Decreased ventricular size and mass mediate the reduced exercise capacity in adolescents and adults born premature

Area of Science:

• Cardiology
• Pediatrics
• Exercise Physiology

Background:

• Premature birth is a significant risk factor for reduced cardiorespiratory fitness (CRF) in adolescents and young adults.
• The specific cardiovascular mechanisms underlying this association remain incompletely understood.

Purpose of the Study:

• To investigate whether cardiac morphology and function differences mediate the reduced CRF observed in individuals born prematurely.
• To identify specific cardiac variables that account for the lower maximal aerobic capacity in preterm-born young adults.

Main Methods:

• Cardiac MRI and maximal exercise testing were performed on adolescents and young adults born preterm (gestational age ≤ 32 weeks or birth weight < 1500g) and matched term-born controls.
• Mediation analysis was employed to determine if cardiovascular variables explained the difference in maximal aerobic capacity (VO2max) between the groups.

Main Results:

• Preterm-born individuals exhibited significantly lower VO2max compared to term-born individuals.
• Significant differences in cardiac parameters were observed, including indexed left ventricular end-diastolic volume (LVEDVi), right ventricular end-diastolic volume (RVEDVi), and left ventricular mass index (LVMi).
• LVEDVi, RVEDVi, and LVMi significantly mediated the difference in VO2max, explaining 74.3%, 50.6%, and 43.0% of the disparity, respectively.

Conclusions:

• Reduced cardiorespiratory fitness in preterm-born young adults is significantly mediated by cardiac structural differences, specifically LVEDVi, RVEDVi, and LVMi.
• These findings suggest preterm-born individuals may face increased long-term risks for cardiac morbidity and mortality.