Abstract 4370903: Association Between Meeting Physical Activity Time-Intensity Guidelines and Calf Muscle Oxygen Saturation in Patients with Symptomatic Peripheral Artery Disease

Purposes: We determined whether meeting the 2018 physical activity time-intensity guidelines was associated with better microvascular function, assessed by calf muscle oxygen saturation (StO 2 ), and better ambulation than failing to meet the guidelines in patients with symptomatic peripheral artery disease (PAD). Methods: Five hundred and two patients were assessed on daily ambulatory activity for one week with a step activity monitor, and were grouped according to whether they achieved less than 150 min of moderate intensity physical activity per week and whether they walked fewer than 7,000 steps/day (Group 1=Do Not Meet Guidelines; n=272), or whether they were above these thresholds (Group 2=Meet Guidelines; n=230). Peak walking time (PWT) was measured during a standardized Gardner-Skinner graded treadmill protocol, and calf muscle StO 2 was continuously measured over the medial gastrocnemius muscle of the more symptomatic leg using a continuous-wave, near-infrared spectrometer system. Results: Peak walking time (PWT) during the treadmill test was greater in Group 2 than in Group 1 (622±326 sec vs. 398±259 sec, p<0.001). Exercise time to reach the minimum calf muscle StO 2 was also greater in Group 2 than in Group 1 (297±329 sec vs. 204±227 sec, p=0.015). In multivariable analyses, the greater time to reach the minimum calf muscle StO 2 in Group 2 persisted after adjusting for ankle/brachial index (p=0.018). Conclusions: Patients with symptomatic PAD who met the 2018 physical activity time-intensity guidelines had better microvascular function and prolonged PWT during treadmill exercise than patients who were less physically active. The clinical significance is that performing enough daily ambulation to meet the physical activity time-intensity guidelines is a simple goal that is associated with better leg microcirculation and ambulation in symptomatic patients with PAD.