Authors

1. Canada, Justin M. PhD, RCEP
2. Park, Tae Shik MD
3. Ravindra, Krishna BS
4. Chiabrando, Juan G. MD
5. Del Buono, Marco Giuseppe MD
6. van Wezenbeek, Jessie MS
7. Trankle, Cory R. MD
8. Kadariya, Dinesh MD
9. Keen, Larry PhD
10. Carbone, Salvatore PhD
11. Billingsley, Hayley MS
12. Wohlford, George F. PharmD
13. Arena, Ross PhD
14. Van Tassell, Benjamin W. PharmD
15. Abbate, Antonio MD, PhD

Abstract

Purpose: Cardiopulmonary exercise testing (CPX) is a well-established assessment with important insight into prognosis and therapeutic efficacy in patients with heart failure (HF). Prior studies have identified several clinical differences between Black or African American (B-AA) and Caucasian patients with HF. Differences in key CPX responses between these two groups require further investigation.

Methods: Using a database consisting of subjects with symptomatic HF who had undergone CPX for inclusion in various prospective randomized clinical trials, we identified 198 (n = 94 [47%] B-AA; n = 105 [53%] Caucasian) patients with a qualifying baseline CPX. Significant univariate predictors of peak oxygen uptake (V[spacing dot above]O_2peak) were included in a multivariate linear regression model.

Results: When compared with Caucasian patients, B-AA were younger (mean +/- SD = 54.8 +/- 10.0 vs 57.9 +/- 9.6 yr, P = .03), had higher C-reactive protein (CRP) (median [IQR] = 4.9 [2.3, 8.8] vs 1.9 [0.6, 5.5] mg/L, P < .0001), lower hemoglobin (13.0 +/- 1.8 vs 13.8 +/- 1.6 g/dL, P = .003), and lower left ventricular ejection fraction (LVEF) (40 [32, 51] vs 53 [43, 59]%, P < .00010). During CPX, B-AA patients also had lower V[spacing dot above]O_2peak (14.6 +/- 3.9 vs 17.6 +/- 4.8 mL[middle dot]kg^-1[middle dot]min^-1, P < .0001). No differences were observed between B-AA and Caucasian in the minute ventilation/carbon dioxide production (V[spacing dot above]E/V[spacing dot above]CO₂) slope (P = .14). The difference in V[spacing dot above]O_2peak between B-AA and Caucasian was largely attenuated after adjusting for age, body mass index, CRP, N-terminal pro-brain natriuretic peptide, hemoglobin, LVEF, and peak HR (14.1: 95% CI, 13.2-14.9 vs 15.6: 95% CI, 14.4-16.8 mL[middle dot]kg^-1[middle dot]min^-1, P = .053).

Conclusions: Directly measured V[spacing dot above]O_2peak was significantly lower in B-AA than in Caucasians with HF. This is largely explained by differences in clinical characteristics, whereas no significant differences were observed in the V[spacing dot above]E/V[spacing dot above]CO₂ slope.