Autoregulation after ischaemic stroke

Objectives—Absent outcome data from randomized clinical trials, management of hypertension in acute ischaemic stroke remains controversial. Data from human participants have failed to resolve the question whether cerebral blood flow (CBF) in the peri-infarct region will decrease due to impaired autoregulation when systemic mean arterial pressure (MAP) is rapidly reduced. Methods—Nine participants, 1–11 days after hemispheric ischaemic stroke, with systolic blood pressure more than 145 mmHg, underwent baseline PET measurements of regional CBF. Intravenous nicardipine infusion was then used to rapidly reduce mean arterial pressure 16 ± 7 mmHg and CBF measurement was repeated. Results—Compared with the contralateral hemisphere, there were no significant differences in the percent change in CBF in the infarct (P = 0.43), peri-infarct region (P = 1.00) or remainder of the ipsilateral hemisphere (P = 0.50). Two participants showed CBF reductions of greater than 19 % in both hemispheres. Conclusion—In this study, selective regional impairment of CBF autoregulation in the infarcted hemisohere to reduced systemic blood pressure was not a characteristic of acute cerebra