Diagnosing acute cardiac ischemia in the emergency department: A systematic review of the accuracy and clinical effect of current technologies

Study objective: Acute cardiac ischemia (ACI) encompasses the diagnoses of unstable angina pectoris and acute myocardial infarction (AMI). Accurate di agnosis and triage of patients with ACI in the emergency department should increase survival for these patients and reduce unnecessary hospital admiss ions. Methods: We conducted a systematic review of the English-language literatur e published between 1966 and December 1998 on the accuracy and clinical eff ect of diagnostic technologies for ACI. We evaluated prospective and retros pective studies of adult patients who presented to the ED with symptoms sug gesting ACI. Outcomes were diagnostic performance (test sensitivity and spe cificity) and measures of clinical effect. Meta-analyses were performed whe n appropriate. A decision and cost-effectiveness analysis was conducted tha t investigated Various diagnostic strategies used in the diagnosis of ACI i n the ED. Results: We screened 6,667 abstracts, reviewed 407 lull articles, and inclu ded 106 articles in the main analysis. Single measurements of biomarkers at presentation to the ED have low sensitivity for AMI, although they have hi gh specificity. Serial measurements greatly increase the sensitivity for AM [ while maintaining their excellent specificity. Diagnostic technologies to evaluate ACI in selected populations, such as electrocardiography, sestami bi perfusion imaging, and stress EGG, may have very good to excellent sensi tivity; however, they have not been sufficiently studied. The Goldman Chest Pain Protocol has good sensitivity (about 90%) for AMI but has not been sh own to result in any differences in hospitalization rate, length of stay, o r estimated costs in the single clinical effect study performed. Its applic ability to patients with unstable angina pectoris has not been evaluated. T he use of an Acute Cardiac Ischemia-Time-Insensitive Predictive instrument led to the appropriate triage of 97% of patients with ACI presenting to the ED and reduced unnecessary hospitalizations, Conclusion: Many of the current technologies remain underevaluated, especia lly regarding their clinical effect. The extent to which combinations of te sts mail provide better accuracy than any single test needs further study. [Lau J, loannidis JPA, Baik EM, Milch C, Terrin N, Chew PW, Salem D. Diagno sing acute cardiac ischemia in the emergency department: a systematic revie w of the accuracy and clinical effect of current technologies.