Methods: Between July 2012 and October 2019, a total of 641 patients with PE (277 males, 364 females; median age: 65 years; range, 51 to 74 years) in whom the diagnostic work-up and risk-based management were performed according to the current pulmonary embolism guidelines were retrospectively analyzed. Clinical, laboratory and imaging data of the patients were obtained from hospital database system.

Results: Syncope was noted in 193 (30.2%) of patients on admission, and was associated with a significantly higher-risk status manifested by elevated troponin and D-dimer levels, a higher Pulmonary Embolism Severity Index scores, deterioration of right-to-left ventricular diameter ratio, right ventricular longitudinal contraction measures, the higher Qanadli score, and higher rates of thrombolytic therapies (p<0.001) and rheolytic? thrombectomy (p=0.037) therapies. In-hospital mortality (p=0.007) and minor bleeding (p<0.001) were significantly higher in syncope subgroup. Multivariate logistic regression analysis showed that higher Pulmonary Embolism Severity Index scores and right-to-left ventricular diameter ratio were independently associated with syncope, while aging and increased heart rate predicted in-hospital mortality. Malignancy and right-to-left ventricular diameter ratio at discharge, but not syncope, were independent predictors of cumulative mortality during follow-up.

Conclusion: Syncope as the presenting symptom is associated with a higher risk due to more severe obstructive pressure load and right ventricular dysfunction requiring more proactive strategies in patients with pulmonary embolism. However, with appropriate risk-based therapies, neither in-hospital mortality nor long-term mortality can be predicted by syncope.