Characterizing Diagnostic Investigations for Suspected Pulmonary Embolism in Postpartum Individuals

Background: Venous thromboembolism (VTE) is a significant concern during pregnancy and the postpartum period, as pulmonary embolism (PE) remains a leading cause of maternal mortality in Western countries and carries serious morbidity including persistent dyspnea with reduced functional capacity, and rarely chronic thromboembolic pulmonary hypertension (CTEPH). While integrated diagnostic algorithms for patients with clinically suspected PE have been well established, pregnant and postpartum individuals have mostly been excluded from these studies. Recent prospective management outcome studies have demonstrated the safety of PE diagnostic algorithms during pregnancy and stressed the importance of tailored diagnostic approaches during this period. However, these studies did not include postpartum individuals. There is a lack of established postpartum-specific clinical prediction rules and high D-dimer levels after delivery may limit the utility of D-dimer testing. Issues such as radiation related to thoracic imaging in the presence of stimulated breast tissue and the importance of limiting unnecessary emergency department visits postpartum, especially considering the intricate care needs of newborns, need to be addressed. The aim of the present work is to capture diagnostic strategies used in postpartum individuals in available studies, PE prevalence among suspected cases, and if numbers permit, to determine the safety and efficiency of different diagnostic strategies for postpartum individuals. Methods: We analysed data from a large individual patient data meta-analysis (IPDMA) database of prospective PE diagnostic studies including more than 20,000 patients (PROSPERO: CRD42018089366), which assessed safety and efficacy outcomes of different PE diagnostic strategies. We identified studies including postpartum individuals with the postpartum period defined according to the study. Various diagnostic algorithms were employed, integrating clinical judgment and pre-test clinical probability assessments, in conjunction with D-dimer measurement, and, where applicable, lower limb venous compression ultrasonography and thoracic imaging. Our study objectives were to (1) provide a descriptive analysis of the diagnostic management of women with suspected PE and (2) report the PE prevalence in postpartum women presenting with suspected PE. Results: We identified 201 postpartum participants among six studies within the IPDMA database evaluating suspected PE strategies among non-pregnant individuals who presented to the emergency department. The follow-up period was 3 months post- presentation in five studies, and 45 days in one study. The mean age was 28.1 (SD 6.3) years. Five participants (2.5%) had a history of previous VTE. Dyspnea and chest pain were present in 68.8% (128/186) and 75.8% (141/186), respectively. Other presenting symptoms included cough (27.4%, 51/186) and syncope (10.2%, 16/156). Among these 201 postpartum individuals presenting with suspected PE, 12 had confirmed PE, corresponding to a PE prevalence of 5.9% (95% CI, 3.5-10.1). Among the 201 with suspected PE presentations, 101 (50.2%) had no D-dimer testing. Among 100 participants with D-dimer testing, 71% had positive D-dimers and 29% had negative D-dimer testing, based on standard lab cutoffs. Among the 29 participants who had negative D-dimer values and no additional chest imaging, there were no (0%, 95% CI, 0.0-11.7%) VTE events. Conclusion: As observed in the pregnancy population, the prevalence of confirmed PE among suspected postpartum patients was generally low. To minimize over-investigation, including radiating chest imaging, further research is needed to refine the diagnostic approach including D-dimer testing for PE in postpartum individuals.