A new study led by investigators from Brigham and Women’s Hospital, a founding member of the Mass General Brigham healthcare system, analyzed the cerebral blood flow (CBF) regulation of individuals who had experienced strokes.
The team found that cerebral autoregulation (CA) — one of the key processes to maintain sufficient blood supply to the brain — displayed a daily rhythm in stroke patients, with more degraded regulation during nighttime and morning hours, as compared to that in the afternoon hours. Their results, which are published in the Journal of Cerebral Blood Flow and Metabolism, are relevant for healthcare planning during stroke recovery.
The research team observationally studied 28 participants being treated in a hospital in São Paulo, Brazil after experiencing a stroke. They received thrombolysis within 5 hours of the onset of their symptoms. After undergoing this procedure, the participants’ CA was assessed over the course of 48 hours at various time points by examining the relationship between temporal changes in blood pressure and cerebral blood flow velocity of the middle cerebral artery.
Analysis of the results showed evidence of differing cerebral blood flow regulation during various times of the day, especially when cerebral blood flow and pressure fluctuated at large time scales or low frequencies < 0.05 Hz. In particular, a more degraded regulation motif was seen during the nighttime and morning hours when compared to the afternoon. This dysregulation interval coincides with the increased prevalence of recurrent and first-ever stroke events during morning times.
