Post-Thrombotic Syndrome

Post-thrombotic syndrome (PTS), also known as postphlebitic syndrome and venous stress disorder, is a medical condition that may develop as a long-term complication of deep vein thrombosis (DVT).

Signs and Symptoms

The signs and symptoms of PTS in the leg may include pain (either aching or cramping), heaviness, itching or tingling, swelling (oedema), varicose veins, brownish or reddish skin discolouration, and ulcers. These symptoms can vary among patients and may change over time. Typically, symptoms worsen after prolonged walking or standing and improve with rest or leg elevation. PTS significantly impacts a patient's quality of life, especially by causing both physical discomfort and psychological distress, and by limiting daily activities.

Cause

The exact cause of PTS remains unclear, although inflammation and damage to venous valves by the thrombus are believed to play a significant role. The resulting valvular incompetence, along with persistent venous obstruction, leads to increased pressure in veins and capillaries. This venous hypertension causes rupture of small superficial veins, subcutaneous haemorrhage, and increased tissue permeability, resulting in pain, swelling, skin discolouration, and ulceration.

Risk Factors

Several factors increase the risk of developing PTS:

• Age over 65
• Proximal DVT
• Recurrent ipsilateral DVT (second DVT in the same leg as the first)
• Persistent DVT symptoms one month after diagnosis
• Obesity
• Poor quality of anticoagulation control (dose too low) during the initial three months of treatment

Diagnosis

Diagnosis of PTS is considered when a patient with a history of DVT presents with suggestive symptoms. Ultrasonography is essential to assess the degree of obstruction by clots, their location, and deep or superficial venous insufficiency. Since the symptoms of DVT and PTS can be similar, PTS diagnosis should be delayed for 3-6 months after the initial DVT diagnosis to ensure an accurate assessment.

Prevention

Preventing PTS begins with preventing initial and recurrent DVT. Hospitalised patients at high risk of DVT may benefit from early ambulation, compression stockings, electrostimulation devices, and/or anticoagulant medications. Elastic compression stockings can reduce the occurrence of PTS following clinically confirmed DVT. Increasingly, catheter-directed thrombolysis is being used to break up clots. For patients who have experienced a DVT, appropriate anticoagulation therapy is the best way to prevent recurrence. Additionally, weight loss in overweight or obese patients can reduce stress on leg veins and decrease the likelihood of developing PTS.

Treatment

Treatment options for PTS include proper leg elevation, compression therapy with elastic stockings or electrostimulation devices, pharmacotherapy (e.g., pentoxifylline), herbal remedies (such as horse chestnut and rutosides), and wound care for leg ulcers. The effectiveness of compression bandages in treating edemas remains unclear, though they may provide some benefit.

Upper Extremities

Patients with upper-extremity DVT may develop upper-extremity PTS, though the incidence is lower (15-25%) compared to lower-extremity PTS. While no established prevention or treatment methods exist for upper-extremity PTS, patients with persistent symptoms may benefit from wearing a compression sleeve.

Epidemiology

PTS can affect 23 to 60% of patients within two years following a leg DVT. Of these, 10% may develop severe PTS, including venous ulcers.

Society and Culture

Treating PTS adds substantial costs to DVT management. In the United States, the annual healthcare cost of PTS is estimated at $200 million, with costs exceeding $3800 per patient in the first year alone, and increasing with disease severity. Severe PTS and venous ulcers also result in lost work productivity, with affected individuals losing up to two workdays per year.

Research Directions

Several important research questions remain unanswered, including fully defining the pathophysiology of PTS, developing a PTS risk prediction model, evaluating the role of thrombolytic drugs in PTS prevention, determining the efficacy of elastic compression stockings, and looking at additional treatment options with proven safety and efficacy.

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Self-assessment MCQs (single best answer)

What is another name for Post-thrombotic syndrome (PTS)?

Which of the following is NOT a common symptom of PTS in the leg?

What is believed to play a significant role in the cause of PTS?

Which of the following is a risk factor for developing PTS?

What is essential for diagnosing PTS?

Which of the following is NOT a preventive measure for PTS?

What is a treatment option for PTS?

What percentage of patients may develop severe PTS, including venous ulcers, within two years following a leg DVT?

What is the estimated annual healthcare cost of PTS in the United States?

Research directions for PTS include evaluating the role of which of the following in PTS prevention?