Aneurysmal subarachnoid hemorrhage (aSAH) is the most deadly kind of stroke. Each year, 40,000 Americans have SAH. Case-fatality approaches 60% and more than half of those who die do so before reaching the hospital. Most commonly, SAH results from rupture of an intracranial aneurysm. Screening high-risk individuals could identify those at greatest risk and decrease the devastating effect of SAH. Aortic Aneurysm also constitutes a major public health problem with high lethality. Current estimates are that ruptured aortic aneurysm kills 13,000 Americans each year. Screening efforts have effectively lowered mortality from aortic aneurysm rupture but a high proportion of those who die did not have a diagnosis of aortic aneurysm prior to rupture.
The relationship between intracranial and aortic aneurysm has long been recognized, but poorly quantified. Recent genome-wide association studies (GWAS) provide a molecular biological evidence for a shared pathophysiology. The chromosome 9p21 locus confers increased risk for both intracranial aneurysms and aortic aneurysms. These GWAS data, along with linkage data for other susceptibility loci, indicate that individuals and families harboring one type of aneurysm may be at especially increased risk of the other.
The rationale for this project is that opportunistic screening for abdominal aortic aneurysms (AAA) may be warranted in patients who present with aneurysmal subarachnoid hemorrhage. This study is meant to see if the yield of screening in this population is too low to justify its routine use. The investigators plan to systematically screen for AAA in all cases of aSAH presenting to MCH for treatment. If no individual out of 81 consecutively screened cases of aSAH has evidence of AAA, then the investigators can have strong confidence that there is a less than 5% chance of finding an AAA in the patient population.