Diagnostic yield of pulmonary embolism testing in patients presenting to the emergency department with syncope.

Background: Syncope occurs in 1 in 4 people during their lifetime and accounts for 1% to 1.5% of emergency department (ED) visits. Most causes of syncope are benign, but syncope may be caused by life-threatening conditions including pulmonary embolism (PE) in up to 2% of cases. A recent publication reported the prevalence of PE in patients with syncope to be over 17%.

Aims: We sought to determine the frequency and diagnostic yield of testing for PE in patients presenting to the ED with syncope in our large, integrated health care system.

Methods: We performed a retrospective, longitudinal cohort study of patients who presented with syncope to EDs within a 21-hospital integrated health care system from 2010 to 2015 to find the frequency and diagnostic yield of testing for PE in patients with syncope at index ED visit and within 180 days afterward.

Results: We screened 2 749 371 ED encounters to find 32 440 (1.2%) with syncope. Median age was 52 (interquartile range, 31-71), 57.5% were female, and 90% were Caucasian. PE was diagnosed on the index ED visit in 259 (0.8%; 95% confidence interval [CI], 0.7%-0.9%) cases. Assessment for suspected PE with D-dimer occurred in 5089 (15.7%) patients, and 2338 (7.2%) underwent computed tomography pulmonary angiography (CTPA). The yield of CTPA was 7.9%. PE was detected in 2.2% in whom a D-dimer was performed. From index visit to 180 days, 467 (1.4%; 95% CI, 1.3%-1.6%) patients were diagnosed with a PE, and 1051 (3.2%, 95% CI, 3.0%-3.4%) patients died.

Conclusion: Diagnostic testing for PE is frequent in patients with syncope presenting to the EDs of a large, integrated health care system. The yield of diagnostic testing is low.