Deep Venous Thrombosis (DVT)

Overview

Veins are the blood vessels that carry blood back to your heart. Some of these veins are deep inside the muscle, some are superficial lying just beneath the skin, and the rest connect the deep veins to the superficial veins. The deep veins lead to the vena cava, the largest vein of the body, which runs directly to the heart. A deep vein thrombosis is a blood clot in the deep vein system of the body. It occurs most commonly in the pelvis, thigh or calf, but can also occur in an arm or your chest.

How Did I Get a Deep Vein Thrombosis?

There are a variety of risk factors that can contribute to deep vein thrombosis:

• Surgery: particularly surgery of the hip, leg or abdomen
• Trauma or bone fracture
• A long period of bed rest or sitting for a long period of time
• Cancer
• Pregnancy
• Birth control pills or hormones taken for symptoms of menopause
• Varicose veins
• PICC line
• Having a pacemaker or implantable cardioverter defibrillator (AICD)

There are also risk factors that do not necessarily cause a DVT, but may put you at increased risk of getting one:

• Obesity
• An inherited tendency that increases risk for blood clots
• Age greater than 60
• Type A blood group

How Is Deep Vein Thrombosis Diagnosed?

A physical exam and diagnostics testing in addition to patient report of symptoms, generally is how a DVT is diagnosed. However, it is important to note that half of all patients with a DVT do not report any symptoms. If present they may include:

• Swelling of the affected extremity
• Redness or warmth
• Tenderness or pain that worsens with walking or standing

The tests used to confirm diagnosis include:

• Duplex ultrasound
• Venogram

What Are My Treatment Options for Deep Vein Thrombosis?

Treatment depends upon the extent of disease, signs and symptoms, tolerance to certain medications/therapies, and your age and current health. The goal is to prevent the clot from getting any larger, making sure it does not break off and travel to the lungs, and reducing the chances of new clots from forming.

• Compression Stockings:These elastic stockings should be worn during the day to reduce swelling and prevent blood from pooling in your leg veins.
• Anticoagulant therapy:These medications thin your blood and prevent the current clot from increasing in size, as well as prevent new clots from forming. These medications do not dissolve the clots that you have. You may be on IV heparin for several days or an injection called Lovenox that is given in the abdomen once daily for 5 to 7 days. You will be started on a medication called warfarin (Coumadin), which is an anticoagulant pill. It can take about 3 days for this medication to have effect, so during that time you may be on both warfarin and heparin. You may be on this medication for up to 6 months, during which time you will require routine blood tests to ensure your blood is at the appropriate thinness to prevent clots from forming.
• Thrombolytics:During this procedure, a thin flexible tube called a catheter is guided into the affected vein, and a drug is injected which dissolves the clot over a period of time. There is a much higher risk of bleeding with this therapy as well as stroke, compared to anticoagulants. However, if you are at a higher risk of a blood clot in your lung, this may be recommended.
• Inferior Vena Cava (IVC) filter:During this procedure, a thin flexible tube called a catheter is inserted through a vein in your leg, arm, or neck. The vascular surgeon passes a small special metal filter through the catheter and places it in the inferior vena cava, which is a large vein in your abdomen that carries blood back to the lungs. This filter traps clots that break away from leg veins, preventing them from travelling to your lungs. This therapy may be used if drug therapy is not an option for you or it has failed to work.
• Venous Thrombectomy:During this procedure, the clot is surgically removed. This may be required if non-surgical therapies have failed or if you have a rare severe form of DVT called phlegmasia cerulea dolens.

How Can I Prevent Developing a DVT?

Prevention of DVT is most successful by addressing the preventable risk factors.

Lengthy convalescence from surgery, especially hip, leg, or abdominal surgeries in which postoperative pain discourages movement and ambulation can create the stasis in veins that leads to thrombosis. In such cases, ambulation as soon as is safe, based on criteria related to the particular surgery, is the best preventative. Should ambulation be discouraged to ensure proper healing, passive range-of-motion techniques and physical therapy help protect from DVT.

The same applies for other causes of prolonged bed rest or convalescence, including trauma, bone fractures, cancer, or pregnancy.

Patients with a high risk of DVT, based on an inherited predisposition or a previous history of DVT, should avoid hormonal contraception or menopausal hormone replacement that involves estrogen.

If there is increased risk from cardiovascular interventions such as indwelling venous or implantable cardiac devices, added surveillance is prudent in prevention.

Obesity, especially in those >60 years of age, should be managed via certified dietitian/nutritionist counseling with weight reduction goals that are reasonable.

Anticoagulation

Although anticoagulation is required for treatment of acute DVT, there are patients as severe risk of recurrence that make an on-going and indefinite anticoagulation treatment protocol prudent:

•  Patients with an unprovoked proximal DVT. DVT of the upper leg’s popliteal, femoral, or iliac veins who have no risk factors or precipitating events to explain DVT occurrence.
• Recurrence of DVT. The risk of recurrence after a course of anticoagulation is completed is approximately 10% in the first year and a 5%/year thereafter. At 5 years, the risk will have risen to 30%. 

Anticoagulation causes a 90% reduction in the rate of DVT recurrence. This benefit outweighs the risk of bleeding that anticoagulation can cause, unless there is an increased bleeding risk, as there is with diabetes, advanced age, kidney and liver disease, alcohol abuse, thrombocytopenia, anemia, or recent surgery.