Prevalence of Previously Undiagnosed Abdominal Aortic Aneurysms in Patients with Intracranial Aneurysms: From the Brain and Aortic Aneurysms Study (BAAS).

Background: A relationship between intracranial and abdominal aortic aneurysms (AAA) has been appreciated through genome-wide association studies suggesting a shared pathophysiology. However, the actual prevalence of AAA in patients presenting with ruptured intracranial aneurysms is not known. Our aim was to estimate the prevalence of previously undiagnosed AAA in patients presenting with aneurysmal subarachnoid hemorrhage (aSAH) to see if it may be high enough to justify formally testing the utility of screening.
Methods: A prospective, observational inception cohort study of 81 consecutive patients presenting to Mayo Clinic Florida with aSAH was performed from August 14, 2011 to February 10, 2014. These individuals were then screened using an abdominal ultrasound technique for an AAA. Our primary end point was detection of AAA. Our secondary end points were 30-day good-to-fair functional status (modified Rankin scale < 4) and all-cause mortality.
Results: We detected an AAA in 10 patients (rate: 12%; 95% CI 6-22%) with aSAH. The mean diameter of these AAA was 3.4 ± 1.0 cm. Among these 10 patients, there was one death within the first month of aSAH hospitalization. There were no significant differences in demographic or clinical characteristics based on AAA detection status. Mean follow-up time was 4.7 years. The rate of good-to-fair functional status at 30-days was 79%. All-cause mortality during follow-up at 1-year was higher for patients with AAA (36%; 95% CI 0-61%) compared to patients without AAA (7%; 95% CI 1-14%) (log-rank p = 0.045).
Conclusions: The co-prevalence of AAA in patients presenting with ruptured brain aneurysms may be sufficiently high such that screening for AAA among likely survivors of aSAH might be appropriate. Larger studies would be needed to establish a net clinical benefit from screening AAA and then treating newly identified large AAAs in this morbid population.