Introduction: Perfusion dependence is observed in acute ischemic stroke caused by large vessel occlusion.  We present a case of a patient with flow limiting lesions causing neurological symptoms, with a negative MRI, and symptomatic improvement after permissive hypertension.  

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Case: 67-year-old male presented with focal symptoms and an NIHSS of 8.  He was past the time window, so tPA was not given.  CT angiogram/perfusion revealed occlusion of the right ICA bifurcation and multifocal intracranial stenoses.  Cerebral angiography showed occlusion of the R ICA distal to the origin with reconstitution from the ECA through the ophthalmic, and non-filling of the ACA. Mechanical thrombectomy was performed, and TICI 3 achieved in the R ICA.  Post-procedural NIHSS score was 8.  Right MCA symptoms continued despite complete recanalization. Nicardipine was initiated to target systolic blood pressure (SBP) <160. MRI done during symptoms was normal. BP remained in the 150s. Bedside point of care TCD showed lower right MCA velocities suggesting relative hypoperfusion vs left MCA. This was confirmed by clinical TCD, when BP in the left arm was 142/65 mmHg. The nicardipine was stopped, and BP rose to 160-170 mmHg, without much clinical improvement. When SBP reached the 180s-200s symptoms rapidly improved. Repeat TCD showed improved R MCA and ACA velocities.  Repeat NIHSS score was 2, but there were no persisting symptoms the next day. Oral antihypertensive was started and titrated to a BP of 160-180 mmHg, with discharge on day 3, with NIHSS score of 0.

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This patient demonstrated TCD evidence of a perfusion dependent MRI negative stroke that responded to systemic perfusion augmentation. TCD may help identify the problem and inform treatment for such patients.  Future studies assessing target BP in large vessel strokes should employ use of noninvasive strategies like TCD in acute evaluation, management and follow up of stroke.