Abstract Body (Do not enter title and authors here): Introduction
Peripheral artery disease (PAD), an atherosclerotic disease of the peripheral arteries, also results in microvascular dysfunction. PAD patients are recommended to undergo supervised walking and medical management; however, compliance with supervised walking programs is limited due to inconvenience and pain, necessitating alternative non-pharmacological interventions. We have shown that daily muscle stretching improved microvascular function in aged rats. This prompted us to study the effect of daily muscle stretching on microvascular function of the calf muscles in PAD patients.
Methods
A randomized, single-blinded study was conducted on 24 PAD patients. Patients were assigned to either stretching or placebo stretching using a dorsiflexion splint (Image 1) for 30 min/day, 5 days/wk for 4 wks. Calf muscle oxygen saturation (smO₂) was recorded using near-infrared spectroscopy during the six-minute walking test (6MWT) before (Visit 1) and after (Visit 2) stretching or placebo stretching. The percentage decrease in smO₂ (from baseline) at minute 1 (Δ1) and minute 2 (Δ2) of the 6MWT was determined. Two-way ANOVA was used to compare Δ1 and Δ2 between the stretching and placebo stretching groups.
Results
The mean age of the patients was 74.1±11.4 yrs with 52% (13/23) males. There was no significant difference in the changes in smO₂ during the 6MWT at either minute 1 (Δ1: 44.1±7.3% vs 27.1±7.0%, p=0.12) or minute 2 (Δ2: 78.7±8.2% vs 58.1±7.9%, p=0.08) between the stretching group and placebo stretching group at Visit 1. In contrast, at Visit 2, there was a significantly greater change in smO₂ at minute 2 (D2: 83.1±8.2% vs 51.3±7.9%, p=0.008) in the stretching group compared to the placebo stretching group with a trend towards a statistically greater change in smO₂ at minute 1 (Δ1: 39.0±7.3% vs 20.4±7.0%, p=0.06) (Image 2).
Conclusion
Daily stretching of the calf muscles for 4 weeks is associated with increased oxygen extraction by the calf muscles during walking.