Neurovascular coupling in severe aortic valve stenosis

Area of Science:

• Cardiovascular Medicine
• Neurology
• Medical Imaging

Background:

• Aortic stenosis (AS) obstructs left ventricular outflow, potentially impairing brain perfusion.
• Hemodynamic alterations in AS may disrupt cerebral blood flow regulation.
• Understanding neurovascular coupling in AS is crucial for assessing cognitive function.

Purpose of the Study:

• To evaluate neurovascular coupling in patients with severe aortic stenosis.
• To investigate cerebral blood flow regulatory mechanisms in AS using Transcranial Doppler ultrasonography.

Main Methods:

• Assessed visually evoked cerebral blood flow velocity responses (VEFR) in the posterior cerebral artery.
• Analyzed peak systolic, mean, and end-diastolic VEFR in 54 severe AS patients and 43 controls.
• Utilized 10 cycles of visual stimulation and repeated-measures ANOVA for data comparison.

Main Results:

• Severe AS patients exhibited significantly higher peak systolic VEFR (12.9% ± 5.6%) compared to controls (10.5% ± 4.5%; p = .009).
• Mean VEFR was also significantly elevated in AS patients (14.4% ± 5.8%) versus controls (12.2% ± 4.9%; p = .021).
• A trend towards higher end-diastolic VEFR was observed in AS patients (p = .061).

Conclusions:

• This study demonstrates, for the first time, dysregulated neurovascular coupling in severe AS patients, evidenced by elevated VEFR.
• Impaired neurovascular coupling may be a contributing factor to cognitive decline in individuals with aortic stenosis.
• Transcranial Doppler ultrasonography is a valuable tool for assessing cerebral hemodynamics in AS.