Introduction: The popularity of using CT Angiography (CTA) to identify an aneurysm as the source of a spontaneous subarachnoid hemorrhage (SAH) has been increasing in recent years. The ability to non-invasively characterize a ruptured aneurysm and make earlier treatment decisions are obvious advantages to this technology; however, with the increasing frequency of endovascular treatments for ruptured aneurysms, some have argued that this practice is an unnecessary use of time and resources. We explored this issue using from a cost-effectiveness perspective.
Methods: A two-armed decision tree was created using TreeAge Pro Suite 2012; comparing SAH follow up with Digital Subtraction Angiography (DSA) or CTA. Based on an extensive literature review, costs and utilities were assigned to each potential outcome accounting for screening methods, treatment modalities, and complications. Sensitivity analysis was performed to determine the most significant variables in the model and 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: For our model we assumed a 25% aneurysm clipping rate and a 95% CTA sensitivity based on our recent institutional data. In the base case scenario (all variables kept at the mean value of their distribution), DSA was found to be the more cost-effective screening test. Sensitivity analysis revealed that CTA became the more cost-effective screening when the proportion of aneurysms clipped was greater than 28.7%. The results of the 10,000-iteration Monte Carlo simulation revealed that DSA was the more cost-effective strategy in 64.6% of cases.
Conclusions: The most important factor in determining the cost-effectiveness of CTA as a screening test for ruptured aneurysms is the proportion of cases that are ultimately treated with microsurgical clipping. Our model suggests that the threshold for which CTA would be more cost-effective is a clipping rate of = 28.7%.
Patient Care: Participants will be able to analyze their own practice and determine, based on the parameters presented in this model, if changes can be made to make care of patient with ruptured aneurysms more cost-effective.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Understand the basic principles of cost-effectiveness research and its application to the problem analyzed.
2) Identify the key variables affecting the choice of screening test for a ruptured aneurysm.
3) Review their own data to determine if their institutional data is consistent with cost-effective care.