Clinical Trial: Multi-Detector Spiral Computed Tomography Alone Versus Combined Strategy With Lower Limb Compression Ultrasonography in Outpatients Suspected of Pulmonary Embolism

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Multi-Detector Spiral Computed Tomography Alone Versus Combined Strategy With Lower Limb Compression Ultrasonography in Outpatients Suspected of Pulmonary Embolism: A Rand

Brief Summary:

The main hypothesis for this study is that the diagnostic approach of pulmonary embolism (PE) by evaluation of clinical probability, D-dimer test dosage and multi-detector helical computed tomography (hCT) is as safe as the classical "approach" using clinical probability, D-dimer test, lower limb compression ultrasonography and multi-detector helical computed tomography.

The second hypothesis involves evaluating the role of searching distal, i.e. infrapopliteal, deep venous thromboses (DVTs) in the diagnostic approach of pulmonary embolism.


Detailed Summary:

Suspected pulmonary embolism [PE] is a frequent clinical problem and remains a diagnostic challenge. The diagnostic approach of PE relies on sequential diagnostic tests, such as plasma D-dimer measurement, lower limb compression ultrasonography, ventilation-perfusion lung scan or helical computed tomography [hCT] and pulmonary angiography. In addition, the diagnostic workup is usually stratified according to the clinical probability of pulmonary embolism.

First-generation hCTs were based on a single-detector technique and had a limited 70% sensitivity. Moreover, in two recent outcome studies, a proximal deep venous thrombosis diagnosed by lower limb compression ultrasonography was found in 15% of patients with a normal single-detector hCT. However, in management studies, the association of a normal lower limb compression ultrasonography and a normal single-detector hCT has been proved safe to rule out PE in patients with a non-high clinical probability, with a less than 2% rate of thromboembolic events during a 3-month follow-up in patients left untreated based on that combination. Hence, lower limb compression ultrasonography must be combined with a single-detector CT to safely rule out pulmonary embolism.

More recently, the multi-detector hCT has become widely available. These new scanners allow one to improve image definition and to diminish slice thickness without increasing acquisition time and, hence, to better visualize the segmental and sub-segmental pulmonary arteries. In a recent study [CTEPm], the investigators evaluated the performances of a multi-detector hCT. The rate of false negative results, assessed by the rate of patients with proximal DVT on ultrasonography and a negative hCT, was much lower using the multi-detector CT [0.9%, 95% confidence interval: 0.3-3.3%] than with the single-detector technique [15
Sponsor: University Hospital, Geneva

Current Primary Outcome: The primary outcome variable will be the number of thromboembolic events in the 3-month follow-up period in each group.

Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Costs incurred in each study arm. (Costs will be directly measured and will represent direct costs, not charges. Measurements will include all costs due to diagnosis of PE, including the costs associated with the length of stay in the emergency ward)
  • Classification performances of the revised Geneva standardised clinical score, as assessed by its capacity to distinguish patients having low, intermediate and high probability of PE
  • Proportion of patients in whom hCT could have been avoided by using the presence of a distal DVT to rule in the diagnosis of PE (proportion of patients with both distal DVT on ultrasonography and PE on multi-detector hCT)
  • Proportion of patients with distal DVT on ultrasonography but without pulmonary embolism on multi-detector hCT and without thromboembolic event during the 3 months follow-up


Original Secondary Outcome: Same as current

Information By: University Hospital, Geneva

Dates:
Date Received: June 30, 2005
Date Started: January 2005
Date Completion: October 2006
Last Updated: October 12, 2012
Last Verified: October 2012