title: Cost-effectiveness of a novel indication of computed tomography of the coronary arteries.
abstract: OBJECTIVE
  A common strategy for excluding coronary artery disease among patients presenting with low-risk chest pain is observation unit (OU) admission with serial cardiac biomarkers and stress testing for cardiac risk stratification. Patients with positive- or indeterminate-stress tests are often admitted for cardiac catheterization despite a low likelihood of disease. The aim of this study is to estimate the cost-effectiveness of computed tomography of the coronary arteries (CTCA) in the OU for the evaluation of low-risk chest pain patients with indeterminate- or positive-stress test results.
  
  
  METHODS
  We conducted a decision analytic study to compare health outcomes and costs between 3 cardiac risk-stratification strategies in a population of patients at low cardiac risk admitted to the OU, who later had indeterminate- or abnormal-stress tests. Our population and test characteristics were based on data obtained both from the published literature and from a retrospective cohort review previously performed at our institution. The 3 strategies compared were (1) A CTCA strategy in which patients with positive- or indeterminate-stress tests subsequently underwent CTCA, and only received catheterization if results were positive, (2) A standard-of-care arm in which all patients with positive- or indeterminate-stress tests were admitted for catheterization, and (3) A do-nothing strategy in which all patients were discharged home after stress testing regardless of outcome. Outcomes measured were cost of care and life expectancy. Sensitivity analysis was performed with a multivariate Monte Carlo methodology.
  
  
  RESULTS
  Both the CTCA and standard-of-care strategies dominated the do-nothing strategy in the base case. When comparing the standard-of-care with the CTCA strategy, the incremental cost-effectiveness ratio was $3,423,309 per additional year of life gained. Sensitivity analysis showed that below a willingness to pay of $600,000 per additional year of life, CTCA was the most likely strategy to be cost-effective.
  
  
  CONCLUSIONS
  In this computer-modeled analysis, the addition of CTCA following positive- or indeterminate-stress tests to an OU cardiac risk-stratification pathway for low-risk chest pain patients achieved significant cost savings with a small decrease in life expectancy per patient. Adding CTCA after indeterminate- or positive-stress test results is a cost-effective intervention for further risk-stratifying low-risk chest pain patients in the OU setting before proceeding to traditional coronary angiography.
authors.affiliation: Department of Emergency Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA. emilie-powell@md.northwestern.edu
authors.forename: Emilie S
authors.initials: ES
authors.lastname: Powell
authors.forename: Brian W
authors.initials: BW
authors.lastname: Patterson
authors.forename: Arjun K
authors.initials: AK
authors.lastname: Venkatesh
authors.forename: Rahul K
authors.initials: RK
authors.lastname: Khare
mesh_terms: D006328:Cardiac Catheterization / Q000191:economics / Q000706:statistics & numerical data; D002637:Chest Pain / Q000175:diagnosis / Q000191:economics / Q000209:etiology; D017023:Coronary Angiography / Q000191:economics / Q000706:statistics & numerical data; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000191:economics / Q000628:therapy; D003331:Coronary Vessels / Q000473:pathology*; D017046:Cost Savings / Q000379:methods; D003362:Cost-Benefit Analysis / Q000379:methods; D019091:Critical Pathways / Q000191:economics / Q000592:standards; D003661:Decision Support Techniques; D019468:Disease Management; D004636:Emergency Service, Hospital / Q000191:economics / Q000706:statistics & numerical data; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care; D019057:Quality-Adjusted Life Years; D018570:Risk Assessment / Q000191:economics / Q000379:methods; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000191:economics / Q000706:statistics & numerical data