A normal computed tomography pulmonary angiography (CTPA) remains a controversial criterion for ruling out acute pulmonary embolism (PE) in patients with a likely clinical probability. We set out to determine the risk of VTE and fatal PE after a normal CTPA in this patient category and compare these risk to those after a normal pulmonary angiogram of 1.7 % (95 %CI 1.0–2.7 %) and 0.3 % (95 %CI 0.02–0.7 %). A patient-level meta-analysis from 4 prospective diagnostic management studies that sequentially applied the Wells rule, D-dimer tests and CTPA to consecutive patients with clinically suspected acute PE. The primary outcome was the 3-month VTE incidence after a normal CTPA. A total of 6,148 patients were included with an overall PE prevalence of 24 %. The 3-month VTE incidence in all 4,421 patients in whom PE was excluded at baseline was 1.2 % (95 %CI 0.48–2.6) and the risk of fatal PE was 0.11 % (95 %CI 0.02–0.70). In patients with a likely clinical probability the 3-month incidences of VTE and fatal PE were 2.0 % (95 %CI 1.0–4.1 %) and 0.48 % (95 %CI 0.20–1.1 %) after a normal CTPA. The 3-month incidence of VTE was 6.3 % (95 %CI 3.0–12) in patients with a Wells rule >6 points. In conclusion, this study suggests that a normal CTPA may be considered as a valid diagnostic criterion to rule out PE in the majority of patients with a likely clinical probability, although the risk of VTE is higher in subgroups such as patients with a Wells rule >6 points for which a closer follow-up should be considered.

Additional Metadata
Keywords Computed tomography, Diagnosis, Pulmonary embolism, Safety
Persistent URL dx.doi.org/10.1160/TH17-02-0076, hdl.handle.net/1765/100952
Journal Thrombosis and Haemostasis: international journal for vascular biology and medicine
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Citation
van der Hulle, T, van Es, N, den Exter, P.L, van Es, J, Mos, I.C.M, Douma, R.A, … Klok, F.A. (2017). Is a normal computed tomography pulmonary angiography safe to rule out acute pulmonary embolism in patients with a likely clinical probability?. Thrombosis and Haemostasis: international journal for vascular biology and medicine, 117(8), 1622–1629. doi:10.1160/TH17-02-0076