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Cerebral flow velocities during daily activities depend on blood pressure in patients with chronic ischemic

Vera Novak1, Kun Hu, Laura Desrochers

  • 1Division of Gerontology, Beth Israel Deaconess Medical Center, 110 Francis Street, Boston, MA 02215, USA. vnovak@bidmc.harvard.edu

Stroke
|December 5, 2009
PubMed

Insights

Blood flow velocities (BFVs) are lower in stroke patients and decrease with daily activities. Maintaining mean arterial pressure above 100 mm Hg may improve cerebral perfusion after ischemic stroke.

Area of Science:

  • Neurology
  • Cerebrovascular Medicine
  • Medical Physiology

Background:

  • Optimal blood pressure (BP) targets for cerebral perfusion post-ischemic stroke remain unclear.
  • Investigating the relationship between BP and cerebral blood flow velocities (BFVs) during everyday activities is crucial.

Purpose of the Study:

  • To examine the association between blood pressure and cerebral blood flow velocities in patients with chronic ischemic stroke during various daily activities.
  • To understand how postural changes affect cerebral perfusion in stroke survivors.

Main Methods:

  • Studied 43 chronic large vessel ischemic stroke patients and 67 age-matched controls.
  • Measured middle cerebral artery BFVs during supine, sitting, standing, and tilt positions.
  • Employed regression and dynamic phase analysis to quantify the BP-BFV relationship.

Main Results:

  • Stroke patients exhibited significantly lower baseline BFVs (approx. 30% reduction) compared to controls.
  • BFVs declined further with postural changes, remaining lower in stroke patients during sitting, standing, and tilt.
  • BFVs positively correlated with mean arterial pressure, with potential increases of 30-50% at BP >100 mm Hg. Orthostatic hypotension was linked to lower BFVs.

Conclusions:

  • Cerebral blood flow velocities are reduced in stroke survivors, and activities like standing can induce hypoperfusion.
  • Elevating mean arterial pressure above 100 mm Hg may enhance cerebral perfusion.
  • BP management strategies post-stroke should consider the dependency of BFVs on arterial pressure to potentially improve functional recovery.
Abstract

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