Impact of technetium-99m sestamibi imaging on the emergency department management and costs in the evaluation of low-risk chest pain

Objectives: To assess the impact of rest sestamibi scanning on emergency ph ysicians' (EPs') diagnostic certainty and decision making (as assessed by t he hypothetical disposition of patients) for 69 consenting stable patients with suspected acute cardiac ischemia and nondiagnostic electrocardiograms. The resultant impact on costs was examined as a secondary outcome. Methods : Patients with suspected acute cardiac ischemia were injected with 25 mCi of sestamibi within two hours of active pain in one of three emergency depa rtment study sites. The probability of acute myocardial infarction (AMI) an d unstable angina (UA), and hypothetical disposition decisions were recorde d immediately before and after physicians were notified of scan results. Ch anges in disposition were classified as optimal or suboptimal. For the cost determinations, a cost-based decision support program was used. Results: F or the subgroup found to be free of acute cardiac events (ACEs) (n = 62), t he EPs' post-sestamibi scan probabilities for AMI decreased by 11% and UA b y 18% (p < 0.001 for both conditions). In seven patients with ACEs, the pos t-scan probabilities of AMI and UA increased, but neither was statistically significant. Scan results led to hypothetical disposition changes in 29 pa tients (42%), of which 27 (93%) were optimal (nine patients were reassigned to a lower level of care, two to a higher level, and 16 additional patient s to "discharge-home" status). The strategy of scanning all patients who we re low to moderate risk for acute cardiac ischemia would result in an incre ase of direct costs of care of $222 per patient evaluated, due to added cos t of sestamibi scanning. Conclusions: Sestamibi scanning results appropriat ely affected the EPs' estimates of the probability of AMI and UA and improv ed disposition decisions. Scanning all low-risk patients would likely be as sociated with increased costs at this medical center.