When patients go to the emergency department (ED) with chest pain, more than half will not have coronary artery disease (CAD). Some patients are admitted to observation units (OUs) where physicians can rule out any problems in low-risk patients. This type of chest-pain evaluation is cost-effective compared with standard hospital admission. However, when low-risk patients complete their OU evaluation with a positive or indeterminate stress test, they are admitted to the hospital and often undergo cardiac catheterization with negative results (i.e., less than 50 percent stenosis, absence of three-vessel disease, and no percutaneous intervention completed) which, in turn, significantly increases costs.
The researchers retrospectively studied the charts of 1,194 patients admitted to the OU over a period of 9 months. Chart reviews were conducted on all patients with positive and indeterminate stress tests and on a sample of patients with negative stress tests. The majority of study patients (90.8 percent) had negative stress tests. Of the 59 patients who underwent cardiac catheterization, 41 were negative. The prevalence of positive or indeterminate stress tests with negative catheterization among all OU stress test patients was 3.4 percent. The prevalence of significant CAD at cardiac catheterization was 1.5 percent.
Costs increased across the board for patients with positive or indeterminate stress tests and subsequent negative catheterizations. When compared with costs for patients with negative stress tests, these patients had increases in ED ($520 vs. $467) and OU ($440 vs. $307) costs, total costs ($7,298 vs. $1,562), and total charges ($23,499 vs. $6,973). The researchers indicate that studies are needed to determine the effectiveness and cost/benefit of other methods to risk stratify patients with lost-risk chest pain.
The study was supported in part by the Agency for Healthcare Research and Quality (HS00078).
See "Diagnostic uncertainty and costs associated with current emergency department evaluation of low risk chest pain," by Rahul K. Khare, M.D., F.A.C.E.P., Emilie S. Powell, M.D., M.B.A., Arjun K. Venkatesh, M.B.A., and D. Mark Courtney, M.D., F.A.C.E.P., in the September 2008 Critical Pathways in Cardiology 7, pp. 191-196.