The goal of this observational study is to evaluate the role of blood pressure (BPV) variability in patients suffering from acute ischemic stroke. The main questions it aims to answer are:

1. To determine the association of BPV with functional/cognitive outcome after ischemic stroke.
2. To determine a pathophysiologic mechanism of BPV's deleterious effect on functional outcome.
3. To evaluate potential treatment targets to pharmacologically reduce BPV after ischemic stroke.

Increased blood pressure variability (BPV) has consistently been associated with two to three times higher risk of disability or mortality after acute ischemic stroke (AIS) in retrospective analyses, independent of mean blood pressure. The investigators' central hypothesis is that increased BPV is harmful after AIS and warrants reduction. However, prior BPV research in AIS patients has been retrospective and limited by non-standardized BP measurement and, therefore, BPV is not mentioned in current stroke guidelines. To address the limitations of prior BPV research, determine mechanisms of BPV's deleterious effect, and identify potentially effective methods to reduce BPV, the proposed study will: 1) prospectively validate that "short-term" and "long-term" BPV after AIS onset is associated with functional outcome and define the effect size of different levels of BPV, 2) utilize portable MRI to confirm that final infarct volume is mechanistically related to BPV, and 3) utilize bedside pupillometry to determine how the autonomic nervous system contributes to BPV after AIS and evaluate the class effect of antihypertensive medications on BPV. To achieve these goals, the study will enroll 150 patients who have anterior circulation stroke and a baseline NIH Stroke Scale ≥4 within 48 hours of AIS onset at three study sites. With completion of the Aims, the study will define the outcome for a future trial, the effect size of BPV on individual outcomes and composites, the duration for lowering BPV (24-72 hours vs. weeks or months), and potential interventions to reduce BPV. Pharmacologic BPV reduction would be an inexpensive and widely available intervention, able to be administered in a range of healthcare settings. By completing the proposed aims, the investigators will be ideally positioned to test accessible targeted interventions to diminish the morbidity and mortality of AIS.

Inclusion Criteria:

• Ischemic stroke according to the American Heart Association (AHA) definition and either:

  1. CT or MRI showing ischemic stroke in the anterior circulation (frontal, parietal or superior temporal lobes), or

  2. Occlusion of the internal carotid, middle cerebral or anterior cerebral arteries on computed tomography angiography (CTA) or magnetic resonance angiography (MRA)

     Onset of ischemic stroke within 48 hours and able to get baseline pMRI within 72 hours of arrival

     4) NIH Stroke Scale ≥ 4 at time of enrollment

     Exclusion Criteria:

• Pre-morbid mRS ≥3

• Predicted hospital system admission <72 hours

• Pacemaker or other MRI contraindications per American College of Radiology guidelines

Patients with acute ischemic stroke serve as the source population for the study and will be identified as inpatients at participating centers.