Abstract 12121: Association of Exercise Performance During Heart Transplant Evaluation with Freedom from Death or Deterioration in Children
Maximum oxygen consumption (Peak VO2) <50% predicted is a class I indication for heart transplant (HT) listing in children (American Heart Association guidelines). Data supporting this indication are scant. We assessed the association of peak VO2<50% predicted during HT evaluation with freedom from death or deterioration in children. Methods All children who underwent exercise testing during HT evaluation at our center during 2002-2011 were included. Patients with peak VO2<50% predicted were compared with those with peak VO2≥50% predicted for a composite outcome of (1) death before HT, (2) initiation of mechanical circulatory support, and (3) urgent HT using time-to-event analyses (log-rank test and Cox regression). Children who received HT less urgently were censored at HT. Results There were 50 children in the study (median age 15 yrs, IQR 13-17 yrs, 24 female, 18 with palliated single ventricle). Children with peak VO2<50% predicted delivered less oxygen per heart beat (peak O2 pulse, median 39% vs. 58% predicted, P<0.001) vs. children with peak VO2≥50% predicted and had less efficient ventilation during exercise (median VE/VCO2 slope 43 vs. 33, p=0.009). Overall, 25 children reached the composite endpoint. Peak VO2 <50% predicted was associated with outcome in children with biventricular circulation (Hazard ratio [HR] 4.7, 95% CI 1.8, 12.3, P<0.001, see Fig) but not in those with palliated single ventricle (HR 1.3, CI 0.1, 12.0, P=0.80). Further, VE/VCO2 slope ≥34 was associated with outcome in children with biventricular circulation (HR 2.7, 95% CI 1.1, 7.1, P<0.001) but not in children with palliated single ventricle. Conclusions Exercise testing during HT evaluation in children with a biventricular circulation identifies those at higher risk of death or deterioration thus supporting a role of exercise testing in these children. Larger studies are needed to assess the role of exercise testing during HT evaluation in children with a palliated single-ventricle.
- © 2012 by American Heart Association, Inc.