title: Cost-effectiveness of digital subtraction angiography in the setting of computed tomographic angiography negative subarachnoid hemorrhage.
abstract: BACKGROUND
  Recent studies have documented the high sensitivity of computed tomography angiography (CTA) in detecting a ruptured aneurysm in the presence of acute subarachnoid hemorrhage (SAH). The practice of digital subtraction angiography (DSA) when CTA does not reveal an aneurysm has thus been called into question.
  
  
  OBJECTIVE
  We examined this dilemma from a cost-effectiveness perspective by using current decision analysis techniques.
  
  
  METHODS
  A decision tree was created with the use of TreeAge Pro Suite 2012; in 1 arm, a CTA-negative SAH was followed up with DSA; in the other arm, patients were observed without further imaging. Based on literature review, costs and utilities were assigned to each potential outcome. Base-case and sensitivity analyses were performed to determine the cost-effectiveness of each strategy. A Monte Carlo simulation was then conducted by sampling each variable over a plausible distribution to evaluate the robustness of the model.
  
  
  RESULTS
  With the use of a negative predictive value of 95.7% for CTA, observation was found to be the most cost-effective strategy ($6737/Quality Adjusted Life Year [QALY] vs $8460/QALY) in the base-case analysis. One-way sensitivity analysis demonstrated that DSA became the more cost-effective option if the negative predictive value of CTA fell below 93.72%. The Monte Carlo simulation produced an incremental cost-effectiveness ratio of $83 083/QALY. At the conventional willingness-to-pay threshold of $50 000/QALY, observation was the more cost-effective strategy in 83.6% of simulations.
  
  
  CONCLUSIONS
  The decision to perform a DSA in CTA-negative SAH depends strongly on the sensitivity of CTA, and therefore must be evaluated at each center treating these types of patients. Given the high sensitivity of CTA reported in the current literature, performing DSA on all patients with CTA negative SAH may not be cost-effective at every institution.
authors.affiliation: Department of Neurological Surgery, UMDNJ - New Jersey Medical School, Newark, NJ, USA. pinakin.jethwa.md@gmail.com
authors.forename: Pinakin R
authors.initials: PR
authors.lastname: Jethwa
authors.forename: Vineet
authors.initials: V
authors.lastname: Punia
authors.forename: Tapan D
authors.initials: TD
authors.lastname: Patel
authors.forename: E Jesus
authors.initials: EJ
authors.lastname: Duffis
authors.forename: Chirag D
authors.initials: CD
authors.lastname: Gandhi
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Prestigiacomo
mesh_terms: D015901:Angiography, Digital Subtraction / Q000191:economics*; D002533:Cerebral Angiography / Q000191:economics* / Q000379:methods; D003362:Cost-Benefit Analysis / Q000191:economics / Q000379:methods; D003661:Decision Support Techniques; D006801:Humans; D009010:Monte Carlo Method; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis / Q000191:economics*; D014057:Tomography, X-Ray Computed / Q000191:economics* / Q000379:methods