Cerebral vasospasm affects arterial critical closing pressure

Area of Science:

• Neurology
• Critical Care Medicine
• Cerebrovascular Physiology

Background:

• Cerebral vasospasm (CVS) is a critical complication following aneurysmal subarachnoid hemorrhage (SAH).
• The impact of CVS on critical closing pressure (CrCP), a measure of cerebral perfusion pressure, remains incompletely understood.
• Understanding CrCP dynamics during CVS is crucial for managing cerebral blood flow.

Purpose of the Study:

• To investigate the behavior of critical closing pressure (CrCP) during cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage (SAH).
• To assess whether CrCP changes reflect alterations in vascular tone in small distal vessels affected by vasospasm.
• To correlate CrCP levels with patient outcomes after SAH and CVS.

Main Methods:

• Retrospective analysis of 52 patients diagnosed with CVS via transcranial Doppler.
• Noninvasive calculation of CrCP using arterial blood pressure and cerebral blood flow velocity.
• Assessment of neurological outcomes using the Glasgow Outcome Scale at discharge and 3 months post-ictus.

Main Results:

• The onset of CVS led to a significant decrease in CrCP (P=0.025), while intracranial pressure (ICP) remained unchanged (P=0.134).
• CrCP was significantly lower on the side ipsilateral to CVS compared to the contralateral side (P=0.025), indicating asymmetry.
• Lower CrCP levels post-CVS onset were significantly associated with unfavorable patient outcomes at both discharge (P=0.014) and 3 months (P=0.020).

Conclusions:

• Critical closing pressure is reduced during cerebral vasospasm, both temporally and spatially.
• The observed decrease in CrCP, independent of ICP changes, likely reflects diminished vascular wall tension in distal small vessels.
• Reduced CrCP is a potential indicator of poor neurological outcomes in patients with SAH and subsequent CVS.