SAFETY AND CRITERIA FOR SELECTIVE USE OF LOW-OSMOLALITY CONTRAST FOR CARDIAC ANGIOGRAPHY

OBJECTIVES. Recommendations to restrict low-osmolality contrast to hig h-risk patients having cardiac angiography have been challenged becaus e of safety and uncertainty about selection criteria. The authors docu ment frequency and severity of adverse events with diagnostic cardiac angiography under the influence of guidelines for selective use of low -osmolality contrast in highrisk patients and refine high-risk criteri a. METHODS. Subjects of this prospective cohort study were 7,448 unsel ected patients having diagnostic cardiac angiography in St. John's, Ne wfoundland or Ottawa, Ontario. Measures included prespecified risk fac tors, procedure, contrast, and adverse events such as death within 24 hours, myocardial infarction, stroke, arrhythmias, hypotension, and an aphylactoid reactions. RESULTS. Patients were similar at both sites. F ourteen point two percent received low-osmolality nonionic agents in S t. John's. Thirty-four point one percent received low-osmolality (most ly ionic) media in Ottawa. Overall adverse event rates were similar at both sites: death, 0.07%; myocardial infarction or stroke, 0.03%; mod erate events, 2%; and mild events, 16.8%. Event rates were low in thos e given high-osmolality media: death, 0.02%; myocardial infarction or stroke, 0.24%; moderate events, 1.6%; and mild events, 18%. The risk w ith cardiogenic shock and prior severe reaction to contrast could not be examined, but otherwise only current heart failure and markers of r ecent ischemia were associated with events after high-osmolality media . CONCLUSIONS. Clinicians, using guidelines, can identify high-risk pa tients and should be able to safely limit use of low-osmolality media to them.