Screening for intracranial aneurysms after subarachnoid hemorrhage: do our patients benefit?

Abstract

Despite ongoing advances in the medical, surgical, and endovascular management of subarachnoid hemorrhage (SAH) and its complications, the short-term case fatality rate and morbidity continues to be substantial.1 In addition to optimizing acute SAH management, strategies for reducing the impact of SAH include 1) identifying and treating environmental or genetic factors that cause brain aneurysm formation or SAH and 2) defining a cost-effective aneurysm screening program for a carefully selected patient population that decreases long-term morbidity and mortality among those screened. Previously, the only means of aneurysm screening was by cerebral arteriography, a diagnostic study not without risks.2 CT angiography (CTA)3 and MRA4 now provide widely available, noninvasive highly sensitive and specific screening modalities. After aneurysm detection, management is enhanced by the availability of large, multicenter, prospective natural history data,5,6⇓ clinical trials,7 and evolving interventional options with aneurysm coiling and clipping. So methods of screening are available, as are some of the data needed to guide management after screening has detected an intracranial aneurysm. What is not clear is whether our patients benefit from screening, or on the contrary, whether routine screening may be detrimental to our patients’ long-term well being. In this issue of Neurology , Wermer et al. report a well-constructed decision model evaluating screening vs no screening for aneurysm in the years after a ruptured aneurysm is treated.8 A Markov chain decision model9 is used, which considers the likelihood of a patient moving from one health status to another. The modeling mandates that accurate data be available regarding the likelihood of developing each of the conditions that put the patient at risk for having any outcome of interest. For aneurysm screening following initial subarachnoid hemorrhage, some of the key baseline risks or so-called “transitional probabilities” include the risk …