Researchers working on a new way to assess the progression of peripheral artery disease here note how this consequence of atherosclerosis harms function of muscles via reduced blood flow. Reduced blood flow is in fact something of a theme in aging, as the heart weakens, physical activity is reduced, capillary density in tissues declines, and atherosclerotic lesions grow to the point of narrowing critical arteries. This is all good reason to find approaches to minimize and treat atherosclerosis, develop strategies to provoke greater angiogenesis in later life to better maintain capillary networks, and stay active.
Peripheral artery disease (PAD) affects more than 7% of Americans over age 40 and more than 29% of those over 70. The disease can cause pain when walking, coldness or numbness in the lower leg, painful leg or arm cramps, difficulty sleeping and erectile dysfunction, among other symptoms, though it also may cause no symptoms at all. The lack of adequate blood flow to the limbs may make it difficult for wounds to heal and can, in severe cases, lead to amputation. Existing treatments include medicine to improve blood flow and manage pain; for appropriate cases, doctors may also consider options such as surgery or the placement of a stent to open clogged arteries.
Researchers were able to use a new magnetic-resonance imaging (MRI) technique at the end of exercise to understand the effects of PAD in the calves of patients with the disease and distinguish them from normal volunteers. The approach they used, called chemical exchange saturation transfer, or CEST, produced results comparable to the current gold standard. CEST, they found, offered added benefits without requiring highly specialized equipment unavailable to many hospitals and researchers. “The beauty of CEST is that it creates an image of energy stores in the muscle which we can match to images of blood flow. This gives us a new understanding of how atherosclerosis in the leg arteries causes problems in the muscles downstream.”