Performance of a new, structured diagnostic algorithm for suspected pulmonary embolism in pregnant patients

Rationale: In non-pregnant patients, well established algorithms exist, including combination of clinical decision rule, D-dimer test and in case of a "likely" clinical decision rule or abnormal D-dimer test, computed tomography pulmonary angiography (CTPA) to rule out the diagnosis. This strategy is no option for pregnant patients since no validated pregnancy-specific clinical decision rules exist and D-dimer levels often rise physiologically in pregnancy. Current practice is to perform V-Q lung scan or CTPA as standalone test, but both have drawbacks. Recently, a new diagnosed algorithm for suspected PE was developed and validated (van Es et al, JTH 2015). We set out to evaluate the safety and efficiency of this algorithm in pregnant patients with suspected PE.



Objectives: 1) to validate the clinical utility and safety of the study algorithm by determining the three-months VTE incidence in pregnant patients in whom PE was excluded at baseline. 2) to assess the number of required CTPA and compare that to the numbers from historical cohorts.
Design: Prospective multicenter management study of consecutive pregnant patients with suspected (recurrent) PE. Participants will be evaluated according to the study algorithm consisting of three items of the original Wells rule (clinical signs DVT, hemoptysis, "PE most likely diagnosis") and a D-dimer test. In patients with clinical signs of DVT, a compression ultrasonography will be performed to rule out deep vein thrombosis. Patients with confirmed DVT are considered to have PE and anticoagulant treatment will be initiated. In the remaining patients without any of the three items and a D-dimer level < 1.0 µg/ml, and in patients with ≥ 1 items and a D-dimer level < 0.5 µg/ml PE is excluded without CTPA. In the other patients a CTPA will be performed. If PE is confirmed by CTPA, anticoagulant treatment will be initiated. If CTPA result is normal, PE is considered to be ruled out and anticoagulant therapy is withheld. All patients will be followed for a period of three months.

To evaluate the safety and efficiency of a new diagnostic strategy for pregnant patients with suspected pulmonary embolism

the primary and secondary endpoints will be determined after three months follow-up

Prospective multicenter management study of consecutive pregnant patients with suspected (recurrent) PE. Participants will be evaluated according to the study algorithm consisting of three items of the original Wells rule (clinical signs DVT, hemoptysis, "PE most likely diagnosis") and a D-dimer test. In patients with clinical signs of DVT, a compression ultrasonography will be performed to rule out deep vein thrombosis. Patients with confirmed DVT are considered to have PE and anticoagulant treatment will be initiated. In the remaining patients without any of the three items and a D-dimer level < 1.0 µg/ml, and in patients with ≥ 1 items and a D-dimer level < 0.5 µg/ml PE is excluded without computed tomography pulmonary angiography (CTPA). In the other patients a CTPA will be performed. If PE is confirmed by CTPA, anticoagulant treatment will be initiated. If CTPA result is normal, PE is considered to be ruled out and anticoagulant therapy is withheld. All patients will be followed for a period of three months.