Neurovascular Coupling and Poststroke Cognitive Performance: Exploring Correlations and Future Predictive Potential

Abstract

Introduction: Poststroke cognitive decline can affect activities of daily living, decrease survivors' quality of life and increase health care costs. The mechanisms of long-term cognitive decline are not well understood, but 6 months after stroke the prevalence is approximately 52%. Hemodynamics parameters are described as altered in poststroke patients. Impairment of the neurovascular coupling (NVC) was found to be crucial in the development of dementia in several animal models. We aimed to study if our NVC protocol study presents a correlation with the variables that influence the cognitive function and if can be considered in future studies of prediction of the cognitive function. Methods: We prospectively included 135 patients with ischemic stroke and occlusion in anterior circulation; admitted to our acute stroke unit in 12 months and with Modified Rankin Score (mRS)≤4. Evaluations were carried out in the stroke unit with the patient recumbent with bed head at 30°. Cerebral Blood Flow Velocity (CBFV) was recorded in both the P2 segment of the left and right posterior cerebral artery, with 2-MHz TCD probes secured with a headframe (Doppler BoxX, DWL, Singen, Germany). NVC was determined by the peak relative increase in CBFV during a visual stimulus paradigm of each of 5 cycles of increasing length (20-sec ON-OFF phases) of a flickering checkerboard. Arterial blood pressure was recorded with Finometer (FMS, Amsterdam, Netherlands). Data were exported from the machine software as peak systolic velocity trends and stored for offline analysis (Image 1) Results: We analyzed 135 patients, 66% males (Table 1). The median of the peak amplitude percentage value was 18 [14-23]. The magnitude of CBFV during stimulus paradigm (20-sec) does not correlate with age (p=0.13), NIHSS 24 hours-after stroke (p=0.22), NIHSS 7 days-after stroke (p=0.45), years of education (p=0.92) or with infarct volume measured in 24 hours-CT (p=0.25). Discussion: The method used to assess neurovascular coupling in the acute phase after stroke does not show a correlation with predictive variables of cognitive function. Therefore, this method can be a useful tool to be used in future studies of post-stroke cognitive performance.