Effects of Passive Muscle Stretching on Vascular Function and Symptoms of PAD

Patients with peripheral arterial disease often have walking impairment due to insufficient oxygen supply to lower extremity skeletal muscle. In an aging rat model, we have previously shown that daily calf muscle stretching improves endothelium-dependent dilation of soleus muscle arterioles and blood flow during exercise. The effect of muscle stretching on endothelial function and walking distance in patients with peripheral arterial disease is unknown. We performed a prospective, randomized, non-blinded, crossover study in 13 patients with stable symptomatic peripheral artery disease. Patients were randomized to undergo either 4 weeks of passive calf muscle stretching (ankle dorsiflexion splints applied 30 minutes/day, 5 days/week) followed by 4 weeks of no muscle stretching (control group) and vice versa. Endothelium-dependent flow-mediated dilation and endothelium- independent nitroglycerin-induced dilation of the popliteal artery and a 6 minute walk test were evaluated at baseline and after each 4 week treatment interval. Patients crossed over to the other treatment arm after 4 weeks and endothelium-dependent flow-mediated dilation and endothelium- independent nitroglycerin-induced dilation of the popliteal artery and the 6 minute walk test were repeated.