Post-Thrombotic Syndrome Symptoms And Causes

If you have suffered from deep vein thrombosis (DVT) you might not have recovered completely, rather you could have developed some long-term side effects like post-thrombotic syndrome (PST). 

Post-thrombotic syndrome is a painful condition that will cause swelling, redness, heaviness and fatigue in the arm or leg that previously developed DVT. This complication will likely occur within 3-6 months after being diagnosed with DVT, although it can also happen within 2 years.¹

Read further to understand better what causes PST, what are its symptoms, potential risk factors, and some other useful information about this issue.

Post-thrombotic syndrome: definition and overview

Post-thrombotic syndrome is a chronic complication that occurs as a consequence of deep vein thrombosis. DVT is the blockage or blood clot formation in a deep vein in your limbs, usually the legs. Consequently, blood cannot flow properly and it pools in your veins, resulting in increased pressure in these vessels called venous hypertension. Below there is an illustration to give you a better understanding.

PTS develops in approximately 20% to 50% of patients who have had DVT, within 2 years, even if they received anticoagulant treatment. Moreover, 5% to 10% of cases can present severe PTS, which includes the appearance of leg ulcers.¹ In addition, this condition can also affect 26% of children who were diagnosed with DVT.² 

Unfortunately, if you suffer from post-thrombotic syndrome, not only your quality of life will be negatively impacted, but your productivity will decrease as well. 

Symptoms of post-thrombotic syndrome

PTS symptoms appear on the limb where DVT previously occurred. These are the clinical signs that you might experience on your affected arm or leg, which may range from mild to severe:

• Limb Pain 
• Heaviness or fatigue sensation in the limb
• Swelling or oedema
• Redness
• Telangiectasia (spider veins)
• Hyperpigmentation
• Stasis eczema
• Varicose veins
• Lipodermatosclerosis (thickening of the skin and subcutaneous tissue in lower extremities)
• Ulceration and wound formation in legs, in severe cases^1,2

Your symptoms may come and go, and they can appear in different combinations. Additionally, they might worsen when you’re walking, standing or making an effort for a long period, and they could ease when you rest. If you have suffered from DVT and begin noticing these symptoms, you should consult your physician.

Causes of post-thrombotic syndrome

Valve dysfunction and venous hypertension 

Post-thrombotic syndrome happens as a sequel of deep vein thrombosis. DVT causes damage to the deep veins in your limbs. These veins in your arms and legs have one-way valves which conduct blood towards the heart and prevent backwards flow.³ However, when DVT happens, it means that a blood clot blocks and damages these valves and vessels, resulting in disturbed blood flow and accumulation of this liquid in the veins. Consequently, the pressure inside your vein walls in your limbs rises, and this is responsible for your symptoms.^1,2

Inflammation and tissue damage

Inflammation of your legs or arms may also contribute to the development of PTS. As your tissue swells, your veins become more compressed, so the clot or blockage is harder to remove, and it also takes longer to do so. Moreover, inflammation also makes the walls of the veins thicker, which in turn results in improper blood circulation - also known as valvular reflux-.^1,2

Failure of blockage removal

While you might be taking anticoagulants to prevent another blot clot from happening after DVT, these medications may not always completely remove or eliminate the already-existing blockage. This can lead to venous outflow obstruction, which again can result in poor circulation and venous hypertension.⁴ 

Risk factors for developing post-thrombotic syndrome

If you have been diagnosed with DVT, you’re at risk of developing PTS. Other additional risk factors include:

• DVT location: the risk is higher if DVT happens in your upper tight or pelvis rather than in your calf. Especially if the blockage was in your iliac or common femoral vein
• Recurrent DVT in the same affected limb
• Pre-existing primary venous insufficiency
• Having a body mass index (BMI) above 30 ( this is considered obesity)
• Increasing age (although it appears there are mixed conclusions about this, so more research might be needed)²
• Subtherapeutic (lower) doses of anticoagulant treatment, especially if it’s not started on time 
• Type of anticoagulant prescribed. There is research that indicates that the risk of developing PTS is lower if you’re taking low-molecular-weight heparin (LMWH) as opposed to taking LMWH combined with vitamin K antagonists (medicines that prevent the action of vitamin K and reduce blood clots).⁵ However, more studies are needed to determine this
• Having persistent symptoms after 1 month of DVT
• The blood clot wasn’t fully removed after treatment (residual thrombosis)
• Elevated levels of D-dimer (a protein in your body that breaks down blood clots) months after DVT
• Genetic predisposition, from genes involved in vein wall restoration, may also be a risk factor ^1,2

Diagnosis of post-thrombotic syndrome

Your general practitioner (GP) will perform a clinical assessment to diagnose PTS, by asking you questions about your symptoms, looking at your medical history to see if you have had DVS, and examining your limbs. Furthermore, they can also ask for blood tests to check for blood clots or ultrasounds to determine where the problem lies in your limb veins.^1,2 

Your health provider can also use the Villalta scale to determine the severity of your condition. This tool is commonly used for diagnosis. It’s a standard numeric scale that consists of the following:

• 5 symptoms reported by the patient
• 6 clinically assessed signs
• Each component is rated from 0 to 3, and afterwards, your GP will add them, and discuss the results with you
• You are diagnosed with PTS if you have 5 points or more. Your score will also determine the severity
• Mild:5-9; Moderate:10-14; Severe: 15 or more, or the presence of limb ulcers^1,2 

Other measurement methods for diagnosis might be:

• The Ginsberg measure, which focuses on daily pain and swelling
• The CEAP classification is used to assess treatment outcomes for patients with venous diseases
• The VCSS (Venous Clinical Severity Score) evaluates venous diseases by combining the CEAP scale, number of ulcers and compression therapy elements^1,2 

Prevention and management strategies

Unfortunately, you can’t always prevent post-thrombotic syndrome from happening, but there are some actions you can take to reduce the risk. Ideally, you want to reduce your chances of having deep vein thrombosis, since PTS develops as a result of it. Here are the prevention strategies you could take:

• If you are at risk of DVT, your GP should prescribe you pharmacological (medication) or mechanical thromboprophylaxis. This will prevent the formation of blood clots
• Early and adequate anticoagulation therapy, with follow-ups to ensure you are taking the appropriate doses. This will reduce the recurrence of DVT
• Compression therapy is suggested to reduce swelling and venous hypertension. However, the studies that have been conducted so far have conflicting results, so more research is needed. Be aware that elastic compression socks might be difficult to put on and uncomfortable
• Thrombolysis therapy (breakdown of blood clots) can also reduce the risk of PTS. Your healthcare provider can either prescribe you medication like heparin, or a safer approach with fewer side effects like catheter-directed thrombolysis (CDT) or pharmacomechanical CDT (catheter-directed thrombolysis plus mechanical disruption of the blockage)^1,2 
• Exercise and physical activity can reduce your PTS severity, pain and oedema, and improve your quality of life. Besides, it doesn’t need to be some strenuous activity, just moving around and walking can be enough. A study identified that patients who performed early mobilisation in the acute phase of DVT had better quality of life and reduced pain and after 2 years the severity of their PTS also decreased⁶
• Maintaining a healthy weight for you is another key factor for reducing the risk of PTS 

Prognosis and long-term outlook

There is no cure for PTS. This is a chronic condition that your GP will help you manage with the appropriate medication and tools. Moreover, if you do some exercise while eating a healthy balanced diet, you may decrease the risk of developing this complication. In addition, if you do have it, taking your medicines adequately, walking a bit without forcing it, elevating your limbs while you’re resting and moisturising your skin around the affected area can help you deal with your symptoms and improve your quality of life. 

Summary

If you have suffered from deep vein thrombosis, the deep veins in your legs have blood clots and damage, leading to venous hypertension, and consequently, post-thrombotic syndrome develops. This painful chronic condition is manifested by swelling, redness and heaviness in the affected limbs. Whilst the main cause of PST is DVT, some risk factors could lead to developing this condition, including recurrent DVT in the same limb, inadequate anticoagulant therapy, and weight, among others. Unfortunately, PTS cannot always be prevented, but you can take some actions to reduce its risk of appearing by exercising, taking anticoagulants appropriately, and having blood clot reduction therapy. These actions will also improve your quality of life, and help you deal with it through your life as there is no cure yet.