Blood Pressure Management After Intracerebral and Subarachnoid Hemorrhage

The Knowns and Known Unknowns

Jatinder S. Minhas, MD; Tom J. Moullaali, MD, PhD; Gabriel J.E. Rinkel, MD, PhD; Craig S. Anderson, MD, PhD

Disclosures

Stroke. 2022;53(4):1065-1073. 

In This Article

BP Lowering in the Context of Raised ICP

Although elevated ICP can initially impair CBF and cerebrospinal fluid exchange, and later cause cerebral ischemia and herniation, our understanding of the relationship between BP and ICP in ICH is limited, as is the broader management of cerebral edema in general. Any deviation from a normal ICP (range, 7–15 mm Hg) and excessive variability, are associated with poor prognosis in ICH.[65] Raised ICP is related to impaired dynamic cerebral autoregulation,[66] but it is unclear whether larger hematomas cause high ICP, low compliance and impaired myogenic response, or is it solely that high ICP leads to lower CPP.[67] To date, there have been no RCTs of the effects of ICP monitoring after ICH,[68] and in SAH. One single center RCT suggests that tailoring treatment according to mean ICP wave amplitude rather than absolute values results in better clinical outcome,[69] while several small studies have shown variable changes in ICP from different BP lowering agents. Clearly, larger mechanistic studies are needed.[70]

Uncertainty remains as to whether BP lowering benefits the sickest patients after ICH: those with large hematomas (>50 mL) who are at high risk of cerebral hypoperfusion from both the treatment and high ICP, with consequently low CPP.[21] RCTs have failed to include large numbers of such patients, and only smaller mechanistic studies have shown low CPP without attention to interventions such as BP lowering. The international third, INTERACT3 (Intensive Care Bundle With Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial; NCT03209258) endeavours to provide further evidence for goal-directed care bundle including early intensive BP lowering in a broad range of patients with acute ICH, using a multicenter, stepped wedge cluster randomized design.[71]

In SAH, much of our understanding of thresholds and approaches to care have been extrapolated from patients with traumatic brain injury, the distinction clearly is around bleeding risks and relationship to ICH change, an RCT in this area is a high priority.[72]

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