widely used for percutaneous coronary interventions. Currently, about a dozen types of contrast media are available in France. On account of their overall safety, only low osmolar and isosmolar contrast media are used in practice. However, the appropriate use of contrast media remains difficult as accurate recommendations are lacking. Several doubts are still present regarding potential adverse effects of contrast media. Our review summarizes contrast media-related risks (hypersensitivity, arrhythmic risk, effects on coagulation and platelets, contrast media-induced nephrotoxicity) underlying mechanisms, prophylaxis strategies, and differences among contrast media. Many questions remain in this area and we need further prospective randomised trials.

Effects of iodinated contrast media on blood and endothelium

The aim of the study was to assess the effects of iodinated contrast media on blood components and endothelium based on experimental and clinical studies and to produce clinically relevant guidelines for reducing thrombotic and hematologic complications following the intravascular use of contrast media. A report was drafted after review of the literature and discussions among the members of the Contrast Media Safety Committee of the European Society of Urogenital Radiology. The final report was produced following discussion at the 12th European Symposium on Urogenital Radiology in Ljubljana, Slovenia (2005). Experimental data indicate that all iodinated contrast media produce an anticoagulant effect and that this effect is greater with ionic contrast media. Several of the in vitro and experimental in vivo studies on haematological effects of contrast media have not been confirmed by clinical studies. Low- or iso-osmolar contrast media should be used for diagnostic and interventional angiographic procedures, including phlebography. Meticulous angiographic technique is the most important factor for reducing the thrombotic complications associated with angiographic procedures. Drugs and interventional devices that decrease the risk of thromboembolic complications during interventional procedures minimize the importance of the effects of contrast media.

Cardiac events after low osmolar ionic or isosmolar nonionic contrast media utilization in the current era of coronary angioplasty

OBJECTIVES

Our study aimed to compare the isosmolar nonionic dimer iodixanol and the low osmolar ionic agent ioxaglate in the current era of percutaneous coronary intervention (PCI), using clopidogrel, enoxaparine, direct stenting, and drug eluting stent.

BACKGROUND

Previous studies have suggested an association between thrombus-related events and type of contrast media.

METHODS

Our prospective single-center study included 498 consecutive patients who were assigned to receive either iodixanol (n = 231) or ioxaglate (n = 267). The primary endpoint was the cumulative rate of in-hospital major adverse clinical events (MACE). A secondary endpoint was the rate of angiographic or procedural complications.

RESULTS

Clinical and angiographic baseline characteristics and procedural data were similar in the 2 groups. A peak anti-Xa > 0.5 IU/ml was obtained in 97% in both groups. Glycoprotein IIb/IIIa inhibitors were used in 42% of patients. Coronary stenting was performed in 91% of patients, with direct stenting in 70%, and drug-eluting stent in 28% of patients. In-hospital MACE was more frequent in patients receiving iodixanol compared with those receiving ioxaglate (4.8% vs. 0.3%, P < 0.005). This difference was mainly related to the appearance of a large thrombus during PCI (6% with iodixanol vs. 0.3% with ioxaglate, P < 0.0001). In multivariate analysis, independent predictors of in-hospital MACE were use of iodixanol (P < 0.01), the higher number of stent used (P < 0.008), bifurcation/ostial lesion (P < 0.01), and balloon dilation before stenting (p < 0.001).

CONCLUSIONS

In our study reflecting the current era of PCI, thrombus-related events are more frequent with the isosmolar nonionic dimer iodixanol than with the low osmolar ionic agent ioxaglate.

Adverse Reactions of Low Osmolar Non-Ionic and Ionic Contrast Media When Used Together or Separately During Percutaneous Coronary Intervention

BACKGROUND

Due to perceived advantages in the use of non-ionic contrast agents for diagnostic angiography and ionic agents for percutaneous coronary intervention (PCI), patients often receive various combinations of both types of agents.

AIM

To assess potential adverse effects of non-ionic and ionic contrast media when used together or separately during percutaneous coronary intervention.

METHODS

We retrospectively evaluated the outcomes of 532 patients undergoing percutaneous coronary intervention in our institution. Patients were divided into two groups: those that underwent diagnostic angiography and "follow on" PCI; and those that underwent "planned" PCI. The groups were subdivided on the basis of the use of the ionic agent ioxaglate or the non-ionic agent iopromide during PCI. The frequency of allergic reactions and major adverse cardiac events (MACE) were noted.

RESULTS

With respect to the "follow on" group, allergic reactions occurred in 9 of 150 patients (6.0%) who received the combination of ioxaglate and iopromide versus 1 of 93 (1.1%) who only received iopromide (p=0.094). There was no difference with respect to MACE [6 (4.0%) ioxaglate and iopromide versus 4 (4.3%) iopromide alone, p=1.00]. In the "planned" group, 7 of 165 patients (4.2%) receiving ioxaglate had an allergic reaction as opposed 0.0% (0 of 124 patients) in the iopromide group (p=0.021). All contrast reactions were mild. The incidence of a MACE was similar in both groups [1 (0.6%) ioxaglate versus 2 (1.6%) iopromide, p=0.579]. The incidence of allergic reactions was similar if ioxaglate was used alone or in combination with iopromide (p=0.478).

CONCLUSIONS

Whilst combining ionic and non-ionic contrast agents in the same procedure was not associated with any more adverse reactions than using an ionic contrast agent alone, the ionic contrast agent ioxaglate was associated with the majority of allergic reactions. With respect to choice of contrast agent, using the non-ionic agent iopromide alone for coronary intervention is associated with the lowest risk of an adverse event.

Influence of ionic and non-ionic radiographic contrast media on leukocyte adhesion molecules

BACKGROUND: Many papers have focused on the importance of granulocytes in the process of reperfusion and ischemia. Most of the clinical studies measured several parameters of this process during and after coronary angiography, without taking into account the effect of the radiographic contrast media (RCM) used during this procedure. MATERIALS AND METHODS: We performed a randomized patient study (n = 37) to evaluate the effect of ionic and non-ionic RCM on granulocyte adhesion during coronary angiography. We also evaluated the influence of the ionicity and osmolarity of the different substances on granulocyte adhesion molecules in in vitro experiments. RESULTS: The osmolarity of patient serum samples increased from 302 +/- 1 to 309 +/- 1 mOsm/kg (p < 0.05) after infusion of RCM. The CD11b expression in the samples of the non-ionic RCM treated group increased from 221 +/- 21 MFI to 377 +/- 30 MFI (p < 0.05) measured as the absolute mean fluorescence intensity (MFI), yet did not alter significantly in the ionic RCM group. In contrast, the in vitro experiments showed a reduction of the CD11b expression from 360 +/- 70 MFI to 149 +/- 30 MFI (p < 0.05) in the ionic RCM group. CONCLUSIONS: The upregulation of adhesion molecules was significantly reduced in vivo with ionic RCM, while ionic substances caused opposite effects in vitro. This effect should be taken into account when performing leukocyte functional analysis of samples taken during angiography.

Nonionic low-osmolar contrast media have no impact on major adverse cardiac events in patients undergoing coronary stenting with appropriate antiplatelet therapy

The aim of this study was to assess the impact of two nonionic low-osmolar monomers (iopamidol and iopromide) and one ionic low-osmolar dimeric contrast medium (ioxaglate) on 30-day major adverse cardiac events in patients undergoing coronary interventions involving the use of new-generation stents and appropriate antiplatelet agents. Thirteen hundred and eight patients treated with stent implantation were randomized to receive ioxaglate (438 patients), iopamidol (442 patients), or iopromide (428 patients). Most of them (55%) had an acute coronary syndrome. Glycoprotein IIb/IIIa inhibitors were used in 37% of cases. All of the patients were on aspirin and ticlopidine for 1 month after the procedure. There was no significant between-group difference in the incidence of the primary composite endpoint of major adverse cardiac events 30 days after stenting (ioxaglate 3.6%; iopamidol 2.3%; iopromide 4.2%; P = 0.27). Adverse drug reactions were more frequent in the ioxaglate group (4.6% vs. 1.1% vs. 0.5%; P = 0.001). Multivariate analysis showed that intracoronary thrombus (P = 0.002), diabetes mellitus (P = 0.01), and postprocedure minimum lumen diameter (P = 0.04) independently correlated with an adverse outcome after 1 month. In conclusion, no significant differences in 30-day major ischemic complications were observed in this unselected population of patients undergoing coronary stenting who received ioxaglate, iopamidol, or iopromide. These data seem to suggest that the use of nonionic low-osmolar contrast media does not adversely affect stent patency.

Inflammatory markers increase following exposure to radiographic contrast media

PURPOSE

Increased levels of markers of systemic inflammation have been noted in patients following coronary angiographic procedures. The purpose of the present study was to examine the influence of the type of the angiographic procedure as well as the type of radiographic contrast media (RCM) on markers of inflammation.

MATERIAL AND METHODS

Thirty-seven patients undergoing diagnostic or interventional coronary angiographic procedures were randomly assigned to receive one of three RCM - an ionic low osmolar agent; a non-ionic, iso-osmotic agent; or a non-ionic, low osmolar agent. Sera were analyzed at baseline (prior to receiving RCM), and at 2, 6 and 24 h thereafter for interleukin (IL)-6 and soluble receptors for tumor necrosis factor alpha (TNFalpha)-1 and TNFalpha- 2.

RESULTS

Statistically significant increases over time in each RCM group were noted for IL-6 and both TNFalpha receptors. Comparable increases in inflammatory markers were observed in patients undergoing diagnostic angiography and in patients undergoing an associated coronary intervention. While these markers increased following exposure to both ionic and non-ionic RCM, there was a consistent trend towards lessened marker release with non-ionic RCM.

CONCLUSION

Both diagnostic and interventional coronary angiographic procedures are associated with an increase in serum inflammatory markers. While both ionic and non-ionic RCM are associated with increases in serum inflammatory markers, this increase may be attenuated with non-ionic RCM.

Radiocontrast-induced nephropathy and percutaneous coronary intervention: a review of preventive measures

Injectable and absorbable contrast media for the use in radiology, all of which contains iodine as an essential component, has been, and continues to be, one of the main sources of agents which cause hospital-acquired renal failure. Although numerous methods have been explored to prevent renal contrast damage, radiocontrast-induced nephropathy continues to be a concern in patients with existing renal insufficiency, who undergo contrast-enhanced radiographic examinations. Patients who develop contrast-induced nephropathy (CIN) have a worse prognosis and an increased risk of complications and mortality. Prevention of CIN during radiocontrast procedures continues to elude clinicians and is a chief concern during percutaneous coronary intervention, as these patients often have multiple comorbidities. A wide variety of animal and clinical investigations, and substances have been tried in order to prevent this complication, including: dialysis, contrast volume and type; adenosine antagonists; acetylcysteine; fenoldopam; and various others. The purpose of this review is to appraise all the past and current strategies employed to prevent CIN, especially during percutaneous coronary intervention.

Comparative tolerability of contrast media used for coronary interventions

Radiographic contrast media (CM) are necessary to provide x-ray absorption of the bloodstream; all other observed effects need to be regarded as adverse. Four types of CM are currently used in diagnostic and interventional cardiology: ionic high-osmolar CM (HOCM), either ionic or non-ionic low-osmolar CM (LOCM), and non-ionic iso-osmolar CM (IOCM). Focusing on the potential cardiovascular effects caused by the CM, there is a clear difference between HOCM and the LOCM or IOCM. HOCM have a poorer profile due to a higher incidence of hypotension and electrophysiological effects. To prevent contrast-induced nephropathy, HOCM should be avoided and patients should receive the minimal dose of LOCM or IOCM with intravenous hydration before and after the procedure. Clinical hyperthyroidism has been detected after CM use, but the condition appears, ultimately, to be self-limited and to occur mainly in elderly patients. When assessing the need for a CM in terms of improved patient safety, preventing serious complications should be the major factor determining the choice. CM should not be selected on the basis of minor adverse effects since these are, ultimately, of low clinical relevance. Thrombotic events, in contrast, carry a high clinical relevance and we consider that these should be the main issue governing current choice. Ionic LOCM appear to have better profile than other CM with respect to interaction with platelet function and coagulation. In relation to thrombotic events in randomised clinical studies, ionic CM have been associated, mainly, with favourable and some neutral results compared with non-ionic agents. Only one trial indicated a more pronounced antithrombotic effect of the non-ionic IOCM relative to the ionic LOCM. The antithrombotic advantages of ionic over non-ionic LOCM are, in part, balanced by a greater frequency of minor adverse effects such as nausea, vomiting or cutaneous rashes. A matter of concern is the delayed adverse effects observed with non-ionic IOCM. However, severe and life-threatening reactions are exceptional and there are probably no significant differences between IOCM and LOCM whether ionic or non-ionic. However, in patients with known allergies, non-ionic CM are to be recommended. On the basis of the available pre-clinical and clinical data, the ionic LOCM or the non-ionic IOCM are the agents to be recommended in percutaneous coronary interventions because of their antithrombotic advantages over non-ionic LOCM.

The increased histamine release in ischaemic heart disease patients undergoing coronaroangiography is not mediated by specific IgE

BACKGROUND

The release of histamine by iodinated contrast media (ICM) is higher in coronary artery disease patients than in noncoronary patients during coronary angiogram.

METHODS

Eighty-eight patients who underwent a coronary angiography were classified either as having coronary artery disease or as noncoronary patients. Histamine concentration was higher than the 6.8 nM upper limit in 7 cases (group 1), of whom six were coronary artery disease patients. We compared the IgE and complement fractions in plasma of these patients to two control groups with normal histamine blood level, one (group 2) with and the other (group 3) without coronary artery disease.

RESULTS

No difference of total IgE and C(3c) and C(4) complement fractions was found among the three groups. Anti-ioxaglate IgE-RIA was positive in only one patient from group 1. The affinity of drug-IgE binding in the serum of this patient was very low (Kd: 18.7 mM). The level of anti-ICM IgE detected by ioxitalamate- and iomeprol-Sepharose RIA was significantly higher in groups 2 and 3 than in group 1.

CONCLUSIONS

The higher histamine release in ischaemic heart disease patients undergoing coronaroangiography is not mediated by IgE or complement activation. Further studies are needed to investigate the implication of histamine release factors.

Influence of two non-ionic radiographic contrast media with different osmolalities on coagulation in invasive cardiology. A prospective, randomised comparative study

PURPOSE

To investigate the influence of two non-ionic radiographic contrast media with different osmolality on thrombocytic function and the plasmatic coagulation system.

MATERIAL AND METHODS

The study was carried out as a randomised, prospective, comparative study with two contrast media in a heart catheter laboratory.

RESULTS

Activating influences on platelet aggregation, procoagulatory or profibrinolytic functions or injury to the endothelium could be ruled out. Apparently, also differences in substance properties, such as the media's ionic character or osmolality had no demonstrable influence on the interaction with haemostatis and blood vessels. An adjuvant, antithrombotic therapy was carried out, which consisted of platelet aggregation inhibitors and heparins.

CONCLUSION

Our findings agree with the results of recent clinical trials, which demonstrated no relevant disadvantage of non-ionic contrast media as regards thrombotic complications.

A randomized prospective trial of ioxaglate 320 (Hexabrix) vs. iodixanol 320 (Visipaque) in patients undergoing percutaneous coronary intervention

We performed a randomized, prospective, double blind trial comparing the use of the ionic dimer contrast agent ioxaglate 320 (Hexabrix) with the nonionic dimer contrast agent iodixanol 320 (Visipaque) in 618 patients undergoing percutaneous coronary intervention (PCI) for stable or unstable coronary artery syndromes. The aim was to determine whether the different anticoagulant and antiplatelet properties of these two contrast agents resulted in a significant difference in the incidence of a combined endpoint comprising the major complications of PCI. Procedural success rates were marginally higher in the Visipaque group compared to the Hexabrix group, although this did not reach statistical significance (96.7% vs. 93.9%; P = 0.09). There was a borderline statistically significant higher requirement for bailout stenting in the Visipaque group compared to the Hexabrix group (6.8% vs. 3.2%; P = 0.05), although this was not a predefined endpoint. The incidence of the combined primary endpoint of failed catheter laboratory outcome/requirement for bailout stenting/requirement for abciximab/myocardial infarction/death before hospital discharge was higher in the Visipaque group compared to the Hexabrix group (17.9% vs. 14.8%), although this did not reach statistical significance (P = 0.29). When subgroup analysis was performed, the incidence of the combined endpoint in patients with stable coronary artery disease randomized to receive either Visipaque or Hexabrix was identical (13.7%). In patients with an acute coronary syndrome, there was a trend toward a reduced incidence of the combined endpoint in the Hexabrix compared to the Visipaque group, although this did not reach statistical significance (17.2% vs. 24.8%; P = 0.17). More adverse reactions occurred in the Hexabrix group compared to the Visipaque group (8.7% vs. 4.9%; P = 0.06). We conclude that there is no clear advantage with the use of an ionic contrast agent in a large population of patients undergoing PCI for both stable and unstable coronary artery disease. Although the study was underpowered to detect significant differences with the use of either agent when patients with either stable or unstable coronary disease were studied, it is highly unlikely that the ionicity of the contrast agent confers any advantage for patients with stable coronary disease. There remains a possibility that ionic agents do have advantages for patients with unstable coronary artery disease undergoing PCI, although a larger study than ours would be required to confirm or refute this.

Do clinically relevant circulating concentrations of radiographic contrast agents inhibit platelet-dependent arterial thrombosis?

OBJECTIVES

The purpose of this study was to determine if radiographic contrast agents (RCAs) inhibit thrombosis in a rat carotid artery injury model.

BACKGROUND

Whether ionic and nonionic RCAs differentially affect thrombus formation during coronary artery angioplasty is controversial. Although there are numerous in vitro studies and clinical trials addressing this issue, it is unknown whether clinically relevant plasma concentrations of RCA inhibit platelet-dependent thrombosis after injury of medium-sized arteries.

METHODS

Rats received RCA or control solution by bolus (0.7 ml/kg) and constant (0.04 ml/kg/min) intravenous infusion. Carotid arteries were injured with ferric chloride. Blood flow was monitored for 1 h. In vitro platelet aggregation and plasma clotting were studied.

RESULTS

After injury, mean times free from formation of an occlusive, platelet-rich thrombus were 16.2+/-2.3, 49.6+/-18.9, 47.9+/-21.0, and 37.1+/-22.8 min for rats (n=5/group) that received saline, diatrizoate (P<.002 vs. saline), ioxaglate (P<.002 vs. saline), and iohexol (P=.06 vs. saline), respectively. Reperfusion after initial occlusion did not occur in saline-treated animals, but was common in rats that received RCA. The antithrombotic properties of RCA were not explained by their high osmolarities or by detectable effects on in vitro platelet aggregation and plasma clotting. Plasma concentrations of RCA were <1%.

CONCLUSIONS

Systemic administration of RCA at doses that achieve low, clinically relevant plasma concentrations can inhibit platelet-rich thrombus formation after arterial injury. Antithrombotic properties of ionic RCA appear to be greater than those of nonionic RCA.

Comparison of effects of ioxaglate versus iomeprol on histamine and tryptase release in patients with ischemic cardiomyopathy

We observed a release of histamine, but not of tryptase, in arterial blood from 64 patients with ischemic heart disease and 24 patients without coronary disease, which was provoked by ioxaglate, a ionic compound, but was not provoked by iomeprol, a non-ionic radiocontrast compound. The release of histamine in arterial blood after ionic contrast medium injection was higher in patients with ischemic heart disease compared with patients without coronary disease, suggesting that an increased release from heart mast cells previously observed exists also for systemic blood basophils.

Impact of contrast agent type (ionic versus nonionic) used for coronary angiography on angiographic, electrocardiographic, and clinical outcomes following thrombolytic administration in acute myocardial infarction

The goal of this study was to examine the relationship between contrast agent type (ionic vs. nonionic) and angiographic, electrocardiographic, and clinical outcomes after thrombolytic administration. Ionic or nonionic contrast agents were selected in a nonrandomized fashion for 90-min angiography and percutaneous coronary intervention (PCI) following thrombolytic administration in the TIMI 14 trial [tissue plasminogen activator (tPA) or reteplase (rPA) vs. low-dose lytic + abciximab]. There was no relationship between contrast agent type and overall patency, rate of TIMI grade 3 flow, or corrected TIMI frame counts (CTFCs) in open culprit arteries and in post-PCI patency rates or post-PCI CTFCs. In patients treated with ionic contrast, ejection fractions at 90 min were slightly but significantly lower (56.2 +/- 16.5, n = 122, vs. 59.8 +/- 14.4, n = 322; P = 0.02), chest pain duration was longer (2.8 +/- 4.1 hr, n = 255, vs. 1.7 +/- 3.6, n = 550; P = 0.0003), and complete ST segment resolution was less frequent (41.5% vs. 50.8%; P = 0.04). While there was no difference in epicardial blood flow, ionic contrast agent use was associated with poorer ST segment resolution, longer chest pain duration, and poorer ejection fractions, perhaps as a result of microvascular dysfunction.

Iomeprol: current and future profile of a radiocontrast agent

RATIONALE AND OBJECTIVES

To review the safety and efficacy profiles of iomeprol by examining the most indicative comparative clinical studies of iomeprol with widely used low-osmolar ionic or nonionic contrast agents, and to illustrate the recent development in iomeprol liposomal formulations for liver imaging and intravascular enhancement.

METHODS

Randomized, double-blind, comparative studies were performed of iomeprol versus iopamidol, iopromide, ioxaglate, iopentol, iodixanol, ioversol, and iohexol. In all studies, safety controls included pre- and postadministration physical examinations, monitoring of vital signs, electrocardiography, clinical laboratory investigations, and 24- or 72-hour postadministration monitoring of patients for adverse events. Technically adequate images were rated for diagnostic efficacy by masked assessors.

RESULTS

Iomeprol showed similar safety and diagnostic efficacy compared with the nonionic monomers iopamidol, iohexol, and ioversol, and no statistically significant differences were observed. No differences in diagnostic efficacy between iomeprol and iopromide were observed, but in one study on 1,200 patients, the incidence of adverse events and adverse reactions was significantly higher with iopromide than with iomeprol. Iomeprol caused significantly less heat/pain than iopentol in one study; it showed similar safety and tolerability to the nonionic dimer iodixanol, the two agents causing no or modest, superimposable pain and heat sensation at injection and showing similar renal tolerability after intra-arterial injection. A comparison of iomeprol versus ionic dimer ioxaglate in 2,000 patients undergoing percutaneous coronary interventions showed that the incidence of thrombus-related events was similar with the two agents, but ioxaglate caused a significantly higher incidence of allergy-like reactions. First results with iomeprol-containing liposomal formulations show that these agents may facilitate the CT assessment of intrahepatic malignancies and CT angiography procedures.

CONCLUSIONS

The overall results of numerous randomized, double-blind, comparative clinical studies in a variety of indications show that the diagnostic efficacy of iomeprol solutions does not differ significantly from that of the low-osmolar contrast media available on the marketplace when similar iodine strengths are used, although iomeprol may have better tolerability and safety than the ionic dimer and some of the nonionic monomers in selective applications. First results obtained with iomeprol-containing liposomal formulations are promising and may foster additional clinical testing.

Randomized trial of contrast media utilization in high-risk PTCA: the COURT trial

BACKGROUND

Previous in vitro and in vivo studies have suggested an association between thrombus-related events and type of contrast media. Low osmolar contrast agents appear to improve the safety of diagnostic and coronary artery interventional procedures. However, no data are available on PTCA outcomes with an isosmolar contrast agent.

METHODS AND RESULTS

A multicenter prospective randomized double-blind trial was performed in 856 high-risk patients undergoing coronary artery intervention. The objective was to compare the isosmolar nonionic dimer iodixanol (n=405) with the low osmolar ionic agent ioxaglate (n=410). A composite variable of in-hospital major adverse clinical events (MACE) was the primary end point. A secondary objective was to evaluate major angiographic and procedural events during and after PTCA. The composite in-hospital primary end point was less frequent in those receiving iodixanol compared with those receiving ioxaglate (5.4% versus 9.5%, respectively; P=0.027). Core laboratory defined angiographic success was more frequent in patients receiving iodixanol (92.2% versus 85. 9% for ioxaglate, P=0.004). There was a trend toward lower total clinical events at 30 days in patients randomized to iodixanol (9.1% versus 13.2% for ioxaglate, P=0.07). Multivariate predictors of in-hospital MACE were use of ioxaglate (P=0.01) and treatment of a de novo lesion (P=0.03).

CONCLUSIONS

In this contemporary prospective multicenter trial of PTCA in the setting of acute coronary syndromes, there was a low incidence of in-hospital clinical events for both treatment groups. The cohort receiving the nonionic dimer iodixanol experienced a 45% reduction in in-hospital MACE when compared with the cohort receiving ioxaglate.

Iomeprol: a review of its use as a contrast medium

Iomeprol is a nonionic, monomeric iodinated contrast medium. Unlike the older ionic agents, iomeprol has low chemotoxicity, osmolality and viscosity and high water solubility. Compared with other nonionic contrast media, the osmolality and viscosity are lower and the water solubility is reported to be higher with iomeprol. Most radiographs (about 67 to 100%) obtained with iomeprol (containing 150 to 400 mg/ml of iodine) were of good or excellent quality in noncomparative and comparative trials recruiting 40 to 6127 patients undergoing various radiographic procedures. As expected, the diagnostic efficacy of iomeprol did not differ significantly from that of other nonionic agents (iopamidol, iopromide, iohexol and iotrolan). Iomeprol (containing 150 to 400 mg/ml of iodine) was well tolerated in clinical trials. Most adverse events were transient and of mild to moderate intensity and were similar to those observed with other contrast media. The overall incidence of adverse events ranged from 3 to 49.7% and mainly included localised pain (< or =6%) and heat sensations (8 to 45%), taste disturbances (3 to 27%) and various pseudoallergic reactions (< or =20% for each type of event). The incidence of heat or pain and taste disturbances with iomeprol was similar to that observed with iopromide and iopamidol. Pain (but not heat sensations) was reported significantly less frequently and taste disturbances reported significantly more frequently with iomeprol than with iohexol in a comparative trial. Pseudoallergic reactions (such as nausea, vomiting, skin reactions, dizziness, headache) were significantly less common with iomeprol than with ioxaglate and occurred at a similar frequency to that with iopromide and iopamidol. Cardiovascular events were rarely observed with iomeprol. Currently available iomeprol solutions contain a range of iodine concentrations (150 to 400 mg/ml) and are approved for a wide variety of diagnostic procedures. Iomeprol solutions are chemically stable which negates the need for chelating agents. Formulations of this agent are therefore the first not to contain edetic acid (EDTA).

CONCLUSIONS

Iomeprol shows equivalent diagnostic efficacy, and a similar adverse event profile, to that of other nonionic contrast media. The availability of a range of iodine concentrations enables iomeprol to be used in a variety of diagnostic procedures. Iomeprol, like others in its class, is suitable for use in diagnostic imaging.

A comparison of ionic versus nonionic contrast medium during primary percutaneous transluminal coronary angioplasty for acute myocardial infarction (GUSTO IIb). Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes

The clinical impact of contrast medium selection during primary percutaneous transluminal coronary angioplasty for acute myocardial infarction (AMI) has not been studied. We compared the clinical outcomes of patients who received ionic versus nonionic low osmolar contrast medium in the setting of primary percutaneous transluminal coronary angioplasty for AMI in the second Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes (GUSTO IIb) trial. Univariable and multivariable analyses were performed to assess the relation between contrast medium selection and clinical outcome (death, reinfarction, or refractory ischemia) at 30 days. Although baseline clinical and angiographic characteristics were generally similar between the 2 groups, patients who received ionic, low osmolar contrast were less likely to have been enrolled at a US site (23% vs 43%, p = 0.001) and less likely to have occlusion of the left anterior descending coronary artery (34% vs 47%, p = 0.03) or a history of prior AMI (8% vs 16%, p = 0.02). The triple composite end point of death, reinfarction, or refractory ischemia occurred less frequently in the ionic group, both in the hospital (4.4% vs 11%, p = 0.018) and at 30 days (5.5% vs 11%, p = 0.044). Although the trend favoring ionic contrast persisted, the differences were no longer statistically significant after adjustment for imbalances in baseline characteristics using a risk model developed from the study sample (n = 454, adjusted odds ratio for ionic contrast 0.48 [0.22 to 1.02], p = 0.055), and using a model developed from the entire GUSTO IIb study cohort (n = 12,142, adjusted odds ratio for ionic contrast 0.50 [0.23 to 1.06], p = 0.072). The results of this observational study warrant further elucidation by a randomized study design in this setting.

Influence of a nonionic, iso-osmolar contrast medium (iodixanol) versus an ionic, low-osmolar contrast medium (ioxaglate) on major adverse cardiac events in patients undergoing percutaneous transluminal coronary angioplasty: A multicenter, randomized, double-blind study. Visipaque in Percutaneous Transluminal Coronary Angioplasty [VIP] Trial Investigators

BACKGROUND

The potential merits and disadvantages of the use of ionic or nonionic contrast media in patients undergoing percutaneous transluminal coronary angioplasty (PTCA) have been the subjects of controversy. The present study was designed to evaluate the possible influence of both types of contrast media on major adverse cardiac events (MACE) in patients undergoing PTCA.

METHODS AND RESULTS

In a randomized, parallel-group, double-blind study, 1411 patients received either iodixanol (a nonionic, iso-osmolar contrast medium) or ioxaglate (an ionic, low-osmolar contrast medium) during PTCA. A standardized anticoagulation regimen was followed. Patients were monitored in the hospital for 2 days and followed-up at 1 month. The primary end point, a composite of MACE (death, stroke, myocardial infarction, coronary artery bypass grafting, and re-PTCA) after 2 days, occurred in 4.3% of the total population, with no statistically significant difference between groups (iodixanol, 4.7%; ioxaglate, 3.9%; P=0.45). Further, between 2-day and 1-month follow-ups, no significant difference (P=0.27) existed between the groups in the rates of MACE. Hypersensitivity reactions (P=0.007) and adverse drug reactions (P=0.002) were significantly less frequent in the iodixanol group. The only significant predicting factors for the occurrence of MACE were dissection/abrupt closure and country.

CONCLUSIONS

No significant differences were observed between the iodixanol and ioxaglate groups with regard to MACE, although hypersensitivity and adverse drug reactions were significantly less frequent in patients who received iodixanol.

Thrombotic risk associated with the use of iodinated contrast media in interventional cardiology: pathophysiology and clinical aspects

A review of the current knowledge of the anti-thrombotic properties of iodinated contrast media (CM) has been conducted. CM are classified according to their chemical structure, either ionic or non-ionic (monomeric or dimeric). Numerous in vitro and in vivo data show that, although all CM have anti-coagulant properties, ionic molecules are more potent than non-ionic and, furthermore, do not activate resting platelets, unlike non-ionic agents. These properties may lead to a decrease in thrombus formation during interventional procedures. Several clinical trials have shown that CM may play a role in the occurrence of acute thrombotic complications but also in delayed ischaemic events during interventional procedures. A recent meta-analysis showed that, compared to non-ionic monomers, ionic low-osmolar CM reduce the rate of coronary artery abrupt closure, but no significant difference was found with respect to ischaemic complications. Ionic CM lead to a lower deposit of thrombotic materials on catheters and guide-wires. To date, clinical data comparing ionic CM and non-ionic dimers are scarce, significantly heterogeneous and, unlike experimental data, they do not show differences between both classes of CM. Further studies are required to better understand the precise mechanisms of such interactions and to analyse the effect of CM when new antiplatelet agents or new procedures (stenting) are used, to comply with new clinical strategies.