Cerebrovascular response time to a breath-holding challenge

Area of Science:

• Neuroscience
• Vascular Medicine
• Medical Imaging

Background:

• Cerebrovascular reserve is crucial for brain health.
• Breath-holding challenges can assess cerebrovascular reactivity.
• Internal carotid artery (ICA) stenosis impacts cerebral blood flow.

Purpose of the Study:

• To evaluate the timecourse of cerebrovascular reserve response to breath-holding.
• To assess the impact of internal carotid artery (ICA) stenosis on this response.
• To determine if the response normalizes after intervention.

Main Methods:

• Simultaneous bilateral transcranial Doppler (TCD) recordings of middle cerebral artery (MCA) velocity.
• Breath-holding challenge performed in patients with critical ICA stenosis, non-critical ICA stenosis, and healthy controls.
• Measurement of time interval from baseline to peak MCA blood flow velocity.

Main Results:

• Normal controls and patients with non-critical stenosis showed near-simultaneous peak MCA velocities bilaterally.
• Patients with critical ICA stenosis exhibited a delayed peak response time ipsilateral to the stenosis (2.40 +/- 3.43 sec).
• This delay resolved post-carotid endarterectomy.

Conclusions:

• Unilateral critical ICA stenosis significantly prolongs the MCA velocity rise time during breath-holding.
• This finding indicates impaired cerebrovascular reserve in critical ICA stenosis.
• The observed delay is reversible, highlighting the effectiveness of revascularization.