Potential Complications of DVT

Many people choose to see a vein specialist when they dislike the look of their spider veins or varicose veins. However, not all vein problems are visible, and some can severely impact your health. Deep vein thrombosis, also known as DVT, can cause pain, swelling, and discomfort and occurs when a clot begins to form in a deep vein, usually in the lower leg or thigh. Have you been diagnosed with deep vein thrombosis in Houston? If so, then it’s important to know the facts about this condition. Read on to learn about potential complications that are associated with DVT.

Pulmonary Embolism

Your doctor will tell you that the most concerning complication related to deep vein thrombosis is a pulmonary embolism. This problem occurs when a blood clot travels from one part of the body and reaches a blood vessel in a lung, where it blocks the flow of blood. Because pulmonary embolisms can be fatal, it is critical to be vigilant of the symptoms of this condition if you have been diagnosed with DVT and to seek out medical attention right away at the first signs of a pulmonary embolism. Signs and symptoms that can indicate a pulmonary embolism include:

• Chest discomfort that worsens when you cough or take a deep breath
• Sudden and unexplained shortness of breath
• Coughing up blood
• Having a rapid pulse
• Fainting or feeling dizzy or lightheaded

Postphlebitic Syndrome

A common complication that can develop after deep vein thrombosis is known as postphlebitic or postthrombotic syndrome. These are both terms used describe the set of symptoms that a patient may experience after suffering from DVT. These symptoms can include leg pain, skin sores, skin discoloration, and edema, or swelling of the legs. Postphlebitic syndrome results from the damage that was caused by the DVT blood clot, which reduces the flow of blood in the affected area. It is possible for postphlebitic syndrome to occur several years after a case of DVT.

Why DVT Complications Happen

A deep vein thrombosis is a clot inside one of the large veins in the leg, thigh or pelvis, and sometimes the arm. Two things make it dangerous. First, a fresh clot is soft and can break apart, sending fragments toward the heart and lungs. Second, even when the clot stays put, it inflames the vein wall and can scar the delicate valves inside it. The first problem causes the sudden, short-term complications. The second causes the slow, long-term ones.

That is why DVT treatment has two goals. Blood thinners (anticoagulants) stop the clot from growing and new clots from forming while the body gradually dissolves and remodels the existing clot. Follow-up care focuses on protecting the leg from the lasting effects of valve damage. You can read more about diagnosis and treatment on our deep vein thrombosis page.

Potential Complications of DVT at a Glance

Pulmonary embolism and post-phlebitic syndrome are the best-known complications. Here is how they compare with the other complications we watch for in our practice.

Clot Extension and Recurrent DVT

A clot that starts in the calf can grow upward into the knee, thigh or pelvic veins, where the risk of a pulmonary embolism is higher. This is one reason why calf clots are monitored with repeat ultrasound when they are not treated with anticoagulants straight away.

After a first DVT, the chance of another one stays higher than in someone who has never had a clot. The risk depends a great deal on why the first clot happened. A clot that followed surgery, a cast or a long hospital stay, where the trigger has now passed, tends to carry a lower risk of coming back than a clot that appeared without any obvious cause. That difference is a major factor in deciding how long anticoagulation should continue, which is a decision you make with your doctor, not one to make alone by stopping your tablets.

Common reasons clots come back

• Stopping blood thinners early or missing doses
• An ongoing risk factor such as cancer, an inherited clotting tendency or limited mobility
• Estrogen-containing medications
• Long periods of immobility, such as long-haul travel or recovery from surgery
• Residual narrowing or scarring in the treated vein

Bleeding: The Complication of Treatment Itself

Anticoagulants are life-saving, but they do raise the risk of bleeding. Most bleeding is minor, such as easier bruising, bleeding gums or longer bleeding from a shaving cut. Serious bleeding is uncommon but needs urgent care. Patients on blood thinners should:

• Take the medication exactly as prescribed and keep a list of it with you
• Tell every doctor, dentist and pharmacist that you are on an anticoagulant
• Avoid adding over-the-counter anti-inflammatory pain relievers such as ibuprofen or naproxen unless your doctor approves
• Ask before starting any new supplement, as some affect clotting
• Seek care quickly after a significant fall or head injury, even if you feel fine

Post-Thrombotic Syndrome: The Long-Term Leg Complication

When a DVT damages the valves in a deep vein, blood can no longer be pushed up the leg efficiently. Pressure in the lower leg stays high whenever you stand, much like in chronic venous insufficiency. Sometimes the vein also stays partly blocked by scar tissue, which adds an obstruction to the reflux.

The symptoms tend to build slowly. Patients describe a leg that feels heavy and tight by the afternoon, swelling that improves overnight, cramping, and itching or darkening of the skin above the ankle. In more advanced cases the skin becomes hard and fragile, and a minor injury can turn into a venous ulcer that is slow to heal.

Lowering the risk of post-thrombotic syndrome

• Start anticoagulation promptly and keep it at the right dose for the full course.
• Walk early. Once treatment has begun, walking is encouraged. The calf muscle pump helps clear swelling and supports recovery.
• Use compression for symptoms. Graduated compression stockings can ease swelling and aching. Current guidelines no longer recommend them routinely for everyone just to prevent post-thrombotic syndrome, but they remain very helpful for patients with symptoms.
• Manage weight and stay active, which reduces pressure in the leg veins.
• Treat superficial reflux when present, because overloaded surface veins add to the pressure in the leg.

Chronic Thromboembolic Pulmonary Hypertension

Most people who survive a pulmonary embolism recover their lung function as the clot dissolves. In a small minority, the clot does not fully clear and instead turns into scar tissue inside the lung arteries. This raises pressure in the lungs and strains the right side of the heart. It is called chronic thromboembolic pulmonary hypertension, or CTEPH.

The warning sign is shortness of breath that persists or gets worse months after a pulmonary embolism, rather than steadily improving. If that describes you, ask your doctor about follow-up testing with a heart or lung specialist, because specific treatments are available.

DVT Complications in Special Situations

Pregnancy and after delivery

Pregnancy raises clotting factors and slows blood flow from the legs, and the risk stays elevated for several weeks after delivery. Left-leg clots are more common in pregnancy because the left iliac vein is compressed in the pelvis. Treatment is usually with injectable heparin, because some oral blood thinners are not used in pregnancy. Any new leg swelling or breathlessness during pregnancy or after childbirth should be checked promptly rather than assumed to be normal pregnancy swelling.

Cancer-associated clots

Cancer and some cancer treatments make the blood more likely to clot, and clots in patients with active cancer are more likely to recur. The choice of blood thinner and the length of treatment are usually tailored by the oncology team, and patients with a port or other venous access device should know the signs of an arm or neck vein clot.

Arm and upper-body DVT

Clots can also form in the arm veins, often around a catheter, a port or a pacemaker lead, and occasionally after strenuous repetitive arm activity. Symptoms include arm swelling, a heavy or tight feeling, and visible veins across the shoulder or chest. Arm clots can also travel to the lungs, though less often than leg clots, and long-term arm swelling can follow.

After surgery or injury

Orthopedic surgery on the hip or knee, major abdominal surgery and leg fractures in a cast are classic triggers. Preventive blood thinners, early walking and leg exercises are used to lower the risk. If one calf becomes painful and swollen in the weeks after an operation, it should be checked even if you were given preventive treatment.

Who Is at Higher Risk of DVT Complications?

• People with a large clot in the thigh or pelvic veins rather than a small calf clot
• Those whose treatment was delayed or interrupted
• Patients with cancer, inherited clotting disorders or ongoing immobility
• People with excess weight or pre-existing varicose veins
• Anyone who has already had more than one DVT in the same leg

How We Evaluate the Leg After a DVT

Many patients come to us months or years after a clot because their leg never felt quite right again. Our evaluation is designed to show what is happening in the veins now.

1. Focused history. We review when and why the clot happened, how long you took blood thinners, current medications and how your symptoms change through the day.
2. Examination. We look at swelling, skin color and texture, any wounds, varicose veins and pulses.
3. Venous duplex ultrasound. Performed in our IAC-accredited vascular lab, the venous ultrasound shows whether the deep veins have reopened, whether there is residual clot or scarring, and whether the deep or superficial valves are leaking.
4. Arterial check if needed. An ankle-brachial index confirms that compression is safe when pulses are weak.
5. A clear plan. We explain the findings and recommend compression, skin and wound care, treatment of superficial reflux, or coordination with your hematologist or primary care physician.

DVT Follow-Up Care in Houston

If you have had a blood clot and still have swelling, heaviness, skin changes or a wound, or you simply want to know how well your veins have recovered, it is worth having them checked. Dr. Syed Raza is a fellowship-trained interventional radiologist with more than 15 years of experience in venous disease and DVT care. Our vein clinic in Houston usually offers same-week appointments, performs testing on site, and accepts most insurance plans, including Medicare.

Frequently Asked Questions

Can a DVT go away without complications?

Many people recover from a DVT without lasting problems, especially when it is diagnosed early and treated promptly with blood thinners. However, some develop post-thrombotic syndrome months or years later, so follow-up is important if swelling or skin changes appear.

How long after a DVT can a pulmonary embolism happen?

The risk is highest in the first days and weeks, before anticoagulation has fully taken effect and while the clot is fresh. It falls substantially once treatment is established. Any sudden shortness of breath or chest pain needs emergency care regardless of timing.

Is leg swelling after a DVT permanent?

Swelling often improves over weeks to months as the clot is reabsorbed and collateral veins open up. If it persists beyond that, it may be post-thrombotic syndrome, which can usually be managed with compression, activity and, in some cases, treatment of leaking veins.

Can I exercise after a DVT?

For most patients, walking is encouraged once blood thinners have been started, and it can help reduce swelling. Check with your doctor before returning to contact sports or heavy lifting, because of the bleeding risk on anticoagulants.

Can you fly after having a DVT?

Many patients can fly once they are stable on anticoagulation, but timing should be discussed with your doctor. On the flight, walk the aisle when you can, do ankle exercises, stay hydrated and consider compression stockings if advised.

What is the difference between post-thrombotic syndrome and a new clot?

Post-thrombotic syndrome causes gradual, long-term swelling and heaviness that is usually worse in the evening. A new clot tends to cause sudden new or worsening pain, warmth and swelling. Only an ultrasound can reliably tell them apart.

Trusted Health Resources

1. Venous Thromboembolism, National Heart, Lung, and Blood Institute (NIH)
2. About Venous Thromboembolism (Blood Clots), Centers for Disease Control and Prevention