DVT occurs when a thrombus (blood clot) develops in a vein deep in your body. The clot forms as a result of sluggish blood flow due to damaged or unhealthy veins and/or a long immobilization (such as a long plane ride). In a healthy vein, blood flows freely and mixes with natural substances in the blood that keep it from clotting. If blood flow is slowed, the blood does not mix with these natural anticoagulants and clots more easily. Most DVTs happen in your lower leg, thigh, or pelvis, but they can also occur in other parts of your body such as the arms, brain, intestines, liver or kidney.
Why is DVT dangerous?
A DVT is dangerous in all situations, and can lead to many life-threatening conditions:
- Pulmonary embolism happens when blood clots break free and travel through the bloodstream. If a clot becomes lodged in blood vessels in the lung, it can cause a pulmonary embolism, a life-threatening condition that requires immediate treatment.
- Chronic venous insufficiency is a complication of DVT in which the leg veins are damaged, interfering with blood flow so that blood pools in the leg rather than traveling back up to the heart. The affected leg becomes painful and is prone to swelling.
- Post-thrombotic syndrome is scarring following a blood clot in a leg vein. In addition to causing pain, swelling, and redness, post-thrombotic syndrome can lead to ulcers and sores on the leg that make walking painful and limit activity.
DVT symptoms
Roughly half of people with DVT in the legs suffer from leg pain, cramping, and swelling. The skin near the affected area may appear reddish or purple and be warm to the touch. Veins may enlarge and leg ulcers known as venous stasis ulcers can develop. Pain in the belly or flanks may occur if the clotting problem affects veins in the abdomen. If clots reach veins in the brain, a person may experience severe headache and/or seizures.
Pulmonary Embolism Symptoms
A pulmonary embolism requires immediate medical attention. Symptoms include:
- Chest pain while inhaling or coughing
- Rapid breathing and a rapid pulse
- Sudden shortness of breath
- Coughing up or vomiting blood
- Lightheadedness and fainting
Causes and risk factors
DVT is caused by damage to a vein from surgery, inflammation, infection, or injury. Lack of movement, such as sitting for a long time while driving or flying, long-term bedrest, or paralysis is an important contributing factor because muscle contractions from walking and moving the legs stimulate blood flow. Certain factors increase the risk of developing DVT, such as:
- Being 60 or older (although DVT can occur at any age)
- Pregnancy, which increases the pressure in the veins in the pelvis and legs
- Inherited clotting disorders
- The use of oral contraceptives or hormone replacement therapy, both of which increase the blood's ability to clot
- Excess weight, which puts more pressure on the veins in the pelvis and legs
- Smoking cigarettes, which can impact blood flow and clotting
- Cancer – certain cancers alter blood chemistry which can increase clotting
- Heart failure
- Crohn's disease, ulcerative colitis, lupus, vasculitis, or irritable bowel syndrome (IBS)
- A personal or family history of DVT or pulmonary embolism
- A broken hip or leg
- A recent hip or knee replacement
- A pacemaker or central venous catheter
- Varicose veins
- COVID-19
Treating DVT
DVT treatment has several goals: keeping a clot from enlarging, preventing it from breaking off and traveling to the lungs, and reducing the chances of developing more clots and complications. Treatment will depend on the size and location of the clot, how long it’s been there, and whether the person has developed post-thrombotic syndrome.
- Blood thinning medications may be administered, initially via injection and then orally. While they don’t dissolve the clot itself, these drugs allow blood to flow around a trapped clot so it doesn’t travel to the lungs.
- An IVC filter may be prescribed in cases where blood thinners are not indicated. The filter is implanted in the inferior vena cava, or IVC, the large vein that returns blood to the heart. The device blocks a trapped clot from traveling to the lungs while allowing blood to flow around the clot.
- DVT Thrombolysis is a minimally invasive catheter-based procedure used to treat large clots. The catheter is threaded up to the clot using guided imagery and serves as a direct delivery mechanism for clot-dissolving medications. Tiny devices can be inserted through the catheter to broaden a narrowed vein.
- Interventional vascular procedures such as angioplasties and implantation of stents may be necessary for people who have had clots for months or even years and/or suffer from post-thrombotic syndrome.
Prevention
After orthopedic surgery, the risk of developing DVT is highest from 2 to 10 days post-procedure and the risk remains elevated for about 3 months. In order to control that risk, physicians prescribe a combination of preventive measures, including leg exercises, compression stockings, and blood thinners.
You don't need to break a leg or have orthopedic surgery to develop DVT, especially if you have one or more of the risk factors listed earlier in this article. Here are a few preventive measures you can take to maintain your circulatory health and reduce your chances of developing DVT:
- If you are under the weather and have been on bed rest, try to move as soon as possible Don’t cross your legs while sitting – doing so can restrict blood flow
- Stretch your legs when traveling – stand or walk occasionally on a place, and stop every hour or so to walk around when you're driving
- Consider wearing compression hose when traveling by plane or car for lengthy trips. Talk to your doctor to determine the compression level that is right for you, and note that some high compression models may require a prescription.
- In confined spaces where walking is difficult (such as an airplane or during a concert) raise and lower your heels while keeping your toes on the floor and then raise your toes while keeping your heels on the floor.
- Don't smoke
- Manage your weight
- Try to get at least 30 minutes of moderate physical activity every day
This article appeared in the March 2024 edition of the HealthPerks newsletter.
