P6-4 - Inverse Relationship Between Hemoglobin Oxygen Saturation Measured by Pulse Oximetry and Exercise Capacity in the Patients With Heart Failure

Abstract

Background: Exercise capacity (EC) is a key prognostic factor in the patients with heart failure (HF). Peak oxygen consumption (peak VO2) measured by maximal symptom-limited cardiopulmonary exercise test (CPET) is the most objective method to determine EC. Hemoglobin oxygen saturation measured by pulse oximetry (SpO2) is a simple tool to evaluate oxygenation. The relationship between SpO2 at rest and EC is unclear. Purpose: To investigate the relationship between SpO2 at rest and EC measured by maximal symptom-limited CPET in the patients with HF. Methods: We examined the association between SpO2 and EC among 46 patients with HF (age 54 ± 13, male 76%) who underwent maximal symptom-limited CPET. Results: Peak VO2/weight and peak respiratory exchange ratio were 16.2 ± 5.6 mL⋅min−1⋅kg−1 and 1.2 ± 0.1, respectively. SpO2 at rest inversely correlated with peak VO2/weight (r = −0.43, P = .003). Compared with the patients who had preserved EC (peak VO2/weight > 11.0 mL⋅min−1⋅kg−1, n = 39), the patients who had low EC (peak VO2/weight < 11.0 mL⋅min−1⋅kg−1, n = 7) showed significantly higher SpO2 at rest (99.0 ± 0.8 vs 98.0 ± 1.6%, P = .03). Multiple regression analysis revealed that higher SpO2 at rest (β = −0.29, P = .006), age, BMI and lower hemoglobin, sodium are independent predictors of lower peak VO2/weight. Conclusion: In patients with HF, higher SpO2 at rest may detect lower EC.