[O-HT-01-2] Home-based Daily Calf Muscle Stretching Improves Endothelial Function of Lower Limb Artery and Walking Capacity in Elderly Patients With Peripheral Artery Disease
A Randomized, Non-blinded, Crossover Study
Keywords:Muscle stretching, Endothelial function, 6-minute walking test
【Purpose】Patients with peripheral artery disease(PAD)frequently have reduced walking capacity due to insufficient oxygen supply to skeletal muscle. Our preliminary results in a rat model of aging indicate that a program of daily calf muscle stretching improves endothelium-dependent dilation of soleus muscle arterioles and increases soleus muscle blood flow during exercise;however, little is available for the effects of muscle stretching on the function of arteries supplying the legs of PAD patients. We hypothesized that home-based daily calf muscle stretching improves endothelial function of popliteal artery and walking capacity in PAD patients.
【Methods】A randomized, non-blinded, crossover study was performed to test our hypothesis. Four weeks of muscle stretching(30 min/d, 5 days/wk)and 4 weeks of usual lifestyle(no stretching)were performed in random order. Thirteen patients with PAD participated in this study(71±2 years old;7 males and 6 females). During the stretching intervention both ankle joints were maintained at 15o of dorsiflexion using ankle dorsiflexion splints to stretch their calf muscles at home. Flow-mediated dilation(FMD;vascular endothelial function)and nitroglycerin-induced dilation(vascular smooth muscle function)of popliteal artery were measured after muscle stretching and no stretching period using ultrasound. A six-minute walk test was also performed to obtain walking distance covered during the 6 minutes(6MD).
【Results】FMD and 6MD significantly improved after 4 weeks of muscle stretching than those measured after 4 weeks of no stretching(P<0.01, respectively). No difference in nitroglycerin-induced dilation was found between groups(P=0.54). Percentage change of 6MD(%change =[(stretching-no stretching)/no stretching]x100)positively correlated with the %change of FMD(P<0.05).
【Discussion】These results indicate that daily calf muscle stretching enhances endothelial function of popliteal artery, resulting in improvement of walking capacity in elderly PAD patients.
【Methods】A randomized, non-blinded, crossover study was performed to test our hypothesis. Four weeks of muscle stretching(30 min/d, 5 days/wk)and 4 weeks of usual lifestyle(no stretching)were performed in random order. Thirteen patients with PAD participated in this study(71±2 years old;7 males and 6 females). During the stretching intervention both ankle joints were maintained at 15o of dorsiflexion using ankle dorsiflexion splints to stretch their calf muscles at home. Flow-mediated dilation(FMD;vascular endothelial function)and nitroglycerin-induced dilation(vascular smooth muscle function)of popliteal artery were measured after muscle stretching and no stretching period using ultrasound. A six-minute walk test was also performed to obtain walking distance covered during the 6 minutes(6MD).
【Results】FMD and 6MD significantly improved after 4 weeks of muscle stretching than those measured after 4 weeks of no stretching(P<0.01, respectively). No difference in nitroglycerin-induced dilation was found between groups(P=0.54). Percentage change of 6MD(%change =[(stretching-no stretching)/no stretching]x100)positively correlated with the %change of FMD(P<0.05).
【Discussion】These results indicate that daily calf muscle stretching enhances endothelial function of popliteal artery, resulting in improvement of walking capacity in elderly PAD patients.