Effects of a rehabilitation program on microvascular function of CHD patients assessed by near‐infrared spectroscopy

This study aimed to evaluate whether near‐infrared spectroscopy (NIRS)‐derived reperfusion slope would detect the effects of a 12‐week rehabilitation program on lower limb microvascular responsiveness in patients with coronary heart disease (CHD). Ten CHD patients (7 males and 3 females; 57.3 ± 7.6 years) underwent 12 weeks of drug treatment and high‐intensity interval training (HIIT), 2 times per week (40 min/session). Microvascular responsiveness was assessed by using NIRS assessment of muscle oxygen saturation (StO(2)) combined with a vascular occlusion test (VOT) (NIRS‐VOT). NIRS‐VOT measures were taken at pre‐ and postintervention, and microvascular responsiveness was evaluated by examining the slope 2 of re‐oxygenation rate (slope 2 StO(2)) and the area under the curve (StO(2) (AUC)) of StO(2) signal following cuff release subsequent to a 5‐min occlusion period. The slope 2 StO(2) was significantly steeper after 12 weeks of training (4.8 ± 1.6% sec(−1)) compared to the pretraining (3.1 ± 1.6% sec(−1)) (P < 0.05). The area under the curve for the change in the % StO(2) signal during re‐oxygenation increased significantly from 3494 ± 2372%∙sec at pretraining to 9006 ± 4311%∙sec at post‐training (P < 0.05). NIRS‐VOT technique detected the improvements of 12 weeks of rehabilitation program in the lower limb microvascular responsiveness of CHD patients.