Determining a balance between blood pressure that is neither too high leading to hematoma expansion, nor too low leading to hypoperfusion has always been a challenge in patients with acute intracranial hemorrhage. Butcher et al. randomized 75 spontaneous ICH patients within 24 hours to two groups, one with goal SBP<150 and the other with goal SBP<180. They obtained CT perfusion images to assess perihematoma relative CBF, which was defined as the difference between perihematoma and contralateral homologous region CBF. The result was that perihematoma relative CBF was not different in both groups, leading to the conclusion that acute BP reduction does not lead to cerebral ischemia.
This study reproduced the safety of acute BP lowering shown in the INTERACT trial. A recent study has shown the development of ischemic DWI lesions on MRI in bilateral hemispheres associated with BP reduction in ICH patients. This raises the question that relative CBF may not the best parameter to determine risk of ischemia, and this may be better demonstrated in a prospective study utilizing MRI. The authors address this concern by pointing out that there was no significant difference found in relative CBF of the contralateral hemisphere in the two groups. Neverthless, this study addresses an important and commonly encountered question regarding the safety of aggressive BP lowering in the acute phase in ICH patients.