Identifying and Treating Peripheral Artery Disease
Don’t dismiss cramps in your calves that act up while walking or climbing stairs but calm down at rest. You could have blockages in the arteries supplying blood flow to your legs. This condition is called peripheral artery disease, or PAD, a condition in which the legs and feet don’t get the blood flow they need, says Carlo Dall’Olmo, MD, a vascular surgeon and a member of the Michigan Vascular Society. For people with diabetes, a few factors contribute to PAD: narrowed arteries due to plaque (a buildup of cholesterol and fatty substances), changes to the vessel lining, and blood platelets becoming stickier.
Even though only about 10 to 15 percent of people with diabetes develop PAD, “the risk is probably double [that of the general population],” says Benjamin Pearce, MD, associate professor of vascular surgery at the University of Birmingham in Alabama. Read on for five things you need to know about PAD.
1. Narrowing Path
Fatty deposits and plaque build up over time on the walls of blood vessels in the legs, says Niten Singh, MD, of the Division of Vascular Surgery at the University of Washington in Seattle. Smokers, obese people, and those with diabetes, high cholesterol, or a family history of artery disease are at greater risk for PAD.
2. Body wars
Excess glucose in the blood also can lead to a hardening of the arteries, which impedes blood flow. “The increased glucose alters the lining of the arteries, which has a very thin layer that keeps blood flowing smoothly and creates a balance in our system between clotting and not clotting,” Dall’Olmo says. When this layer is disrupted with high blood glucose or fatty deposits, your body has an inflammatory response—a reaction to infection or injury. That sets off biochemical reactions that can speed up the formation of plaque.
High blood glucose can also cause changes in the platelets, making them sticky and more prone to clumping, plugging the small vessels. “You have a series of events, including an inflammatory response, that all together create a perfect storm to lead to … vessel blockages,” says Dall’Olmo.
3. Warning signs
Usually the first symptom of a blockage in the leg is pain or cramping in the calves that occurs while walking or climbing stairs but goes away with rest, says Singh. You may also have cold feet, numbness, and a pins-and-needles sensation in the legs that feels different than the burning pain of diabetic neuropathy (nerve damage).
A wound on the foot that doesn’t seem to heal could be another sign of PAD, says Singh. For people with peripheral neuropathy, a hard-to-heal wound, often called an ulcer, may even be the first indication of PAD. “They may not notice [symptoms], because they may not have sensation in their foot,” Singh says.
4. Testing time
If you suspect you have symptoms of PAD, your doctor will first check the pulse in your foot. A weak pulse is likely a sign that blood isn’t flowing properly into your legs and feet. If that’s the case, your health care provider will perform a few more tests:
Ankle-Brachial Index (ABI)
For this test, your doctor will take the blood pressure in your arm and compare it with the blood pressure in your ankle. An ABI of between 1.3 and 0.9 is considered normal. Anything less than 0.9 indicates PAD, says Dall’Olmo. An ABI of 0.7 to 0.9 is considered mild, 0.4 to 0.7 is moderate, and below 0.4 is considered severe PAD.
Because people with diabetes can have hardening of the arteries, it can sometimes be difficult to compress the ankle artery to get an accurate blood pressure reading. When this is the case, you may be referred to a vascular lab, where you’ll get your blood pressure taken in the toe—the arteries there are usually spared from becoming hardened, says Singh. The normal range is a little different in the toe compared with the ankle. A reading of 0.7 and above is considered normal. Mild PAD is between 0.5 and 0.7, moderate is between 0.3 to 0.5, and severe is below 0.3. A reading of 0.3 would be of particular concern if a person has already developed a wound on his or her foot, Singh says.
An ultrasound, computed tomography angiography (CTA), interventional diagnostic angiography, and magnetic resonance angiography (MRA) can show a roadmap of the arteries in the legs and pelvis to see which are open to blood flow and which are blocked, says Dall’Olmo.
5. Treatment Types
People can have some degree of blockages in the arteries and still live completely normal lives without treatment, says Pearce.
The American Diabetes Association’s 2016 Standards of Medical Care in Diabetes recommends that asymptomatic people age 50 and older get an ankle-brachial index test each year. The test should be considered in those under 50 who have other PAD risk factors, such as high cholesterol, high blood pressure, or a smoking habit.
Stages of Peripheral Artery Disease
Mild (ABI: 0.7 to 0.9)
If you have deep, aching pain or cramps in the calves while walking but are pain free at rest, you may have mild PAD. Several lifestyle modifications can help relieve the pain (and prevent PAD in the first place).
Stop smoking. Smoking affects big vessels, such as those in the legs.
Start a walking program. When you have poor circulation from PAD, your muscles don’t get the oxygen they need from your blood, which causes pain and cramping. You can train your muscles to use oxygen more efficiently by walking until you feel discomfort, resting, and then walking some more, says Pearce. Eventually, you’ll be able to walk longer distances without feeling pain.
Control blood pressure and blood glucose. This can help prevent PAD and complications, such as kidney disease.
Take statins. These medications reduce cholesterol and help stabilize plaque buildup in the blood vessels.
Consider aspirin. Talk to your doctor about whether aspirin or blood thinners are right for you.
Moderate (ABI: 0.4 to 0.7)
Some minimally invasive procedures, performed under local anesthesia, can be done if pain is affecting your lifestyle.
Angioplasty During the procedure, a vascular surgeon will insert a flexible catheter into the artery, guiding it to the plaque and fatty deposits that have built up on the artery wall. The surgeon will then inflate a balloon, which pushes the deposits up against the artery wall to restore blood flow. A small tube called a stent may be placed in the artery to keep that area open. This procedure is best for larger arteries in the legs.
Atherectomy During this procedure, a vascular surgeon will use a catheter with a sharp blade, or less commonly a laser, to cut or vaporize plaque and remove it from the wall. This procedure is typically performed in tandem with angioplasty or when angioplasty and stenting cannot be done. A new device that was approved by the Food and Drug Administration in March uses infrared light to identify blockages and helps surgeons remove the plaque more precisely.
Severe (ABI: 0.4 or below)
If you have a near-complete blockage in the artery, surgical bypass may become necessary. This requires general anesthesia and involves creating a bypass around the blockage in the artery. “Surgical bypass still saves a lot of limbs and probably has the best durability in patients with diabetes,” says Pearce. You’ll have to stay in the hospital about a week for recovery, which may include physical therapy.
Know your Choices
Surgical options are not right for everybody. People with diabetes need to be particularly careful, says Singh, because complications, coupled with poor glucose control, can turn a simple procedure into a limb-threatening event.
This is why it’s important to go over your options with a vascular surgeon. “We can look at each individual, look at their anatomy, and make the recommendation that’s best for that person,” says Pearce.