Prevalence and Predictors of Pulmonary Embolism in Hospitalized Patients With Syncope

Hussam Ammar, MD; Chaand Ohri, MD; Said Hajouli, MD; Shaunak Kulkarni, MD; Eshetu Tefera, MS; Ragai Fouda, PhD, MD; Rukma Govindu, MD


South Med J. 2019;112(8):421-427. 

In This Article

Abstract and Introduction


Objectives: Approximately one in six patients hospitalized with syncope have pulmonary embolism (PE), according to the PE in Syncope Italian Trial study. Subsequent studies using administrative data have reported a PE prevalence of <3%. The aim of the study was to determine the prevalence and predictors of PE in hospitalized patients with syncope.

Methods: We retrospectively reviewed the records of patients who were hospitalized in the MedStar Washington Hospital Center between May 1, 2015 and June 30, 2017 with deep venous thrombosis, PE, and syncope. Only patients who presented to the emergency department with syncope were included in the final analysis. PE was diagnosed by either positive computed tomographic angiography or a high-probability ventilation-perfusion scan. Univariate and multivariate logistic regressions were used to assess the associations between clinical variables and the diagnosis of PE in patients with syncope.

Results: Of the 408 patients hospitalized with syncope (mean age, 67.5 years; 51% men [N = 208]), 25 (6%) had a diagnosis of PE. Elevated troponin levels (odds ratio 6.6, 95% confidence interval 1.9–22.9) and a dilated right ventricle on echocardiogram (odds ratio 6.9, 95% confidence interval 2.0–23.6) were independently associated with the diagnosis of PE. Age, active cancer, and history of deep venous thrombosis were not associated with the diagnosis of PE.

Conclusions: The prevalence of PE in this study is approximately one-third of the reported prevalence in the PE in Syncope Italian Trial study and almost three times the value reported in administrative data-based studies. PE should be suspected in patients with syncope and elevated troponin levels or a dilated right ventricle on echocardiogram.


Syncope accounts for 1% to 3% of emergency department (ED) visits and 6% of hospital admissions.[1] The etiology of syncope has been found to remain undiagnosed in 2% to 52% of cases, depending on the patient population and the nature of the studies.[2–6] Pulmonary embolism (PE) is an uncommon cause of syncope, with a reported rate of 0.2% to 1.4% in various syncope studies.[2–9] A study, the PE in Syncope Italian Trial (PESIT), reported a PE prevalence of 17.3% in patients hospitalized with syncope,[10] whereas two subsequent studies using administrative data reported a PE prevalence of <3% for hospitalized patients with syncope.[11,12] Patients with PE initially presenting with syncope or presyncope have much higher 30-day mortality rates than patients not presenting with syncope (42.5% vs 6.2%).[13] The 2017 American Heart Association guidelines on syncope briefly mentioned PE as an example of a serious medical condition that may warrant evaluation.[14] In addition, the 2018 European guidelines on syncope suggested that D-dimer testing should be ordered if a diagnosis of PE is suspected.[15] The primary objective of this study was to determine the prevalence of PE in patients hospitalized with syncope in a tertiary center and to elucidate clinical findings that can predict PE in patients hospitalized with syncope.