ELEVATED RISK OF ANAPHYLACTOID REACTION FROM RADIOGRAPHIC CONTRAST-MEDIA IS ASSOCIATED WITH BOTH BETA-BLOCKER EXPOSURE AND CARDIOVASCULAR DISORDERS

Background: A case-control study, with both retrospective and concurre nt subject selection, was performed (1) to determine whether greater r isk for anaphylactoid reaction from contrast media associated with bet a-blocker exposure reflects presence, or is independent of underlying cardiovascular disorder; and (2) to characterize further the risk of a naphylactoid reaction from contrast media in patients with cardiovascu lar disorders and patients with asthma. Methods: Adverse reactions fro m intravenous contrast media were recorded in accordance with quality assurance guidelines. Anaphylactoid reactions were classified as mild to moderate (urticaria/angioedema), severe (stridor, bronchospasm, or hypotension), or major and life-threatening (hypotension with or witho ut the need for subsequent hospitalization). Medical records from reac tors were compared with those from matched (gender, age, date, and typ e of contrast study) controls who received conventional contrast media without adverse reaction.Results: Of 34 371 intravenous contrast medi a procedures performed, 122 anaphylactoid reactions were recorded. The risk of anaphylactoid reaction was significantly associated with asth ma (odds ratio [OR], 8.74; 95% confidence interval [CI], 2.36 to 32.35 ; P=.0012). The risk of bronchospasm was associated with beta-blocker exposure (OR, 3.73; 95% Cl, 1. 18 to 11.75; P=.025) and with asthma (O R, 16.39; 95% Cl, 4.30 to 62.46; P=.0001). The risk of major and life- threatening reaction was associated with the presence of cardiovascula r disorder (OR, 7.71; 95% CI, 1.04 to 57.23; P=.046). Among patients w ith severe reactions, the risk of hospitalization was elevated by the presence of cardiovascular disorder (P=.001), exposure to beta-blocker s (OR, 7.67; 95% Cl, 1. 79 to 32.85; P=.029), or asthma (OR, 20.7; 95% Cl, 1.21 to 355.55; P=.065). Although beta-blocker exposure and the p resence of cardiovascular disorder were highly associated (chi2=49, P< .001), a greater risk of bronchospasm with severe reaction was observe d in nonasthmatic patients with cardiovascular disorders receiving bet a-blockers (OR, 15.75; P=. 02 3). Among reactors with asthma, receivin g beta-blockers, or with a cardiovascular disorder, 60.8% (31/51) expe rienced severe anaphylactoid reactions, compared with 35.2% (25/71) of patients without these risk factors (OR, 3.62; P=.005). Conclusions: Beta-Blocker exposure and cardiovascular disorder are both statistical ly significant risk factors for severe anaphylactoid reaction from con trast media. Thus, patients receiving beta-adrenergic blockers and pat ients with asthma, on the basis of greater risk for bronchospasm, and patients with cardiovascular disorders, on the basis of elevated risk of major and life-threatening reaction, are appropriate target populat ions for risk reduction measures before receiving intravenous infusion of contrast media.