Intracranial Aneurysms in Sickle Cell Disease

Background: The exact causes of intracranial aneurysms (IAs) are still unknown. However, certain diseases are known to be associated with IAs. Objective: To analyze the differences in IA characteristics in the general population and in individuals with sickle-cell disease (SCD). Methods: We systematically searched PubMed, Scopus, Web of Science, and Cochrane Library for Data on SCD patients with IAs. We compared IA characteristics of SCD patients with those from 2451 healthy IA carriers from our observational cohort. Results: 129 SCD patients with IAs were identified in 42 studies. The SCD patient cohort was characterized by younger age (mean 27.1 vs 54.9 years, p<0.0001) and lower female prevalence (57.7% vs 68.4%, p=0.0177). The prevalence (47% vs 34.5%, p=0.004) and the number (3.02 vs 2.56 IAs/patient, p=0.004) of multiple IAs were also higher in the SCD cohort. Unruptured IAs (3.27 vs 6.16 mm, p<0.0001), but not ruptured IAs (7.8 vs 7.34 mm, p=0.9086) were significantly smaller in the SCD cohort. In addition, IAs were more frequently located in the internal carotid artery (45% vs 29%, p<0.0001) or posterior circulation (43% vs 20%, p<0.0001). Higher age (≥30 years, p=0.007), IA size ≥7 mm (p=0.008), and location in posterior circulation (p=0.01) were independently associated with subarachnoid hemorrhage in SCD. Conclusion: There is a distinct demographic and radiographic pattern of IA in SCD. Risk factors for IA rupture in SCD are mostly congruent with those in healthy individuals.