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Cost-effectiveness of computed tomographic angiography in screening for aneurysm in spontaneous subarachnoid hemorrhage.

S ubarachnoid hemorrhage (SAH) is a significant cause of morbidity and mortality in neurosurgical patients. The most common cause of spontaneous SAH is a ruptured intracranial aneurysm, accounting for roughly 75% to 85% of cases. The gold standard test for diagnosing and characterizing an aneurysm is a digital subtraction angiogram (DSA) with 3-dimensional rotational angiography of the cerebral vessels. Although DSA is a safe procedure, there are associated risks, including puncture site hematoma, contrast-induced nephropathy, and stroke. As a result, noninvasive tests have been developed to visualize and characterize intracranial aneurysms. Computed tomographic angiography (CTA) has gained popularity as an initial imaging test in patients with SAH because of its reportedly high sensitivity and specificity for detecting ruptured aneurysms. The noninvasive nature of CTA and the ease and rapidity with which the study can be performed are additional reasons for its acceptance in the workup of spontaneous SAH. Another advantage of CTA is that treatment decisions regarding endovascular coiling or microsurgical clipping can be made without a formal DSA on every patient. However, with the rise in the number of aneurysms being treated with coiling, some have argued that the practice of performing a CTA is an unnecessary use of time and resources because a diagnostic angiogram isperformed as part of the endovascular treatment. The purpose of this study is to perform a costeffectiveness analysis of 2 strategies for treating patients found to have spontaneous SAH using a decision treemodel. In 1 strategy, a spontaneous SAHwas followed up with a CTA, whereas in the other, it was followed up with a DSA. The parameters of the decision tree were then allowed to vary over plausible distributions to understand which strategy would be most cost-effective in different scenarios. METHODS