Abstract W P124: Atherosclerosis Of The Circle Of Willis Is Strongly Associated With Downstream Cerebral Amyloid Angiopathy In Parenchymal Arterioles And Capillaries: Possible Mechanism For Atherosclerosis-related Intracranial Hemorrhage

Abstract

Introduction: Atherosclerosis is highly associated with risk for intracranial hemorrhage. Presumed mechanisms include artery to artery embolization, arteriolar disruption by small vessel atherosclerosis, aberrant angiogenesis in poorly perfused vascular beds, and possible involvement of downstream cerebral amyloid angiopathy (CAA). Direct associations between atherosclerosis and downstream CAA have been not been supported in most studies, however these results may be confounded by the distinction between highly prevalent meningeal CAA and less frequent parenchymal CAA. Hypothesis: We hypothesized that large vessel intracranial atherosclerosis would be associated with downstream parenchymal, but not meningeal (supplied by extracranial circulation), CAA. Methods: Data were derived from the University of Kentucky brain bank (n=741). Atherosclerosis of the circle of Willis was graded on semiquantitative scale (1=0-25% occlusion; 2=25-50% occlusion; 3=50-75% occlusion; 4=75-100% occlusion). Cases were divided into those with absent (with or without meningeal CAA; n=493) and those with parenchymal CAA (n=248). Standard descriptive and comparative statistics were used for the analysis. Results: Atherosclerosis in the circle of Willis was highly associated with parenchymal (p<0.001), but not meningeal CAA. Conclusions: The strong association seen between severity of atherosclerosis and parenchymal CAA suggests possible shared pathogenesis or perhaps causal development of CAA by high grade atherosclerosis. Further studies exploring this association in animal models would be helpful in clarifying this complex relationship.