Relation between quality of anticoagulant treatment and the development of the postthrombotic syndrome.

BACKGROUND: About 30% of patients with an episode of adequately treated deep venous thrombosis (DVT) develop the postthrombotic syndrome (PTS) within 2 years. During treatment with vitamin K antagonists (VKA) patients spend only 60% of time between an International Normalized Ratio (INR) of 2.0 and 3.0. We hypothesized that patients who spend a large amount of their time beneath this range will have an increased risk of the PTS. OBJECTIVE: To investigate the relation between the quality of anticoagulant therapy with VKA and the risk of the development of the PTS. METHODS: The time spent beneath the therapeutic range was calculated for patients with a first episode of DVT, who were treated with VKA for at least 3 months. At follow-up assessments for a maximum of 5 years, presence and severity of signs and symptoms of PTS were recorded. RESULTS: A total of 244 patients, with a median duration of follow-up of 4.9 years were included for analysis. Of these, 81 patients (33%) developed the PTS. The multivariate model showed that patients who spend more than 50% of their time beneath an INR level of 2.0 are at higher risk for PTS [odds ratio (OR): 2.71, 95% CI: 1.44-5.10]. CONCLUSIONS: Low quality treatment with VKA, which is a common condition, is related to the occurrence of the PTS in patients with DVT. Strategies aimed at improving the quality of long-term anticoagulation might have the potential to reduce the incidence of this complication.

Postthrombotic syndrome: incidence, prevention, and management.

Mild to severe postthrombotic sequelae, including chronic pain, edema, and ulceration, arise in one third of patients short after deep vein thrombosis (DVT). Recurrent DVT is closely associated with the development of postthrombotic syndrome (PTS), whereas if the extent and location of DVT might be relevant remains unclear. Chronic venous hypertension and abnormal microvessel or lymphatic function also correlates with PTS. The diagnosis of PTS is based on clinical grounds only if patients report a history of documented DVT; otherwise, objective testing is required. To abate the prevalence of PTS, the best policy is represented by prevention of recurrent thrombosis and use of stockings. Despite a plenty of surgical options, conservative treatment is preferable because half of the patients improve or remain stable during follow-up, provided they wear elastic stockings. Clinical presentation has a prognostic value, as patients with initially severe symptoms enjoy a more favorable outcome than those who progressively deteriorate over time.