Heart failure classification based on resting ejection fraction does not display a unique exercise response pattern.

BACKGROUND

Heart failure with preserved (HFpEF), mildly reduced (HFmrEF) and reduced (HFrEF) ejection fraction (EF) remains a controversial categorization. Whether these three categories reflect a distinct pattern of exercise limitation in cardiopulmonary exercise testing (CPET) needs to be investigated. We aimed to analyze whether CPET variables differ between all heart failure categories (HF).

METHODS

We analyzed CPET variables of stable HFpEF (n = 123), HFmrEF (n = 31), and HFrEF (n = 153; 74 patients with and 79 patients without left ventricular assist device, LVAD) patients. The association between HF and peak oxygen consumption (VO) was used as a primary outcome, while the association between HF, oxygen uptake efficiency slope (OUES), and increase of O pulse (ΔO pulse) were analyzed as secondary outcomes.

RESULTS

VO displayed a consistent decline across all HF categories (19.8 ml ± 6.2/kg/min vs. 17.5 ± 7.9 ml/kg/min vs. 13.7 ± 4.0 ml/kg/min, p < 0.001). OUES only showed differences between HFpEF and HFrEF (1.8 ± 0.6 vs. 1.4 ± 0.5, p < 0.001) as well as HFmrEF and HFrEF (1.9 ± 0.9 vs. 1.4 ± 0.5, p = 0.004). ΔO pulse differed between HFpEF and HFrEF (7.7 ± 3.5 ml/beat/kg100 vs. 5.5 ± 3.0 ml/beat/kg100, p < 0.001) as well as HFpEF and HFmrEF (7.7 ± 3.5 ml/beat/kg100 vs. 6.3 ± 4.1 ml/beat/kg100, p = 0.049). Outcome variables did not differ between HFrEF with and without LVAD support (VO: p = 0.364, OUES: p = 0.129, ΔO pulse: p = 0.564).

CONCLUSIONS

HF did not display a distinct CPET profile. Thus, EF-based categorization does not entirely reflect exercise limitations. CPET variables could contribute to better characterize HF phenotypes.