Abstract 3281: The Prognostic Characteristics of Cardiopulmonary Exercise Testing in Caucasian and African-American Patients with Heart Failure
Introduction: Peak oxygen consumption (VO2) and the minute ventilation (VE)/carbon dioxide production (VCO2) slope are prognostically important in the heart failure (HF) population.
Hypothesis: We assessed the hypothesis that the prognostic characteristics of peak VO2 and the VE/VCO2 slope would be comparable between Caucasian and African-American subjects with HF.
Methods: Four hundred and ninety one HF patients (339 Caucasian/152 African-American) underwent cardiopulmonary exercise testing and were tracked for major cardiac events for three years.
Results: The following comparisons are reported as Caucasian vs. African-American subgroups, respectively. Age (56.7 ±14.4 vs. 47.1 ±13.4 years, p<0.001) and ejection fraction (30.6 ±12.9 vs. 25.2 ±11.7%, p<0.001) were significantly lower in the African-American subgroup. Peak VO2 (15.7 ± 5.6 vs. 14.8 ± 5.7 mlO2·kg−1·min−1, p<0.11) and the VE/VCO2 slope (35.4 ±9.8 vs. 36.8 ±9.7, p=0.15) were not significantly different. There were 44 (annual event rate: 8.3%) major cardiac events (25 deaths/14 heart transplants/5 left ventricular assist device implantations) in the Caucasian subgroup and 25 (annual event rate: 10.1%) major cardiac events (18 deaths/5 heart transplants/2 left ventricular assist device implantations) in the African-American subgroup. Receiver operating characteristic (ROC) curve analysis and hazard ratios for exercise test variables are listed in Table 1⇓. Peak VO2 and the VE/VCO2 slope were prognostically significant in both subgroups.
Conclusions: Despite differences in baseline characteristics between Caucasian and African-American subjects, the optimal prognostic threshold values of established exercise testing variables were similar. The VE/VCO2 slope was the superior prognostic marker in both subgroups. While, peak VO2 was prognostically significant in Caucasian and African-American subjects, its value was diminished in the latter subgroup.