Ventilatory Efficiency and Aerobic Capacity Predict Event-Free Survival in Adults With Atrial Repair for Complete Transposition of the Great Arteries

ObjectivesThe goal of this study was to assess the prognostic value of the cardiopulmonary exercise test (CPET) in patients who received a Mustard and Senning (M/S) operation.BackgroundPatients who received an M/S operation have increased long-term risk of cardiovascular morbidity and mortality. Limited information is available on how to stratify risk in this population.MethodsBetween 1996 and 2007, 274 adults (age 26.3 ± 8.9 years, range 16 to 50 years) who had received a Mustard (n = 144) or Senning (n = 130) operation in infancy were studied with CPET. During a follow-up of 3.9 ± 2.3 years (range 0.2 to 10.8 years), 12 patients died at an age of 36 ± 14 years, and 46 patients required a cardiac-related emergency (<24 h from the onset of symptom/condition) hospital admission at an age of 30 ± 11 years.ResultsAt multivariate Cox analysis, the slope of ventilation per unit of carbon dioxide output (VE/VCO2slope) (hazard ratio: 1.088, p < 0.0001) and percentage of predicted peak oxygen uptake (Vo2%) (hazard ratio: 0.979, p = 0.0136) were the strongest predictors of death/cardiac-related emergency hospital admission among demographic, clinical, and exercise variables. A VE/VCO2slope ≥35.4 (hazard ratio: 10.7, 95% confidence interval [CI]: 7.8 to 24.6), and a peak Vo2% ≤52.3% (hazard ratio: 3.4, 95% CI: 2.5 to 8.2) were associated with an increased 4-year risk of death/cardiac-related emergency hospital admission. Patients who had both a VE/VCO2slope ≥35.4 and a peak Vo2% ≤52.3% of predicted value were at highest risk (4-year event rate: 78.8%).ConclusionsCPET provides important prognostic information in adults with M/S operation. Subjects with enhanced ventilatory response to exercise or those with poor exercise capacity have a substantially higher 4-year risk of death/cardiac-related emergency hospital admission.