Table III.

Univariate regression models between calf muscle hemoglobin oxygen saturation (StO₂) variables and clinical exercise outcome variables in 151 symptomatic patients with peripheral artery disease. Values are Pearson correlation coefficients.

Calf Muscle StO2 Variables	COT	PWT	6MWPFD §	6MWD	Total Steps	MV Steps	WIQ Dist	WIQ Speed	WIQ Stairs	PF Score
Absolute drop in StO2 from rest to 1 minute of exercise	−0.25 †	−0.17	0.02	0.14	0.18 *	0.15	−0.06	−0.06	−0.09	−0.05
Percentage drop in StO2 from rest to 1 minute of exercise	−0.30 ‡	−0.26 †	−0.08	−0.03	0.09	0.07	−0.11	−0.15	−0.19 *	−0.13
Absolute drop in StO2 from rest to the minimum exercise value	−0.08	0.02	0.11	0.22 *	0.25 †	0.25 †	−0.00	0.03	0.06	0.03
Percentage drop in StO2 from rest to the minimum exercise value	−0.14	−0.08	−0.02	0.04	0.13	0.17	−0.07	−0.06	−0.06	−0.05
Exercise time to minimum StO2 §	0.49 ‡	0.56 ‡	0.19 *	0.31 ‡	0.14	0.20 *	0.33 ‡	0.39 ‡	0.37 ‡	0.32 ‡
StO2 rate of decline to exercise minimum §	−0.48 ‡	−0.49 ‡	−0.11	−0.19 *	−0.00	−0.06	−0.30 ‡	−0.33 ‡	−0.31 ‡	−0.28 ‡

^*(p < 0.05),

^†(p < 0.01),

^‡(p < 0.001).

^§Log transformed data.

COT = claudication onset time

PWT = peak walking time

6MWPFD = 6-minute walk pain-free distance

6MWD = 6-minute walk distance

MV = moderate-to-vigorous walking

WIQ = walking impairment questionnaire

Dist = distance

PF = physical function from the Medical Outcomes Study Short-Form 36 survey