Longitudinal change in ventricular volume is accelerated in astronauts undergoing long-duration spaceflight

Area of Science:

• Cardiovascular Physiology
• Space Medicine
• Medical Imaging

Background:

• Astronauts exhibit ventricular volume increases post-spaceflight.
• The cause of this enlargement (spaceflight vs. aging) remains unclear due to long pre- to post-flight intervals.

Purpose of the Study:

• To quantify the annual rate of ventricular volume change in astronauts.
• To compare astronaut ventricular changes against healthy controls and older adults to isolate spaceflight effects.

Main Methods:

• Analyzed pre- to post-flight MRI scans from 18 NASA ISS astronauts.
• Compared astronaut percent ventricular volume change per year (PVVC/yr) with two control groups: 18 age/sex-matched adults and 79 older adults.
• Calculated PVVC/yr for each group.

Main Results:

• Astronauts showed a significantly higher PVVC/yr (6.86%) compared to age-matched controls (2.23%) and older adults (4.18%).
• Spaceflight exposure resulted in an additional 4.63% PVVC/yr beyond normal aging.
• The difference was statistically significant (p < .001 vs. controls, p = .04 vs. older adults).

Conclusions:

• ISS missions accelerate ventricular volume increases beyond normal age-related changes.
• Astronauts experience a unique, spaceflight-specific ventricular enlargement.
• Post-flight follow-up scans are crucial to monitor the long-term trajectory and clinical relevance of these changes.