heart and blood vessel disorders
Occlusive Peripheral Arterial Disease
Diagnosis of Occlusive Peripheral Arterial Disease
Physical examination and symptoms Measurement of blood pressure and blood flow The diagnosis of occlusive peripheral arterial disease is based on the symptoms and the results of a physical examination. Doctors examine the skin of the legs or arms, noting the color and temperature and pressing gently to see how quickly color returns after pressure is removed. These observations can help doctors determine whether circulation is adequate. Procedures that directly measure blood pressure or blood flow are also done. Blood pressure measurementis done using a standard blood pressure cuff and a special electronic stethoscope. The systolic blood pressure is measured in both arms and both legs. The pressure should be the same in the arms and legs. If blood pressure in the ankle is lower than that in the arms by a certain amount (less than 90% of arm pressure), blood flow to the legs is inadequate, and occlusive peripheral arterial disease is diagnosed. If doctors suspect a blockage in an arm artery, they measure systolic blood pressure in both arms. Pressure that is consistently higher in one arm suggests a blockage in the arm with lower blood pressure, and occlusive peripheral arterial disease is diagnosed. Pulse assessmentis also useful to assess blood flow. A doctor or nurse assesses each pulse, including those at the armpits, elbows, wrists, groin, ankles, and feet, and those behind the knees. The pulse in arteries beyond the blockage may be weak or absent. For example, if doctors suspect a blockage in a leg artery, they check the pulse below a certain point in the leg. For arteries in which the pulse is inaccessible, such as the renal arteries, procedures that provide images of blood flow are done. A stethoscope is used to listen for abnormal sounds caused by turbulent blood flow through a narrowed artery (bruits). Transcutaneous oxygen tension testing measures the oxygen level of the tissue beneath the skin. Because oxygen is carried to the tissues by the blood, this test is an indirect measure of the blood flow. This painless test is done by placing sensors on the skin of the affected leg or arm and on the upper chest. Electrodes in the sensors heat the area underneath the skin to temporarily widen the blood vessels so that the oxygen level can be easily measured by the sensor. Echocardiography and Other Ultrasound Procedures None Angiography , Most medical centers are doing angiography using a less invasive method such as computed tomography (CT angiography) or magnetic resonance imaging (called Magnetic resonance angiography (MRA) , or MRA). Rather than requiring an insertion of a flexible catheter into a major artery, these tests use small amounts of a contrast agent that are injected into the bloodstream by vein using a standard intravenous catheter in the arm. For people with atherosclerosis, doctors try to identify risk factors, often by doing blood tests to measure levels of cholesterol, sugar (glucose), and, occasionally, homocysteine. Blood pressure is measured on more than one occasion to determine if it is consistently high. Blood tests also may be done to identify other causes of narrowed or blocked arteries, such as inflammation of blood vessels due to an autoimmune disorder. Such blood tests include measuring the erythrocyte sedimentation rate (ESR) and level of C-reactive protein, which is produced only when inflammation is present. For blockage of an arm artery, doctors try to determine if the cause is atherosclerosis, Thoracic Outlet Syndromes (TOS) , or inflammation of the artery (arteritis). Doctors may use magnetic resonance imaging (MRI) to rule out spinal stenosis (narrowing of the spinal canal), which can also cause pain during physical activity. However, this pain, unlike intermittent claudication, requires sitting, not just rest, for relief. 