Impact of cerebral oxygen saturation on mortality and rehospitalisation in patients with heart failure and the role of physical activity as a modifying factor: the HARVEST-Malmö Study.

Abstract

The cross-sectional association between cerebral tissue oxygen saturation (SctO₂) and heart failure (HF) has been previously studied, but the prognostic significance of SctO₂ in HF remains uncertain. This study aimed to assess the role of SctO₂ as a risk factor for all-cause mortality and rehospitalisation, as well as to explore the cross-sectional association between physical activity and SctO₂ in a Swedish HF cohort. In 102 patients with HF (mean age 70.2 years (±12.4); 21.6% women), near-infrared spectroscopy was used to assess SctO₂. Adjusted Cox regression analyses were conducted to examine the associations between resting SctO₂ levels and all-cause mortality and the initial occurrence of postdischarge rehospitalisations. The associations between self-reported physical inactivity and SctO₂ were explored by using multivariable linear and logistic regression analyses. The median follow-up time to death of any cause and first-of-any rehospitalisation was 830 (IQR: 519-1283) and 208 (72-584) days, respectively. During follow-up, 31 (30.4%) patients died and 63 (61.8%) were rehospitalised. Higher SctO₂ was associated with lower risk of mortality (HR 0.86; 95% CI 0.77 to 0.95; p=0.002) but not with rehospitalisation risk (HR 0.96; 95% CI 0.90 to 1.02; p=0.162). Physical inactivity (≤1 hour per week of strenuous activity) was associated with lower SctO₂ (β-1.56; 95% CI -3.07 to -0.05, p=0.043). Higher SctO2 at rest is associated with lower risk of all-cause mortality but it was not possible to show significant association with first-of-any rehospitalisation risk in patients with HF. Physical inactivity is associated with lower cerebral oxygen saturation at rest. These findings could suggest SctO2 as a potential marker associated with long-term outcomes in HF, warranting larger confirmatory studies.