This article is more than 5 years old. Information may no longer be current.
BASEL IX: Pulmonary embolism 'uncommon cause' of syncope
Click Here to Manage Email Alerts
Pulmonary embolism appears to be rare in patients presenting with syncope to the ED, according to data published in the Journal of the American College of Cardiology.
“Previous studies provided highly conflicting estimates about the prevalence of pulmonary embolism in patients with syncope,” Patrick Badertscher, MD, from the Cardiovascular Research Institute Basel (CRIB) and the department of cardiology at University Hospital Basel, University of Basel, in Switzerland, wrote in an email to Healio Pulmonology. “This information is, however, necessary to decide on the potential medical benefit or harm of systematic PE screening in patients presenting with syncope to the ED.”
For the ongoing, prospective, multicenter, international BASEL IX study, Badertscher and colleagues enrolled unselected patients older than 40 years in 13 hospitals in eight countries who presented to the ED within 12 hours after a syncopal event.
Using the two-level Wells score and D-dimer testing with age-adapted cutoffs, the researchers assessed clinical probability for PE. They also evaluated the presence of PE using imaging modalities, including computed tomographic pulmonary angiography (CTPA) or ventilation perfusion (V/Q) scan, as part of the clinical assessment by the ED physician or by long-term follow-up.
The primary outcome was prevalence of PE at presentation to the ED and the incidence of new PE and cardiovascular death after 2 years.
Low PE prevalence
The analysis included 1,397 of 1,895 consecutive patients (median age, 69 years; 42% women) presenting to the ED with syncope enrolled in BASEL IX from 2010 to 2017. The median follow-up was 751 days.
Among these patients, the combination of low clinical pretest probability for PE, defined as a Wells score of 4 or less, and a negative D-dimer test ruled out PE at presentation in 44% of patients, and CTPA or V/Q scan ruled out PE at presentation in 6.3% of patients.
Overall, the prevalence of PE detected at presentation was 1.4% (95% CI, 0.87-2.11), and the incidence of new PEs or CV death during 2-year follow-up was 0.9% (95% CI, 0.5-1.5).
In the 656 patients who were hospitalized, 2.3% (95% CI, 1.4-3.7) had PE detected at presentation and 0.9% (95% CI, 0.4-2) had new PEs or CV death during 2-year follow-up. For the 254 hospitalized patients with their first episode of syncope, the prevalence of PE was 4.3% (95% CI, 2.4-7.6) and the incidence of new PEs or CV death during 2-year follow-up was 0.8% (95% CI, 0.2-3).
In additional analyses, the researchers also found that the diagnostic yield of imaging for PE in patients with syncope was 14% in those evaluated with CTPA or V/Q scans upon presentation to the ED, 16% in hospitalized patients and 29% in those hospitalized for a first episode of syncope.
In light of their findings, Badertscher said, “PE is an uncommon cause of syncope, and routine testing for PE is generally not productive in the evaluation of patients with syncope in the ED.”
He noted, however, that further study could provide more information.
“Additional research should be directed to characterizing the occasional clinical situations in which syncope is a more frequent manifestation of PE,” he told Healio Pulmonology.
Interpreting conflicting results
In an accompanying editorial, Samuel Z. Goldhaber, MD, from the division of CV medicine in the section of vascular medicine at Brigham and Women’s Hospital and Harvard Medical School, placed these findings in context alongside another study on PE and syncope.
Specifically, in the PESIT trial, 17% of 560 patients hospitalized for a first episode of syncope could attribute the syncopal event to PE, which was usually occult, according to Goldhaber.
“From the viewpoint of the PESIT trial, PE is as common as a horse in patients presenting to the ED who are hospitalized with a first episode of syncope,” he wrote, noting how those results contrast with the BASEL IX findings. “From the viewpoint of the BASEL IX study, PE as a cause of syncope is as rare as a zebra.”
The strengths and limitations of these two studies can be debated to determine which study “got it right,” according to Goldhaber, but clinicians may perhaps reap the most benefit from considering the findings together.
“The third side of the PESIT versus BASEL IX story might involve applying the best attributes of each study in our daily practice. For patients with first-time syncope, minimal workup for PE with a clinical probability assessment and D-dimer makes sense. If this workup points to a high probability for PE, imaging should be obtained. In the current era, where the threshold for being hospitalized is high, first-time syncope patients should be worked up for PE even if they are going to be discharged home after ED evaluation. Perhaps the relation between syncope and PE is best described as the ‘progeny of a horse and a zebra,’” he wrote. – by Melissa Foster
For more information:
Patrick Badertscher, MD, can be reached at patrick.badertscher@usb.ch; Twitter: @BadertscherPat; @CRIBasel.
Disclosure s: Badertscher reports he has received research funding from the University of Basel, the Stiftung für Herzschrittmacher und Elektrophysiologie and the Freiwillige Akademische Gesellschaft Basel. Please see the study for all other authors’ relevant financial disclosures. Goldhaber reports no relevant financial disclosures.