DVT Blood Clots
Deep vein thrombosis, or DVT, is caused by a blood clot in the deep veins. This most often happens in a leg or in the pelvis, but it can happen anywhere in the body.
Blood clots form in blood that moves too slowly through the veins. The cells stick together and form a “clump” or clot instead of moving smoothly through the cardiovascular system. Blood clots that break free can obstruct other parts of the body, including the lungs. A pulmonary embolism occurs when a blood clot causes fluid to build up in the lungs, preventing proper breathing. Pulmonary embolism can be fatal if not treated immediately.
Risk factors of DVT include being sedentary, having a high body mass index (BMI), pregnancy, previous blood clots, and being over the age of 40. People who were born with certain blood clotting disorders are also at a greater risk for DVTs. Injuries that involve a vein and other diseases, including cancer, inflammatory bowel disease, heart disease, lung disease, and even some of the treatments for cancer can make DVTs more likely.
Most people (about 60 percent) who suffer from DVT recover fully and have no recurrent symptoms. Even patients who have damage to the veins as a result of DVT can sometimes avoid having recurring symptoms. In a minority of cases (about 40 percent of the time), after the body heals from the acute DVT, a set of chronic symptoms develop that are referred to as post-thrombotic syndrome.
As the result of a DVT, the valves of the veins in the affected limb are often damaged. This results in impaired blood flow. When a vein is completely blocked as a result of this damage, the blood flows into smaller, connecting veins called collaterals. These collaterals can become quite large after taking on the extra blood flow and can sometimes be seen under the skin. If the collaterals are not able to keep up with the demand on them, chronic swelling called edema can result. This swelling in the arms or legs can also result in pain or a feeling of pressure, which are some of the symptoms of post-thrombotic syndrome.
Some people have symptoms similar to these without having been diagnosed with DVT. In these cases, the condition is referred to as venous stasis syndrome. Chronic venous stasis syndrome can be caused by heart failure, obesity, or sometimes by causes that aren’t so apparent.
DVT is considered chronic when a blood clot has been blocking a vein for two months or longer. The clot hardens, scars the vein, and causes the vein to narrow. Symptoms of chronic DVT include swelling, pain, and skin discoloration. Although chronic DVT is a slightly different issue than PTS, some of the treatments for PTS can also be used to help with chronic deep vein thrombosis.
PTS is a chronic complication resulting from deep vein thrombosis. The symptoms can range from mild to severe. Symptoms of PTS include the following:
• Atrophie blanche (a type of scarring)
• Bluish discoloration
• Chronic pain
• Dark skin pigmentation
• Dry skin
• Formation of varicose veins
• Hardening of the skin
• Lipodermatosclerosis (inflammation of the fat layer beneath the skin)
• Skin ulcer
• Swelling in the arms or legs
• Unspecified discomfort in the affected limb
• Waxing and waning pain
Symptoms of acute DVT can affect the patient for 3-6 months after the acute condition has passed. Physicians defer diagnosing PTS until after this period has passed to avoid confusing the chronic condition with the healing process that follows the acute phase of DVT.
It’s estimated that about 330,000 Americans have some form of PTS. Venous hypertension is considered a risk factor for PTS. Other risk factors include having had DVT that occurs in the larger veins, DVT that occurs in the shoulder or upper chest (referred to clinically as axillary or subclavian vein thrombosis), and residual thrombosis (in which the blood clot doesn’t break up completely, but part of it remains in the body even after the acute phase of the DVT). Among patients who’ve have DVT in an arm, only about 15 percent experience PTS.
Those who’ve had a DVT in the leg and who experience edema in the affected leg afterward can wear compression stockings to help reduce the swelling. Compression stockings need to fit well to be effective, so the patient should be measured for a customized compression stocking. If the DVT occurred about the knee, the patient should wear an above-knee stocking. Sleeves or “gauntlets” are also made for the arms of patients who’ve had DVT in an arm.
DVT patients are sometimes reluctant to wear compression garments because of comfort or other issues. These patients should be aware that compression garments come in a wide array of styles, materials, and sizes and that if one particular garment isn’t practical, the patient can find another option that will be more suitable. Note that the low-compression garments used in hospitals to help prevent embolisms during bed rest are not suitable for preventing PTS, since the amount of compression these garments provide is too low to be useful.
Treatment for PTS
Treatment for PTS may include any of all of the following:
• Balloon opening (angioplasty) and stenting of the narrowed vein (a radiologic procedure)
• Compression pump
• Elevation of the affected limb while resting
• Exercises to strengthen the affected limb
• Pain management
• Weight loss
A compression pump may be recommended in situations in which the patient has extensive swelling in the legs that is not relieved with compression stockings. Compression pumps are available in small, battery-powered form that the patient can take with him or her when traveling.
Venous skin ulcers are one symptom of PTS that can be particularly difficult to treat, especially with reduced or restricted blood flow in the affected limb. Since patients must learn to practice proper wound care consistently, it may be necessary for the patient to visit a wound care specialist.