Melissa Trotman-Lucas, PhD, BSc
Thakkar P, McGregor A, Barber PA, Paton JFR, Barrett C, McBryde F. Hypertensive Response to Ischemic Stroke in the Normotensive Wistar Rat: Mechanisms and Therapeutic Relevance. Stroke. 2019;50:2522-2530.
Sudden increased blood pressure (BP), known as hypertension, following an ischaemic insult is the scenario for ~80% of acute ischaemic stroke (AIS) patients. This poststroke hypertension is the subject of continued scientific debate, with both the mechanism and its therapeutic relevance still poorly understood. There are two potential sides to the role of poststroke hypertension in AIS tissue damage: exacerbation and protection. Exacerbation of damage to vulnerable ischemic tissue may occur alongside promotion of edema formation; moreover, this abrupt increase in BP can increase the risk of cardiovascular events, including further strokes and heart attacks. On the flip side, this increased BP may be a reaction by the body to increase blood supply to the brain tissue, increasing oxygenation of the penumbral tissue. Therefore, creating the conundrum that treatment to reduce BP levels in AIS may be protective but, on the other hand, it may also escalate tissue damage and increase the risk of a poorer patient outcome.
A recent study by Thakkar et al., published in Stroke, sought to answer whether a neurally mediated increase in systemic BP protects cerebral perfusion by opposing the increase in intracranial pressure (ICP) through increasing supply pressure to the tissues. Undertaking this by characterising the cerebrovascular, ICP and cerebral oxygenation responses in a rat AIS model. Testing also the physiological impact of hypertension prevention on the maintenance of oxygenation in the penumbra and on functional recovery poststroke.