Body composition and maximal exercise capacity after heart transplantation

Area of Science:

• Cardiology
• Exercise Physiology
• Transplantation Science

Background:

• Maximal exercise capacity, measured by peak oxygen consumption (pVO2), is significantly reduced in heart transplant recipients (HTR) compared to healthy individuals.
• Understanding factors influencing pVO2 recovery is crucial for improving long-term outcomes in HTR.

Purpose of the Study:

• To investigate the relationship between body composition and pVO2 in HTR during the first decade after transplantation.
• To identify key determinants of exercise capacity changes over time post-heart transplant.

Main Methods:

• Dual-energy X-ray absorptiometry (DXA) was used to assess body composition (appendicular lean mass [ALM] and fat mass [FM]).
• Cardiopulmonary exercise testing (CPET) measured pVO2, peak heart rate (HR), and anaerobic threshold (AT).
• Linear and partial correlation analyses examined associations between body composition, CPET parameters, and calcineurin inhibitor (CNI) dose over four sequential periods (1-9 years post-transplant).

Main Results:

• pVO2 and peak HR significantly increased from 1-2 years to 7-9 years post-transplant.
• ALM, normalized to body mass index, increased significantly and was a major predictor of pVO2 variance (45%).
• Elevated fat mass index (FMI) persisted, and higher CNI doses were negatively correlated with ALM.

Conclusions:

• Peripheral skeletal muscle gain positively impacts pVO2 post-heart transplant, but this effect is counteracted by increased fat mass.
• Lifestyle interventions to reduce adiposity and potential CNI dose reduction in the chronic stable phase may promote favorable adaptations in peripheral muscle mass and exercise capacity.