Peripheral Artery Disease (PAD) is a condition of the hardening or narrowing of the arteries that supply certain parts of the body. It is highly associated with heart and coronary artery disease. PAD may affect the arteries of the neck which can lead to a stroke. It may also involve the arteries going to the legs, leading to pain with walking. For men, it can be a cause of erectile dysfunction. PAD is usually easily diagnosed with a simple ultrasound test.