The Use of CTPA in Diagnosing Pulmonary Embolism during Pregnancy and Puerperium Period: A 5 Year- retrospective Study at a Regional Referral Hospital in Malaysia

Introduction: The cumulative incidence of pulmonary embolism (PE) in South Asia is 1.03 per 10 000 pregnancies with maternal mortality rate of 11.1%. Given the morbidity and mortality of undiagnosed PE in pregnancy, the threshold to perform computed tomography pulmonary angiography (CTPA) is low due to the fear of missing the diagnosis of PE. Often the pre-test clinical scores are bypassed especially the modified Well score (MWS), which is widely used in the general population yet not validated in pregnant women. The objectives of our studies were:

To assess CTPA ordering trend and its positive rate
To evaluate the diagnostic accuracy of MWS in predicting PE in pregnancy
To identify the rate of contrast-associated acute kidney injury (CA-AKI) post CTPA
Study Design: It was a retrospective study which included all pregnant and postpartum patients who underwent CTPA for suspected PE in Hospital Raja Permaisuri Bainun, Malaysia from Jan 2018 to December 2022. A total of 185 CTPA results were retrieved and MWS were calculated retrospectively: ≤ 4 (unlikely PE) or >4 (likely PE).

Results: The positive rate of CTPA was 20/185 (10.5%). From 185 patients, the sensitivity, specificity, positive predicate value (PPV) and negative predictive value (NPV) of MWS were 90%, 14.5%, 11.3%, and 92.3% respectively, in predicting PE. The receiver operating characteristic (ROC) curve analysis showed a non-discriminating value (0.5). 7.1% of patients had CA-AKI post-CTPA.

Conclusion: The trend of using CTPA in diagnosing PE in pregnant women had been steady despite our finding of its low diagnostic yield. Although Modified Wells score is widely used in the general population, its implications for pregnant patients are still a matter of debate.