Use Of Nonionic Contrast Agents Research Articles

Volume Changes in Gallbladder in Association with Intravenous Use of Nonionic Contrast Agents

Background To determine whether use of intravenous (IV) nonionic contrast agent affects the gallbladder (GB) volume in the preceding sonographic imaging. Materials and methods The GB volume was measured sonographically before and 15 minutes after the IV contrast agent injection in 200 patients referred to the teaching hospitals of Mashhad University of Medical Sciences (Mashhad, Iran). Results There was a statistically significant difference between GB volumes after the injection of contrast media (19.59 ± 4.49 compared with 16.06 ± 3.89 m 3 , respectively; p Conclusion The GB volume reduces 15 minutes after IV use of the contrast agent. This reduction should be taken into consideration when ordering an imaging modality with IV contrast injection accompanied by ultrasound evaluation of GB.

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

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

The potential role of statins in contrast nephropathy

Administration of contrast agents may result in an acute reduction in renal function and occasionally end-stage renal disease. Risk factors for contrast-induced nephropathy (CN) are preexisting renal dysfunction, diabetes and reduced effective arterial volume. Hydration and use of nonionic contrast agents have been reported to ameliorate CN. Reactive oxygen species may have a role in the pathogenesis of CN. Statins decrease free oxygen radicals in animals. We retrospectively tested the hypothesis that administering statins prior to cardiac catheterization decreases the incidence of CN. A total of 1,002 patients were studied. Patients with a stable baseline serum creatinine (SCr) > or = 1.5 mg/dl who had cardiac catheterization between July 1997 and June 2002, were included in the study. None of the patients were taking statins before admission. 250 patients were started on a statin before the procedure and 752 patients were not. The SCr was followed for 7 days after the procedure looking for an acute decrement in renal function, dialysis requirement and survival. The baseline characteristics, SCr, GFR, amount of intravenous fluids and contrast were similar in both groups. The post cath SCr (2.26 vs 3.1 mg/dl, p = 0.001) was significantly better in the statin group. Length of stay (2.72 vs 3.32 days, p = 0.01) and number of patients with acute renal failure (43 (17.2%) vs 168 (22.3%) patients, p = 0.028) were significantly lower in the statin group. Dialysis requirement within 7 days and 28-day survival were similar in both groups. Prophylactic administration of statins along with hydration may be associated with less CN induced by a nonionic, low-osmolality contrast.

Implementing HCFA guidelines on appropriate use of nonionic contrast agents for diagnostic arteriography: Effects on complication rates and management costs

Implementing HCFA guidelines on appropriate use of nonionic contrast agents for diagnostic arteriography: Effects on complication rates and management costs

Intravenous use of ionic and nonionic contrast agents in children.

To determine the use of intravenous ionic and nonionic contrast agents in children. The director of pediatric radiology at 59 of 65 large children's hospitals in North America responded to a questionnaire. Thirty-nine institutions used only nonionic contrast agents, one used only ionic, and 19 used both. Among those who used both, various criteria were used for selection of nonionic contrast agents. These criteria were rigidly enforced in only five of 18 institutions. The most common indication for the use of nonionic contrast agents was a severe reaction to any contrast agent, allergy, or poor renal function. Because nonionic contrast agents are more expensive, 18 of 58 directors of pediatric radiology were under pressure from hospital administrators to decrease use of these agents. The use of nonionic agents was justified because patients experienced fewer minor reactions to the agent. Most pediatric institutions are nonionic contrast agents, but many still use ionic agents for intravenous administration for selected indications.

The Use of Nonionic Contrast Agents in Neuroangiography

Several large studies have demonstrated the improved safety record of nonionic versus ionic contrast agents for intravenous administration. However, nonionic agents are much more expensive than ionic agents. The author addresses whether, given this large cost differential, nonionic contrast agents should always be used in neuroangiography (cerebral and spinal cord angiography and intravascular neurointerventional procedures). The answer could come from a closer examination of the effects of contrast agents on the brain. There have been a number of animal experiments and clinical trials performed using a variety of available intravascular contrast agents. In an attempt to arrive at some reasonable conclusions regarding the use of contrast agents today, the author reviews several of these studies. In the human studies, three areas were analyzed: 1) cerebral angiography, 2) spinal cord angiography, and 3) intravascular neurointervention. The author explains why demonstrating the effect of a contrast agent on the brain or spinal cord in the clinical setting is more difficult than studying the effect of this agent on the liver, heart, or kidney. For example, obtaining objective measurements of altered cerebral physiology following intravascular injection of a contrast agent may itself alter the physiology. In lieu of objective measurements, investigators must rely on apparent changes in behavior, mentation, or the production of a focal neurologic deficit. However, it is extremely difficult, if not impossible, to separate the effect of the contrast agent from the effects of the arteriographic procedure, or from the disease process being evaluated. The neuronal environment is protected by the blood-brain barrier. A number of animal experiments have demonstrated that nonionic agents produce breakage of the blood-brain barrier less frequently than do ionic agents. In these studies, nonionic agents also produced fewer neurologic effects than did ionic agents. The human studies showed no statistically significant differences in neurologic effects when ionic and nonionic agents were compared. Cerebral: minor changes in heart rate were more common with ionic than with nonionic agents; there were no significant electroencephalogram changes in any of the patients studied. Spinal cord: the effects of intravascular injections of contrast material into the spinal cord of experimental animals have been rarely evaluated; direct comparisons of contrast agents in human spinal cord angiography have not been performed. Neurointervention: there have been no comparative studies of different contrast agents used during intravascular neurointerventional procedures in humans. Extensive animal data demonstrate that nonionic contrast agents are safer than ionic for cerebral angiography. Animals in the cited studies show less blood-brain barrier disruption, fewer direct neuronal effects, and fewer neurobehavioral deficits. However, the overwhelming conclusion from the human studies is that, while there is evidence in the experimental animal that nonionic agents produce fewer neurologic effects than do ionic agents, no study to date has been able to translate these findings into an apparent clinical difference in humans, mainly because it's so difficult to detect and measure neurologic changes in human trials. In addition, differences in neurologic effects between contrast agents used in human studies may be relatively small. Thus, one must make an educated guess as to the appropriate use of contrast agents in the context of their apparent clinical safety and cost-benefit ratio.

Ionic versus nonionic contract use

It has taken many years of research, development and intense scientific investigation to produce intravascular contrast media. Research on relations between chemical structure, animal toxicity, and water-solubility has produced a number of highly water-soluble, iodinated compounds for use in diagnostic radiology as intravascular contrast agents. The currently used intravascular agents may be classified into four groups according to their chemical structure: 1. 1. Ionic monomers 2. 2. Ionic monoacid dimers 3. 3. Nonionic monomers 4. 4. Nonionic dimers It is the objective of this publication to review the history and development of intravascular contrast media as well as their properties, general effects and clinical use. The four types of contrast media differ significantly in their chemical structure and physico-chemical properties, and these differences determine their osmotoxicity, chemotoxicity, and ion toxicity. We analyze the organ specific toxic effects of intravascular contrast media upon the central nervous system, the cardiovascular system, and the renal system. We also review the secondary effects, clinical manifestations, and the incidence of adverse events associated with different types of contrast. The choice of contrast media has become critical since the introduction of nonionic agents because their toxicological and pharmacological properties differ from those of the ionic agents. The application of basic concepts involved in the use of contrast media in excretory urography, computed tomography, angiography, and angiocardiography is discussed, and the advantages of the use of nonionic contrast agents are outlined. Economic and ethical issues are presented with emphasis upon strategies to reduce the risk associated with the injection of intravascular contrast and to curtail consumption according to rational principles of use.

Comparison of ionic and low-osmolar contrast media during cardiac catheterization

The use of nonionic contrast agents during cardiac catheterization decreases the incidence of both major and minor cardiovascular complications when compared with ionic contrast. Hemodynamic and electrophysiologic effects are less profound especially in patients who have severe coronary artery disease or left ventricular dysfunction. Sparse data exist comparing ionic and nonionic contrast in patients undergoing percutaneous transluminal coronary angioplasty. No clinical evidence suggests that nonionic contrast agents are less nephrotoxic than ionic contrast though patients with significant baseline renal dysfunction (creatinine > 3.0) might benefit. The incidence of thrombotic events appears to be similar for both types of agents. Finally, the risk reduction of cardiovascular events must be weighed against markedly higher costs.

Elimination of variable vasomotor tone in studies with repeated quantitative coronary angiography

In quantitative coronary angiographic studies, unintentional changes of coronary vasomotor tone may have a significant influence on the coronary artery diameters, thereby increasing the variability in the measurements. To obtain objective data on these measurement variabilities, two protocols were designed to assess the influences of ionic and nonionic radiographic contrast media on the mean diameters of angiographically normal coronary arteries. The vessel sizes were determined with the CAAS using automated edge detection techniques. In 21 patients (study no. I), coronary angiograms were taken in identical angiographic projections before (control), and immediately following several (at average 7) subsequent diagnostic dye injections administered over a period of about 7 min. The ionic contrast agent diatrizoate 76% induced a coronary dilation of 19 +/- 7% (mean +/- s.d., p less than 0.001; n = 10); the nonionic agent iopromide 370 increased the coronary artery diameters by only 6 +/- 4% (p less than 0.01; n = 11). In another 11 patients (study no. II) coronary angiograms were obtained using the nonionic contrast medium iopamidol 300 at 5, 8, 10 and 11 min after the control acquisition; this protocol was repeated in the same patients with diatrizoate 76%. With iopamidol, coronary diameter changes were not significant at any time; with diatrizoate, however, coronary dilation was measured at 10 min (2 +/- 2%; p less than 0.01) and at 11 min (10 +/- 3%; p less than 0.001). In a third study it was tested, whether standardization of coronary vasomotor tone (e.g. in coronary angiographic follow-up studies) is possible by the induction of a reproducible maximum coronary dilation with nitrocompounds. In 12 patients, the mean diameters of angiographically normal coronary segments were analyzed before and at various times after i.v. administration (over 4 min) of 0.025 mg SIN-1/kg bodyweight. Coronary dilation was maximal at 10 or 15 min after the onset of the SIN-1-infusion (29 +/- 5%; p less than 0.001). 0.8 mg nitroglycerin given s.l. at 15 min did not further dilate the coronary arteries (28 +/- 7%). One hour after SIN-1, coronary dilation still amounted to an average of 24 +/- 8% (p less than 0.001) and became 'maximal' again, when 0.8 mg nitroglycerin was again administered sublingually (28 +/- 8%; p less than 0.001). In conclusion, short-term variability of coronary vasomotor tone induced by ionic radiographic contrast media can be eliminated by the use of nonionic contrast agents and observation of injection intervals of at least 2 min. In quantitative coronary angiographic follow-up studies, as well as during acute interventions (e.g., PTCA), identical baseline vasomotor tone can be achieved by induction of the maximal coronary dilation using nitrocompounds.

Thrombogenic Potential of Nonionic Contrast Media: Dr. King replies

Dr. Robertson's commentary about the complex issue of thrombogenic potential of nonionic contrast media is timely and important when the appropriate use of the nonionic contrast agents is being discussed. The recent studies by Fareed, Hwang, and Kopko and their associates1Fareed J Walenga JM Saravia GE Moncada RM Thrombogenic potential of nonionic contrast media?.Radiology. 1990; 174: 321-325PubMed Google Scholar, 2Hwang MH Piao ZE Murdock DK Messmore HL Giardina JJ Scanlon PJ Risk of thromboembolism during diagnostic and interventional cardiac procedures with nonionic contrast media.Radiology. 1990; 174: 453-457PubMed Google Scholar, 3Kopko PM Smith DC Bull BS Thrombin generation in nonclottable mixtures of blood and nonionic contrast agents.Radiology. 1990; 174: 459-461PubMed Google Scholar addressed the issue of the relative lack of anticoagulation that the nonionic contrast media seem to possess. Although most studies have dealt with in vitro situations, it is not unreasonable to be concerned about possible in vivo thrombogenic complications when these new nonionic agents are used, especially in coronary angiography and cerebral angiography. Also, one should be concerned when certain patients are already at high risk for thrombogenic complications. In the report by Fareed and colleagues,1Fareed J Walenga JM Saravia GE Moncada RM Thrombogenic potential of nonionic contrast media?.Radiology. 1990; 174: 321-325PubMed Google Scholar certain risk factors for possible nonionic contrast media-induced thrombosis were identified (Table 1). In addition, Fareed and associates showed that thrombin generation was dramatically increased with use of nonionic contrast agents when glass syringes were used in angiography. Thus, their conclusion was that nonionic contrast media should be used only with plastic syringes.Table 1Risk Factors for Nonionic Contrast Media-Induced Thrombosis 1.Antithrombin III deficiency2.Protein C or protein S deficiency3.Hyperfibrinogenemia4.Thrombocytosis5.Increased factor VIII levels6.Hemoconcentration7.Hyperviscosity syndrome8.Paraproteinemias9.Leukemias (increase in number of leukocytes)10.Hemolysis11.Oral contraceptives and smokingFrom Fareed and associates1Fareed J Walenga JM Saravia GE Moncada RM Thrombogenic potential of nonionic contrast media?.Radiology. 1990; 174: 321-325PubMed Google Scholar By permission of the Radiological Society of North America, Inc. Open table in a new tab From Fareed and associates1Fareed J Walenga JM Saravia GE Moncada RM Thrombogenic potential of nonionic contrast media?.Radiology. 1990; 174: 321-325PubMed Google Scholar By permission of the Radiological Society of North America, Inc. In light of Dr. Robertson's commentary and studies that have been reported recently, it is apparent that the potential for thrombotic complications is higher with nonionic contrast agents than with ionic contrast agents. In addition, extreme care and meticulous technique should be used during angiography to prevent the mixing of blood and the contrast medium. It is now apparent that large-scale prospective clinical trials should be conducted to determine the clinical significance of the thrombogenic risk with nonionic contrast media. Until then, maintaining a continuous saline drip flowing through the intravascular catheter and systemic or local administration of heparin (or both) are two commonly used safety precautions that may provide an improved safety margin until further information is gained from future clinical studies. Thrombogenic Potential of Nonionic Contrast MediaMayo Clinic ProceedingsVol. 65Issue 4PreviewThe review article, “Low-Osmolality Contrast Media: A Current Perspective,” by King and associates in the August 1989 issue of the Proceedings (pages 976 to 985) provides a thoughtful overview of contemporary literature on the subject. The question of interaction of blood and low-osmolar contrast media (LOCM) and spontaneous formation of blood clots merits further comment, in light of recent articles in the radiologic literature. Full-Text PDF