CT pulmonary angiography vs ventilation-perfusion lung scanning in suspected pulmonary embolism
Anderson 2007 trial design and results
Design
Randomised controlled non-inferiority trial
Treatment
CT pulmonary angiography
Control
Ventilation-perfusion scanning
Population
1417 patients with suspected pulmonary embolism
Follow-up
3 months
Primary endpoint
Symptomatic venous thromboembolism during follow-up in patients in whom PE was excluded
Result
Pulmonary embolism was diagnosed in the initial evaluation in 133 of 701 (19.2%) with CT pulmonary angiography versus 101 of 716 (14.2%) with ventilation-perfusion scanning — a difference of 5.0 percentage points. CT was non-inferior for ruling out pulmonary embolism.
Secondary endpoints
Proportion diagnosed at initial evaluation, subsequent venous thromboembolism
In this study, CTPA was not inferior to V/Q scanning in ruling out pulmonary embolism. However, significantly more patients were diagnosed with pulmonary embolism using the CTPA approach. Further research is required to determine whether all pulmonary emboli detected by CTPA should be managed with anticoagulation.
The trial authors, in the published abstract
How it has aged
The authors ask the question that has only grown since: if CT finds 5% more emboli with no difference in outcome, are those extra clots disease or incidental findings? This trial is the origin of the overdiagnosis debate in pulmonary embolism, and it has never been resolved.
Publications
Computed tomographic pulmonary angiography vs ventilation-perfusion lung scanning in patients with suspected pulmonary embolism: a randomized controlled trial
Anderson DR, Kahn SR, Rodger MA, et al. Computed tomographic pulmonary angiography vs ventilation-perfusion lung scanning in patients with suspected pulmonary embolism: a randomized controlled trial. JAMA 2007 Dec 19;298(23):2743-53.
CT non-inferior to V/Q scanning for safely excluding PE
5 percentage points more emboli diagnosed by CT
Raises the unresolved question of whether the extra emboli need treatment