Syncope on presentation is a surrogate for submassive and massive acute pulmonary embolism

There are conflicting data regarding the prognostic value of syncope in patients with acute pulmonary embolism (APE).

We retrospectively reviewed data of 552 consecutive adults with computed tomography pulmonary angiogram-confirmed APE to determine the correlates and outcome of the occurrence of syncope at the time of presentation.

Among 552 subjects with APE (mean age 54years, 47% men), syncope occurred in 12.3% (68/552). Compared with subjects without syncope, those with syncope were more likely to have admission systolic blood pressure<90mmHg (odds ratio (OR) 5.788, P<0.001), and an oxygen saturation<88% on room air (OR 5.560, P<0.001), right ventricular dilation (OR 2.480, P=0.006), right ventricular hypokinesis (OR 2.288, P=0.018), require mechanical ventilation for respiratory failure (OR 3.152, P=0.014), and more likely to receive systemic thrombolysis (OR 4.722, P=0.008). On multivariate analysis, syncope on presentation was an independent predictor of a massive APE (OR 2.454, 95% CI 1.109-5.525, P=0.03) after adjusting for patients' age, sex, requirement of antibiotics throughout hospitalization, peak serum creatinine, admission oxygen saturation<88% and admission heart rate>100bpm. There was no difference in mortality in cases with APE with or without syncope (P=0.412).

Syncope at the onset of pulmonary embolization is a surrogate for submassive and massive APE but is not associated with higher in-hospital mortality.