Perihematomal oligemia is associated with progression to ischemia and poor outcome in a subset of patients with intracerebral hemorrhage

Objectives: We aimed to characterize the longitudinal evolution of perihematomal oligemia in acute intracerebral hemorrhage (ICH). Materials and methods: A single center prospectively collected cohort of 150 patients with primary spontaneous ICH were imaged with computed tomography perfusion within 6 h from onset (T0), at 24 h (T1) and at 7 days (T7). Perihematomal cerebral blood flow (pCBF) was measured in the manually outlined perihematomal low-density area and categorized into ischemic (< 20 mL/100 g/min), oligemic (20–39.9 mL/100 g/min), normal (40–55 mL/100 g/min) and hyperemic (> 55 mL/100 g/min). Results: pCBF values were ischemic in 20.7%, oligemic 47.3%, normal in 17.3%, and hyperemic in 14.7% of patients at T0. All patients with T0 ischemia remained ischemic at T7, normal and hyperemic patients at T0 maintained good perfusion values at T7, whereas 46.5% of oligemic patients at T0 developed delayed perihematomal ischemia. In patients with T0 perihematomal oligemia, the risk of conversion into delayed ischemia at T7 was higher in those with pCBF < 30 mL/100 g/min (p < 0.001). A total of 42.7% patients had perihematomal ischemia at T7 and this profile correlated with poor outcome, regardless of baseline perfusion status. Conclusion: Our findings suggest that perihematomal oligemia may not represent a benign entity and indicate that delayed perihematomal ischemia is common and associated with unfavorable outcome. Key Points: Question The natural history and longitudinal evolution of perihematomal oligemia over time in patients with intracerebral hemorrhage (ICH) remains to be established. Findings Conversion of baseline perihematomal oligemia into ischemia occurs in 46.5% of oligemic ICH patients at 7 days, where a total of 42.7% patients were ischemic. Clinical relevance Evolution of perihematomal oligemia into ischemia during the transition from hyperacute to subacute phases is common. ICH patients with perihemorrhagic cerebral blood flow values < 30 mL/100 g/min are at high risk of ischemic progression, which in turn contributes to poor outcome.