Abstract 13763: Exercise Test Results Have Prognostic Value in Chidren with Dilated Cardiomyopathy
Introduction: Children with dilated cardiomyopathy (DCM) are at risk of death due to worsening heart failure and sudden arrhythmias. Cardiopulmonary exercise test (CPET) is prognostically important in ambulatory adults with heart failure, but its value in the pediatric age group is under researched.
Hypothesis: We assessed the hypothesis that CPET might have prognostic value in pediatric DCM.
Methods: Between 2001 and 2009 we studied with CPET 82 ambulatory children (age 13.5±2.3 years, 51 males) with DCM. Clinical end-point was defined as death without heart transplantation (HTx) or acute deterioration requiring bridge to urgent HTx with either inotrope administration or extracorporeal membrane oxygenator. Peak heart rate and peak oxygen uptake (VO2) were expressed as a percentage of predicted value based on gender, age and weight.
Results: Peak heart rate was 87±13% of predicted, and peak VO2 was 67±22% of predicted, whereas ventilatory efficiency was 32±8 and left ventricular ejection fraction was 20±9%. During a follow-up of 27.5±22.6 months (range 0.3 to 82.5 months), 18 patients reached the defined clinical end-point for clinical deterioration with bridging to urgent HTx (on inotropes in 6 and on extracorporeal membrane oxygenator in 5) or death (sudden in 2 and due to rapid clinical deterioration in 5). At univariate analysis, left ventricular ejection fraction, peak heart rate, peak VO2, peak systolic blood pressure, and ventilatory efficiency were all associated with adverse outcome. At multivariable Cox analysis, only peak VO2 (p=0.040), and peak systolic blood pressure (p=0.039) were associated with the study end-point. ROC curve analysis identified peak VO2 ≤52% of predicted, and peak exercise systolic blood pressure ≤98 mmHg as being associated with the study end-point. Kaplan-Maier survival curves showed a higher study event rate at 24 months in patients with a peak VO2 ≤52% (63.7 vs. 10.5%, HR 22.6, p<0.0001) and in patients with a peak systolic blood pressure ≤98 mmHg (59.6 vs. 13.9%, HR 18.5, p<0.0001).
Conclusions: CPET is useful in children with DCM to identify patients at risk of accelerated clinical deterioration and death, and can be used to assess the need for heart transplantation in children as well as their waiting list priority.
- © 2010 by American Heart Association, Inc.