Postthrombotic Syndrome

What is Postthrombotic Syndrome?

Postthrombotic syndrome is a condition that happens after having a specific type of blood clot, known as acute deep vein thrombosis (DVT). This syndrome is about the chronic failure of blood flow in the veins, and is recognized by leg discomfort and a feeling of heaviness. Other symptoms may include widened veins, swelling (edema), changes in skin color, and ulcers caused by poor vein function. DVT happens to about 1 in 1,000 people every year. Despite proper blood-thinning treatment, 20%-50% of patients who’ve had DVT could still experience postthrombotic syndrome.

Postthrombotic syndrome greatly affects people’s quality of life and can lead to high healthcare costs, which makes it a significant public health issue. Its impact on society is expected to grow in the coming years. Although we’ve made progress in understanding this syndrome, there are still many questions that need to be answered. Right now, there are only a limited number of effective treatment options. The best way to manage the syndrome is to prevent DVT from happening in the first place, quickly identify it when it does occur, and stop it from happening again.

What Causes Postthrombotic Syndrome?

The reasons behind postthrombotic syndrome, a condition following a blood clot, aren’t entirely clear. However, doctors believe it mostly occurs due to increased pressure in the veins. This pressure rise is usually because of damage to the vein valves or the narrowing of blood vessels due to lingering clot and scarring of the vessel walls.

Let’s simplify this: Veins have doors (valves) that ensure blood flows in the right direction. But when a severe clot, or DVT (deep vein thrombosis), partially or completely blocks the veins, the doors may not work properly.

Typically, within about 6 weeks of the clot occurring, blood flow might return to normal, but if this doesn’t happen, the blockage can cause the vessel walls to become scarred and damaged. Inflammation can also harm the ‘doors’ of the veins directly.

The changes brought on by blood clot can lead to increased pressures within veins, affecting the tiny vessels (capillaries). This can cause tissue swelling, skin hardening in the lower leg (lipodermatosclerosis), and eventually, a lack of oxygen in the tissue and formation of painful sores on the skin, known as venous ulcers.

Risk Factors and Frequency for Postthrombotic Syndrome

Postthrombotic syndrome is a condition that follows a previous deep vein thrombosis (DVT), which is a clot in a deep vein. Unfortunately, there isn’t an abundance of data on this syndrome. However, studies suggest that 20% to 50% of people who had a DVT may develop postthrombotic syndrome. About 8% to 10% of these cases can be severe and greatly affect the person’s quality of life.

A review of various studies has shown that the rates of postthrombotic syndrome can differ between countries. On average, about 37.5% of people might develop this syndrome within 2 years. In another study with over 1,000 patients, about 27.8% developed the syndrome within 3 years. Older individuals and those with ongoing DVT risk factors can be at a higher risk.

• Postthrombotic syndrome is common among former DVT patients.
• 20% to 50% of these patients may experience this syndrome.
• Of these cases, 8% to 10% can be severe and affect their quality of life.
• The condition’s occurrence rates may vary on a per-country basis.
• About 37.5% of sufferers develop the syndrome within two years.
• In a study of over 1,000 patients, about 27.8% developed the syndrome within three years.
• The reviews show that older people and those with DVT risk factors are at an increased risk.
• Research shows symptoms can occur as far as 6 years after an acute DVT in around one-third of patients.

Signs and Symptoms of Postthrombotic Syndrome

Postthrombotic syndrome is a condition that can come with a variety of symptoms. These symptoms can range from mild to severe and may show up weeks or months after an episode of deep vein thrombosis (DVT), or during the acute phase of DVT. The symptoms include:

• Changes in skin color
• Appearance of small, widened blood vessels (telangiectasia)
• Mild discomfort
• Swelling (edema) which is found in about two-thirds of individuals suffering from postthrombotic syndrome. This swelling can also be accompanied by a heavy feeling in the limb and discomfort, especially after being on your feet for a long time or walking. Resting or elevating the limb can often relieve these symptoms.
• About one-third of individuals may experience skin changes such as discoloration, telangiectasia, eczema, varicose veins, or what is called lipodermatosclerosis.
• In less than 5% of patients, ulcers on the skin can occur.
• The changes in the skin usually show up 2 to 4 years after an acute DVT.

Testing for Postthrombotic Syndrome

Diagnosing postthrombotic syndrome, a condition that can occur after a deep vein thrombosis (DVT), is usually done through a clinical evaluation. There isn’t a universally accepted test for this condition. If you’ve had a history of DVT, your doctor may suspect this syndrome.

Different clinical scores exist that can help your doctor diagnose and determine the severity of this condition. One commonly used is the Villalta scale. This scale looks at six symptoms, six physical signs, and the presence of venous ulcers (or sores on the skin caused by abnormal vein function). If you have a venous ulcer or score more than 5, you could be diagnosed with postthrombotic syndrome. Your doctor can use this scale to classify the syndrome’s severity: a score between 5 and 10 is considered mild, 10 to 14 is moderate, and 15 and above is severe.

While the Villalta scale is generally used for the lower limbs, a different scale called the upper-extremity postthrombotic syndrome (UE-PTS) is used for the upper limbs. This scale measures symptoms like swelling, fatigue, pain, and limitations in using your arm, as well as clinical signs such as asymmetry in your arms, discoloration, and presence of collateral veins (additional veins your body makes to bypass blockages).

For individuals with upper-extremity disorders, the shortened Disabilities of the Arm, Shoulder, and Hand Questionnaire (QuickDASH) is used. This short 11-question survey looks at your ability to perform day-to-day activities, work-related tasks, recreational activities, and assesses any symptoms like pain or numbness you may experience.

If you’re experiencing severe symptoms, your doctor may recommend imaging tests to check if there’s any remaining blockage or abnormal vein function. This can be done using methods like venous duplex, intravascular ultrasonography, and venography. Remember, even if imaging shows persistent obstruction or vein abnormalities, if you’re not experiencing symptoms, you don’t meet the criteria for postthrombotic syndrome.

Treatment Options for Postthrombotic Syndrome

Postthrombotic syndrome is a condition that can occur after a blood clot in a deep vein, often in the leg. The main ways to manage this condition usually involve exercise, raising the affected limb, and compression therapy. However, scientists need to do more research to find out the best way to treat this condition.

Exercise can help increase blood flow, which reduces the likelihood of more blood clots forming. Recent findings also suggest that exercise doesn’t increase the risk of a blood clot reaching the lungs (a condition called pulmonary embolism) in patients with deep vein thrombosis (DVT). In severe cases, doctors might consider inserting a filter in the main vein in your abdomen (the inferior vena cava) to prevent clots from reaching the lungs. Exercise can also help reduce symptoms of postthrombotic syndrome, and weightlifting can improve muscle strength and walking ability by shrinking the clot and helping it dissolve more quickly.

Using compression-based treatments can also reduce symptoms and make day-to-day life easier for people with postthrombotic syndrome. Depending on how severe the symptoms are, and whether there is swelling, skin changes or ulceration, doctors might recommend compression socks, stretch bandages, multilayer compression, or bandages coated with zinc paste. Patients with moderate-to-severe postthrombotic syndrome who don’t get relief from elastic compression stockings alone might also benefit from a portable device that provides intermittent compression. It’s important to note that most of the current evidence for this treatment comes from trials where the assessors weren’t blind to the patients’ treatment, which could introduce bias.

Drugs that affect blood flow through the veins (venoactive drugs), such as diosmin and rutosides, have been used to alleviate symptoms in the lower body. However, there’s not enough high quality data from randomized trials to strongly recommend these drugs for treating postthrombotic syndrome.

It’s also crucial to manage any changes in the skin and venous ulcers that can occur in postthrombotic syndrome. Doctors commonly recommend moisturizers and corticosteroids, a type of anti-inflammatory medication, to manage dry skin, itching, and changes caused by prolonged inflammation. Dressings can cover ulcers and create a moist environment that helps wounds heal more quickly.

One clinical trial of 208 patients with acute DVT of the leg showed that those taking a cholesterol-lowering medication called rosuvastatin along with anticoagulant medications experienced a greater decrease in inflammation and leg size than those on anticoagulants alone, indicating this could be a beneficial adjuvant therapy.

If severe symptoms continue and if there is a blockage or abnormal blood flow in the veins, doctors might need to consider vascular procedures. These can include non-surgical procedures to widen the veins (angioplasty), with or without the insertion of a small mesh tube to keep the vein open (stenting), as well as surgical procedures to bypass the vein or remove the inner lining of the vein. This can decrease the recurrence of ulcers and skin changes, therefore improving the patient’s quality of life. Some research also suggests that eliminating the sources of abnormal blood flow can improve how the veins work.

Preventing postthrombotic syndrome is best done by prompt treatment of the initial, or acute, deep vein blood clot. A study comparing different anticoagulants found that edoxaban was more effective than rivaroxaban in preventing postthrombotic syndrome.

What else can Postthrombotic Syndrome be?

Postthrombotic syndrome is a condition that can cause symptoms like pain, heaviness, and swelling in the lower limbs. But these symptoms can also be seen in several other health issues. These include:

• Primary venous insufficiency (weakness in the leg veins)
• Obesity
• Lipedema (fat disorder causing swelling in the legs)
• Lymphedema (swelling caused by a blockage in the lymphatic system)
• Soft tissue masses
• Changes after an injury

A history of Deep Vein Thrombosis (DVT) can help differentiate postthrombotic syndrome from primary venous insufficiency. This is because the symptoms of postthrombotic syndrome usually only affect the leg where the DVT happened, while primary venous insufficiency often occurs in both legs.

Some conditions can cause blockages in the veins, such as arterial aneurysms, Baker cysts, and soft tissue tumors. These may be felt by a doctor during a physical examination of the groin and behind the knee. In cases where the patient is obese or has significant swelling in the leg, these blockages can be challenging to detect. However, ultrasound or imaging techniques can help identify and distinguish these masses.

What to expect with Postthrombotic Syndrome

Postthrombotic syndrome, a chronic and debilitating complication of a condition known as deep vein thrombosis (DVT) or blood clots in the deep veins, currently doesn’t have many treatment options, despite recent medical advancements. Yet, more than half of the patients who are given special medical socks, known as elastic compression stockings, and receive the right doctor follow-ups hold stable or show signs of improvement. It doesn’t matter how severe their syndrome was at the start.

However, the effectiveness of these special socks has shown differing results in different studies. For example, in the SOX study, one of the biggest studies comparing these socks with a placebo (a treatment with no active effect), it didn’t prove to have a major effect. The results showed 14.2% of patients using the special socks ended up getting postthrombotic syndrome, compared to 12.7% in the placebo group.

Nevertheless, these findings could be influenced by the fact that the patients didn’t use the socks consistently. This might be because the socks are uncomfortable, expensive, and difficult to put on.

Possible Complications When Diagnosed with Postthrombotic Syndrome

Having a proximal DVT, or blood clot, often has a higher risk of occurrence and more severe symptoms of postthrombotic syndrome compared to a distal DVT. Despite these differences, complications can present in either situation, especially in patients that continually experience the primary venous symptoms related to DVT.

One major complication of postthrombotic syndrome is leg ulceration, which can be a significant cause of disability. This condition also places a financial burden on both the individuals affected and the healthcare systems that treat them. Venous ulcers are typically not painful. They are superficial lesions showing irregular borders and features like red granulation tissue, yellow fibrin at the base, and exudates.

There are also several factors that indicate a poor prognosis for the healing of these ulcers:

• Existence for more than 3 months
• Initial size greater than 10 cm
• Presence of arterial disease
• Advanced age
• Elevated body mass index

Preventing Postthrombotic Syndrome

To help prevent a condition called postthrombotic syndrome, which is a group of symptoms that might occur after having a blood clot in your legs (a condition called deep vein thrombosis, or DVT), the following steps are advised:

* Walking regularly
* Keeping up physical activity
* Wearing compression stockings, which are tight-fitting socks that help improve blood flow in your legs
* Sticking to blood thinning medication after being treated for an acute (sudden and severe) DVT

These simple yet effective steps can help you avoid suffering from postthrombotic syndrome. Doctors and other healthcare professionals can provide support and guidance to help their patients understand and follow these preventive actions.