|| Checking for direct PDF access through Ovid
Introduction: The microvascular cerebral blood flow response (rCBF) to orthostatic stress has been shown to be altered in acute ischemic stroke (AIS) by diffuse correlation spectroscopy (DCS). However, its relevance to the outcome is unknown.Hypothesis: CBF response to head-of-the-bed (HOB) elevation within the first hours after AIS is related to outcome.Methods: Patients with a large anterior circulation stroke of less than 48h from the stroke onset were monitored with DCS to follow rCBF in the frontal lobes during a HOB elevation from supine to 30°. All patients were placed flat during the first 24 hours and later, mobilization was initiated depending on the clinical condition. We categorized measurements as early (<12h) or late (>12h) from stroke onset. NIHSS was recorded at baseline, during HOB, at 24h and 48h. The modified Rankin scale (mRS) score was utilized as the outcome measure (favorable when 0-2).Results: We studied 34 patients (age 78±13y, male 47%, median NIHSS 19 (14-21)) at 16±11 hours from stroke. Ipsilateral extracranial and/or intracranial occlusion was present in 61%. Frontal CBF decreased in both hemispheres after HOB (-5±14%). A paradoxical response (increase/no change) was observed in 18%. rCBF was not correlated to NIHSS and age. Unfavorable outcome was found in 85%. Only at early hours (<12h, n=16), rCBF to HOB elevation in the ipsilateral (not in contralateral) hemisphere (p=0.04, Figure 1) and NIHSSHOB (p=0.008) were associated with poor outcome.Conclusions: This result suggests that paradoxical CBF response to a mild HOB elevation in the early hours of stroke onset is associated with a poor outcome in patients with AIS. Optical continuous monitoring in the bedside may help to individualize management strategies in the early hours of AIS.Figure 1: rCBF due to HOB elevation versus mRS for the ipsi-lateral side in patients measured <12h after stroke.