At my wound center, I recently had several patients whom I was treating for leg ulcers. At first glance, the ulcers seemed like classic venous wounds. After reviewing the patient histories, the one thing that they all had in common was a history of deep vein thrombosis (DVT). If one refers to venous stasis syndrome occurring after a DVT, an appropriate term is “postthrombotic syndrome.” Prior to this research, I was familiar with postthrombotic syndrome but was unsure of the best way to treat these patients.
Postthrombotic syndrome or postphlebitic syndrome is a medical condition that can develop in patients who experience a DVT in the leg. When the body tries to heal from these clots, the valves in the veins are often damaged. The obstruction of the veins and the destruction of valves lead to impaired blood flow. It is a result of venous hypertension, which occurs as a consequence of recanalization of major venous thrombi. This leads to patent but scarred and incompetent valves or, less frequently, persistent outflow obstruction produced by large proximal vein thrombi. Recanalization and valve destruction result in a malfunction of the muscular pump mechanism, which leads to increased pressure in the deep veins of the calf.
This high pressure results in progressive incompetence of the valves of the perforating veins of the calf. When this occurs, blood flow directs from the deep vein into the superficial system during muscle contraction, leading to edema and impaired viability of subcutaneous tissues and, in its most severe form, ulceration of venous origin. Symptoms include chronic leg pain, swelling, redness and sometimes ulcers.
Post-thrombotic syndrome affects an estimated 330,000 people in the United States with 23 to 60 percent occurring two years following DVT of the leg.1,2 Approximately 60 percent of patients will recover from a leg DVT without any residual symptoms. Forty percent will have some degree of postthrombotic syndrome, 4 percent will have severe symptoms and 10 percent develop venous ulcerations. Symptoms usually occur within the first six months but can occur up two years after the clot.
What are the risk factors of postthrombotic syndrome?3
- History of proximal deep vein thrombosis (above the knee)
- Having more than one blood clot in the same leg more than once
- Still having blood clot symptoms one month after being diagnosed with the blood clot
- Difficulty with international normalized ratio levels during the first three months after starting anticoagulants
- Chronic aching
- Subcutaneous fibrosis in the affected limb
- Venous claudication
- Venous leg ulcers
Preventing And Treating Postthrombotic Syndrome
Prevention is the key to preventing complications after a DVT. If a person has leg swelling after an acute DVT, he or she should wear a compression stocking to decrease the swelling.4 If the leg swelling is below the knee, then a below-knee stocking is appropriate. If swelling also involves the thigh, then patients should wear an above-knee stocking. The most common recommended size for compression stockings following a DVT is 30-40 mmHg.4 It is also referred to as grade 2. One should measure the leg to ensure correct fit. TED-stockings are not sufficient as the pressure is too low for treatment after a DVT.
If you see a postthrombotic syndrome patient with a high-grade leg wound, use three-layered compression in the same way you would treat a venous wound. Once the wound has healed, the patient should wear compression stockings. Be sure to determine the patient’s arterial status before using high-grade compression stockings or layered compression for ulcerations.
With careful screening of at-risk patients and working together with other specialists, we can help prevent complications related to postthrombotic syndrome.
1. Nayak L, Vedantham S. Multifaceted management of the postthrombotic syndrome. Semin Intervent Radiol. 2012; 29(1):16-22. Available at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3348767/ .
2. Kahn SR, Ginsberg JS. Relationship between deep venous thrombosis and the postthrombotic syndrome. Arch Intern Med. 2004;164(1):17-26.
3. Vazquez SR, Kahn SR. Postthrombotic syndrome. Circulation. 2010; 121(8):e217-9. Available at http://circ.ahajournals.org/content/121/8/e217.full .
4. Hirsh J, Hoak J. Management of deep vein thrombosis and pulmonary embolism. Circulation. 1996; 93(12):22-12-45.
Original Posted on Podiatry Today.