Age-associated changes in regional aortic pulse wave velocity.

Area of Science:

• Cardiovascular Physiology
• Medical Imaging
• Biomedical Engineering

Background:

• Aortic pulse wave velocity (PWV) increases with age.
• Previous PWV measurements were limited to single locations or comparisons between distant arterial sites.

Purpose of the Study:

• To noninvasively assess age-associated changes in regional aortic mechanical properties.
• To utilize phase-contrast magnetic resonance imaging (PCMRI) for this assessment.

Main Methods:

• Phase-contrast MRI (PCMRI) was used to measure PWV in three aortic segments in 24 volunteers (aged 21-72).
• Applanation tonometry (TONO) was used for validation, measuring PWV between the carotid and femoral arteries.

Main Results:

• PCMRI-derived average PWV correlated well with TONO measurements.
• Older volunteers (>=55 years) showed significantly higher PWV in the ascending and proximal descending aorta compared to younger volunteers.
• PWV increased with age, particularly in the proximal aorta, while remaining consistent across locations in younger individuals.

Conclusions:

• In-plane PCMRI enables multi-site PWV determination in a single scan.
• Age-related regional increases in PWV, especially in the proximal aorta, may stem from elastic fiber fragmentation and altered vascular tone regulation.