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 l-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.