What is deep vein thrombosis?

Arteries bring oxygen-rich blood from your heart to the rest of your body, whereas your veins are the blood vessels that return oxygen-poor blood back to your heart. You have three kinds of veins. Superficial veins lie close to your skin, and the deep veins lie in groups of muscles. Perforating veins connect the superficial veins to the deep veins with one-way valves. Deep veins lead to the vena cava, your body’s largest vein, which runs directly to your heart. Deep vein thrombosis (DVT) is a blood clot in one of the deep veins. Usually, DVT occurs in your pelvis, thigh, or calf, but it can also occur less commonly in your arm, chest, or other locations.

DVT can cause sudden swelling, pain or a sensation of warmth. DVT can be dangerous because it can cause a complication known as pulmonary embolism. In this condition, a blood clot breaks free from your deep veins, travels through your bloodstream, and lodges in your lungs. This clot can block blood flow in your lungs, which can strain your heart and lungs. A pulmonary embolism is a medical emergency. A large embolism can be fatal in a short time.

It can sometimes be difficult to recognize the symptoms of DVT. However, the condition can be effectively treated once your physician diagnoses it.

What are the symptoms?

About half of all DVT cases do not cause symptoms. The symptoms you feel can depend on the location and size of your blood clot. They include swelling, tenderness, leg pain that may worsen when you walk or stand, a sensation of warmth, and skin that turns blue or red.

What causes DVT?

When something goes wrong with your body’s blood clotting system, DVT can occur. Once a small clot forms in your vein, it can cause an inflammation that may encourage more blood clots to form.

Often, poor blood flow, or stagnation of blood flow, in your leg veins increases the risk for DVT. This poor flow can occur when you are not able to move for long periods of time. As a result, when your blood pools in your veins, clots are more likely to form. Some specific causes of DVT include:

• Major surgery on your hip, knee, leg, calf, abdomen, or chest
• A broken hip or leg
• Prolonged travel (this is sometimes called economy class syndrome because people flying coach on airplanes have less room to move their legs)
• Inherited blood clotting abnormalities
• Cancer

Although it is true that long airplane flights can increase your risk of DVT, this rarely occurs. Most cases of DVT occur in sick, hospitalized patients.

You have a greater chance of developing DVT if you are obese, have a history of heart attack, stroke or congestive heart failure, are pregnant, nursing or taking birth control pills, or have inflammatory bowel disease.

Most cases of DVT affect the legs, but DVT in the upper body is becoming more commonly recognized. Some factors that increase your chances of developing DVT in the upper body include:

• Having a long, thin flexible tube called a catheter inserted in your arm vein. Catheters can irritate your vein wall and cause clots to form
• Having a pacemaker or implantable cardioverter defibrillator (ICD) for the same reason
• Having cancer
• Performing vigorous repetitive activities with your arms. This type of DVT is rare and occurs mostly in athletes such as weight lifters, swimmers and baseball pitchers. This disease is known as Paget-Schroeter syndrome, and can often be associated with other anatomic abnormalities

What tests will I need?

First, your physician asks you questions about your general health, medical history, and symptoms. In addition, your physician conducts a physical exam. Together these are known as a patient history and exam. To confirm a diagnosis of DVT, the physician may order a duplex ultrasound test or another test called a venogram.

Duplex ultrasound uses high-frequency waves higher than human hearing can detect. Duplex ultrasound allows your physician to measure the speed of blood flow and to see the structure of your veins and sometimes the clots themselves.

A venogram is an x ray that allows your physician to see the anatomy of your veins and sometimes the clots within them. During this test, your physician injects a dye that makes your veins appear on an x ray.

How is DVT treated?

Your physician or vascular surgeon can usually treat DVT with medications or minimally invasive procedures. Rarely, surgery may be required.

If you have DVT, your physician may inject an anticoagulant drug called heparin. Anticoagulants are also called blood thinners. They don’t literally thin your blood, but they help prevent your blood from clotting too easily. Heparin helps prevent clots from forming and keeps clots you already have from growing larger. However, heparin cannot break up a clot that you already have. Heparin acts rapidly but must be given by vein. Alternatively, your physician may prescribe a medication known as a low molecular weight heparin (LMWH). This has many of the same effects as heparin, but is given through an injection in the abdomen once or twice a day.

Usually, you will receive heparin (or LMWH) for five to seven days. After that, you will take an anticoagulant pill called warfarin (Coumadin), usually for 6 months. It can take a few days for the warfarin to take effect, and during that time period you may be on both heparin (or LMWH) and warfarin. During the time you are receiving medication, your physician will order blood tests to make sure your anticoagulation level is adequate to prevent clots, but not too high to cause excessive bleeding. Anticoagulants can cause bleeding problems if the dosage is too high.

If your physician wants to dissolve the clot, he or she may recommend thrombolysis. In this procedure, your vascular surgeon injects clot-dissolving drugs through a catheter directly into the clot. Thrombolysis has a higher risk for bleeding complications and stroke than anticoagulant therapy. However, thrombolysis can also dissolve very large clots. Your vascular surgeon may prefer to use thrombolysis if you have a high risk for pulmonary embolism or, sometimes, if you have DVT in your arm.

Rarely, physicians recommend surgery to remove a deep vein clot. The procedure is called venous thrombectomy. You may need this surgery if you have a severe form of DVT called phlegmasia cerulea dolens, which does not respond to adequate non-surgical treatment. Phlegmasia cerulea dolens, if not adequately treated, can cause gangrene, which is tissue death and occurs when tissues in your body do not receive enough oxygen and blood. Gangrene is very serious and can lead to amputation.

A special metal filter can protect you from a pulmonary embolism if you are unable to take anticoagulants. This device is called a vena cava filter. The vena cava is a large vein in your abdomen. It carries blood back to your heart and lungs. Your vascular surgeon may recommend a vena cava filter if you are not a candidate for drug therapy for DVT or if drugs didn’t reduce your clots. Vena cava filters trap the clots that break away from your leg veins before they can reach your lungs. Usually, your vascular surgeon inserts the filter into your vena cava through a catheter placed into a leg, neck or arm vein.

Elastic compression stockings may be used to reduce your swelling and prevent blood from pooling in your veins in your legs.

What can I do to stay healthy?

Physicians know that DVT is more likely if you have surgery. If you are scheduled for surgery, your physician may recommend one or more of the following, to prevent DVT:

• Taking anticoagulants before and immediately after your surgery. This technique is especially helpful if you are undergoing orthopedic joint replacement surgery, such as knee replacement. Your physician may also recommend anticoagulants if you experience heart attacks or are hospitalized for other major illnesses
• Being fitted with a sleeve-like device on your legs during surgery. This device compresses your legs regularly to help blood keep flowing through your veins until you can walk again
• Elastic compression stockings, which prevent blood from pooling in your veins
• Walking or doing other leg exercises as soon as possible after surgery

Find a Vascular Specialist

Revised December 2010

What is an angiogram?

An angiogram is an imaging test that uses x-rays to view your body’s blood vessels. Physicians often use this test to study narrow, blocked, enlarged, or malformed arteries or veins in many parts of your body, including your brain, heart, abdomen, and legs. When the arteries are studied, the test is also called an arteriogram. If the veins are studied, it is called a venogram.

To create the x-ray images, your physician will inject a liquid, sometimes called “dye”, through a thin, flexible tube, called a catheter. He or she threads the catheter into the desired artery or vein from an access point. The access point is usually in your groin but it can also be in your arm or, less commonly, a blood vessel in another location. This “dye, ” properly called contrast, makes the blood flowing inside the blood vessels visible on an x-ray. The contrast is later eliminated from your body through your kidneys and your urine. Your physician may recommend an angiogram to diagnose a variety of vascular conditions, including:

• Blockages of the arteries outside of your heart, called peripheral artery disease (PAD)
• Enlargements of the arteries, called aneurysms
• Kidney artery conditions, called renovascular conditions
• Problems in the arteries that branch off the aorta, called aortic arch conditions
• Malformed arteries, called vascular malformations
• Problems with your veins, such as deep venous thrombosis (DVT) or blood clots in the lungs called pulmonary emboli

Sometimes physicians can also treat a problem during an angiogram. For instance, your physician may be able to dissolve a clot that he or she discovers during the test. A physician may also perform an angioplasty and stenting procedure to clear blocked arteries during an angiogram, depending on the location and extent of the blockage. An angiogram can also help your physician plan operations to repair the arteries for more extensive problems.

How do I prepare?

Your physician will perform blood tests to determine your blood’s ability to clot and to assess your kidney function. Based on the test results, the nature of the particular angiogram, and your particular situation, your physician may instruct you to stop taking aspirin or other drugs that prevent clotting. Your physician will also tell you which medications you should continue to take. Usually your physician will ask you not to eat or drink anything within 6 hours of your angiogram. Depending on your particular situation, however, you may be encouraged to take extra fluid before an angiogram. Sometimes this fluid will be given to you by intravenous administration. Also, if you have problems with your kidney functions, you may benefit from medication given to you before the test as well as the extra fluid administration. If you have allergies to the contrast material or to iodine or shellfish, you may require medication before the test to lessen your risk for an allergic reaction. Your vascular surgeon will advise you regarding the best treatment options for your particular situation.

Because you shouldn’t drive immediately after an angiogram, you should arrange for a ride home.

Am I at risk for complications?

Blood clotting problems, kidney problems, obesity, and advanced age can increase your risk for developing complications during and after an angiogram. Allergies can increase your risk of a reaction to the contrast dye. The extra fluid associated with angiograms can sometimes cause problems for patients whose hearts have poor pumping ability, such as those with congestive heart failure.

What happens during an angiogram?

Your test will take place in a room equipped with a specialized x-ray machine. Your physician will insert an IV to provide you with fluids and medications. Your physician will choose where to insert the angiographic catheter, usually into an artery in your groin or near your elbow. Before the insertion, he or she will clean your skin and shave any hair in the area to reduce your risk of infection. Your physician then numbs your skin with a local anesthetic and then makes a tiny puncture to reach the artery below. He or she punctures your artery with a hollow needle, advances a thin wire through the needle, threads a catheter over the wire, and guides it to the desired location. Your physician uses x-rays that are projected on a video screen, a process called fluoroscopy, to see the catheter as it moves through your arteries. Usually, he or she moves the x-ray table to follow the catheter as it is moved through your blood vessel.

Once your physician has positioned the catheter properly, he or she injects the contrast dye. The contrast causes a brief, mild warm feeling as it enters your bloodstream. Your physician takes more x-ray images to see how the contrast is flowing through your arteries. During the test, your physician may ask you to hold your breath for about 5 to 15 seconds. In addition, your physician may ask you to lie perfectly still to prevent sudden movements from blurring the x-ray pictures.

When the test is over, your physician will remove the catheter and press the insertion site for 10 to 20 minutes to help stop bleeding.

Angiograms generally take about 1 hour to complete if only x-rays are required. However, it may take longer if your physician also performs angioplasty and stenting.

What can I expect after an angiogram?

After the test, the medical team will monitor you for about 6 hours. During this time, you should keep the arm or leg that was punctured straight to minimize bleeding from the puncture site. You will also be asked to drink fluids to prevent dehydration and flush the dye from your kidneys. Once any bleeding from the insertion site has stopped and your vital signs are normal, your physician will tell you that you can leave.

At home, you can eat normally, but you should continue drinking extra fluids for 1 to 2 days. For at least 12 hours after the angiogram, avoid strenuous physical activities such as climbing stairs, driving, and walking. You should be able to resume normal activities within a day or two of the procedure.

Are there any complications?

Complications from angiography may include bleeding, pain, or swelling where the catheter was inserted, or pain, numbness, or coolness in your arm or leg. These symptoms may signify either bleeding from the puncture site or blockage of your artery. Bruising at the puncture site is common and usually resolves on its own. Rarely, impaired kidney function, or kidney failure, can occur following an angiogram, especially if you already have kidney disease. Also rarely, severe allergic reactions can occur, especially among people who have had previous allergic reactions to the contrast dye. Infrequently, a patient may experience shortness of breath or fluid overload if they have a heart condition associated with poor pumping action, such as congestive heart failure.