RESUMEN
INTRODUCTION: Frailty is highly prevalent in heart failure (HF) patients. HF is associated with oxidative stress and chronic inflammation, which impair oxygen use by skeletal muscles. Little is known about the influence of frailty on vascular responsiveness and tissue oxygenation. OBJECTIVE: Analyze the influence of frailty on vascular responsiveness and muscle oxygenation in elderly individuals with and without HF. METHODS: Individuals aged ≥60 years, with or without HF, were evaluated for frailty (phenotype). Near-infrared spectroscopy (NIRS) was used to assess muscle oxygenation at rest (oxygen saturation - StO2 and deoxyhemoglobin) and during handgrip exercise (minimum StO2 and maximum deoxyhemoglobin), and oxygenation variables. STATISTICAL ANALYSIS: Results were grouped according to the frailty phenotype: non-frail, pre-frail, and frail. Shapiro-Wilk test was used to assess normality. Data were compared using a two-way analysis of variance (ANOVA). Bonferroni post hoc test was applied to determine the influence of frailty or HF on NIRS variables. SPSS software was used in the analyses; p < 0.05 was considered significant. RESULTS: 55 elderly participants (61.8% female; 70.4 ± 7.2 years old; 28 HF patients) participated in the study. 32.7% (n = 18) were classified as non-frail, 43.3% (n = 24) as pre-frail, and 23.6% (n = 13) as frail. The analysis of vascular responsiveness (n = 52) identified an influence (p < 0.05) of frailty on the reperfusion rate (slope 2 and ∆StO2 of nadir-peak) and desaturation during occlusion (area under the curve of StO2) in HF patients. There was no influence of frailty or HF on muscle oxygenation at rest and during exercise (n = 54; p > 0.05). CONCLUSION: The coexistence of frailty and HF seems to impair vascular responsiveness, as frail elderly participants with HF presented lower reperfusion rates and higher desaturation levels during the arterial occlusion test. However, the presence of frailty or HF alone had no influence on muscle oxygenation at rest or during exercise.