Thromboembolic resolution assessed by CT pulmonary angiography after treatment for acute pulmonary embolism

Thromb Haemost. 2015 Jul;114(1):26-34. doi: 10.1160/TH14-10-0842. Epub 2015 May 28.


The systematic assessment of residual thromboembolic obstruction after treatment for acute pulmonary embolism (PE) has been understudied. This assessment is of potential clinical importance, should clinically suspected recurrent PE occur, or as tool for risk stratification of cardiopulmonary complications or recurrent venous thromboembolism (VTE). This study aimed to assess the rate of PE resolution and its implications for clinical outcome. In this prospective, multi-center cohort study, 157 patients with acute PE diagnosed by CT pulmonary angiography (CTPA) underwent follow-up CTPA-imaging after six months of anticoagulant treatment. Two expert thoracic radiologists independently assessed the presence of residual thromboembolic obstruction. The degree of obstruction at baseline and follow-up was calculated using the Qanadli obstruction index. All patients were followed-up for 2.5 years. At baseline, the median obstruction index was 27.5 %. After six months of treatment, complete PE resolution had occurred in 84.1 % of the patients (95 % confidence interval (CI): 77.4-89.4 %). The median obstruction index of the 25 patients with residual thrombotic obstruction was 5.0 %. During follow-up, 16 (10.2 %) patients experienced recurrent VTE. The presence of residual thromboembolic obstruction was not associated with recurrent VTE (adjusted hazard ratio: 0.92; 95 % CI: 0.2-4.1).This study indicates that the incidence of residual thrombotic obstruction following treatment for PE is considerably lower than currently anticipated. These findings, combined with the absence of a correlation between residual thrombotic obstruction and recurrent VTE, do not support the routine use of follow-up CTPA-imaging in patients treated for acute PE.

Keywords: Pulmonary arteries; multidetector computed tomography; pulmonary circulation; pulmonary embolism.

Publication types

  • Multicenter Study

MeSH terms

  • Acute Disease
  • Adult
  • Aged
  • Aged, 80 and over
  • Anticoagulants / adverse effects
  • Anticoagulants / therapeutic use*
  • Female
  • Humans
  • Kaplan-Meier Estimate
  • Male
  • Middle Aged
  • Multidetector Computed Tomography*
  • Netherlands
  • Predictive Value of Tests
  • Prospective Studies
  • Pulmonary Artery / diagnostic imaging*
  • Pulmonary Embolism / diagnostic imaging*
  • Pulmonary Embolism / drug therapy*
  • Pulmonary Embolism / mortality
  • Recurrence
  • Remission Induction
  • Risk Factors
  • Thromboembolism / diagnostic imaging*
  • Thromboembolism / drug therapy*
  • Thromboembolism / mortality
  • Time Factors
  • Treatment Outcome


  • Anticoagulants