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

J Thromb Haemost. 2005 May;3(5):939-42. doi: 10.1111/j.1538-7836.2005.01333.x.


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.

MeSH terms

  • Aged
  • Anticoagulants / pharmacology*
  • Bandages
  • Clinical Trials as Topic
  • Cohort Studies
  • Female
  • Humans
  • International Normalized Ratio
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Neoplasms / complications
  • Odds Ratio
  • Postphlebitic Syndrome / prevention & control*
  • Quality Control
  • Retrospective Studies
  • Risk
  • Time Factors
  • Venous Thrombosis / drug therapy*
  • Vitamin K / antagonists & inhibitors*


  • Anticoagulants
  • Vitamin K