Conclusions
This focused update has outlined the current evidence, knowledge gaps, and emerging concepts on systemic hemodynamics, cerebral autoregulation, and perfusion. We summarize several clinical research priorities in ICH and SAH (Table). Specifically, the emergence of PaCO2 change as an important modifier of response to intervention (BP lowering) and prognostic marker may allow ultra-acute data on systemic and cerebral hemodynamics in ICH to be obtained, particularly pre- and post-BP agent delivery. Given the overlap in clinical questions, pathophysiology and complications across these 2 subtypes of hemorrhagic stroke, we call for greater international and cross-disciplinary capacity-building collaborations between ICH and SAH researchers. There is potential value in further IPD meta-analyses of RCT data to understand differences in ICH associated with SAH, and vice versa, but also in using novel platform registries with nested RCTs that can address multiple research questions within a common infrastructure. Although less ideal for assessing effectiveness, the use of propensity-score matching and artificial intelligence methodologies of large prospective cohort datasets can allow an assessment of all aspects of patient management. Lastly, by considering the pathophysiological overlap between ICH and SAH, we may better understand the potential benefits of pharmacological agents in both contexts rather than isolation (eg, is there a role for nimodipine in ICH?).
Nonstandard Abbreviations and Acronyms
ATACH-II = Antihypertensive Treatment of Acute Cerebral Hemorrhage
BP = blood pressure
CBF = cerebral blood flow
CPP = cerebral perfusion pressure
DCI = delayed cerebral ischemia
GTN = glyceryl trinitrate
HIMALAIA = Hypertension Induction in the Management of Aneurysmal Subarachnoid Haemorrhage With Secondary Ischemia
ICH = intracerebral hemorrhage
ICP = intracranial pressure
INTERACT2 = Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial
INTERACT3 = Intensive Care Bundle With Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial
INTERACT4 = Intensive Ambulance-Delivered Blood Pressure Reduction in Hyper-Acute Stroke Trial
IPD = individual participant data
MRI = magnetic resonance imaging
RCT = randomized controlled trial
SAH = subarachnoid hemorrhage
Sources of Funding
Dr Minhas is an National Institute for Health Research Clinical Lecturer in Older People and Complex Health Needs. The views expressed in this publication are those of the author(s) and not necessarily those of the National Health Service, the National Institute for Health Research, or the Department of Health, or the authors' respective organizations. Dr Anderson is supported by a Senior Investigator Leadership Fellowship from the National Health and Medical Research Council (NHMRC) of Australia.
Stroke. 2022;53(4):1065-1073. © 2022 American Heart Association, Inc.
