To assess the outcome and value of computed tomography pulmonary angiogram(CTPA) as the initial diagnostic test for pulmonary embolism(PE). Previously, we had evaluated the diagnostic value of ventilation/perfusion scan(V/Q) in our institution.
Retrospective review of inpatient records from 01/2001 to 12/2001.
92 patients had CTPA for suspected PE. They were divided in 3 groups according to their pretest clinical probability(CP) of PE. Of the 62 patients(67.4%) with low CP, 3(4.8%) had a positive CTPA and were anticoagulated. Of the 22 patients(23.9%) with intermediate CP, 4(18.2%) had a positive CTPA and were anticoagulated. Of the 8 patients(8.7%) with high CP, 4(50%) had positive CTPA and were anticoagulated. 18 patients (8 with low CP, 8 with intermediate CP, and 2 with high CP) out of the 81 with negative CTPA had additional testing for venous thromboembolism(VTE). Only 1 (from the high CP group) of these 18 patients had a positive test for VTE (a high probability V/Q) and was anticoagulated. Of all the negative CTPA, 17 of them provided significant, additional diagnostic information that was not evident on the chest radiograph.CONCLUSIONS: The yield for a positive CTPA in our intermediate/high CP group was 27% (8 out of 30 patients). In the same CP group in the PIOPED study, the yield of a high probability V/Q was 17%. Unlike the V/Q, CTPA offers additional diagnostic information of diseases of the chest. Because of the very low yield of a positive CTPA in patients with low CP (5%), medical centers should set up specific pathways and screening processes to limit wasteful testing.
CTPA is emerging as the primary diagnostic test for PE. Evaluating patient‘s CP for PE remains an important first step before deciding on the appropriateness of a diagnostic work-up for PE.
A.S. Bucerzan, None.