Blood Pressure Reduction Does Not Reduce Perihematoma Oxygenation: A CT Perfusion Study

Abstract

for the ICHADAPT InvestigatorsBlood pressure (BP) reduction after intracerebral hemorrhage (ICH) is controversial, because of concerns that this may cause critical reductions in perihematoma perfusion and thereby precipitate tissue damage. We tested the hypothesis that BP reduction reduces perihematoma tissue oxygenation.Acute ICH patients were randomized to a systolic BP target of o150 or o180 mm Hg. Patients underwent CT perfusion (CTP) imaging 2 hours after randomization. Maps of cerebral blood flow (CBF), maximum oxygen extraction fraction (OEF max ), and the resulting maximum cerebral metabolic rate of oxygen (CMRO 2 max ) permitted by local hemodynamics, were calculated from raw CTP data.Sixty-five patients (median (interquartile range) age 70 (20)) were imaged at a median (interquartile range) time from onset to CTP of 9.8 (13.6) hours. Mean OEF max was elevated in the perihematoma region (0.44 ± 0.12) relative to contralateral tissue (0.36±0.11; Po0.001). Perihematoma CMRO 2 max (3.40±1.67 mL/100 g per minute) was slightly lower relative to contralateral tissue (3.63±1.66 mL/100 g per minute; P ¼ 0.025). Despite a significant difference in systolic BP between the aggressive (140.5 ± 18.7 mm Hg) and conservative (163.0 ± 10.6 mm Hg; Po0.001) treatment groups, perihematoma CBF was unaffected (37.2±11.9 versus 35.8±9.6 mL/100 g per minute; P ¼ 0.307). Similarly, aggressive BP treatment did not affect perihematoma OEF max (0.43±0.12 versus 0.45±0.11; P ¼ 0.232) or CMRO 2 max (3.16±1.66 versus 3.68±1.85 mL/100 g per minute; P ¼ 0.857). Blood pressure reduction does not affect perihematoma oxygen delivery. These data support the safety of early aggressive BP treatment in ICH.

Intensive Blood Pressure Lowering in Intracerebral Hemorrhage

“…However, focused studies have not confirmed any such harm by showing no significant relationship between BP lowering and cerebral blood flow or oxygenation in the perihematomal region or cerebral hemispheres in ICH patients [2]. …”

Perihematomal Diffusion Restriction in Intracerebral Hemorrhage Depends on Hematoma Volume, But Does Not Predict Outcome

“…However, the degree of perfusion delay did not reach the threshold for true ischemia, as observed in ischemic stroke [26][27][28] . PET and CT perfusion studies on the metabolism of the perihematomal region demonstrated reduced oxygen extraction fraction and cerebral metabolic rate of oxygen, indicative of reduced metabolic demands rather than ischemia [29,30] . Considering these observations, true ischemic injury in the perihematomal zone is thought to be unlikely.…”

Altered Long Noncoding RNA and Messenger RNA Expression in Experimental Intracerebral Hemorrhage - a Preliminary Study

“…A high enrichment score on the mitochondrial matrix indicates that the cerebral tissue is still in a state of overactive energetic metabolism. It is demonstrated that there is no marked cerebral blood flow reduction or hypoxia following ICH [37]. Thus, under adequate oxygen supply one glucose molecule will generate 36 molecules of adenosine triphosphate (ATP) by proton flow via ATP synthase [38].…”