Muscle oxygen extraction and lung function are related to exercise tolerance after allogeneic hematopoietic stem cell transplantation.

ABSTRACT

PURPOSE: This study aimed to investigate the relationship between exercise intolerance, muscle oxidative metabolism, and cardiopulmonary function following allogeneic hematopoietic stem cell transplantation (allo-HSCT) in a sterile isolation room setting. METHODS: This was a prospective observational cohort study conducted in a single center. Fourteen patients with hematopoietic malignancies who had undergone allo-HSCT were included in this study from June 2015 to April 2020. Patients received donor HSCT after high dose-chemotherapy and total-body irradiation. Physical activity was limited during treatments. Outcome measures included body anthropometric measurements, exercise tolerance tests using the ramp protocol, pulmonary function tests, and near-infrared spectroscopy (NIRS) measurements. Data of pre- and posttransplant measurements were compared using the paired t test or nonparametric Wilcoxon U test. Associations were assessed using the Pearson or nonparametric Spearman correlations. RESULTS: NIRS showed reduced muscle consumption and extraction of oxygen in the posttransplant period compared to the pretransplant period (ΔStO2 min pre -18.6% vs. post -13.0%, P = 0.04; ΔHHb max pre 4.21µmol/l vs. post 3.31µmol/l P = 0.048). Exercise tolerance had reduced following allo-HSCT (Peak workload pre 70.3 W vs. post 58.0 W P = 0.014). Furthermore, exercise intolerance was associated with pulmonary function, muscle oxygen consumption, and muscle oxygen extraction (all P <0.05). CONCLUSION: This analysis revealed that exercise intolerance following allo-HSCT was associated with pulmonary dysfunction and muscle oxidative dysfunction. These findings could help identify the physical function associated with impaired tissue oxygen transport leading to exercise intolerance following allo-HSCT.