Peripheral Artery Thrombosis

Peripheral artery thrombosis occurs when a blood clot forms in arteries that carry blood to the arms or legs, blocking or restricting blood flow and potentially causing serious complications if left untreated.

Table of contents

• Understanding Peripheral Artery Disease and Thrombosis
• Symptoms and Warning Signs
• Causes and Risk Factors
• How It Is Diagnosed
• Treatment Options
• Living with the Condition

Understanding Peripheral Artery Disease and Thrombosis

Peripheral artery disease (PAD) is a condition where arteries in your limbs, usually your legs, become narrowed or blocked^[1]. This limits how much blood can get through and may lead to symptoms like leg pain^[2]. The condition affects more than 200 million people around the world and around 12 million adults age 40 or older in the United States^[2].

The most common cause of PAD is atherosclerosis, a condition where a waxy substance called plaque builds up inside the arteries^[1]. Plaque is made of fat and cholesterol. Over time, this plaque gradually narrows the arteries, making it harder for blood to flow freely^[4]. When enough plaque builds up on the inside of an artery, the artery becomes clogged, and blood flow is slowed or stopped^[3].

Thrombosis refers to the formation of a blood clot inside a blood vessel. In peripheral artery thrombosis, a blood clot forms in an artery that is already narrowed by plaque buildup^[5]. This can cause sudden, complete blockage of the artery. A blood clot may also form when the hard surface of plaque cracks or tears, allowing platelets (disc-shaped particles in your blood that help it clot) to come to the area^[2].

• Peripheral arteries (legs and arms)
• Iliac arteries (pelvic area)
• Femoral arteries (thighs)
• Popliteal arteries (knees)
• Tibial and peroneal arteries (calves)

Symptoms and Warning Signs

Many people with PAD may not notice any symptoms, especially in the early stages^[4]. However, when symptoms do occur, they vary depending on which artery is affected and how completely the artery is blocked^[5].

The most common symptom is leg discomfort when you’re active. This happens when your arteries can’t keep up with your muscles’ increased demand for blood^[2]. You might feel pain, cramping, numbness or fatigue in your calves, thighs or buttocks. It starts during physical activity, like walking or climbing stairs, and it stops when you stop moving, typically within 10 minutes^[2]. This type of pain is called claudication^[1].

As PAD progresses, you may have leg or foot pain when you’re resting. You’ll feel a burning or aching pain in your legs, feet or toes. This often happens when you’re lying flat. Dangling your leg or feet over the edge of your bed may relieve the pain^[2].

Other symptoms include foot and toe ulcers, which are wounds on your skin that may get infected and can take a long time to heal^[2]. You may also notice coldness in your lower leg or foot, with one leg feeling colder to the touch than the other^[4].

Changes in skin color or temperature can signal severe PAD. A sudden blockage in your artery can make your skin turn purple, green, black or very pale. Your skin may also feel cool to the touch or like “pins and needles.” These are signs of severe PAD and require immediate medical care^[2].

Additional signs include slow nail or hair growth on your legs, which can lead to little or no hair on the toes, feet, or lower legs^[4]. Males might also experience erectile dysfunction related to peripheral artery disease when there’s narrowing of the lower aorta or iliac arteries^[2].

Causes and Risk Factors

The gradual buildup of plaque in your arteries is the most common cause of peripheral artery disease^[2]. Your arteries are shaped like hollow tubes with a smooth lining that prevents blood from clotting and promotes steady blood flow. When you have PAD, plaque slowly forms inside your artery walls, narrowing the space where blood can flow^[2].

Thrombosis in peripheral artery disease can occur through different mechanisms. A blood clot may form in an artery that is already narrowed by plaque. Sometimes a clot breaks off from a site such as the heart or aorta, travels through the bloodstream, and lodges in an artery downstream^[5]. An atheroma (plaque deposit) can also rupture into the blood vessel and trigger the formation of a blood clot that suddenly blocks an artery^[5].

There is accumulating evidence that thrombosis contributes to peripheral arterial disease, and that treatment should be considered at all symptomatic stages^[9].

The most significant risk factors for PAD are high cholesterol, high blood pressure, diabetes, chronic kidney disease, and smoking. The presence of three or more factors increases PAD risk by 10 times^[12]. Anyone can develop peripheral artery disease, but your risk goes up with age^[2]. Black people face a higher risk compared to non-Hispanic white people, especially after age 50 in males and age 60 in females^[2].

Smoking is particularly dangerous. In one large study, more than 80% of patients with PAD were current or former smokers^[12]. Cardiovascular mortality rates of current smokers with PAD are more than double that of those with PAD who have never smoked^[12].

Other factors that contribute to PAD include being male, having obesity, being physically inactive, and having a family history of atherosclerosis^[5]. Some disorders increase the risk of blood clot formation, including atrial fibrillation, other heart disorders, and clotting disorders^[5].

How It Is Diagnosed

To diagnose peripheral artery disease, a healthcare professional will examine you and ask questions about your symptoms and medical history^[8]. Patients at increased risk of PAD should be assessed for exertional leg symptoms, ischemic rest pain, and nonhealing wounds. Vascular examination should include palpation of lower extremity pulses^[12]. If you have peripheral artery disease, the pulse in the affected area may be weak or missing^[8].

Current guidelines recommend resting ankle-brachial index (ABI) testing for patients with history or examination findings suggesting PAD^[12]. This is a common test used to diagnose PAD. It compares the blood pressure in the ankle with the blood pressure in the arm^[8]. You may be asked to walk on a treadmill, and blood pressure readings may be taken before and right after exercising to check the arteries during walking^[8].

Patients with symptoms of PAD but a normal resting ABI can be further evaluated with exercise ABI testing^[12]. Routine ABI screening for those not at increased risk of PAD is not recommended^[12].

Additional tests may include ultrasound of the legs or feet, which uses sound waves to create pictures of how blood moves through the blood vessels^[8]. Doppler ultrasound is a special type of ultrasound used to spot blocked or narrowed arteries^[8].

Angiography is a test that uses imaging and a dye to look for blockages in the arteries. The dye is given through a blood vessel and helps the arteries show up more clearly on the test images^[8].

Blood tests are done to check for things that increase the risk of PAD, such as high cholesterol and high blood sugar^[8].

Treatment Options

The goals of treatment for peripheral artery disease are to manage symptoms, such as leg pain, so exercise is comfortable, and to improve artery health to reduce the risk of heart attack, stroke and other complications^[8].

Treatment of PAD includes lifestyle modifications, including smoking cessation and supervised exercise therapy, plus secondary prevention medications^[12]. There’s no cure for peripheral arterial disease, but lifestyle changes and medicine can help reduce the symptoms^[11].

Medications play an important role in managing PAD. Statins are prescribed if blood tests show that your levels of LDL cholesterol (“bad cholesterol”) are high. Statins work by helping to reduce the production of LDL cholesterol by your liver^[11]. Antihypertensives are medications used to treat high blood pressure. A common type is an angiotensin-converting enzyme (ACE) inhibitor, which blocks the actions of some hormones that help regulate blood pressure^[11].

Medicines to prevent blood clots are also used. One of the biggest potential dangers if you have atherosclerosis is a piece of fatty deposit (plaque) breaking off and blocking an artery^[11]. Antiplatelet therapy is recommended as part of treatment^[12].

In claudication, antiplatelet therapy is indicated in addition to lifestyle advice and sometimes surgery or angioplasty^[9]. In chronic critical limb ischemia, prophylaxis of venous thromboembolism by low-dose heparin is indicated during hospitalization, as is long-term antiplatelet therapy; local thrombolysis or systemic prostanoid infusions are increasingly used^[9]. In acute critical limb ischemia, full dose heparinization is followed by thromboembolectomy, local thrombolysis, angioplasty and surgery as appropriate^[9].

Thrombolysis, an established and effective treatment for peripheral arterial thrombosis, has been popular for decades. During thrombolysis, administration of a thrombolytic drug destroys the blood clot^[14]. All currently available thrombolytic agents are plasminogen activators; they induce blood clot destruction by converting plasminogen into plasmin, an enzyme that cuts and destroys the fibrin polymer network that unites the thrombus^[14].

Surgery may be used in severe cases or when initial treatment has not effectively reduced your symptoms^[11]. Surgical revascularization should be considered for patients with lifestyle-limiting claudication who have an inadequate response to lifestyle and medical therapies^[12]. Patients with acute or limb-threatening limb ischemia should be referred immediately to a vascular surgeon^[12].

Living with the Condition

PAD is a lifelong medical condition. Once you have been diagnosed with PAD, you will see a healthcare provider regularly who specializes in vascular (blood vessel) diseases. You will need to take steps to prevent complications^[20].

The two most important lifestyle changes that you can make if you’re diagnosed with PAD are exercising more regularly and stopping smoking, if you smoke^[11]. Evidence suggests that regular exercise helps to reduce the severity and frequency of PAD symptoms, while also reducing the risk of developing another cardiovascular disease^[11].

Supervised exercise is recommended as one of the first steps for managing PAD. This may involve group exercise sessions with other people with cardiovascular disease, led by a trainer. The exercise programme usually involves 2 hours of supervised exercise a week for 3 months^[11].

One of the best exercises you can do is walking. It’s normally recommended that you walk as far and as long as you can before the symptoms of pain become intolerable. Then rest until the pain goes. Begin walking again until the pain returns. Keep using this “stop-start” method until you’ve spent at least 30 minutes walking in total. Do this several times a week^[11].

Stopping smoking will reduce your risk of PAD getting worse and another serious cardiovascular disease developing. Research has found that people who smoke after receiving their diagnosis are much more likely to have a heart attack and die from a complication of heart disease than people who quit after their diagnosis^[11].

As well as exercising and stopping smoking, there are a number of other lifestyle changes you can make to reduce your risk of developing other forms of cardiovascular disease. These include eating a balanced diet, managing your weight, and cutting down on alcohol^[11].

Diet changes can help prevent or slow the progression of PAD. High cholesterol is a risk factor for the disease, so eating a diet low in saturated and trans fats is important for keeping blood cholesterol levels down^[19]. The Mediterranean diet may be beneficial for preventing PAD and has been linked to more stable blood sugar levels and lower cholesterol^[19].

Taking care of your feet and legs is important. Check your feet and toes every day for sores, cracks, or anything that doesn’t look right. Sores may not heal well^[15]. Wear shoes that fit you well. You want to be as comfortable as possible when you walk^[15].

PAD can cause severe pain and disrupt your life. If you’re dealing with depression or anxiety it’s important to access support to look after your mental wellbeing^[11].

PAD can lead to complications. Trouble managing daily activities without help because of reduced mobility is one complication. Chronic (long-term) poor blood flow in your leg, called critical limb ischemia, is another complication. Symptoms may include pain during rest, sores, infections, and death of tissue, called gangrene, because of lack of blood flow. Gangrene is a severe complication that may require amputation (surgical removal) of the affected body part^[20].