Neuroimaging-Based Responses to Blood Pressure Augmentation in Acute Ischaemic Stroke: A Systematic Review.

Introduction: In acute ischaemic stroke, the key treatment to reduce infarct growth is reperfusion, achieved through thrombolysis, endovascular thrombectomy, or endogenous reperfusion. Prior to definitive reperfusion therapy, blood pressure augmentation may enhance cerebral perfusion and reduce interim infarct growth. This study aimed to summarise the existing evidence from randomised controlled trials on the use of imaging for patient selection and the assessment of blood pressure augmentation in acute ischaemic stroke. Methods: A systematic review was conducted of the databases PubMed, Embase, and Cochrane Library in accordance with the PRISMA guidelines. The systematic review was prospectively registered on PROSPERO. Results: Initial searches returned 266 results, of which 4 fulfilled inclusion criteria. Most identified studies did not utilise imaging for patient selection and the assessment of blood pressure augmentation in ischaemic stroke. Only two studies utilised magnetic resonance imaging and/or magnetic resonance perfusion imaging for patient selection, while one study used non-contrast CT brain. No studies utilised CT perfusion imaging for patient selection or outcome assessment post-blood pressure augmentation. There is also a lack of evidence regarding the association between specific perfusion imaging parameters, such as cerebral blood volume and delay time, and clinical outcomes post-blood pressure augmentation. Conclusion: Imaging is a potentially valuable surrogate marker of cerebral perfusion, yet it has not been routinely used for patient selection and assessment in blood pressure augmentation in acute ischaemic stroke trials. Additional research is required to determine its utility in assessing the efficacy of blood pressure augmentation in ischaemic stroke.