Ischemic core volumes and collateral status have diurnal fluctuations – A retrospective cohort study of 18,137 patients

Abstract

IntroductionRecent observations suggest that circadian rhythms are implicated in the timing of stroke onset and the speed of infarct progression. We aimed to replicate these observations in a large, multi-center, automated imaging database. MethodsThe RAPID Insights database was queried from 02/01/2016 to 01/31/2022 for patients with perfusion imaging and automated detection of an ischemic stroke due to a presumed large vessel occlusion. Exclusion criteria included: patient age ≤25, mismatch volume of <0 cc, and failure to register a positive value on either relative cerebral blood flow (rCBF) reduction of 38% less than normal or total mismatch volume. Imaging time was subdivided into three epochs: Night: 23:00h-06:59h and Day: 07:00h-14:59h, and Evening: 15:00h-22:59h. Perfusion parameters were defined using standard conventions for core volume, penumbra, and collateral circulation (measured via the Hypoperfusion Intensity Ratio, HIR). Statistical significance was tested using a sinusoidal regression analysis. ResultsA total of 18,137 cases were analyzed. The peak incidence of stroke imaging of patients with LVOs occurred around noon. A sinusoidal pattern was present, with larger ischemic core volumes and higher HIR during the night compared to the day: peak ischemic core volume of 23.4 cc occurred with imaging performed at 3:56 AM (p<0.001) and peak HIR of 0.35 at 3:40 AM (p<0.001). ConclusionWe found that ischemic core volumes were larger and collateral status worse at nighttime compared to daytime in this large national database. These findings support prior data suggesting that poor collateral recruitment with subsequent larger ischemic stroke volumes may occur at night.