Effects Of Contrast Media Research Articles

Transient global amnesia following cerebral angiography with non‐ionic contrast medium

Transient global amnesia (TGA) is an uncommon syndrome of recent memory deficit and inability to learn new data, usually resolving within 24 h. Two cases following use of non-ionic contrast media in cerebral angiography are described. The neuroanatomy of memory is reviewed. Possible aetiologies of TGA in relation to cerebral angiography include ischaemia (embolic, arterial spasm), epilepsy that may be primary or tumour-related and direct toxic effects of contrast media.

Effects of contrast media on platelet activation using flowing whole blood aggregometry and flow cytometry of platelet membrane glycoproteins.

Grabowski EF, Head C, Michail HA, Jang IK, Gold H, Benoit SE, Michelson AD. Effects of contrast media on platelet activation using flowing whole blood aggregometry and flow cytometry of platelet membrane glycoproteins. Invest Radiol 1994;29:S198–S200.

Intravascular Contrast Media and Thrombin Generation

This study focuses on the effect of contrast media (CM) on thrombin generation. In vitro studies consisted of incubating nonanticoagulated whole blood with ionic CM (sodium meglumine diatrizoate, ioxaglate), nonionic CM (iohexol, iopamidol) or glucose in plastic tubes. Thrombin generation was assessed by measuring F1 + 2, ATM and FpA levels in plasma using ELISA assay kits. In a separate protocol, the procoagulant activity of 3 nonionic CM (iohexol, iopamidol, and iopromide) was investigated by one-stage plasma recalcification time method. Rabbit brain tissue thromboplastin and physiologic saline were used as standard and experimental controls. Incubation of ionic and nonionic CM with whole blood did not enhance thrombin generation compared to glucose control. Similarly, the plasma recalcification times were not significantly shortened by either of the 3 nonionic CM tested. These studies suggest that ionic and nonionic CM exhibit different levels of anticoagulant properties in vitro and the latter are not procoagulant materials.

Modulation of the Expression of the Granulocyte Adhesion Molecule, CR3, by Percutaneous Transluminal Coronary Angioplasty and Contrast Media

The effects of percutaneous transluminal coronary angioplasty (PTCA) and iodinated contrast media on the functional state of polymorphonuclear leukocytes (PMN) were determined; the expression of the PMN adhesion molecule, CR3, was assessed. CR3 expression was measured by flow cytometry in whole blood samples in vivo, before and after PTCA (n = 17) or coronary angiography (n = 16); and in vitro, before and after incubation of PMNs with iodinated contrast media (n = 5). CR3 expression (mean +/- standard error of the mean, arbitrary units) decreased significantly after PTCA (221 +/- 25 to 168 +/- 21, P < .005) and coronary angiography (297 +/- 43 to 218 +/- 25, P < .05). In vitro, there was a dose-dependent decrease of CR3 expression and a significant and strong inverse correlation between CR3 expression and the contrast agent concentrations regardless of the type of contrast agent used. These data suggest that PTCA does not activate circulating PMNs, and that contrast media decrease CR3 expression. Whether this is related to the systemic adverse effects of contrast media remains to be clarified.

The effects of contrast media (CM) on the fibrinolytic system in an in vitro model. Possible consequences in local arterial thrombolysis

The effects of contrast media (CM) on the fibrinolytic system in an in vitro model. Possible consequences in local arterial thrombolysis

Intravascular contrast media and thrombin generation

This study focuses on the effect of contrast media (CM) on thrombin generation. In vitro studies consisted of incubating nonanticoagulated whole blood with ionic CM (sodium meglumine diatrizoate, ioxaglate), nonionic CM (iohexol, iopamidol) or glucose in plastic tubes. Thrombin generation was assessed by measuring F1 + 2, ATM and FpA levels in plasma using ELISA assay kits. In a separate protocol, the procoagulant activity of 3 nonionic CM (iohexol, iopamidol, and iopromide) was investigated by one-stage plasma recalcification time method. Rabbit brain tissue thromboplastin and physiologic saline were used as standard and experimental controls. Incubation of ionic and nonionic CM with whole blood did not enhance thrombin generation compared to glucose control. Similarly, the plasma recalcification times were not significantly shortened by either of the 3 nonionic CM tested. These studies suggest that ionic and nonionic CM exhibit different levels of anticoagulant properties in vitro and the latter are not procoagulant materials.

Effects of Contrast Media on the Stria Vascularis

The effects of contrast media on the stria vascularis were electron microscopically studied in mice after intravenous injection of amidotrizoate, iopamidol or ioxaglic acid at 10 or 20 ml/kg body weight. In furosemide-load groups, contrast media were injected via the tail vein at 10 ml/kg with preadministration of furosemide at 20 mg/kg body weight. In both groups, the stria vascularis was prepared for study 10 min after the injection of contrast media. No morphological changes could be found after administration of 10 ml/kg injection of any of the three contrast media. However, administration of 20 ml/kg of amidotrizoate caused a high degree of intercellular dilatation between marginal and intermediate cells. Iopamidol caused a slight degree of dilatation, and ioxaglic acid caused no change. In the furosemide-load groups, amidotrizoate induced severer effects than iopamidol while ioxaglic acid induced no effect. From these results it was concluded that contrast media affect the stria vascularis parallel with osmolality, although some ionic effect of amidotrizoate should be considered when it is used in combination with furosemide.

Effects of contrast agents on renal function.

Contrast-induced changes produced in normal renal function are discussed, and possible mechanisms by which such changes may occur are described. Animal experiments are reviewed, with the dog model providing results most closely approximating observations in humans. In the previous studies considered, standard clearance techniques were used to assess glomerulo-vascular changes, while urinary enzyme and protein excretions, along with changes in tubular reabsorption of electrolytes, were examined as indirect measures of contrast-induced tubular effects. The selection of papers for review was based primarily on studies conducted in large animals and humans. To be incorporated, traditional studies regarding accepted methods of analyzing renal function that did not involve extensive surgical preparation were reviewed. Renal vascular effects of contrast media induce a biphasic change in renal blood flow--a brief increase followed by a more prolonged decline--the magnitude of which varies by dose and route of administration. Tubular effects include increased excretion of cytosolic enzymes plus changes in tubular reabsorption of sodium, potassium, and chloride. A transient osmotic diuresis also occurs. Changes in renal blood flow, glomerular filtration rate, urinary electrolyte and solute excretion, and modification of the urinary concentrating-diluting mechanisms have yielded insights into the tubulo-glomerular actions of contrast media. The link between acute renal effects and subsequent contrast-associated nephropathy, while not absolutely defined, is becoming better understood as new information is gained using experimental models that more closely approximate high-risk states, including states of volume depletion, circulatory insufficiency, and pre-existing renal damage. Current attention is focused on the tubulo-glomerular feedback mechanism as accounting for the renal effects of contrast media.

Effects of Vasoconstrictors on Rabbit Coronary Arteries Exposed to Isotonic Ionic and Nonionic Contrast Media

Vasodilation is a well-known side effect of contrast media (CM) that is primarily explained by the hyperosmolality of the media. Few reports have dealt with the influences of chemotoxicity and ion toxicity on vessel tone. We compared the effects of solutions iso-osmolar to plasma of iohexol (nonionic monomer), ioxaglate (ionic dimer), diatrizoate (ionic monomer), and mannitol on responses to vasoconstrictors (potassium chloride [KCl], histamine, and endothelin-1). The aim of this study was to investigate if differences in chemotoxicity and ion toxicity could contribute to the changes in vessel tone seen clinically during arteriography. Segments of rabbit coronary arteries were mounted between two L-shaped prongs in tissue baths with buffer solution or CM solutions. Their responses to increasing concentrations of a vasoconstrictor were measured. The maximal contraction of the vasoconstrictor (Emax) and the concentration of the vasoconstrictor causing half maximal contraction (EC50) were calculated. Iohexol caused the same changes as the nonionic solution of mannitol. The media reduced the actions of KCl, histamine, and endothelin-1 to 50% to 60% of their action in buffer. The ionic CM, ioxaglate and diatrizoate, caused a more pronounced inhibition of histamine and almost totally inhibited the action of KCl. The action of endothelin-1 was inhibited to a greater extent by iohexol and mannitol than by ioxaglate and diatrizoate. Different types of iso-osmolar CM interact differently with vasoconstrictors. These effects are caused by differences in chemo- and ion toxicity. These interactions might contribute to the differences in vasodilatation found clinically.

Modulation of the Renal Effects of Contrast Media by Endothelium-Derived Nitric Oxide in the Rat

A possible involvement of endothelium derived relaxing nitric oxide (NO) in the pathogenesis of iodinated contrast media (CM)-induced nephrotoxicity was investigated in the rat. Male rats (6 to 12 per group) were uninephrectomized. Six days later, the aorta was clamped above the renal artery and a low-osmolar contrast medium (CM), ioxaglate, was injected (1 mL/min; 3 minutes) via an aortic puncture in the single remaining kidney. Contrast medium was injected with or without the NO-synthase inhibitor L-NAME (100 mg/kg intravenously [i.v.] 5 minutes before CM). One group received L-Arginine, the physiological precursor of NO (100 mg/kg i.v.), 5 minutes before L-NAME. Phenylephrine (300 micrograms/kg; 30 min) was used as a vasoconstrictive NO-independent control. The effects of iohexol, another low-osmolar CM, on creatinine clearance (CrCl) were also studied with and without pretreatment with L-NAME. A control group was subjected to a 3-minute renal ischemia only. Creatinine clearance and urinary N-acetyl-beta-D-glucosaminidase (NAG) excretion were determined before, and 24 and 48 hours after CM administration. Blinded histologic analysis was carried out after completion of the study. When administered alone, neither L-NAME nor L-arginine modified CrCl. Ioxaglate mildly but significantly decreased CrCl at 24 hours (-26.5% of preinjection value). This was similar to the effect observed in the control group subjected to ischemia only. When associated with L-NAME, ioxaglate markedly decreased CrCl (-58 + 11% at 24 hours, P < .05 vs. ioxaglate alone). A similar interaction was noted in the case of iohexol. L-NAME also markedly increased ioxaglate-induced urinary NAG excretion. Phenylephrine had a similar impact on renal function. L-arginine pretreatment reduced the increase in serum creatinine induced by L-NAME+ioxaglate (68 + 17 mumol/L vs. 175 + 59 mumol/L for L-NAME+ioxaglate; P < .05) and urinary NAG excretion. Ioxaglate alone induced only tubular epithelial vacuolization. When associated with L-NAME, this CM induced tubular and vascular lesions, as well as necrosis in the outer medulla. Such histologic effects were clearly inhibited by L-arginine. These data indicate that L-NAME, a specific inhibitor of NO-synthase, and phenylephrine, accentuate the nephrotoxicity of CM in the rat. This is consistent with results from the literature showing that CM-toxicity is enhanced by renal ischemia.

Modulation of the Renal Effects of Contrast Media by Endothelium-Derived Nitric Oxide in the Rat

Modulation of the Renal Effects of Contrast Media by Endothelium-Derived Nitric Oxide in the Rat

Vasoconstriction by angiographic contrast media in isolated canine arteries

Most of the published studies of the effect of contrast media (CM) on blood vessels were carried out in vivo. The response of blood vessels to CM was not uniform in those studies. Thus, we attempted to examine the direct effect of CM on blood vessels in vitro, using isolated canine arteries taken from six different regions.

Sodium—Calcium Balance in Nonionic Contrast Media Effects on the Risk of Ventricular Fibrillation in the Isolated Rabbit Heart

During coronary arteriography the blood is replaced for a short period of time with a contrast medium (CM) solution. The CM may cause a risk of arrhythmias and ventricular fibrillation (VF). Previous investigations have shown that the addition of small amounts of sodium (10-30 mmol/L) to nonionic CM may decrease the risk of VF from these media. Calcium addition to nonionic CM may reduce a negative inotropic effect. In the current investigation, the changed risk of VF from nonionic CM with 19 to 30 mmol/L NaCl was studied when the media also contained calcium or calcium and magnesium. An isolated rabbit heart model was used. The risk of arrhythmias and VF from the nonionic monomer iohexol and the nonionic dimer iodixanol containing 19 to 30 mmol/L NaCl with 0 to 2.5 mmol/L calcium as CaCl2 was studied. In the series with iodixanol, 0 to 0.95 mmol/L MgCl2 also was added to the solutions with sodium and calcium, but the role of magnesium was not especially evaluated in the investigation. Nonionic CM with small amounts of NaCl (19-30 mmol/L), without calcium or with calcium at the level of 0.05 to 0.3 mmol/L, caused the lowest risk of VF. When relatively higher additions of calcium reached the physiologic concentration of 2.5 mmol/L, the CM caused a greater risk of arrhythmias and VF. When calcium is added to a nonionic CM, the concentration of calcium must be balanced against the NaCl concentration to minimize the risk of VF. Excessive calcium concentration will increase the risk of VF.

The effect of contrast media on white cell chemotaxis in vitro: A newly recognized adverse effect

The effect of contrast media on white cell chemotaxis in vitro: A newly recognized adverse effect

Effects of vasoconstrictors on isolated rabbit coronary arteries exposed to isotonic iohexol. Potassium chloride-, histamine-, endothelin-, and prostaglandin-F2 alpha-induced contractions on arteries exposed to iohexol without and with osmotic additions (sodium chloride or glucose).

A major effect of contrast media (CM) on coronary vessels is vasodilatation, but occasionally, both ionic and nonionic media may cause coronary artery spasm. The influence of CM on the actions of vasoactive substances is not well known. To investigate the effects on rabbit coronary arteries of an iso-osmolar nonionic CM, iohexol (140 mg I/mL) the vasoconstrictors potassium chloride (KCl), histamine, endothelin, and prostaglandin-F2 alpha (PGF2 alpha) were used. The effects of iohexol with 30 to 150 mM sodium chloride (NaCl) or with 25-50 g/L glucose also were investigated. Coronary artery segments were mounted between two L-shaped prongs in tissue baths with buffer solution. Before each investigation, buffer was exchanged with iohexol solution. Increasing concentrations of a vasoconstrictor were added, and the constriction of the vessels was recorded. Iohexol caused a comparatively small inhibition of the contractile effects of histamine and endothelin. This meant little reduction in maximal contraction (Emax), and the concentration of constrictory substance resulting in half maximal contraction (EC50) compared with buffer solution. Iohexol also caused a small reduction in Emax of KCl, but EC50 was significantly lower. Adding NaCl or glucose to iohexol decreased Emax and increased EC50. Iohexol inhibited most of the contractile effect of PGF2 alpha, but adding NaCl increased Emax slightly. The effects caused by a nonionic CM on coronary arteries cannot be attributed to osmolality alone. The CM influenced the effects of vasoconstrictors to differing degrees, but the inhibition of the CM per se was usually small.

Low-osmolality versus high-osmolality contrast material

Universal use of low-osmolality contrast agents for intravascular diagnostic procedures has been limited to a large extent by the high cost of these agents, which is generally 10 to 20 times that of high-osmolality contrast media. The question for the radiologist, therefore, is the definition of selected populations and situations for the use of low-osmolality agents to achieve the greatest patient benefit at the least cost. The authors examine controversial issues including the incidence of significant contrast reactions, the definition and incidence of nephrotoxicity, and the effects of contrast media on coagulability.

The effect of iodixanol, anew 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.

Effects of Contrast Media on the RR and QT Interval during Coronary Arteriography

During coronary arteriography, transient prolongation of the RR and QT intervals can be observed to occur. Animal experiments have suggested that low-osmolality contrast media have less effect, but there have been few clinical studies of this phenomenon. We analyzed 95 electrocardiographic records from patients who had undergone coronary arteriography and assessed the maximal prolongation of the RR and QT intervals. The contrast media used for arteriography included meglumine sodium diatrizoate, iopamidol, iohexol, and meglumine sodium ioxaglate. Diatrizoate caused the greatest electrocardiographic changes. Among the low osmolality contrast media, ioxaglate caused the smallest bradycardial effect and iohexol the smallest prolongation of the QT interval. It appears necessary to consider some additional factors for osmolality or ionicity, such as the chemotoxicity of the chemical structure of the iodinated contrast medium moiety, when assessing their potential adverse effect on the cardiac conduction system.

Effect of contrast media on RBC filterability studied with nickel mesh filtration

Effect of contrast media on RBC filterability studied with nickel mesh filtration

Effects of Contrast Media on the RR and QT Interval during Coronary Arteriography

Effects of Contrast Media on the RR and QT Interval during Coronary Arteriography