Blood Pressure in Acute Ischemic Stroke

This article is a narrative review that discusses the safety and efficacy of blood pressure modulation to support cerebral blood flow in the setting of acute ischemic stroke and how it may affect patient outcomes. It includes English only RCTs as well as data from pilot studies, prospective cohort studies, case series, and retrospective analyses that focused on patients with acute stroke between January 1980 and September 2014.

There is currently no defined ideal BP range in the early management of patients with acute ischemic stroke as it is likely patient-dependent. Per the AHA, however, candidates for IV tPA should have a SBP <185 mmHg and DBP <110 mmHg before thrombolytic treatment as well as for 24 hours after. Candidates for intra-arterial recanalization therapies should have a SBP <180 mmHg and DBP 220 mmHg or DBP is >120 mmHg. Lower BP targets are often initiated if there is evidence of end-organ damage due to elevated BP or if an elevated pressure is thought to be exacerbating a comorbid condition.

Studies ultimately found that regional cerebral blood flow in the ischemic penumbra [ischemic but not yet infarcted tissue] is pressure-dependent whereby the goal of permissive HTN is to optimize blood flow to the ischemic penumbra until IV thrombolytics can be administered and intra-arterial recanalization therapies can be performed or optimization of collateral vasculature can occur, the latter of which was the goal for the patient in my case. While SBP for moderate HTN was found to be associated with the best outcomes, and persistent severe elevations in BP during the subacute phase of ischemic stroke was found to be associated with worse outcomes, there is no evidence of a causative relationship. It is therefore suggested that imaging modalities, such as serial perfusion weight imaging, be used to determine perfusion adequacy, as failure to prevent the progression of cerebral ischemia can lead to a larger infarct volume and higher risks of malignant cerebral edema and symptomatic hemorrhagic conversion of the infarction. Still, it is important to bear in mind other patient-specific factors, such as location of the occlusion, status of the collateral circulation, and other medical co-morbidities, to guide the safe augmentation of blood pressure in patients with acute ischemic stroke.