Study designs of evaluations included in the review
Studies that used a consecutive sample, or a well-defined reason for a selected sample, with a minimum of 3 months' follow-up were eligible for inclusion.
Specific interventions included in the review
Studies that evaluated CTPA to diagnose suspected PE were eligible for inclusion. The method of CTPA varied across the included studies. In most studies CTPA was used as part of a diagnostic algorithm in combination with other tests, including pre-test probability, lung scintigraphy, lower-extremity compression ultrasonography and D-dimer testing.
Reference standard test against which the new test was compared
The review did not include any diagnostic accuracy studies that compared the performance of the index test with a reference standard of diagnosis.
Participants included in the review
Studies of adults with suspected PE who had negative or indeterminate CTPA results and in whom anticoagulation therapy was withheld, or there was a clearly reported reason for administering anticoagulation when venous thromboembolism (VTE) was excluded, were eligible for inclusion. Participants who received anticoagulation therapy were excluded from the final analysis. Reasons for administering anticoagulation therapy despite negative CTPA results included the detection of deep vein thrombosis on concomitant ultrasonography, chronic VTE, and cardiac arrhythmias or other cardiac abnormalities.
Outcomes assessed in the review
Studies that reported recurrent VTE events and fatal PE with a means of confirmation were eligible for inclusion. Where reported, objective imaging was used to confirm recurrent VTE events and fatal events were confirmed by autopsy or central adjudication.
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.