Clinical usefulness and cost of echocardiography in patients admitted to a coronary care unit

The usefulness and cost of echocardiography was evaluated in 133 consecutive patients admitted to the Coronary Care Unit. A useful echocardiogram was one that provided new information, which influenced diagnosis, prognosis, or treatment. The cost of a useful echocardiogram was defined as the unit cost ($476 the Medicare global fee) x units (i.e., total echocardiograms / useful echocardiograms). Admission diagnoses were unstable angina (34%), arrhythmia (14%), congestive heart failure (8%), postprocedure monitoring (7%), acute myocardial infarction (6%), and miscellaneous (20%). The echocardiogram provided new information in 29% of patients. Patients without a recent echocardiogram (within 3 months) were twice as likely to have a useful echocardiogram (33 of 99, 33%) as those with a recent echocardiogram (5 of 34, 15%, p <0.05). A cardiologist predicted the overall usefulness of echocardiography with a positive predictive accuracy of 52% and a negative predictive accuracy of 94% (p < 0.0001). The overall cost of a useful echocardiogram of 3.5 units or $1,666 per useful study was decreased to $904 (1.9 units) if only studies predicted to be useful were considered. The usefulness of echocardiography varied significantly (p <0.02) within the admitting diagnostic categories. The usefulness of an echocardiogram was underestimated in patients with congestive heart failure, where it was found to be most useful (64%; $762 or 1.6 units). Thus, usefulness relates to the admission diagnosis, the availability of a recent echocardiogram, and to clinical judgment.