Autoregulation of cerebral blood flow is preserved in primary intracerebral hemorrhage

Background and Purpose-Treatment of acute hypertension after intracerebral hemorrhage (ICH) is controversial. In the context of disrupted cerebral autoregulation, blood pressure (BP) reduction may cause decreased cerebral blood flow (CBF). We used serial computed tomography perfusion to test the hypothesis that CBF remains stable after BP reduction. Methods-Patients recruited within 72 hours of ICH were imaged with computed tomography perfusion before and after BP treatment. Change in perihematoma relative (r) CBF after BP treatment was the primary end point. Results-Twenty patients were imaged with computed tomography perfusion at a median (interquartile range) time from onset of 20.2 (25.7) hours and reimaged 2.1 (0.5) hours later, after BP reduction. Mean systolic BP in treated patients (n=16; 4 untreated as BP<target at baseline) decreased significantly between the first (168±21 mm Hg) and second (141±19 mm Hg; P<0.0001) computed tomography perfusion scans. The primary end point of rCBF was not affected by BP reduction (pretreatment=0.89±0.11; post-treatment=0.87±0.11 mL/100 g per minute; P=0.37). Linear regression showed no relationship between changes in systolic BP and perihematoma rCBF (β=0.001 [.0.002 to 0.003]; P=0.63). Conclusions-CBF remained stable after acute BP reduction, suggesting some preservation of cerebral autoregulation.