Pretreatment with corticosteroids to alleviate reactions to intravenous contrast material

Feasibility of outpatient coronary angiography with "ad hoc" angioplasty

To assess the feasibility and safety of coronary angiography combined, where necessary, with ad hoc angioplasty in an outpatient setting; a prospective, single-center study. The first 172 patients (154 men, 59 +/- 11 years) considered at low risk for complications were enrolled for outpatient-coronary angiography with or without angioplasty via a radial approach. The inclusion criteria were clinical, not based on angiography. After angiography/angioplasty, creatinine and troponin were assayed (outside the hospital) within 24h and patients were telephoned and asked about their clinical condition. Angioplasty was performed in 69 (40%) patients and 130 patients (75.6%) were discharged on the same day. In the angioplasty group, a history of coronary dilatation was more common in patients discharged on the same day (p = 0.05), whereas bifurcation lesions were more frequent in subjects who were kept in hospital (p < 0.0001). No serious complications occurred during the study. Of the 42/172 prolonged hospitalizations, eight were due to minor procedural complications, five due to failure of the radial route and three for indications for bypass surgery; the others were kept in for reasons unrelated to a complication (e.g., the examination was performed late in the day, a particularly complex procedure, etc.). Four (3%) of the 24-hour telephone calls led to a visit, but not hospital admission. Overall, performing angiography and "ad hoc" angioplasty in the course of a single outpatient visit makes it possible to foreshorten the hospital stay and increase patient throughput with a given hospital capacity and, this, without increasing clinical risk. Exactly how these patients are selected remains to be defined and may certainly be improved compared to this initial experiment. An outpatient-coronary angiography and ad hoc angioplasty strategy is a viable option with a low risk for patients selected on the basis of simple clinical criteria. It combines the advantages of increased convenience for the patient and lower costs.

Adverse reactions to intravenous iodinated contrast media: an update

Assessment of patients before intravenous contrast injection can help in detecting predisposing risk factors for adverse reactions to contrast media. Early recognition and treatment of acute adverse reactions can prevent morbidity and mortality (rare).

Maximizing clinical information obtained by CT

CT scanning is an integral part of the urologist's practice today. It is the most commonly used imaging modality and the one with which urologists are most familiar. CT urography, CT angiography, and 3D reconstruction enable the urologist to perform comprehensive evaluations of patients who have different urologic diseases, using a single imaging modality. It is thus prudent that urologists become familiar with CT applications, to maximize the clinical information available from them.

Current understanding of contrast media reactions and implications for clinical management

Iodinated contrast media (CM) are an integral part of modern diagnostic medicine. Although these agents are considered to be relatively safe, adverse effects in the form of allergy-like reactions occur in a significant number of exposed patients. These reactions may be divided into immediate and delayed responses. Immediate (within 1 hour of administration) anaphylactic reactions range from urticaria and angioedema to laryngeal oedema, hypotension and even death. Delayed reactions to CM occur from 1 hour to 1 week after administration and usually have mostly cutaneous manifestations. History of prior CM reactions and atopy predispose patients to CM reactions. Despite intense research into the pathogenesis of the immediate anaphylactoid responses, new evidence shows that true IgE type I hypersensitivity mediation occurs only in rare, severe cases. The aetiology appears to be multifactorial in most individuals. There is strong evidence to conclude that type IV hypersensitivity is responsible for the delayed reactions to CM. Although switching to non-ionic agents significantly reduces the incidence of immediate reactions to CM, there is little consensus regarding corticosteroid prophylaxis in high-risk individuals. Skin testing and provocative challenges also provide little security. Therefore, physicians must be better prepared to treat immediate anaphylactoid responses. Preventing delayed CM reactions is best performed with patch and delayed intradermal testing in those with a history of prior reactions, although false-negative results have been reported. Corticosteroids and antihistamines may be required for treatment. Until newer agents are developed that negate these issues, healthcare providers must strive to better understand the risk factors associated with CM reactions, as well as the available prophylactic and treatment options.

Adverse reactions to intravenous iodinated contrast media: a primer for radiologists

Adverse reactions to intravenous iodinated contrast media may be classified as general and organ-specific, such as contrast-induced nephrotoxicity. General adverse reactions may be subclassified into acute and delayed types. Acute general adverse reactions can range from transient minor reactions to life-threatening severe reactions. Non-ionic contrast media have lower risk of mild and moderate adverse reactions. However, the risk of fatal reactions is similar for ionic and non-ionic contrast media. Adequate preprocedure evaluation should be performed to identify predisposing risk factors. Prompt recognition and treatment of acute adverse reactions is crucial. Risk of contrast induced nephrotoxicity can be reduced by use of non-ionic contrast media, less volume of contrast, and adequate hydration. The radiologist can play a pivotal role by being aware of predisposing factors, clinical presentation, and management of adverse reactions to contrast media.

The prevention of anaphylactoid reactions to iodinated radiological contrast media: a systematic review

Background

Anaphylactoid reactions to iodinated contrast media are relatively common and potentially life threatening. Opinion is divided as to the utility of medications for preventing these reactions. We performed a systematic review to assess regimes for the prevention of anaphylactoid reactions to iodinated contrast media.

Methods

Searches for studies were conducted in the Medline, EMBASE, CINAHL and CENTRAL databases. Bibliographies of included studies and review articles were examined and experts were contacted. Randomised clinical trials that examined agents given prior to iodinated contrast material for the prevention of anaphylactoid reactions were included in the review. The validity of the included studies was examined using a component approach.

Results

Six studies met the inclusion criteria, but only one of these fulfilled all of the validity criteria. There were four studies that examined the use of H1 antihistamines, each was used to prevent anaphylactoid reactions to ionic contrast. The random effects pooled relative risk demonstrated a significant reduction in the overall rate of anaphylactoid reactions (RR = 0.4, 95% CI 0.18-0.9, p = 0.027). There were insufficient studies to produce a pooled statistic for the use of corticosteroids, however regimes of steroids (methylprednisolone 32 mg) given at least six hours and again two hours prior to the administration of contrast suggested a reduction in the incidence of anaphylactoid reactions.

Conclusion

In conclusion, there are few high quality randomised clinical trials that have addressed the question of the optimal methods to prevent allergic type reactions to iodinated radiological contrast media. Allowing for these limitations, the results suggest that H1 antihistamines given immediately prior to the administration of ionic contrast may be useful in preventing reactions to ionic contrast and are suggestive of a protective effect of corticosteroids when given in two doses at least six hours prior and again two hours prior to the administration of contrast, both ionic and non-ionic. These agents should be considered for use in patients who are at high risk of an anaphylactoid reaction to contrast media and for who prophylactic therapy is considered necessary. Further research is needed before definitive recommendations can be made.

ESUR guidelines on contrast media

Since 1996 the Contrast Media Safety Committee of the European Society of Urogenital Radiology has released 15 guidelines regarding safety in relation to the use of radiographic, ultrasonographic, and magnetic resonance contrast media. The guidelines have been well received by the radiologic community in Europe and all over the world and comprise current standards for good practice at many institutions. The present report is an overview of the work accomplished by the European Society of Urogenital Radiology over the past 8 years. The committee has covered renal and nonrenal adverse events and other aspects of contrast media.

Frequently asked questions: iodinated contrast agents

Although iodinated contrast agents are safe and widely used, adverse events occur and questions remain about their use, safety, and interactions. Some questions are easily answered and others still require extensive investigation. For one frequent question--is informed consent necessary before all contrast media injections--the simple answer is no. Another question concerns use of contrast media in patients with prior reactions or allergies. Contrast agents can be safely used in such patients, but special care must be taken to be aware of what the previous reaction was and to be ready to treat any reaction. The protective role of pre-treatment with steroids is well established for minor reactions, but they may not prevent major reactions. It is important to realize that even life-threatening, anaphylactoid reactions are not the result of a true allergy to contrast media. Many questions arise about contrast agent-induced nephropathy. Baseline serum creatinine values should be obtained in patients who are at risk, not all patients. The incidence and natural history of contrast agent-induced nephropathy remain unclear. It occurs only in patients with compromised renal function before contrast agent injection, but even patients with normal serum creatinine levels can have renal dysfunction. Calculated creatinine clearance is a better way to determine risk and to follow this complication. The outcome in almost all patients is benign, with progression to end-stage renal disease being rare. The major risk factors, in addition to renal dysfunction, are long-standing diabetes mellitus, dehydration, and use of other nephrotoxic medications. Recent work in preventing and ameliorating contrast agent-induced nephropathy with N-acetyl cysteine, substitution of an isosmolal nonionic contrast agent, and various hydration regimens has been promising. Another common concern is use of iodinated contrast agents in pregnant or breast-feeding women. In both cases, there is no evidence of harm to the fetus or infant, but it is prudent to weigh the theoretical risks and benefits and avoid contrast agent administration unless it is truly necessary.

Review article: Acute serious and fatal reactions to contrast media: our current understanding

Serious or fatal reactions to a contrast medium (CM) are unpredictable but fortunately rare. History of serious reaction to CM, bronchial asthma or multiple allergies increases the incidence of serious reactions by a factor of 5. Serious or fatal reaction to CM could be due to direct effect on basophils and mast cells or IgE mediated (type 1 hypersensitivity reaction). Activation of the kinin system leading to the formation of bradykinin could also be involved. Complement activation is unlikely to be a primary factor in initiating a serious reaction to CM. Avoiding CM administration in patients at high risk of serious reaction is advisable, but if the administration is deemed essential all precautions should be implemented and measures to treat serious reactions should be readily available. Oxygen supplementation, intravenous administration of physiological fluids and intramuscular injection of 0.5 ml adrenalin (1:1000) should be considered in the first line management of acute anaphylaxis. The ability to assess and treat serious CM reaction effectively is an essential skill that the radiologist should have and maintain.

Allergy-like reactions to iodinated contrast agents. A critical analysis

Allergy-like reactions may occur following administration of iodinated contrast media (CM), mostly in at-risk patients (patients with history of previous reaction, history of allergy, co-treated with interleukin-2 or beta-blockers, etc.) but remain generally unpredictable. Severe and fatal reactions are very rare events. All categories of CM may induce such reactions, although first generation (high osmolar CM) have been found to induce a higher rate of adverse events than low osmolar CM. However, no differences were found between the two categories of CM with respect to mortality. Delayed reactions can also occur. There are no differences between the various categories of CM except for non-ionic dimers, which are more likely to induce such effect. Numerous clinical studies have evaluated the prophylactic value of drugs (mostly antihistamines and corticosteroids). Results are unclear and highly variable. Any prevention depends upon the mechanism involved. However, the mechanism of CM-induced allergy-like reaction remains disputed. Relatively recent data revived the hypothesis of a type-I hypersensitivity mechanism. Positive skin tests to CM have been reported. However, the affinity of IgE towards CM has been found to be very low in the only study which actually evaluated it. Other pathophysiological mechanisms (involving direct secretory effects on mast cells or basophils, or activation of the complement system associated or not with the plasma contact system) are also much debated. Anaphylaxis and anaphylactoid reactions are, in the end, clinically undistinguishable.

Anaphylactoid reactions to radiocontrast media

Adverse reactions to contrast material are a concern because iodinated contrast materials are commonly used drugs. The risk for adverse reaction is 4% to 12% with ionic contrast materials and 1% to 3% with nonionic contrast materials. The risk for severe adverse reaction is 0.16% with ionic contrast materials and 0.03% with nonionic contrast materials. The death rate, one to three per 100,000 contrast administrations, is similar for both ionic and nonionic agents. More than 90% of adverse reactions with nonionic contrast materials are anaphylactoid. The types of severe reactions seen with nonionic contrast administration were initially predominantly anaphylactoid. With the advent of helical CT angiography, the reactions are now predominantly attributable to cardiopulmonary decompensation. With the widespread use of nonionic contrast materials, adverse reactions are now seen less frequently. Skills involved in evaluating and treating adverse reactions are not as frequently used. Periodic reviews and updates of specific treatment plans for various reactions with the physicians and staff who use contrast material are very important to ensure optimal preparedness. The key to successful treatment is preparation and early intervention.

Repeat survey of current practice regarding corticosteroid prophylaxis for patients at increased risk of adverse reaction to intravascular contrast agents

AIM

To compare the findings of a survey undertaken by us in 2002 regarding steroid premedication given in radiology departments to reduce the risk of adverse reactions in patients at increased risk of intravascular contrast media reactions with a similar survey published in 1994 by R. Seymour et al. The high risk patients considered in our survey were patients with history of asthma, drug allergies, hay fever and eczema.

MATERIALS AND METHODS

A total of 225 questionnaires were sent to the consultant in charge for audit for radiology departments from the list given by the Royal College of Radiologists. 175 of the 225 questionnaires were returned (response rate 77.8%) and of these 172 were analysed with respect to the type, dose and duration of steroids.

RESULTS

Compared to the survey in 1994, it was found that the number of departments who use steroid cover for all category of risk factors had increased compared to previous survey (73.8% in 2002 versus 55.3% in 1994 (p=0.001). There is now almost universal use of non-ionic contrast 98.8% versus 82.4% in 1994 (p=0.001). There is no agreed policy among radiology departments for the need or the dose or duration of steroid cover.

CONCLUSION

Despite the more widespread use of non-ionic contrast media, the use of steroid premedication has increased which is contrary to what is expected as the incidence of adverse reaction to non ionic media is less than ionic contrast media.

Safe administration of contrast media: what do physicians know?

BACKGROUND

Radiographic contrast media (RCM) are among the most commonly used materials in medicine. Nevertheless, there seems to be a little agreement between current practice and accepted guidelines regarding their adverse reactions, the indications for premedication, and use of low-osmolar contrast agents (LOCAs). Misconceptions exist regarding the relationship between hypersensitivity to RCM and foods and medications that contain iodine.

OBJECTIVE

To evaluate physicians' knowledge, misconceptions, and attitudes regarding the use of RCM and the prevention of their adverse reactions.

METHODS

Physicians from university-affiliated general hospitals were asked to complete an anonymous questionnaire on RCM.

RESULTS

A total of 157 physicians (45%), including radiologists, internists, pediatricians, surgeons, and primary family physicians, agreed to participate. All physicians demonstrated limited knowledge regarding adverse effects of RCM and the patients who might be at increased risk of developing them. Most physicians were not familiar with accepted guidelines for using premedication and LOCAs. Misconceptions regarding the association between the use of drugs or foods that contain iodine and adverse effects to RCM were common among all physicians.

CONCLUSIONS

The level of knowledge about the adverse reactions of RCM among physicians is unsatisfactory, which may result in unwarranted use of expensive LOCAs or premedication in healthy patients. Alternatively, physicians' failure to use these measures when indicated may endanger patients. Despite the lack of association between adverse effects to RCM and safe consumption of iodine-containing substances, physicians continue to harbor these misconceptions. Educational programs that may improve physicians' knowledge are urgently needed.

Postprocedure pain management of interventional radiology patients

Postprocedure pain management of patients after interventional procedures has to take into account residual drug actions from pre- and intraprocedure medications. A variety of sedatives, narcotics, local anesthetics, nonopioid analgesics, and nonsteroidal antiinflammatory agents can be adjusted to the patient's needs and risk factors. The article addresses the safe use of these agents in addition to reflections on assessment and the cognitive elements of the pain experience.

STUDIES ON EXPERIMENTAL IODINE ALLERGY: 3. LOW MOLECULAR WEIGHT ELICITOGENIC ANTIGENS OF IODINE ALLERGY

We hypothesize that iodine allergy is an immune response to iodinated self proteins produced in vivo from various iodine-containing chemicals. Since an antigenic determinant of experimental iodine allergy is diiodotyrosine (DIT), we designed low molecular weight DIT derivatives having provocative antigenicity without sensitizing immunogenicity. Tetraiododityrosine and hexaiodotrityrosine provoked dose-dependent skin reactions in guinea pigs previously immunized with iodine. No guinea pigs immunized with hexaiodotrityrosine showed anaphylactic reaction by i.v. challenge with hexaiodotrityrosine and none of their antisera showed positive passive cutaneous anaphylaxis (PCA) reaction in guinea pigs, indicating the non-immunogenic nature of the compound. Erythrosine, one of the color additives having a structure common with DIT, was assessed for its immunological property. Enzyme-linked immunosorbent assay (ELISA) inhibition studies on erythrosine revealed that the inhibitory activity of erythrosine was stronger than that of DIT. Furthermore, erythrosine provoked a PCA reaction in animals sensitized with anti-iodine antisera. In conclusion, hexaiodotrityrosine is thought to be useful for skin testing of iodine allergy without any fear of sensitization to the allergen. Erythrosine was shown to provoke an experimental iodine allergy and, also, the relationships between the new concept of iodine allergy and features of clinical findings of adverse effects by iodocontrast media are discussed.

Does prophylactic administration of corticosteroid reduce the risk and severity of post-ERCP pancreatitis: a randomized, prospective, multicenter study

BACKGROUND

Pancreatitis is the most common major complication of diagnostic and therapeutic ERCP. There have been continuing efforts to identify a pharmacologic agent capable of reducing the frequency and severity of this complication. On the basis of several case reports, experimental data, and knowledge of their mechanism of action, corticosteroids might be effective in this regard. The aim of this randomized, double-blind, controlled trial was to determine whether prophylactic, orally administered corticosteroid reduces the frequency and/or severity of post-ERCP pancreatitis.

METHODS

A total of 1115 patients were randomized to receive either prednisone (40 mg) or a placebo orally 15 hours and 3 hours before ERCP. A 160 variable database was prospectively collected according to a defined protocol on patients undergoing diagnostic or therapeutic ERCP at 15 centers in the Midwest Pancreaticobiliary Group. Standardized criteria were used to diagnose and grade the severity of postprocedure pancreatitis.

RESULTS

The overall frequency of pancreatitis was 15.07%. It occurred in 92 of 555 patients in the corticosteroid group (16.6%), and in 76 of 560 patients in the control group (13.6%; p = 0.19). The pancreatitis was mild in 10.04%, moderate in 4.04%, and severe in 0.99%. There was no difference between the groups with regard to the severity of pancreatitis. Moreover, the groups were similar with regard to age, gender, body mass index, frequency of prior pancreatitis, type of procedure performed (diagnostic or therapeutic), difficulty of cannulation, frequency of pre-cut sphincterotomy, pancreatic sphincterotomy, sphincter of Oddi dysfunction, sphincter of Oddi manometry, pancreatic acinarization, chronic pancreatitis, number of pancreatic duct injections, and bile duct diameter.

CONCLUSION

Prophylactic orally administered corticosteroid did not reduce the frequency or severity of post-ERCP pancreatitis.

Review article: Effects of radiographic contrast media on the lung

The pulmonary adverse effects of intravascular use of water soluble radiographic contrast media (RCM) include bronchospasm, pulmonary oedema and increase in the pulmonary arterial blood pressure (Ppa). Symptomatic bronchospasm is rare but subclinical increase in airways resistance is common after intravascular injection of RCM. Experimental studies have demonstrated that the low osmolar ionic dimer ioxaglate can induce significant bronchospasm in comparison with other types of RCM. Histamine and endothelin, which are potent bronchoconstrictors and released in response to the administration of RCM, do not seem to mediate the bronchospastic effect of RCM. Pretreatment with corticosteroids or antihistamine does not appear to prevent RCM induced bronchospasm, but the administration of beta(2) adrenergic agonist can abolish this adverse effect. RCM induced pulmonary oedema can be secondary to endothelial injury causing an increase in the permeability of the microcirculation. It may also occur in patients with incipient cardiac failure, when large doses of RCM particularly of the high osmolar type are used. A rise in Ppa induced by RCM seems to be secondary to an increase in pulmonary vascular resistance through direct effects on the pulmonary circulation. Low osmolar non ionic monomers induce the least changes in the pulmonary circulation and should be the contrast media of choice for intravascular use in patients with pulmonary hypertension. The mechanisms responsible for the effects of RCM on airway resistance and pulmonary circulation remain unclear. Intrabronchial administration of high osmolar water soluble RCM is dangerous and can induce severe bronchial irritation and pulmonary oedema. Low osmolar RCM are well tolerated by the lungs following aspiration with minimal histological reaction.

Intravenous hydrocortisone premedication reduces antibodies to infliximab in Crohn's disease: a randomized controlled trial

BACKGROUND & AIMS

We assessed the relationship between antibodies to infliximab (ATI) and the loss of response postinfliximab, infusion reactions and, in a randomized trial, investigated whether intravenous hydrocortisone premedication can reduce ATI.

METHODS

Initially, we prospectively evaluated clinical response, adverse events, and ATI levels in 53 consecutive patients with Crohn's disease who received 199 infliximab (5 mg/kg) infusions. Subsequently, 80 patients with Crohn's disease were randomized to intravenous hydrocortisone 200 mg or placebo immediately before their first and subsequent infliximab infusions. The primary endpoint was reduction in median ATI levels at week 16. Analysis was by intention to treat.

RESULTS

Nineteen of our initial 53 patients (36%) developed ATI, including all 7 patients with serious infusion reactions (median ATI level, 19.6 microg/mL). Eleven of 15 patients (73%) who lost their initial response were ATI positive compared with none of 21 continuous responders, (8.9 vs. 0.7 microg/mL, P < 0.0001). Administering a second infusion within 8 weeks of the first (OR, 0.13; 95% CI, 0.03-0.5; P = 0.0007) or concurrent immunosuppressants (OR, 0.19; 95% CI, 0.04-1.03; P = 0.007) significantly reduced ATI formation. In the placebo-controlled trial, ATI levels were lower at week 16 among hydrocortisone-treated patients (1.6 vs. 3.4 microg/mL, P = 0.02), and 26% of hydrocortisone-treated patients developed ATI compared with 42% of placebo-treated patients, P = 0.06.

CONCLUSIONS

Loss of initial response and infusion reactions post-infliximab is strongly related to ATI formation and level. Administering a second infusion within 8 weeks of the first and concurrent immunosuppressant therapy significantly reduce ATI formation. Intravenous hydrocortisone premedication significantly reduces ATI levels but does not eliminate ATI formation or infusion reactions.

Effective prophylactic protocol in delayed hypersensitivity to contrast media: report of a case involving lymphocyte transformation studies with different compounds

A patient with maculopapular reactions to iopamidol needed to undergo angiography for a cerebral arteriovenous malformation. In vivo and in vitro tests were performed with ionic and nonionic contrast media, including iopamidol and iobitridol. All results were positive, demonstrating delayed hypersensitivity. The patient received 6-alpha-methylprednisolone and cyclosporine 1 week before and 2 weeks after four angiograms were obtained with the use of iobitridol, which was well tolerated.

New advances in severe adverse drug reactions

Every new drug has the potential for causing cutaneous adverse drug reactions. Usually the clinical pattern is well known and has been described in association with other drugs; new entities, however, are described frequently. This article reviews several of them.

[Anaphylactoid reactions and late skin reactions to iodinated contrast media: present state of the question--idea development]

PURPOSE

Adverse reactions to iodinated contrast media (ICM) share various mechanisms. Anaphylactoid reactions are among the most serious reactions when they are characterized by the elevation of seric tryptase. Pretreatment with corticosteroids and anti-H1 or the use of non-ionic contrast media do not prevent anaphylaxis. Late skin reactions could be mostly related to delayed hypersensitivity. Previous reactions to contrast media, cardiovascular disorders, beta-blockers, asthma, and atopy are risk factors. Female gender and age increase the severity.

CURRENT KNOWLEDGE AND KEY POINTS

Anaphylaxis can be demonstrated by intradermal tests and the identification of specific IgEs. Delayed hypersensitivity is shown by the results of epicutaneous tests and the immunohistology of the skin.

FUTURE PROSPECTS AND PROJECTS

Allergologic tests are advised in the case of previous reactions. In case of emergency, gadopentetate dimeglumine can be alternatively used. The other risk factors lead to the combination of pretreatment and use of non-ionic monomeric contrast media. Immediate hypersensitivity to iodinated media might increase in the near future with the use of divalent molecules.

Leukodepletion and aprotinin improve clinical outcome after extracorporeal circulation

Most cardiac operations involve the use of extracorporeal circulation with its attendant systemic inflammatory response syndrome. Many anti-inflammatory strategies hold promise for reducing the associated morbidity of cardiopulmonary bypass. The application of pharmacological and mechanical strategies to control this inflammatory response now has demonstrable clinical benefit. The additional costs of these successful strategies are offset by the economic savings and improved quality of care.

Carbon dioxide angiography for endovascular grafting in high-risk patients with infrarenal abdominal aortic aneurysms

Allergic reactions to contrast media, preexisting renal dysfunction, and hyperthyroidism are relative contraindications for angiography with conventional contrast medium. Carbon dioxide (CO(2)) angiography is an alternative method in high-risk patients because CO(2) is nontoxic, without allergic potential, and not iodic. CO(2)-related complications are extremely rare. Because renal insufficiency often occurs in vascular patients, this method will become increasingly important for endovascular surgery. We report on three consecutive patients with asymptomatic infrarenal aortic aneurysm and concomitant renal dysfunction or allergic reactions to standard contrast media. Aortic stent grafts were deployed under CO(2) angiographic control without complications or worsening of renal function.

The effect of antihistamine, endothelin antagonist and corticosteroid prophylaxis on contrast media induced bronchospasm

Bronchospasm is a well recognized adverse reaction to radiographic contrast media (RCM) and may occur more frequently in asthmatics and atopics. This study was designed to identify RCM which are most likely to cause bronchospasm and to investigate underlying mechanisms mediating this response. Guinea pigs (mean body weight 550 g, n = 46) were anaesthetized with Hypnorm (5 ml kg-1) and Hypnovel (2 ml kg-1) and tracheal, jugular and pleural cannulae introduced. Total airways resistance (Raw) was calculated from the slope of the pressure/flow relationship. The effects of RCM (diatrizoate 370 mgI ml-1, ioxaglate 320 mgI ml-1, iotrolan 300 mgI ml-1 and iopromide 300 mgI ml-1) at a dose of 4 ml kg-1 body weight or control solutions matched for volume, pH and osmolarity administered via the jugular vein on Raw were studied. The effects of pre-treatment (30 min before the administration of RCM) with antihistamine (Mepyramine (30 mg kg-1 i.p.)) or non-selective endothelin receptor antagonist (SB209670 (1 mg kg-1 i.v.)) were investigated. The effectiveness of corticosteroids prophylaxis (prednisolone (20 mg kg-1 i.p.)) administered 18-24 h and 1 h pre-RCM was also assessed. Control animals received normal saline pre-treatment before RCM administration. Lungs were taken for histological examination 30-40 min post-administration of RCM. Only ioxaglate caused a significant (p < 0.05) increase in Raw (5.19 +/- 0.58 to 13.95 +/- 3.53 mmHg ml-1 min-1). Neither mannitol nor saline control solutions had any effect on Raw. Pre-treatment with Mepyramine, SB209670 or prednisolone caused no significant change in the ioxaglate induced increase in Raw. Histological examination of lung tissue from ioxaglate treated animals showed no important abnormalities. In summary, only the ionic dimer ioxaglate caused an increase in Raw. This effect was independent of osmolarity and could be the result of the chemical composition of the contrast agent. It was not an inflammatory response and could not be prevented by prophylactic treatment with antihistamine, endothelin antagonist or corticosteroids. The mechanisms responsible for the increase in Raw remain uncertain.

Adverse reactions to radiocontrast media in an Indian population

This study was conducted to determine the epidemiological characteristics and clinical presentation of adverse reactions to intravenous radiocontrast media (CM) in patients of Indian origin. 379 of 1798 patients who received either sodium iothalamate or sodium meglumine diatrizoate developed adverse reactions (i.e. 21.08% of patients). The incidence of mild, moderate and severe adverse reactions were 19.47%, 1.33% and 0.28%, respectively. One patient who developed a severe reaction expired. There were no differences in the incidence of adverse reactions according to gender (males 21.2%; females 20.8%; p = 0.907) or age (p = 0.876). The incidence of adverse reactions was significantly higher in patients with a history of previous reactions (45.5%) than in those with no history (20.9%; p = 0.046). The incidence of reactions was also significantly higher in patients with a history of predisposing factors such as bronchial asthma (69.2%) and diabetes mellitus (60.0%) than in those without such a history (20.6%; p = 0). The incidence of adverse reactions in patients who received premedication prior to CM administration because of a history of predisposing factors (21.4%) was not significantly different from that in patients who were not premedicated (21.2%; p = 0.974), a result probably due to inadequate premedication used in the study. The skin was the most commonly affected site of reaction.

Digital subtraction angiography of the abdominal aorta and lower extremities: carbon dioxide versus iodinated contrast material

PURPOSE

To compare the diagnostic value of carbon dioxide to that of iodinated contrast material for digital subtraction angiography of the abdominal aorta and lower extremities.

MATERIALS AND METHODS

Thirty-five patients underwent comparative CO2 and iodinated contrast material arteriography of the abdominal aorta and lower extremities. For each contrast study, three independent observers evaluated the degree of opacification and percentage of stenosis of each vessel, the degree of certainty of their observations, and the overall quality of the study. Data of CO2 and iodinated studies were compared using analysis of variance for repeated measures. Interobserver and intertechnique agreements were estimated with Cohen's kappa and intraclass correlation coefficient.

RESULTS

Iodine-based vascular opacification was superior to that with CO2 in the central and distal arteries (P = .02). The degree of certainty and overall quality score were higher for iodine than for CO2-based contrast studies (P = .00001). The interobserver agreement for categorizing stenoses was higher for iodine as compared to CO2-based angiography. No significant difference was observed between the mean stenosis values obtained with CO2 and iodine-based angiography in any segment. Intraclass correlation coefficient demonstrated a high degree of convergence of the two techniques for assessing the percentage of stenosis.

CONCLUSION

CO2 can be used as an alternative to iodinated contrast material for obtaining arteriograms of the abdominal aorta and lower extremities for investigating atherosclerotic disease.

Common allergic and allergic-like reactions to medications. When the cure becomes the curse

Adverse drug events are the leading cause of medical injury in hospitalized patients in the United States. The number of persons affected is roughly four times the total number killed in automobile accidents every year. The good news is that most adverse drug events are preventable through careful and thorough management. In the spirit of "First, do no harm," the authors of this article discuss common anaphylactic and allergic-like reactions to medications and what you can do to minimize the risks.