Exercise capacity in pediatric heart transplant candidates: Is there any role for the 14 ml/kg/min guideline?

A peak oxygen consumption (VO₂) of < 14 ml/kg/min has been identified as a predictor of 1-year mortality in adults with congestive heart failure (CHF) and is used as a criterion for listing for cardiac transplantation (OHT). The role of VO₂ measurement in children awaiting OHT has not been thoroughly evaluated. We sought to assess the degree of exercise impairment and the clinical applicability of the 14 ml/kg/min rule in children awaiting OHT. Cardiopulmonary exercise test (CPT) and cardiac catheterization data in all patients listed for OHT during the period of 1995-2003 were reviewed. Fourteen patients with a mean age of 15.5 ± 2.9 years underwent CPT with no serious adverse events at an interval of 6.6 ± 5.1 months prior to OHT. The etiology of CHF was multifactorial. Patients had impaired aerobic capacity with a mean peak VO₂ of 20.4 ± 6.8 ml/kg/min. Eleven of 14 patients (79%) had a peak VO₂ higher than the adult cutoff value of 14 ml/kg/min. Pediatric ambulatory patients with CHF can safely undergo CPT. Because of age-related differences in oxygen consumption and varied etiologies of CHF a peak VO₂ of < 14 ml/kg/min is not a useful criterion for listing for OHT in this population.